3/14/89
STUDY PLAN
BIRD USE OF SNAGS IN EASTSIDE PINE HABITATS
IN NORTHEASTERN CALIFORNIA
PROBLEM REFERENCE
FS–PSW–42O2–1: WILDLIFE, RANGE, AND MONITORING RESEARCH (approved 2/4/88).
MANAGEMENT SITUATION AND LITERATURE REVIEW
Current Snag Management Issue
Snags, or standing dead trees, are important nesting and foraging substrates for many species of
wildlife, especially birds. In addition, the dead tops of live trees also provide foraging and nesting
substrates for some species. The importance of this resource to wildlife, and its removal for other
purposes, have caused National Forest units to set objectives for maintenance of specific snag
densities in the environment.
In May of 1987, the Washington Office conducted a review of the Region's Fish and Wildlife
Management Program. One finding of this review was concern over the issue of snag management
in eastside pine habitats on the Modoc National Forest. Evidence presented to the review team
suggested that information on natural snag densities in eastside pine and densities of snags needed to
support cavity-nesting bird populations is lacking. Their general conclusion was that little quantitative
information is available on which to base reasonable guidelines for snag densities in eastside pine. They
recommended that the Regional Office initiate a snag study to begin quantifying relationships between
snag numbers and wildlife use, principally birds, in the eastside pine habitats of northeastern California.
Snag Densities and Historical Management
Direction for management of snags on National Forests in Region 5 (California) was set forth in
the Forest Service Manual in 1979. This direction, "one snag per acre, 11 inches dbh or greater, 12 feet
high or higher in all forest types, plus an average of one-half snag per acre, 16 inches dbh or greater, 12
feet high or higher, in all forest types except lodgepole pine" (FSM 2405.14 11/79 R-5 Supplement 221),
was judged to be sufficient for wildlife based on information available at that time. The Minimum
Management Requirements developed for forest land-management planning are intended to maintain
snags in sufficient density and distribution to provide habitat capability of not less than 40 per cent for
primary cavity-nesting birds on commercial forest lands. Diameter and height standards were designed to
meet the requirements of snag-using birds and mammals. Studies (e.g., Bull and Meslow 1977,
McClelland 1979) done since the manual direction for snags was released in 1979 indicated that diameter
and height standards should be increased to meet the needs of all snag-using birds and mammals within
Region 5. The direction was therefore changed to: "to the extent possible, within each timber
compartment provide, maintain, and manage for an average of 1.5 snags per acre with the following
specifications: 1. 1.2 snags per acre between 15-24 inches dbh and greater than 20 feet high; 2. 0.3
Snag Study Plan - 2.
snags per acre greater than 24 inches dbh and greater than 20 feet high" (Background Paper - Snag MMR,
Forest Service, Pacific Southwest Region Land Management Planning Files).
In eastside pine areas in northeastern California, snag densities do not appear to meet the above
mentioned Minimum Management Requirements. On the Modoc National Forest, approximately 90% of
the eastside pine habitat fails to meet the minimum standard of a mean density of 1.5 snags per acre (3.7
snags per ha) (Studinski and Ross 1986). For example, snag densities in commercially available eastside
pine on the Devil's Garden Ranger District range from 0.4 to 0.6 snags per acre (1.0 to 1.5 snags per ha),
and other Districts on the Forest appear to support fewer than 1.5 snags per acre (3.7 snags per ha)
(Studinski and Ross 1986, M. Ross, pers. comm., G. Studinski, pers. comm.). The situation on the Lassen
National Forest, although not well quantified, appears to be similar (S. Kowalski, pers. comm., L. Schultz,
pers. comm.).
Historically, snags have been regarded as an undesirable component of managed eastside pine
forests. Prior to the early 1970s, the objective was to eliminate snags and dying trees that were about to
become snags. Snags sometimes (1) constitute a fire hazard because they may serve as lightning rods,
increasing the risk of wild fire, (2) increase the spread of wild fire because movement by wind of burning
punk, and (3) constitute a human safety hazard because of the risk of snag limbs or boles falling and
injuring land users (Studinski and Ross 1986); dying trees serve as reservoirs for tree-damaging insects.
Consequently, timber sales generally required removal of all snags in the sale area and many salvage sales
were done to harvest recently dead snags for commercial purposes (Studinski and Ross 1986).
In the 1970s management of snags became passive. No longer were snags to be removed from
timber sale areas. However, they were not actively recruited either. Snags continued to decline in
numbers as a result of continued salvage sales and fuelwood harvest (Studinski and Ross 1986).
Finally, in the early 1980s, snag management policy became more active. The Regional Office
required forests to (1) set minimum snag density requirements, (2) begin to inventory and monitor snag
density, size, and distribution, and (3) plan for snag availability through time.
Relationships of Birds to Snags
Snags are an important feature of the environment for many species of plants, invertebrates, and
vertebrates (Thomas et al. 1979). In the eastside pine habitats of northeastern California, 45 bird and 24
mammal species use snags for nesting or cover (Table 1). Many of these species use cavities excavated
by species or naturally occurring in snags and, in some cases, living trees. Sixteen birds and 4 mammals
require trees with cavities for their persistence. In addition, 12 birds and 20 mammals use habitats that
include trees with cavities, or some other environmental variable that can be substituted for trees with
cavities, to a greater extent than habitats without trees with cavities (see Table 2).
Because of the value of snags to wildlife, National Forests of Region 5, in preparing forest landmanagement plans and plan implementation procedures, are establishing guidelines to provide for snags
under future conditions. In addition, some National Forests in Region 5 have initiated snag recruitment
programs for eastside pine to alleviate the perceived shortage of snags in this vegetation type.
Although a body of information links wildlife use to snags and, in some cases minimum snag
densities, information regarding the numbers of snags needed by snag-using and cavity-nesting birds in
Snag Study Plan - 3.
eastside pine of northeastern California is not extensive. In fact, little is known about the densities of
snags that should be expected in eastside pine habitats under unmanaged conditions.
OBJECTIVES
1. Develop an understanding of snag dynamics in eastside pine of northeastern California to resolve
management concerns about the appropriateness of the Regional snag guidelines.
2. Develop an understanding of historical snag density patterns in eastside pine of northeastern
California.
3. Develop an understanding of and a database for cavity-nesting and other bird relationships to
snags in eastside pine of northeastern California.
4. Evaluate current snag-management guidelines for eastside pine in eastside pine of northeastern
California and recommend changes thereto if data so indicate.
5. Document and monitor use of snags in eastside pine of northeastern California by birds,
especially primary and secondary cavity nesters.
6. Explore the question of snag densities needed to support viable populations of cavity nesters in
eastside pine of northeastern California.
METHODS
1.
Study Areas
Pilot studies revealed that of the 394 potential eastside pine study sites, 355 (90%) had snag densities
of < 1.2 per ha (< 0.5 per acre), 12 (4%) had snag densities of >3.7 per ha (>1.5 per acre), and 4 (1%) had
snag densities of >7.4 per ha (>3.0 per acre). Consequently, the original study design was limited by the
number of sites in the two snag-density classes >3.7 per ha (>1.5 per acre) and a revised design using
seven snag-density classes was developed.
In 1988, 24 (plus 8 alternates) study areas were established in the seven snag-density classes in
eastside pine habitats on the Modoc and Lassen National Forests. The snag-density classes were: 0 per
ha (0 per acre), >0 - 1.2 per ha (>0 - 0.5 per acre), >1.2 - 2.5 per ha (>0.5 - 1.0 per acre), >2.5 - 3.7 per ha
(>1.0 - 1.5 per acre), >3.7 - 4.9 per ha (>1.5 - 2.0 per acre), >4.9 - 7.4 per ha (>2.0 - 3.0 per acre), >7.4
per ha (>3.0 per acre). Three study areas and two alternates were selected for each of the four lower snagdensity classes (< 3.7 per ha (< 1.5 per acre)) whereas the number of study areas in the three higher snagdensity classes depended on the number of sites that meet density criteria for each class--i.e., six in the
>3.7 - 4.9 per ha (>1.5 - 2.0 per acre) class, two in the >4.9 - 7.4 per ha (>2.0 - 3.0 per acre) class, and
four in the >7.4 per ha (>3.0 per acre) class.
2.
Transects
We located one transect 500 m (1640 ft.) long and 100 m (325 ft.) wide (5 ha (12.5 acre)) within each
study area. A dot grid, with each point numbered sequentially, was placed over the study areas as
mapped, on 7.5-minute topographic maps. The transect end point was selected by randomly drawing a
single dot. Transect direction--potentially four cardinal directions and four intermediate directions (e.g.
northeast)--were determined randomly. No transect was permitted to intersect the study area boundary.
Counting stations were placed at 50-m (165-ft.) intervals along the center line of the long axis of the plot.
Snag Study Plan - 4.
3. Vegetation information
Vegetation information will be collected using two methods, one for overstory trees and a second for
understory trees and shrubs. Information on the overstory trees will be collected using standard prism
points (2.5-factor metric prism) located at alternate bird counting stations along each transect (six prism
plots at all odd-numbered points on each strip transect).
Information to be collected from each prism point includes an estimate of total stand density
(measured by basal area), stand density (measured by basal area) by size class (15.2-cm (6-in.) diameter
classes) of all trees with dbh greater than 12.7 cm (5 in.), stand age (two trees in each size class will be
bored and their heights will be estimated), and percent of basal area contributed by snags percent slope
and aspect also will be determined for each prism point. Productivity of the transect area will be estimated
using forest survey site-class procedures on vegetation data collected as described above. The maximum
number of canopy layers within a 50-m (165-ft.) radius of the point will be counted. Dead-and-downed
woody material will be assessed by counting the number of logs with diameters exceeding 30 cm (12 in.)
and lengths exceeding 3 m (10 ft.), and an estimate of the fuel loading will be made using the photo series
for quantifying natural forest residues for ponderosa pine (Blonski and Schramel 1981) in a 25-m (82-ft.)
radius circle centered on each prism point. For each tree or snag in the prism plot, species, dbh, and
height will be recorded.
Understory trees and shrubs as well as grasses, forbs and exposed ground surface will be sampled
using two 25-m (82-ft.) line-intercept lines initiated at the prism points used for overstory trees. The
direction of each line will be randomly determined using the same procedures described for transects
above. Each understory tree or shrub encountered will be identified and the length of the line it intercepts
will be measured. Grasses, forbs, patches of bare ground, rocks, and litter will also be measured, as well
water courses if they are crossed.
4. Snag information
Snag density will be determined by a direct count of all snags in each strip transect. Each snag will be
assigned a unique number relative to the transect and will be mapped on snag maps for each transect.
Information collected for each snag will include species, dbh, height, cause of mortality if possible, decay
condition, percent of bark cover, and the number of nesting cavities; the relative amount of sapwood to
heartwood will be estimated using an increment borer. Decay condition will be measured in three ways:
(1) using classes of decay based on visual standards--e.g., declining, loose bark--(Thomas et al. 1979:64),
(2) using a pilodyn at breast height to evaluate condition of the outer portion of the tree, especially the
sapwood, and (3) using a shigometer at breast height to evaluate the amount of decay in the heartwood.
All snags from each transect will be monitored yearly for the duration of the study (a maximum of 4
years), using the above methods, to begin to quantify snag longevity patterns. During these visits, all new
snags will be mapped, measured, and added to the snag inventory. Information collected during
monitoring visits will include snag status (that is, whether it is still a snag or has fallen and become a log),
decay condition (as described above), change in decay class (if any), and additional nest holes.
Snag Study Plan - 5.
5.
Other landscape characteristics
To the extent possible, location information on springs, streams, and other water sources will be
collected. If found within the boundaries of a study transect, such attributes will be mapped. If not,
proximity to study transects will be noted if appropriate.
6.
Bird mapping
Bird-mapping procedures will generally follow those of Christman (1984) as modified by Noon (pers.
comm.). Briefly, the procedure requires walking each 500-m (1640-ft.) transect in about 1 hr, recording
on a map of the transect all species detected (those within the 50-m (165-ft.) transect border and birds
beyond), their positions along the transect line, and estimated perpendicular distance from the transect
line to within 5 m (16 ft.) of their location (see Table 3 for a list of bird species expected in eastside pine).
Observers will be permitted to move slightly off the transect to ensure that locations are mapped
accurately. Additional information to be taken includes whether the sightings were visual or based on
calls or songs, and if there was simultaneous singing by two or more individuals of the same species.
Bird-mapping efforts will be confined to morning hours beginning shortly after dawn and continuing
for a maximum of 5 hours. Approximately three transects will be surveyed by each observer each field
day. Information from each visit to a transect will be plotted on a fresh map of the site; summary maps
for each of the cavity-nesting species will be developed following field visits.
Each transect will be surveyed 10 times during the breeding season in each of the 4 field years,
beginning at the first of May and ending in mid-June. Each of four field observers will survey each
transect at least twice each field season, to standardize observer variability. Each survey of a transect will
be concluded in approximately 1 hour--about 2 minutes at each of the 11 counting stations and about 4
minutes walking each of the 10 intervals between counting stations. Because the time needed to walk a
transect interval will vary depending on the number of birds seen and mapped, the time spent at each
counting station will be used to recalibrate the timing of the survey--6 minutes will be spent at each
combined interval and point. This approach, combining mapping and time-constrained counting
procedures, will permit estimates of breeding pairs, and relative abundance and, perhaps, densities of
birds for each transect.
7.
Use of snags by cavity nesters
Use of snags by cavity nesters will be studied separately. After completing the morning survey work,
each observer will remain at the last transect to search for nest sites used by all cavity nesters on the
transect and for all cavity nesters encountered in the larger, presumably homogeneous area in which the
transect is located. The time constraints should permit at least three visits to each transect for this purpose
in the season. Additional follow-up visits to transects will be scheduled following the transect survey
period; the number of these visits will vary depending on the amount of time allocated for field work for
the year. Information collected for each nest found of a cavity-nesting bird will include bird species, snag
identification number, nest height, snag diameter at nest height, azimuth of nest entrance, whether nest is
in living or dead part of the tree, distance the nest is below the top of the tree, and snag condition at nest
height (when possible to measure with the pilodyn and shigometer); each nest located will be mapped on
the daily map and summary map for that species.
Preferences by cavity nesters for nest snag and tree species and diameters will be evaluated using a
randomized process to select the nearest alternative snag or tree. If the nest is in a snag, the observer will
search for an alternative nest snag; if the nest is in a tree, the observer will search for an alternative nest
Snag Study Plan - 6.
tree. From each nest snag or tree, the observer will pace 30 m (100 ft.) in a randomly determined
direction (N, NE, E, SE, S, SW, W, NW). After pacing 30 m (100 ft.), the observer will randomly
determine whether to turn left or right. The selected snag or tree will be the first snag or tree greater than
15.2 cm (>6 in) dbh detected within 5 m (16 ft.) of either side of the arc. If no alternative snag or tree are
found within the 30 m (100 ft.) radius circle, the observer will continue out another 10 m (33 ft.) and
repeat the process until an alternative snag or tree is located. The same information recorded for nest
snags and trees will be taken from each of these snags and trees. If nests are found in snags or trees less
than 15.2 cm (>6 in.) dbh, selection criteria for alternative snags and trees will be adjusted accordingly.
8.
Nesting success of cavity nesters
When fledgling or young birds are encountered during regular morning surveys or searches for nest
sites, information on the number and developmental stage of each bird will be collected.
ANALYSES
1.
Vegetation information
Estimates of means and variances will be made for each measure. Multivariate procedures may be
used to explore patterns of vegetation characteristics and differences in vegetation composition and
structure among the study areas.
2.
Snag information
Estimates of means and variances will be made for each measure. Estimates will be made of existing
snag densities. Estimates of potential snag density for each study area will be developed; these estimates
will be based on characteristics of the study area including tree stocking and site productivity.
3.
Bird mapping
All locations of cavity-using birds will be summarized on transect maps for each species for each
year. Territories will be estimated for each pair of birds. Abundances of each species will be estimated
for each year. A species list will be prepared for each transect from information gathered from the spotmapping procedures as well as encounters with other species in the surrounding area of homogeneous
habitat.
4.
Use of snags by cavity nesters
Estimates of means and variances will be made for each measure collected for nesting snags and nest
sites by species and transect. If transects can be grouped into the above snag-density classes, analysis of
bird abundance relative to snag-density class will be accomplished with analysis of variance procedures.
If transects cannot be grouped, analysis of density relationships will be accomplished through correlation
or regression procedures.
DURATION OF THE STUDY
The study is expected to terminate at the end of FY-92. The first year of the study was devoted to
selection of 32 study areas (including 8 alternate study areas), establishment of transects, and pilot work
Snag Study Plan - 7.
on vegetation and bird study methods. The following 4 years will emphasize monitoring of snag status
and condition, bird studies, and collection of vegetation information. Completion of analyses,
development of management guidelines if necessary, and reporting final results of the study to both
management and the scientific community will be completed in the final year of the study.
PUBLICATIONS
The study will result in at least five publications including: estimation of existing snag densities on
the Modoc National Forest, estimation of bird abundances and use of snags in areas with different snag
densities, a plan for monitoring snags and wildlife that use them, recommendations on snag management
guidelines for eastside pine in California, and necessary technology transfer products for National Forests,
Ranger Districts, and other users, for on-the-ground application.
PERSONNEL ASSIGNMENT
A fulltime wildlife biologist will be assigned to the study for its duration. As needed, three to four
temporary wildlife biologists will be hired for assistance with field and office phases of the study (see
tabulation below).
Activity
Assignment
Person-days
Prepare study plan
Wildlife biologist
15
Select field locations
Wildlife biologist
200
Prepare field sites
Wildl. biol. & temporaries
200
Conduct bird surveys
Wildl. biol. & temporaries
1000
Conduct vegetation work
Wildl. biol. & temporaries
200
Data entry
Wildl. biol. & temporaries
100
Preparation of manuscripts
Wildl. biol.
645
TOTAL
2360
Snag Study Plan - 8.
ESTIMATED COSTS (total for 5 years)
Wildlife Biologist (GS-12 PFT) salary……………………………………$209,090
Benefits For GS-12 PFT…………………………………..……$ 20,920
Temporary salaries……………………………………………………….. $ 74,930
Vehicles--fixed costs..…………………………………………………… $ 12,910
--mileage………………………………………………………… $ 17,570
Travel--commercial fares………………………………………………… $
5,800
--per diem………………………………………………………….. $ 27,590
Materials and supplies…………………………………………………… $
8,000
Construction and services…………………………………………………$
5,000
Automated Data Processing……………………………………………… $ 14,500
TOTAL
$396,310
Snag Study Plan - 9.
LITERATURE CITED
Blonski, K.S., and J.L. Schramel. 1981. Photoseries for quantifying natural forest residues: Southern
Cascades, Northern Sierra Nevada. USDA For. Serv. Gen. Tech. Rep. PSW-56.
Bull, E.L., and E.C. Meslow. 1977. Habitat requirements of the pileated woodpecker in northeastern
Oregon. J. Forestry 75:335-337.
Christman, S.P. 1984. Plot mapping: estimating densities of breeding bird territories by combining spot
mapping and transect techniques. Condor 86:237-241.
McCaskie, G., P. De Benedictis, R. Erickson, and J. Morlan. 1979. Birds of Northern California. Golden
Gate Audubon Society, Berkeley, California. 84 pp.
McClelland, B.R. 1979. The pileated woodpecker in forests of the northern Rocky Mountains. pp 283299 in J.G. Dickson, R.N. Connor, R.R. Fleet, J.A. Jackson, and J.C. Kroll (eds.). The role of
insectivorous birds in forest ecosystems. Academic Press, New York.
Oosting, H.J. 1956. The study of plant communities. W.H. Freeman and Co., San Francisco.
Studinski, G., and M. Ross. 1986. Modoc National Forest Snags: Analysis of the management situation.
USDA For. Serv., Modoc Nat'l. Forest, Alturas, Calif.
Thomas, J.W., R.G. Anderson, C. Maser, and E.L. Bull. 1979. Snags. Chapter 5, pp 60-77 in J.W.
Thomas, tech. ed. Wildlife habitat in managed forests--the Blue Mountains of Oregon and Washington.
USDA For. Serv. Agric. Handbook No. 553.
Snag Study Plan - 10.
Table 1. Snag-using birds expected in transects in eastside pine habitats, their expected seasonal
occurrence (from the California Wildlife Habitat Relationships System), and estimates of relative
abundance (McCaskie et al. 1979). Codes for relative abundance ratings are abundant = 1, common =
2, fairly common = 3, uncommon = 4, very uncommon = 5, rare = 6, and irregular = 7.
Species
Season
Relative abundance
Turkey Vulture
Sharp-shinned Hawk
Cooper's Hawk
Spring/Summer
Yearlong
Yearlong
Northern Goshawk
Swainson's Hawk
Red-tailed Hawk
Ferruginous Hawk
Rough-legged Hawk
Golden Eagle
American Kestrel
Merlin
Band-tailed Pigeon
Common Barn Owl
Flammulated Owl
Western Screech Owl
Great Horned Owl
Northern Pygmy-Owl
Spotted Owl
Long-eared Owl
Yearlong
Spring/Summer
Yearlong
Winter
Winter
Yearlong
Yearlong
Winter
Spring/Summer
Yearlong
Spring/summer
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Short-eared Owl
Yearlong
Northern Saw-whet Owl
Lewis' Woodpecker
Yearlong
Yearlong
Yellow-bellied Sapsucker
Red-breasted Sapsucker
Williamson's Sapsucker
Downy Woodpecker
Hairy Woodpecker
White-headed Woodpecker
Northern Flicker
Olive-sided Flycatcher
Western Wood-Pewee
Violet-green Swallow
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Spring/summer
Spring/summer
Spring/summer
Clark's Nutcracker
Mountain Chickadee
Red-breasted Nuthatch
Yearlong
Yearlong
Yearlong
3 to 4
3 to 4
5 to 6 in spring/summer
3 to 4 in fall/winter
5 to 6
3 to 4
1 to 2
5 to 6
1 to 2
3 to 4
1 to 2
5 to 6
1 to 2
1 to 2
3 to 4
3 to 4
1 to 2
3 to 4
5 to 6
5 to 6 in spring/summer
3 to 4 in fall/winter
3 to 4 in spring/summer
1 to 2 in fall/winter
5 to 6
5 to 6 in spring/summer
3 to 4 in fall/winter
3 to 4
3 to 4
3 to 4
1 to 2
1 to 2
3 to 4
1 to 2
1 to 2
1 to 2
1 to 2 in spring/summer
7 in fall/winter
3 to 4
1 to 2
1 to 2
Snag Study Plan - 11.
Table 1 (continued).
Species
Season
Relative abundance
White-breasted Nuthatch
Pygmy Nuthatch
Brown Creeper
Western Bluebird
Mountain Bluebird
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Loggerhead Shrike
Yearlong
European Starling
Yearlong
1 to 2
3 to 4
1 to 2
3 to 4
1 to 2 in spring/summer
5 to 6 in fall/winter
1 to 2 in spring/summer
3 to 4 in fall/winter
1 to 2
Snag Study Plan - 12.
Table 2. Cavity-nesting birds expected on transects in eastside pine habitats, their season of occurrence,
and importance of trees with cavities (from the California Wildlife Habitat Relationships System).
Species preceeded by an * are primary cavity nesters that construct nesting cavities in snags and those
preceeded by an @ are cavity nesters which often use existing cavities for nesting but have been known to
construct their own nesting cavities. Definitions for the importance of cavities are: essential--cavities
must be present within the home range of the species if the species is to be present; secondarily essential
(sec essential)--cavities must be present within the home range of the species if the species is to be present
or it must be compensated by the presence of other secondarily essential elements; and preferable-cavities are used to a greater extent than their abundance would suggest and the presence of cavities
enhances the habitat's capability to support the species.
Species
Season
Importance of Cavities
Wood Duck
Bufflehead
American Kestrel
Spring/summer
Yearlong
Yearlong
Common Barn Owl
Yearlong
Western Screech Owl
Great Horned Owl
Yearlong
Yearlong
Northern Pygmy-Owl
Yearlong
Spotted Owl
Yearlong
Long-eared Owl
Northern Saw-whet Owl
Yearlong
Yearlong
*Lewis' Woodpecker
Yearlong
*Yellow-bellied Sapsucker
Yearlong
*Downy Woodpecker
Yearlong
*Hairy Woodpecker
Yearlong
*White-headed Woodpecker
Yearlong
*Northern Flicker
Yearlong
Ash-throated Flycatcher
Violet-green Swallow
Spring/summer
Spring/summer
Mountain Chickadee
Yearlong
@Red-breasted Nuthatch
Yearlong
Essential for breeding
Essential for breeding
Essential for breeding
Preferable for cover
Preferable for breeding
Preferable for cover
Sec essential for cover
Preferable for breeding
Preferable for cover
Essential for breeding
Essential for cover
Sec essential for breeding
Preferable for cover
Preferable for breeding
Essential for breeding
Sec essential for cover
Essential for breeding
Sec essential for cover
Essential for breeding
Preferable for cover
Essential for breeding
Sec essential for cover
Preferable for foraging
Essential for breeding
Preferable for cover
Essential for breeding
Sec essential for cover
Preferable for foraging
Preferable for breeding
Preferable for cover
Essential for breeding
Sec essential for breeding
Sec essential for cover
Essential for breeding
Essential for cover
Essential for breeding
Snag Study Plan - 13.
Table 2 (continued).
Species
Season
@White-breasted Nuthatch
Yearlong
@Pygmy Nuthatch
Yearlong
Brown Creeper
Yearlong
Bewick's Wren
Winter Wren
Western Bluebird
Mountain Bluebird
Yearlong
Fall/winter
Yearlong
Yearlong
European Starling
Yearlong
Importance of Cavities
Preferable for cover
Essential for breeding
Preferable for cover
Essential for breeding
Preferable for cover
Sec essential for breeding
Preferable for cover
Sec essential for breeding
Preferable for breeding
Essential for breeding
Sec essential for breeding
Preferable for cover
Preferable for breeding
Preferable for cover
Snag Study Plan - 14.
Table 3. List of bird species expected to be encountered on eastside pine transects with abbreviations of
species names to be used in spot mapping (= Sp. Code) and, season of occurrence (list is provided by the
California Wildlife Habitat Relationships System).
Species
Sp. Code
Season of Occurrence
Great Blue Heron
Snowy Egret
Wood Duck
Bufflehead
Turkey Vulture
Osprey
Bald Eagle
Northern Harrier
Sharp-shinned Hawk
Cooper's Hawk
Northern Goshawk
Swainson's Hawk
Red-tailed Hawk
Ferruginous Hawk
Rough-legged Hawk
Golden Eagle
American Kestrel
Peregrine Falcon
Prairie Falcon
Chukar
Blue Grouse
Turkey
California Quail
Mountain Quail
Band-tailed Pigeon
Mourning Dove
Common Barn Owl
Flammulated Owl
Western Screech Owl
Great Horned Owl
Northern Pygmy-Owl
Spotted Owl
Long-eared Owl
Short-eared Owl
Northern Saw-whet Owl
Common Nighthawk
Common Poorwill
Black-chinned Hummingbird
Calliope Hummingbird
Lewis' Woodpecker
Yellow-bellied Sapsucker
Red-breasted Sapsucker
Williamson's Sapsucker
Downy Woodpecker
GBHE
SNEG
WODU
BUFF
TUVU
OSPR
BAEA
NOHA
SSHA
COHA
GOSH
SWHA
RTHA
FEHA
RLHA
GOEA
AMKE
PEFA
PRFA
CHUK
BUGR
TURK
CAQU
MOQU
BTPI
MODO
BAOW
FLOW
SCOW
GHOW
PYOW
SPOW
LEOW
SEOW
SWOW
CONI
POWI
BCHU
CAHU
LEWO
YBSA
RBSA
WISA
DOWO
Yearlong
Spring/summer
Spring/summer
Yearlong
Spring/summer
Spring/summer
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Spring/summer
Yearlong
Winter
Winter
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Spring/summer
Yearlong
Yearlong
Spring/summer
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Snag Study Plan - 15.
Table 3 (continued).
Species
Sp. Code
Season of Occurrence
Hairy Woodpecker
White-headed Woodpecker
Northern Flicker
Olive-sided Flycatcher
Western Wood-Pewee
Hammond's Flycatcher
Dusky Flycatcher
Gray Flycatcher
Say's Phoebe
Ash-throated Flycatcher
Violet-green Swallow
Barn Swallow
Steller's Jay
Scrub Jay
Pinyon Jay
Clark's Nutcracker
Common Raven
Mountain Chickadee
Red-breasted Nuthatch
White-breasted Nuthatch
Pygmy Nuthatch
Brown Creeper
Bewick's Wren
Winter Wren
Golden-crowned Kinglet
Ruby-crowned Kinglet
Western Bluebird
Mountain Bluebird
Townsend's Solitaire
Swainson's Thrush
Hermit Thrush
American Robin
Cedar Waxwing
Northern Shrike
Loggerhead Shrike
European Starling
Solitary Vireo
Warbling Vireo
Orange-crowned Warbler
Nashville Warbler
Yellow Warbler
Yellow-rumped Warbler
Black-throated Gray Warbler
Hermit Warbler
MacGillivray’s Warbler
Wilson’s Warbler
Western Tanager
HAWO
WHWO
NOFL
OSFL
WWPE
HAFL
DUFL
GRFL
SAPH
ATFL
VGSW
BASW
STJA
SCJA
PIJA
CLNU
CORA
MOCH
RBNU
WBNU
PYNU
BRCR
BEWR
WIWR
GCKI
RCKI
WEBL
MOBL
TOSO
SWTH
HETH
AMRO
CEWA
NRSH
LOSH
STAR
SOVI
WAVI
OCWA
NAWA
YEWA
YRWA
BGWA
HEWA
MGWA
WIWA
WETA
Yearlong
Yearlong
Yearlong
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Fall/winter
Yearlong
Yearlong
Yearlong
Yearlong
Yearlong
Spring/summer
Spring/summer
Yearlong
Fall/winter
Fall/winter
Yearlong
Yearlong
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Snag Study Plan - 16.
Table 3 (continued).
Species
Sp. Code
Season of Occurrence
Black-headed Grosbeak
Lazuli Bunting
Green-tailed Towhee
Rufous-sided Towhee
Chipping Sparrow
Brewer’s Sparrow
Lark Sparrow
Sage Sparrow
Fox Sparrow
Song Sparrow
Lincoln’s Sparrow
Golden-crowned Sparrow
White-crowned Sparrow
Dark-eyed Junco
Western Meadowlark
Brewer’s Blackbird
Brown-headed Cowbird
Northern Oriole
Purple Finch
Cassin’s Finch
House Finch
Red Crossbill
Pine Siskin
Lesser Goldfinch
American Goldfinch
Evening Grosbeak
BHGR
LABU
GTTO
RTTO
CHSP
BRSP
LASP
SASP
FOSP
SOSP
LISP
GCSP
WTSP
DEJU
WEME
BRBL
BHCO
NOOR
PUFI
CAFI
HOFI
RECR
PISI
LEGO
AMGO
EVGR
Spring/summer
Spring/summer
Spring/summer
Yearlong
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Yearlong
Spring/summer
Fall/winter
Yearlong
Yearlong
Yearlong
Yearlong
Spring/summer
Spring/summer
Spring/summer
Spring/summer
Yearlong
Yearlong
Yearlong
Spring/summer
Fall/winter
Yearlong
Snag Study Plan - 17.
SNAG DATA
FORM #1
Transect: Use the Quad/Polygon numbering system rather than the random number for the plot.
Observer and Date: Complete name and date, please.
Snag #: Number each snag encountered, locate on map of transect using a circled number, and attach a
numbered aluminum tag to the snag. Numbers will start at 1 for each transect but will not be in any
particular order on the transect.
Spec.: Identify the tree species that produced the snag. Use the following codes: PP = ponderosa pine;
JP = Jeffrey pine; PI = pine if you cannot determine if the predecessor tree was a ponderosa or Jeffrey
pine; IC = incense cedar; JU = juniper; WF = white fir; RF = red fir.
Hgt.: Estimate the height of the snag using either the clinometer or relascop. Report height in meters.
Diam.: Measure the diameter of the snag; report diameter in centimeters.
Decay Condition:
Vis.: Use the visual criteria set forth in Thomas 1979: 64. Record as follows: ST = a live tree with a
Spike top, LT = live tree; DE = declining; DD = dead: LB = loose bark; CL = clean; BR =
broken; DC = decomposed; DM = down material; ST = stump.
Pilo.: Take a measurement with the Pilodyn at breast height.
Shigo.: Take a measurement with the Shigometer at breast height.
% Bark: Visually estimate the percent of the tree surface still covered with bark.
# Nest Cav.: Count the numbers of nesting cavities and nest starts visible. Report as follows:
# NC/ # NS.
# Feed Cav.: Estimate the number of feeding holes by the following classes: L = less than 20: M = 20 to
50; H = greater than 50.
Snag Study Plan - 18.
SNAG DATA
Transect: ________________/_______________
Date:
FORM #1
Observer_______________________________
_________/___________/__________
Snag #
Spec.
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Diam.
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<- - - - Decay Condition- - - ->
Vis.
Pilo.
Shigo.
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% Bark
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#
Nest
Cav.
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Snag Study Plan - 19.
OVERSTORY VEGETATION
FORM #2
Transect: Use the Quad/Polygon numbering system rather than the random number for the plot.
Point #: Record the transect point number (1-11) where sample is taken.
Date and Observer: Complete name and date, please.
Prism Factor: Record the prism factor used. Most, if not all, prism plots will be done using a metric 2.5
factor prism.
Slope: Record the slope of the land at the sample point from the topo map.
Aspect: Record the aspect (N, NE, E, SE, S, SW, W, NW) at the sample point from the topo map.
# Stems in Prism Point: Record the total number of stems in the prism point.
Tree Species: Record appropriate code from Tree Species at right.
dbh: Measure diameter in centimeters at breast height.
Size cl.: Record appropriate code (1-7) from Size Classes at right.
Height: Record tree height in meters from Relascop or inclinometer.
Age: Record age of cored trees from core (reading cores may need to be done in the lab, so ensure that
cores and age data cell on this form are labeled by transect, point number, and key label for the tree
cored {M64/131--1--PP1}).
Canopy layers: Record the maximum number of canopy layers existing in a 50-m circle centered on the
prism point.
Logs: Record the count of all logs with average diameter exceeding 30-cm and 3-m in length within a
25-m circle centered on the prism point.
Fuel Loading Class (< 7.6. cm): Using the photo series for quantifying forest residues (Blonski and
Schramel 1981) record the appropriate code from the Fuel Loading Classes at the right.
Fuel Loading Class (> 7.6 cm): Using the photo series for quantifying forest residues (Blonski and
Schramel 1981) record the appropriate code from the Fuel Loading Classes at the right.
Snag Study Plan - 20.
OVERSTORY VEGETATION
FORM #2
Transect: _____________/_______________
Point #: ____________________________
Date:
Observer: __________________________
________/_________/___________
Prism Factor: __________________________
Slope: __________
Aspect: __________
# Stems in Prism Plot: ___________________
Tree Species
dbh
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Size Cl.
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Height
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Canopy Layers (in 50-m radius circle) = :
Logs (> 30 cm x 3 m) =
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Age
:
Fuel Loading Class ( < 7.6 cm) = :
:
Fuel Loading Class ( > 7.6 cm) = :
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Tree Species
Incense Cedar (IC)
White Fir (WF)
Ponderosa Pine (PP)
Jeffrey a Pine (JP)
Snag IC (S-IC)
Snag WF (S-WF)
Snag PP (S-PP)
Snag JP (S-JP)
Size Classes
1 = 12.7-27.9 cm
2 = 27.9-43.1 cm
3 = 43.1-58.3 cm
4 = 58.3-73.5 cm
5 = 73.5-88.7 cm
6 = 88.7-103.9 cm
7 = >103.9 cm
Fuel Loading Classes
1-MP-4
1-PP-2
2-MP-4
2-PP-2
3-MP-4
3-PP-2
4-MP-4
4-PP-2
5-MP-4
1-PP-3
2-PP-3
3-PP-3
4-PP-3
1-PP-4
2-PP-4
3-PP-4
:
<- - - -:
:
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: in 25-cm circle
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<- - - -:
Snag Study Plan - 21.
UNDERSTORY VEGETATION
FORM #3
Transect: Use the Quad/Polygon numbering system rather than the random number for the plot.
Point #: Record the point # (1-11) of the transect.
Observer and Date: Complete name and date, please.
Line 1 / Line 2 Direction: Record the direction (N, NE, E, SE, S, SW, W, NW) of the line intercept from
the point.
Species: Record the species measured. Use scientific names preferably.
Length: Record to the nearest .1 meter, the length of the line occupied by a plant species or ground cover.
Snag Study Plan - 22.
UNDERSTORY VEGETATION
Transect:
/
Line 1 - -
Point #:
/
Date:
FORM #3
Observer:
/
Line 2 - - Direction:
Direction:
Species
Length
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Species
::
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_
Length
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Snag Study Plan - 23.
BIRD/SNAG MAP
FORM #4
General bird survey procedure is to follow Christman (1984) which is attached.
Transect: Use the Quad/Polygon numbering system rather than the random number for the plot.
Observer and Date: Complete name and date, please.
Wind: Use the appropriate Beaufort Number (0-5) defined as follows:
Beaufort
Number
Wind Speed
miles per hr.
0
1
2
3
less than 1
1 to 3
4 to 7
8 to 12
4
13 to 18
5
19 to 24
Indicators of Wind Speed
Smoke rises vertically
Wind direction shown by smoke drift
Wind felt on face; leaves rustle
Leaves, small twigs in constant motion; light
flag extended
Raises dust and loose paper; small branches are
moved
Small trees in leaf sway; crested, wavelets on
fallen waters
Sky: Record the following Weather Bureau code numbers.
0 – Clear or only a few clouds
1 – Partly cloudy (scattered) or variable sky
2 – Cloudy (broken) or overcast
3 – Overcast
4 – Fog or smoke
5 – Drizzle
6 – Snow
7 – Showers
When mapping snags, use the number on the snag tag.
When mapping birds, use the attached two letter codes for species and symbols for activity.
Snag Study Plan - 24.
Table 1. Abbreviations of bird species names to be used with spot mapping.
American Robin
Anna’s Hummingbird
Band-tailed Pigeon
Black-headed Grosbeak
Black Swift
Black-thr. Gray Warbler
Blue Grouse
Brewer’s Blackbird
Brown Creeper
Brown-headed Cowbird
Bushtit
Calliope Hummingbird
Cassin’s Finch
Chipping Sparrow
Common Raven
Cooper’s Hawk
Dark-eyed Junco
Dusky Flycatcher
Evening Grosbeak
Flammulated Owl
Fox Sparrow
Golden-crowned Kinglet
Great-horned Owl
Green-tailed Towhee
Hairy Woodpecker
Hammond’s Flycatcher
Hermit Thrush
Hermit Warbler
House Wren
Lesser Goldfinch
Lincoln Sparrow
Mountain Chickadee
Mountain Quail
Nashville Warbler
Northern Flicker
Northern Goshawk
Northern Pygmy-Owl
r
ah
bp
g
bs
bw
bg
B
c
b
bt
ch
cf
cs
R
co
j
df
eg
fo
x
gk
go
G
ha
hf
T
hw
ho
L
ls
m
Q
nw
F
ng
po
Northern Saw-whet Owl
Olive-sided Flycatcher
Orange-crowned Warbler
Pileated Woodpecker
Pine Siskin
Purple Finch
Pygmy Nuthatch
Red-breasted Nuthatch
Red-breasted Sapsucker
Red Crossbill
Red-tailed Hawk
Red-winged Blackbird
Ruby-crowned Kinglet
Rufous Hummingbird
Rufous-sided Towhee
Sharp-shinned Hawk
Solitary Vireo
Song Sparrow
Spotted Owl
Steller’s Jay
Swainson’s Thrush
Townsend’s Solitaire
Vaux’s Swift
Violet-green Swallow
Warbling Vireo
Western Bluebird
Western Flycatcher
Western Tanager
Western Wood-Peewee
White-breasted Nuthatch
White-headed Woodpecker
Williamson’s Sapsucker
Willow Flycatcher
Wilson’s Warbler
Winter Wren
Yellow-rumped Warbler
Yellow Warbler
wo
o
ow
pw
ps
pf
pn
n
rs
rc
rt
rb
rk
rh
ru
H
sv
s
so
J
st
ts
vs
vg
v
wb
we
t
p
N
wt
ws
wi
w
wr
aw
yw
Snag Study Plan - 25.
APPENDIX IV
PROCEDURES FOR SPOT MAPPING
STANDARD TERMINOLOGY
1. Contact: Any detection of a bird in the field, whether by sight or sound.
2. Contact with high territorial significance: A contact associated with actions typically indicating a
bird (or birds) on a territory. Different types of contacts differ in the extent to which they indicate
territorial behavior. The following three groups of contacts are in order from highest to lowest
reliability as indicators of territoriality:
A. Territorial dispute; nonvocal territorial display (e.g., diving performance of a hummingbird,
drumming of a woodpecker); singing bird; territorial call; nest with warm eggs or with
nestlings;
B. Obviously mated pair; adult carrying nest materials; adult carrying food for young; family
group;
C. Distraction display; alarm call.
Some of these are applicable only to certain species, so it is important that the observer be familiar
with the biologies of the species being sampled.
3. Precisely located: A bird located to within a 5 m radius circle (for birds with large territories use a
larger radius circle such as 10 m or even 50 m. Use this larger radius circle for species such as
STJA, BTPI, MOQU, most woodpeckers, and all raptors).
4. Imprecisely located: A bird that you cannot locate within a 5 m radius circle or to the larger radius
circle if it is a species with large territories.
5. Contemporary contacts: Two or more simultaneous contacts with the same species, so no doubt
exists that they are different birds. Contemporary contacts are essential for later analysis of results,
especially if they involve contacts with high territorial significance.
6. Probably contemporary contacts: Contact with an individual bird that is probably not the same
individual of the same species contacted immediately preceding the contact in question, although
the two individuals were not contacted simultaneously. This leaves the decision up to the observer
in the field. For example, a singing male often stops singing as an observer passes. If a singing
male is then heard further along the trail, or at some distance away, but the first male was most
unlikely to have moved to the new location undetected by the observer, it is reasonable to assume
that two individuals are involved.
7. Registration: The record of a contact, entered on a field map of the study plot.
Snag Study Plan – 26.
8. Cluster: After all registrations for a single species, made during all field visits, have been
transferred to one summary map for that species, clusters of registrations are delineated and
assumed to correspond to territories (or at least to centers of activity within territories).
SAMPLING THE BIRD COMMUNITY
Maps. -- Take enough maps (at least 7) of the study plot to the field each day to use a separate map for
each grid line traversed that day. This reduces the number of registrations per map, permitting greater
accuracy, and it allows you to use the same data to estimate densities by various transect methods. It also
permits color-coding of observations by grid line traversed when final species maps are compiled,
facilitating interpretation of clusters.
Field notations. -- Abbreviate or symbolize all registrations unambiguously. Abbreviations for names
of bird species are given in Table 1. Symbols to denote different types of registrations are given in Table
2. Other symbols can be developed as required, but a detailed key to all of these must be made and
turned in with the completed maps.
Table 2. Symbols to be used for recording registrations. These use several recommended by the
International Bird Census Committee; others have been developed for this study.
A
A sight or sound contact with a bird of species A. Symbols may added to identify sex when
appropriate.
3A, 4A Contact with three, four etc. birds of the same species in the same place.
A
_
A
Contact with a bird giving a vocal utterance other than song, thought to have territorial
significance.
Contact with an imprecisely located bird giving a vocal utterance, other than song thought to
have territorial significance.
A [in solid triangle]
Contact with a precisely located bird singing part of its song.
A [in dashed triangle]
Contact with an imprecisely located bird singing part of its song.
A [in solid circle]
Contact with a singing bird that was precisely located.
A [in dashed circle]
Contact with a singing bird that was not precisely located.
A
Contact with a bird performing a nonvocal, territorial display.
AA
Contact with a pair.
AA [in a solid circle]
Contact with a pair, with the male singing.
A--->A Contact in which a bird moved from one location to another. An arrow may be used to
indicate the direction of movement.
A--->
Contact with a bird that was first seen at ‘A’ and flew out of sight at the point of the arrow.
Snag Study Plan – 27.
Table 2. Continued.
--->A
Contact with a bird that was first seen in flight at the tail of the arrow and then landed at ‘A’.
- -A->
Contact with a bird flying overhead.
A- - -A Contemporary contact with two different birds of species A. In this and the previous
notation, letters could be circled, underlined, or in other ways supplemented, as
appropriate.
A~~A
Probably contemporary contact with two different birds of species A.
A
(nm)
Contact with a bird carrying nest materials.
A) (A
Territorial dispute between two birds.
A*
Nest of species A. The number of eggs or young may be added.
A
(fn)
Contact with a bird feeding nestlings (appropriate sex symbol may be added).
A
(ff)
Contact with a bird feeding fledglings (appropriate sex symbol may be added).
A(f)
Contact with a fledgling of species A.
A(y)
Contact with an independent juvenile of species A.
Sampling the grid. - - Begin walking the first line at 10 min after official sunrise and continue at a
steady pace until all seven lines for that day’s visit have been completed. You are free to leave the grid
lines for short periods when doing so would significantly improve the information obtained, as follows:
1. To confirm locations of contemporary contacts, especially those of high territorial significance.
2. To follow moving birds and plot their movements. Even employ the consecutive flush technique
described by Wiens (1969).
3. Search for active nests. This is particularly important for delineating clusters for the following
bird species: MOCH, RBNU, DEJU, and BRCR. If you see birds carrying food or nesting
material, it’s worth spending some time to look for a nest.
After such detours, return to the point at which you left the grid line to assure a systematic search of all
portions of the plot. It should take you between 6 and 9 hours to complete one visit to the plot.
Every registration out to about 75 m from the grid line should be recorded during each traverse of a line
(even if you think you recorded the same bird on a line walked earlier that day). For some species,
especially MOQU, WHWO, HAWO, PIWO, STJA, HETH, and AMRO, it’s critical that you record
Snag Study Plan – 28.
registration even if you only have an inexact idea of their location and they seem to be far away. If your
first location of a bird is imprecise but you later precisely locate it, erase the imprecise locations and
write down the precise one. Make sure all nests are recorded on both the daily field sheets and on the
summary sheets.
Sampling beyond plot boundaries. - -Recording registrations out to 50 meters from the boundary
should be adequate for most species. For birds with large territories (e.g., WHWO, HAWO, PIWO,
STJA, MOQU, and raptors), however, it’s important to record even farther out to help determine
boundary cluster size and to minimize overestimation of the proportions of territories on the plot.
__________________________________________________________________________________
*INTERPRETING RESULTS*
Species summary maps. - -All registrations of a given species made during all visits to the plot are
transferred from the daily field sheets to a separate map. EACH FIELD VISIT IS GIVEN A LETTER
CODE to represent the registrations of any given species for that date. For a given visit, TRAVERSES
ALONG SEPARATE GRID LINES ARE SEPARATELY COLOR-CODED on the species map, making
it easier to recognize registrations of the same individual resulting from the observer’s passing through
the same territory along two or more grid lines on the same date.
Definition of a cluster. A cluster is a group of registrations representing one bird’s territory (or at least
a center of activity). A cluster must include one of the following in order to be accepted:
1. Registrations on at least three different visits (i.e. dates), at least two having high territorial
significance, and with at least 5 days separating extreme dates; or
2. Registrations on at least five different visits, none or one with high territorial significance, with at
least 7 days separating extreme dates.
Identifying clusters. - -Contemporary and probably contemporary contacts with high territorial
significance contribute most to reducing ambiguity when delineating clusters; contemporary and probably
contemporary contacts without high territorial significance are less useful. Therefore, the first step in
delineating clusters is to draw “territorial boundaries” across lines connecting contemporary and probably
contemporary registrations. This will leave some unresolved problems.
If you can’t separate clusters using contemporary or probable contemporary registrations, then you can
use one of the two following options:
1. At least two pairs of territorially significant registrations recorded in each cluster as you walked
the same line (e.g., singing males on each of two days in both areas, or a pair in one area and a
third bird in the other, or …) could be used to define clusters.
2. Share at least three registrations from different visits (not necessarily the same lines) with each of
the surrounding clusters it could be merged with. Two of the three registrations must be
territorially significant and any two of the three must be separated by at least five days.
In counting registrations, do not count fledglings. Count known females as one when not with a male;
pairs count as one registration. If a territorial dispute is in a cluster, it counts as one registration.
Snag Study Plan – 29.
Even these criteria may leave doubts about where boundaries ought to be drawn around clusters.
Registrations of movements by individual birds can further help to resolve questions, but in the final
analysis common sense and knowledge of the species must rule the day.
In our opinion, contemporary and probably contemporary contacts and observations of extended
movements of individuals are the most objective sorts of information that can be used to delineate
clusters. For this reason, we agree with Tomialojc (1980) that it is worth considerable extra effort to
obtain such data. We can’t overemphasize the importance of simultaneous registrations.
Determining the number of territories:
Complete clusters. Simply add up the number of complete clusters.
Coping with boundary clusters.- -A boundary cluster is one which overlaps the plot boundary. It must
contain at least one registration within the plot. There are problems with calculating the proportion of the
cluster that falls within the plot as we do not adequately sample these territories. We feel the best way to
determine this proportion is to compare it to the average number of visits contained in complete clusters
(those clusters wholly within the plot). For species with three or more clusters that fall completely within
the plot, determine the mean number of visits in the complete clusters of that species. The percentage of
each boundary cluster assigned to the plot is then calculated by dividing the number of visits it has within
the plot by the mean number of visits in the complete clusters. If this method yields a number that is
obviously too high (i.e. there are 3 boundary territories and the above method yields a number greater
than or equal to 3) then determine the mean number of registrations per complete cluster. The percentage
of each boundary cluster assigned to the plot is then calculated by dividing the number of registrations it
has within the plot by the mean number of registrations in the complete clusters. If this still results in an
estimate that is too high, then use the method described below for species with less than 3 complete
clusters.
For species with too few territories to estimate the mean number of detections per complete cluster,
use a convention similar to that adopted by the National Audubon Society for its annual Breeding Bird
Census (Robbins 1970). The proportion of the cluster assigned to the plot is simply the proportion of
registrations in that cluster that are within the boundary, rounded to the nearest 0.1 cluster. This method
overestimates the proportion of the cluster really within the plot, because little or no sampling is done
outside the plot. More sampling beyond plot boundaries can reduce but not eliminate this bias.
In all of these methods for dealing with edge clusters, registrations in which a single bird moved from
one side of the plot boundary to the other should be given double weighting- -one registration inside the
plot and one outside. A registration directly on a boundary line also receives double weighting. In
counting registrations, do not count fledglings. Count known females as one when not with a male; pairs
count as one registration. If a territorial dispute is in a cluster, it counts as one registration.
All proportional territories from the edge clusters are then summed with the complete clusters within
the plot to arrive at a total for the species, expressed to the nearest 0.1 cluster.
Tips for transferring to summary sheets and for interpreting:
Transfer the most common species first and work you way to the least common species.
Make a list on each daily field sheet of all of the species on that sheet. Then, as you transfer the different
species to their summary sheets, cross off that species from the list. This really speeds up transferring
when you get to the least common species.
Snag Study Plan – 30.
Make sure that you lightly cross off each registration after you transfer it to the summary sheet. This
ensures that each registration gets transferred. A highlighter works great for this.
When interpreting, start in the “easiest” area of the map and work out from there. This will give you an
idea of cluster size and spacing. But also realize that within any given species there will be a range of
territory sizes and spacing depending on available resources.
Use acetate overlays to draw territories. After you have drawn the final territories, transfer them to the
summary map.
Snag Study Plan – 31.
A
3A, 4A
A sight or sound contact with a bird of species A. Symbols may added to identify sex when appropriate.
Contact with three, four, etc. birds of the same species in the same place.
_
A
Contact with a bird giving a vocal utterance other than song, thought to have territorial significance.
Â
Contact with an imprecisely located bird giving a vocal utterance, other than song thought to have territorial significance.
A [in solid triangle]
Contact with a precisely located bird singing part of its song.
A [in dashed triangle]
Contact with an imprecisely located bird singing part of its song.
A [in solid circle]
Contact with a singing bird that was precisely located.
A [in dashed circle]
Contact with a singing bird that was not precisely located.
__
‫ ׀‬A ] ‫׀‬in dashed box]
AA
Contact with a bird performing a nonvocal, territorial display.
Contact with a pair.
AA [in solid circle]
Contact with a pair, with the male singing.
A-->A
Contact in which a bird moved from one location to another. An arrow may be used to indicate the direction of movement.
A--->
Contact with a bird that was first seen at ‘A’ and flew out of sight at the point of the arrow.
--->A
Contact with a bird that was first seen in flight at the tail of the arrow and then landed at ‘A’.
- -A->
Contact with a bird flying overhead.
A- - -A
Contemporary contact with two different birds of species A. In this and the previous notation, letters could be circled,
underlined, or in other ways supplemented, as appropriate.
A~~A
Probably contemporary contact with two different birds of species A.
A
Contact with a bird carrying nest materials.
(nm)
A) (A
Territorial dispute between two birds.
A*
Nest of species A. The number of eggs or young may be added.
A
Contact with a bird feeding nestlings (appropriate sex symbol may be added).
(fn)
A
Contact with a bird feeding fledglings (appropriate sex symbol may be added).
(ff)
A(f)
Contact with a fledgling of species A.
A(y)
Contact with an independent juvenile of species A.
Snag Study Plan – 32.
BREEDING BIRD SPECIES AT SJER
BEAUFORT WIND SCALE
Codes for spotmapping
00 = Smoke rises vertically
SPECIES
CODE
SPECIES
ACWO
A
MODO
M
AMKE
AK
AMRO
ar
NOFL
NF
ANHU
a
NOOR
NO
ATFL
F
NPOW
po
NUWO
N
OCWA
o
15 = Small branches moved, raises dust and
dry leaves
CODE
02 = Direction shown by smoke,
21 = Small trees in leaf begin to sway
but not wind vane
05 = Felt on face; moves wind
28 = Large branches in motion
vane
BAOW
BO
BEWR
be
BGGN
bg
BHCO
bc
PHAI
PH
BLPH
BP
PLTI
P
BRBL
B
BRTO
T
RCSP
rs
BUSH
b
ROAD
RO
ROWR
r
CATH
TH
RTHA
rt
CAWR
ca
RSTO
ru
1 = light drizzle
CAQU
Q
RWBL
rb
2 = steady rain
COHA
co
CORA
R
GHOW
GO
GOEA
G
constant motion
SCJA
J
STAR
ST
TRSW
t
TUVU
TV
VGSW
V
HAWO
ha
HOFI
hf
HOSP
hs
HOWR
ho
WBNU
n
HUVI
HV
WEBL
wb
HUMM
hu
WEXI
WK
WEME
W
WREN
wr
KILL
K
10 = Leaves and twigs in
RAIN
0 = No rain
WSOW SO
LAGO
LA
LASP
LK
LEGO
L
LEOW
LO
LOSH
LS
Snag Study Plan – 33.
BIRD/SNAG MAP
Transect:
Date:
Scale:
/
/
/
+ - - - - - - -- - -+
<---- 50m --->
FORM #4
Observer:
Wind:
Sky:
11
+- - - - - - - - -+- - - - - - - - +
:
:
:
:
:
:
:
: 10
:
+- - - - - - - - +- - - - - - - - +
:
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: 9
:
+- -- - - - - - -+- - - - - - - +
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: 8
:
+- - - - - - - - -+- - - - - - - - +
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:
+- - - - - - - - -+- - - - - - - - +
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: 6
:
+- - - - - - - - -+- - - - - - - - +
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: 5
:
+- - - - - - - - -+- - - - - - - - +
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: 4
:
+- - - - - - - - -+- - - - - - - - +
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: 3
:
+- - - - - - - - -+- - - - - - - - +
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: 2
:
+- - - - - - - - -+- - - - - - - - +
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: 1
:
+- - - - - - - - -+- - - - - - - - +
FINISH Time:
:
PDT
START Time:
:
PDT
Snag Study Plan – 34.
BIRD USE OF SNAGS
FORM #5
Transect: Use the Quad/Polygon numbering system rather than the random number for the plot.
Observer and Date: Complete name and date, please.
Wind: Use the appropriate Beaufort Number (0-5) defined as follows:
Beaufort
Number
Wind Speed
miles per hr.
0
1
2
3
less than 1
1 to 3
4 to 7
8 to 12
4
13 to 18
5
19 to 24
Indicators of Wind Speed
Smoke rises vertically
Wind direction shown by smoke drift
Wind felt on face; leaves rustle
Leaves, small twigs in constant motion;
light flag extended
Raises dust and loose paper; small
branches are moved
Small trees in leaf sway; crested wavelets on fallen waters
Sky: Record the following Weather Bureau code numbers.
0 – Clear or only a few clouds
1 – Partly cloudy (scattered) or variable sky
2 – Cloudy (broken) or overcast
3 – Overcast
4 – Fog or smoke
5 – Drizzle
6 – Snow
7 – Showers
DATA TABLE
For Nesting Site:
Bd Sp: Record four letter code for bird species name.
Snag ID: Record the unique number for the nest snag (if a snag) on the transect.
T/S Sp: Record the code for the tree or snag species.
T/S dbh: Record the dbh of the tree or snag in centimeters.
T/S Ht: Record the height of the tree or snag in meters.
Nest Ht: Record the height of the nest in meters.
Nest Dia: Record the diameter of the tree or snag at the nest in cm.
Nest Az: Record direction nest entrance faces (N, NE, E, SE, S, SW, W, NW).
L/D: Record L if nest is in a live part of a tree or D if in a snag or dead part of live tree.
Ht Grnd: Record the height, in meters, the nest is above the ground.
S Cond: Snag condition; 1 each pilodyn and shigometer measure if possible, if not accessible, visual
condition of the nest area.
For Potential Nesting Site:
Snag ID: Record the snag ID number if appropriate.
T/S Sp: Record as defined above.
T/S dbh: Record as defined above.
T/S Ht: Record as defined above.
Snag Study Plan – 35.
FOUR-LETTER ALPHA CODES FOR BIRDS OF THE SIERRA NEVADA
Eared Grebe
Western Grebe
Pied-billed Grebe
Great Blue Heron
Green-backed Heron
Black-crowned Night Heron
Whistling Swan
Canada Goose
Snow Goose
Mallard
Northern Pintail
Green-winged Teal
Cinnamon Teal
American Wigeon
Northern Shoveler
Wood Duck
Redhead
Ring-necked Duck
Canvasback
Lesser Scaup
Barrow’s Goldeneye
Bufflehead
Harlequin Duck
Ruddy Duck
Hooded Merganser
Common Merganser
Turkey Vulture
California Condor
Black-shouldered Kite
Northern Goshawk
Sharp-shinned Hawk
Cooper’s Hawk
Red-tailed Hawk
Red-shouldered Hawk
Swainson’s Hawk
Golden Eagle
Bald Eagle
Northern Harrier
Osprey
Prairie Falcon
Peregrine Falcon
Merlin
American Kestrel
Blue Grouse
White-tailed Ptarmigan
California Quail
EAGR
WEGR
PBGR
GBHE
GRHE*
BCNH
WHSW
CAGO
SNGO
MALL
NOPI
GWTE
CITE
AMWI
NOSH
WODU
REDH
RNDU
CANV
LESC
BAGO
BUFF
HADU
RUDU
HOME
COME
TUVU
CACO
BSKI
NOGO
SSHA
COHA
RTHA
RSHA
SWHA
GOEA
BAEA
NOHA
OSPR
PRFA
PEFA
MERL
MAKE
BLGR
WTPT
CAQU
Spotted Sandpiper
SPSA
American Avocet
AMAV
Wilson’s Phalarope
WIPH
California Gull
CAGU
Ring-billed Gull
RBGU
Band-tailed Pigeon
BTPI
Mourning Dove
MODO
Greater Roadrunner
GRRO
Barn Owl
BAOW
Western Screech-Owl
WSOW
Flammulated Owl
FLOW
Great Horned Owl
GHOW
Northern Pygmy-Owl
NPOW
Burrowing Owl
BUOW
Spotted Owl
SPOW
Great Gray Owl
GGOW
Long-eared Owl
LEOW
Short-eared Owl
SEOW
Northern Saw-whet Owl
NSOW
Poor-will
POWI
Common Nighthawk
CONI
Black Swift
BLSW
Vaux’s Swift
VASH
White-throated Swift
WTSW
Black-chinned Hummingbird BCHU
Anna’s Hummingbird
ANHU
Allen’s Hummingbird
ALHU
Rufous Hummingbird
RUHU
Calliope Hummingbird
CAHU
Belted Kingfisher
BEKI
Northern Flicker
NOFL
Pileated Woodpecker
PIWO
Acorn Woodpecker
ACWO
Lewis’ Woodpecker
LEWO
Yellow-bellied Sapsucker
YBSA
Red-breasted Sapsucker
RBSA
Williamson’s Sapsucker
WISA
Unidentified Sapsucker
SAPS
Hairy Woodpecker
HAWO
Downy Woodpecker
DOWO
Nuttall’s Woodpecker
NUWO
White-headed Woodpecker
WHWO
Black-backed Woodpecker
BBWO
Unidentified Woodpecker
WOOD
Western Kingbird
WEKI
Ash-throated Flycatcher
ATFL
Snag Study Plan – 36.
FOUR-LETTER ALPHA CODES FOR BIRDS OF THE SIERRA NEVADA
Mountain Quail
Chukar
Wild Turkey
Virginia Rail
American Coot
Killdeer
Common Snipe
MOQU
CHUK
WITU
VIRA
AMCO
KILL
COSN
Olive-sided Flycatcher
Violet-green Swallow
Tree Swallow
Northern Rough-w. Swallow
Barn Swallow
Cliff Swallow
Steller’s Jay
Scrub Jay
Black-billed Magpie
Yellow-billed Magpie
Common Raven
American Crow
Pinyon Jay
Clark’s Nutcracker
Mountain Chickadee
Chestnut-backed Chickadee
Plain Titmouse
Bushtit
White-breasted Nuthatch
Red-breasted Nuthatch
Pygmy Nuthatch
Brown Creeper
Wrentit
Dipper
Winter Wren
House Wren
Bewick’s Wren
Marsh Wren
Canyon Wren
Rock Wren
Northern Mockingbird
California Thrasher
American Robbin
Hermit Thrush
Swainson’s Thrush
Western Bluebird
Mountain Bluebird
Townsend’s Solitaire
Blue-gray Gnatcatcher
OSFL
VGSW
TRSW
NRSW
BASW
CLSW
STJA
SCJA
BBMA
YBMA
CORA
AMCR
PIJA
CLNU
MOCH
CBCH
PLTI
BUSH
WBNU
RBNU
PYNU
BRCR
WREN
DIPP
WIWR
HOWR
BEWR
MAWR
CNWR*
ROWR
NOMO
CATH
AMRO
HETH
SWTH
WEBL
MOBL
TOSO
BGGN
Black Phoebe
Say’s Phoebe
Willow Flycatcher
Hammond’s Flycatcher
Dusky Flycatcher
Western Flycatcher
Unidentified Empidonax
Western Wood-Pewee
Yellow Warbler
Yellow-rumped Warbler
Black-throated Gray Warbler
Townsend’s Warbler
Hermit Warbler
MacGillivray’s Warbler
Common Yellowthroat
Yellow-breasted Chat
Wilson’s Warbler
House Sparrow
Western Meadowlark
Yellow-headed Blackbird
Red-winged Blackbird
Tricolored Blackbird
Northern Oriole
Brewer’s Blackbird
Brown-headed Cowbird
Western Tanager
Black-headed Grosbeak
Blue Grosbeak
Lazuli Bunting
Evening Grosbeak
Purple Finch
Cassin’s Finch
Unidentified Finch
House Finch
Pine Grosbeak
Gray-crowned Rosy Finch
Pine Siskin
American Goldfinch
Lesser Goldfinch
Lawrence’s Goldfinch
Red Crossbill
Green-tailed Towhee
Brown Towhee
Savannah Sparrow
Grasshopper Sparrow
Vesper Sparrow
Lark Sparrow
BLPH
SAPH
WIFL
HAFL
DUFL
WEFL
EMPI
WEPE
YEWA
YRWA
BGWA*
TOWA
HEWA
MGWA
COYE
YBCH
WIWA
HOSP
WEME
YHBL
RWBL
TRBL
NOOR
BRBL
BHCO
WETA
BHGR
BLGR
LABU
EVGR
PUFI
CAFI
CARP
HOFI
PIGR
GCRF
PISI
AMGO
LEGO
LAGO
RECR
GTTO
BRTO
SASP
GRSP
VESP
LASP
Snag Study Plan – 37.
FOUR-LETTER ALPHA CODES FOR BIRDS OF THE SIERRA NEVADA
Golden-crowned Kinglet
Ruby-crowned Kinglet
Water Pipit
Phainopepla
Cedar Waxwing
Loggerhead Shrike
European Starling
Hutton’s Vireo
Bell’s Vireo
Solitary Vireo
Warbling Vireo
Orange-crowned Warbler
GCKI
RCKI
WAPI
PHAI
CEWA
LOSH
EUST
HUVI
BEVI
SOVI
WAVI
OCWA
*Be sure to note species that don’t follow the basic rules.
Rufous-crowned Sparrow
Black-throated Sparrow
Sage Sparrow
Dark-eyed Junco
Chipping Sparrow
Brewer’s Sparrow
Black-chinned Sparrow
White-crowned Sparrow
Golden-crowned Sparrow
Fox Sparrow
Lincoln’s Sparrow
Song Sparrow
RCSP
BTSP
SESP*
DEJU
CHSP
BRSP
BCSP
WCSP
GCSP
FOSP
LISP
SOSP
Snag Study Plan – 38.
BIRD USE OF SNAGS
Transect:
Observer:
Wind:
Sky:
/
Date:
/
FORM #5
/
< - - - - - - - - - - - - - - - - - - - - - - - - - - Nesting Site - - - - - - - - - - - - - - - - - - - - - - - - - - - - >
Bd. Sp.
:
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1
2
3
4
5
6
7
8
9
10
Snag ID
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T/S Sp
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T/S dbh
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T/S Ht
:
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:
<- - - - - - - - - Nesting Site - - - - - - - - - - - - - >
Nest Ht
:
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Nest Dia
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<- - - - - - - Potential Nesting Site - - - - - - - -
>
Nest Az
:
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1
2
3
4
5
6
7
8
9
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L/D
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Ht Grnd
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S Cond
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Snag ID
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T/S Sp
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T/S dhb
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T/S Ht
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Snag Study Plan – 39.
SNAG DENSITY
FORM #6
Transect #: Use the Quad/Polygon numbering system rather than the random number for the plot.
Location: Record the forest or National Park Unit name (Modoc, Lassen, Lassen Volcanic National Park
{LVNP}, Lava Beds National Monument {LBNM})
Random #: Record the random number of the polygon or potential transect.
Date: Complete date.
Direction: Record the general direction of transect (N, NE, E, SE, S, SW, W, NW) its direction
accurately in degrees (360◦)
Snags on Transect: Record the number of snags (> 15 in dh and > 20 ft tall) found on the transect.
Snags/acre: Record the number of snags per acre on the transect (each transect covers 12.5 acres).
Snag Density Class: Record the appropriate snag density class (total of seven) into which the transect
falls: 0, >0 – 0.5, >0.5 – 1.0, >1.0 – 1.5, >1.5 – 2.0, >2.0 – 3.0 and >3.0 per acre.
Observer: Complete name(s), please.
DATA TABLE: Record the following for all snags with dbh > 6 in (15.2 cm)
Snag Sp.: Species of tree.
Distance from start: Distance, in meters, from the start of the transect.
dbh: Diameter of snag at breast height (cm).
Height: Height of snag in meters.
Habitat Description: Do not complete at this time.
Directions: Do not complete at this time.
Snag Study Plan – 40.
Page
of
SNAG DENSITY
Transect #:
Location:
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Date:
Random #:
Direction:
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dbh (cm)
Height (m)
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100 x 500 m
Snags/acre:
Snag Density Class:
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NF
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Dimensions:
○)
Snags on Transect:
Snag Sp.
Distance
from start
FORM #6
Observer:
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RECORD ALL SNAGS GREATER THAN 6 in. DHB (15.2 cm)
Habitat Description:
Directions:
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