Using BBIRD Methodology in a Logistically
Constrained Study
Sallie J. Hejl
Jennifer A. Holmes
Abstract—One of the goals of the Breeding Biology Research and
Monitoring Database (BBIRD) program is to examine the effects of
management and other anthropogenic disturbances on avian breeding productivity. The BBIRD program relies on a network of cooperators using standardized sampling protocols to find and monitor
the nests of all species or a subset (focal group) of species in an area.
In a study of fragmentation effects on forest birds, we initially used
the community-level BBIRD approach, finding and monitoring
nests of as many species as we could. From 1992-1994, we found
twice as many nests in the second year (152 nests of 27 species) and
third year (140 nests of 23 species) as in the first year (65 nests of
15 species), but in most cases, we found insufficient numbers per
species to make good inferences. In general, we found more nests of
common than of uncommon species, but we could not easily find
nests of all of the common species. Cavity nests and enclosed nests
generally were easier to find than open-cup nests, but nests of most
species took large amounts of time to monitor. Each observer was
able to monitor from 10 to 15 nests per day. In 1995, we realized that
to get good information on nesting productivity in these habitats, we
either had to hire more people to cover more plots, or to focus on
fewer species. We decided to focus on two old-growth associates,
with a primary emphasis on Winter Wrens (Troglodytes troglodytes)
and a secondary emphasis on Brown Creepers (Certhia americana),
resulting in our finding 51 wren and 13 creeper nests. We also
colorbanded these species to obtain data on pairing success, probability of renesting, number of broods per season, and return rates.
In addition, colorbanding helped us confirm that we had obtained
most of the wren nests in each area and were able to minimize a
potential bias in nest success studies: that of discovering only easyto-find nests. We obtained good information on Winter Wrens, and
minimal information on Brown Creepers. Our study illustrates that
breeding productivity studies are labor intensive and often encounter budgetary and other logistic constraints (e.g., low nest densities
and difficult habitat in which to work). In addition, when trying to
address landscape-level questions, such as the effects of fragmentation, locating accessible replicate plots of rare habitat can be
difficult. Even for the most common species in cedar/hemlock oldgrowth forests, replicate plots are essential for obtaining sufficient
sample sizes of nests to test hypotheses. We agree with current
BBIRD recommendations that suggest eight 35-50 ha plots/treat-
In: Bonney, Rick; Pashley, David N.; Cooper, Robert J.; Niles, Larry,
eds. 2000. Strategies for bird conservation: The Partners in Flight planning process; Proceedings of the 3rd Partners in Flight Workshop; 1995
October 1-5; Cape May, NJ. Proceedings RMRS-P-16. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research
Station.
Sallie J. Hejl, USDA Forest Service, Rocky Mountain Research Station,
P.O. Box 8089, Missoula, MT 59807. Current address: Wildlife and Fisheries Sciences, Texas A&M University, 2258 TAMU, College Station, TX
77843-2258. Jennifer A. Holmes, USDA Forest Service, Rocky Mountain
Research Station, P.O. Box 8089, Missoula, MT 59807. Current address:
Glen Canyon National Recreation Area, P.O. Box 1507, Page, AZ 86040.
206
ment for areas with low nest density. We found that our habitat
required one person/50-ha plot to find most nests of focal species
and to monitor those nests. Thus, we would need 16 field assistants
for an ideal expanded study comparing nesting success in fragmented and continuous forests, in which we would expect to find
about 20 nests per treatment per year for each of five focal species.
When limited by constraints such as ours, we suggest that researchers focus on one to five focal species. If focusing on a few species, then
colorbanding individual birds to examine additional aspects of
population dynamics also may be possible.
Anthropogenic disturbances have significantly altered
historical landscapes throughout North America since European settlement (Askins and others 1990; Hejl 1994).
These changes have presumably affected the bird species
associated with habitats and landscapes that were once
previously governed by “natural” presettlement processes
(Hejl 1992; Hejl, this proceedings). Birds can be sensitive
indicators of environmental changes (Furness and Greenwood 1993) and many forest birds, in particular, have been
affected by anthropogenic disturbances (Askins and others
1990; Freemark and others 1995; Hejl and others 1995).
Anthropogenic disturbances continue to occur, and managers who are interested in producing commodities while
maintaining healthy populations of birds want to know how
specific management actions will affect birds. In the past,
most studies on the effects of management actions compared
bird distribution and abundances in disturbed and undisturbed areas (Hejl and others 1995; Hejl, this proceedings).
From these comparative studies, researchers hoped to find
indications of whether and how management actions affect
certain bird species. In more detailed studies of bird habitats, based on correlations between bird presence or abundance and habitat features, researchers hoped to find key
elements that species require. Both comparative and birdhabitat relationship studies use presence or abundance data
as an indication of whether a species is affected by a management action or not. These response variables, however, do
not necessarily reflect breeding productivity, and give no
indication of whether sampled birds are members of healthy
populations (Van Horne 1983) or are located in sink habitats, wherein productivity of a species is insufficient to
maintain a viable population without the immigration of
new individuals from healthy populations (Pulliam 1988).
According to Martin (1992a), measures of breeding productivity are more appropriate metrics for examining the effects
of management actions on bird populations. The Breeding
Biology Research and Monitoring Database (BBIRD) program was initiated to encourage studies of breeding productivity using standardized sampling protocols that allow
USDA Forest Service Proceedings RMRS-P-16. 2000
geographic and temporal comparisons (Martin and others
1997). One goal of this national monitoring program is to
better evaluate the effects of forest management practices on
population health for many avian species throughout their
ranges.
The BBIRD program includes a network of cooperators
using standardized sampling protocols (Martin and others
1997). General BBIRD methodology includes: (1) using randomly located (when possible) replicate plots of the habitats
or treatments of interest; (2) conducting point counts to obtain
bird distribution information across the plots; (3) finding and
monitoring nests of all species or focal species to obtain
nesting success information; and (4) sampling vegetation
throughout the plots, at survey points, at nest sites, and at
nonuse sites. Although not part of the protocol, banding
birds for the purpose of survival estimation also is encouraged. In general, BBIRD data document the distribution of
birds and nesting success in relation to different habitats
and vegetation features.
Nesting success is one of the primary factors influencing
population trends in birds. Other important demographic
factors include immigration/emigration, pairing success,
propensity to renest, number of young fledged per nest,
number of broods per season, adult survival, and juvenile
survival. BBIRD protocols do not include all of these parameters, although Martin (1992a) suggests estimating them to
obtain a more complete picture of the demography of a
species in an area or habitat.
We were interested in the effects of fragmentation resulting from clearcutting on bird distribution and productivity
in old-growth western redcedar (Thuja plicata)/western
hemlock (Tsuga heterophylla) forests and began using BBIRD
monitoring protocols in 1992. We had hoped to find at least
20 nests per treatment (in unlogged and logged forests) as
recommended by Hensler and Nichols (1981) and Martin
and Geupel (1993a) as a minimally adequate estimate of
nesting success using Mayfield estimators (Mayfield 1975).
In this paper, we describe our use of community-level BBIRD
methodology (trying to find nests of all species) in cedar/
hemlock forests and the series of modifications we subsequently made in order to increase our sample sizes of nests,
thus increasing our ability to accurately measure effects of
the treatment we examined. Our goal is to aid present and
future cooperators using BBIRD and related methods in
designing and conducting research on breeding bird productivity. We also discuss how colorbanding individual birds
complemented our use of BBIRD protocols and will increase
our knowledge of the effects of forest fragmentation on
specific demographic parameters.
Methods _______________________
We had two primary study sites: (1) an area composed of
recent clearcuts embedded in a matrix of old-growth forest
(the Distillery Bay Timber Sale on the Priest Lake Ranger
District, Idaho Panhandle National Forests) and (2) a continuous block of old-growth forest (Teepee Creek and Bottle
Lake Research Natural Areas on the Priest Lake Ranger
District, Idaho Panhandle National Forests). We had two
plots in each of the two locations. Plot size changed from
25 ha in 1992 to 50 ha in 1993, because we realized we
USDA Forest Service Proceedings RMRS-P-16. 2000
needed to search in as large an area as one person could
adequately cover.
We followed BBIRD protocols (Martin and others 1997)
in these areas for three years (1992-1994): We conducted
point counts, searched for nests, and monitored nesting
success of all nests located in each area. We had four primary
nest searchers each year. We searched for nests in May and
June in 1992, May through early July in 1993, May through
mid-July in 1994, and mid-April through mid-July in 1995.
During 1992, each observer shared two plots with one other
observer. After 1992, each person had one plot for which s/he
was responsible. Three of the nest searchers conducted point
counts one or two times per week, and they searched for
nests the other days in 8- to 10-hr days in a five-day workweek. One to three others helped intermittently to search for
nests each year. Budget constraints required that observers
stop nest-finding in early to mid-July to complete vegetation
sampling for nests and nonuse sites. A separate threeperson field crew measured the general vegetation throughout the study sites each summer.
In 1994, we attempted to increase the number of nests
found per species by focusing on searching for nests of five
focal species: Red-naped Sapsucker (scientific names listed
in table 1), Chestnut-backed Chickadee, Red-breasted
Nuthatch, Brown Creeper, and Winter Wren. We chose
these species because we predicted they might be vulnerable
to fragmentation and we previously had been successful in
finding their nests. We also continued to look for nests of
other species but with less effort.
In 1995, we realized that to get good information on
productivity in these habitats, we had to increase search
effort either by increasing the number of searchers or by
focusing on fewer species; we chose the latter. The point
count information obtained as part of the BBIRD protocol
from 1992-1994 (Hejl and Paige 1994; see table 1 for 1992
point counts) and a literature search on forest fragmentation
indicated that Winter Wrens and Brown Creepers were two
of the species most likely to be negatively affected by the type
of forest fragmentation in our area. Therefore, in 1995, we
decided to focus on Winter Wrens and Brown Creepers,
emphasizing the wrens. We also monitored any Chestnutbacked Chickadee nests that we found in our searches for
wren and creeper nests. In addition, we attempted to band
all the Winter Wrens and Brown Creepers in the study
areas. In 1996 and 1997, we resighted banded wrens on our
plots.
Results ________________________
In 1992, we found 65 nests of 15 species (table 1). In 1993,
we found 152 nests of 27 species. As expected, we found more
total nests in 1993 due to a better understanding of potential
nest locations and nesting phenology of each species, larger
plot sizes, plot ownership (one person/plot), extending the
nest-searching time into July, and an unusually competent
field crew. However, we found less than 20 nests per species
per treatment even after pooling data from both years.
In 1994, when we focused on searching for nests of five
focal species, we found 140 nests of 23 species (table 1). While
we found more nests of Winter Wrens, we did not find any
more nests of the other focal species, and we still had low
207
Table 1—Number of nests found for each species by year and area (forests fragmented by clearcuts = Frag and continuous forest = Unfrag) as
compared to point count results from 1992 (Hejl and Paige 1994) in cedar/hemlock forests in northern Idaho (“—” indicates not sampled
in 1995).
Species
American Kestrel
(Falco sparverius)
Calliope Hummingbird
(Stellula calliope)
Rufous Hummingbird
(Selasphorus rufus)
Red-naped Sapsucker
(Sphyrapicus nuchalis)
Hairy Woodpecker
(Picoides villosus)
Three-toed Woodpecker
(P. tridactylus)
Northern Flicker
(Colaptes auratus)
Pileated Woodpecker
(Dryocopus pileatus)
Dusky Flycatcher
(Empidonax oberholseri)
Tree Swallow
(Tachycineta bicolor)
Common Raven
(Corvus corax)
Chestnut-backed Chickadee
(Parus rufescens)
Red-breasted Nuthatch
(Sitta canadensis)
Brown Creeper
(Certhia americana)
Winter Wren
(Troglodytes troglodytes)
Golden-crowned Kinglet
(Regulus satrapa)
Mountain Bluebird
(Sialia currucoides)
Townsend’s Solitaire
(Myadestes townsendi)
Swainson’s Thrush
(Catharus ustulatus)
Hermit Thrush
(C. guttatus)
American Robin
(Turdus migratorius)
Varied Thrush
(Ixoreus naevius)
Yellow-rumped Warbler
(Dendroica coronata)
Townsend’s Warbler
(D. townsendi)
Northern Waterthrush
(Seiurus noveboracensis)
MacGillivray’s Warbler
(Oporornis tolmiei)
Western Tanager
(Piranga ludoviciana)
Chipping Sparrow
(Spizella passerina)
Dark-eyed Junco
(Junco hyemalis)
Evening Grosbeak
(Coccothraustes vespertinus)
Total
208
1992
counts
Frag
Unfrag
1992
nests
Frag Unfrag
1993
nests
Frag Unfrag
1994
nests
Frag Unfrag
1992-1994
nests
Frag Unfrag
1995
nests
Frag Unfrag
0.07
0.00
2
0
0
0
0
0
2
0
—
—
0.00
0.00
0
0
1
1
0
0
1
1
—
—
0.00
0.03
0
0
4
1
1
1
5
2
—
—
0.22
0.08
7
3
10
1
8
2
25
6
—
—
0.08
0.08
1
1
1
1
1
1
3
3
—
—
0.00
0.00
0
0
1
1
2
0
3
1
—
—
0.07
0.01
4
0
1
0
2
0
7
0
—
—
0.07
0.07
0
0
1
0
1
0
2
0
—
—
0.10
0.07
0
0
1
0
1
0
2
0
—
—
0.00
0.00
0
0
0
2
0
1
0
3
—
—
0.13
0.03
0
0
1
0
1
0
2
0
—
—
0.60
0.51
7
4
6
5
4
7
17
16
3
3
0.72
0.56
4
4
17
9
16
5
37
18
—
—
0.21
0.57
3
3
6
2
2
5
11
10
4
9
0.40
0.92
1
2
6
5
8
21
15
28
18
33
0.38
0.69
1
0
0
3
0
0
1
3
—
—
0.00
0.00
0
0
4
0
0
0
4
0
—
—
0.19
0.00
1
0
1
0
0
0
2
0
—
—
0.36
0.76
2
0
4
4
1
4
7
8
—
—
0.06
0.10
0
1
1
4
2
3
3
8
—
—
0.43
0.01
3
0
7
0
6
0
16
0
—
—
0.36
0.57
0
0
2
0
0
1
2
1
—
—
0.50
0.22
0
0
2
1
1
0
3
1
—
—
0.67
0.43
0
0
0
0
1
0
1
0
—
—
0.00
0.00
0
0
0
1
0
0
0
1
—
—
0.15
0.04
0
0
0
0
1
0
1
0
—
—
0.21
0.06
0
0
2
0
1
0
3
0
—
—
0.25
0.03
2
0
10
1
2
0
14
1
—
—
1.22
0.64
7
2
15
5
14
13
36
20
—
—
0.00
0.00
0
0
1
0
0
0
1
0
—
—
45
20
105
47
76
64
226
131
25
45
USDA Forest Service Proceedings RMRS-P-16. 2000
numbers of nests per species in each treatment. Furthermore, even after pooling across all three years, we had
greater than or equal to 20 nests per treatment for only one
species, the Dark-eyed Junco, not a focal species. After three
years of study and as a result of low sample sizes, we had not
yet obtained adequate estimates of nesting productivity for
the focal species in our habitats, according to the suggestions
of Hensler and Nichols (1981).
By concentrating on one species in 1995 and making a
special effort to learn the behaviors of this species, we came
close to finding enough nests of the difficult but, for our
habitat, fairly abundant Winter Wren (18 in fragmented
forests and 33 in continuous forests). In addition, in 1995, we
successfully banded all male and about half the female
Winter Wrens. For the Brown Creepers, our secondarily
emphasized species, we were able to find only 13 nests and
band a small subset of the individuals.
Banding the birds did take time away from nest finding.
However, it helped us to focus our nest searches based on
observations of banded adults, and also helped us confirm
that we had found most of the wren nests in both areas. We
were able to avoid a potential problem in nesting success
studies—that of discovering only easy-to-find nests. In
addition, from the data obtained from colorbanding individual birds, we will be able to examine density, site tenacity, pairing success, propensity to renest, number of broods
per season, adult survival, and territory size and quality, as
well as nesting success and number of young fledged per nest
for the Winter Wrens in our study. We will not be able to
determine juvenile survival, because we chose not to remove
nestlings from their delicate nests, partly for fear of influencing predation. We do not have enough data to examine
these factors for Brown Creepers.
In general when we used community-level BBIRD methodology, more nests were found of the more common (e.g.,
greater than 0.20 individuals/point count in an area) than of
the uncommon species every year (table 1). Yet, we could not
easily find nests of all of the common species. We found only
a few nests for some of the common species. Cavity-nests and
enclosed nests generally were easier to find than open-cup
nests, but nests of most of our species took large amounts of
time to monitor. Each observer was able to monitor from 10
to 15 nests per day in our forests. In general, using BBIRD
methodology to assess breeding productivity was practical
for only some of the most common species in our forests.
Discussion _____________________
It is difficult to assess the effects of anthropogenic disturbances on bird populations by using presence/absence or
abundance data alone (Martin 1992a). The BBIRD program
was established to identify habitat conditions affecting
breeding bird productivity, providing a general methodology
for researchers and managers (Martin and others 1997). Our
study illustrates that breeding productivity studies are relatively intensive and have the potential to encounter certain
logistic constraints in the following areas: (1) budget, including how many people one can hire, transport, and house; (2)
availability of the habitat of concern, including sufficient
number of replicate areas of adequate size, proximity, and
accessibility; (3) structural characteristics of the habitat of
USDA Forest Service Proceedings RMRS-P-16. 2000
interest; and (4) characteristics of the birds in the habitat,
including the density of the species and the behavior of the
birds and hidden nature of the nests.
Many factors contributed to our small sample size of
nests: (1) we had few nesting plots (only two per habitat
condition); (2) the density of individuals within species was
low (i.e., an average of 9 territories per 50-ha plot of continuous forest for Winter Wren, our second-to-most abundant
species); (3) it was often very time consuming to move
between nests (traveling between nests usually consisted of
hiking 100 to 400 m over large logs in rugged terrain) and to
monitor nests (a majority of the nests were cavity nests,
which can commonly take 0.50 to 1 hr to confirm activity
during a visit); (4) the vegetation was structurally complex
and had a very high canopy (30-60 m), resulting in difficulty
locating and following individuals; (5) the physical conditions were often dark and rainy, hindering nest finding; and
(6) many of the species had cryptic behavior and nests. The
relative importance of each factor in determining the probability of finding an active nest varies across species. For
example, cryptic behavior and nest placement (tree canopy)
limited our ability to find nests of abundant species such as
Golden-crowned Kinglet and Townsend’s Warbler (compare
point count results with nest numbers in table 1). Height of
four kinglet nests ranged from 11 to 27 m in 27 to 43 m tall
trees. Alternatively, many of the species’ for which we could
find nests fairly easily have relatively large territories
(Northern Flicker territories are 16 ha in mature conifer
forest [Lawrence 1967]), resulting in few total nests found
because only about 100 ha were thoroughly covered in each
habitat condition.
When using BBIRD methodology to monitor nests of all
coexisting species, those with hard-to-find nests (even
fairly common species) are likely to be undersampled. For
example, the Winter Wren was one of the most abundant
species recorded during point counts in continuous old growth
(Hejl and Paige 1994), yet we found relatively few active
nests in 1992 (table 1). Winter Wrens are cryptically colored
and secretive, and they build multiple, well-concealed nests
in a variety of nesting substrates each year. Due to the
diversity of nesting locations, it took a relatively long time to
develop search images for wren nests. In addition, only some
of the nests that are built in a year are used in that particular
year (e.g., of 101 wren nests found in 1995, only 51 were
active that year). Because we originally were trying to get as
much information as we could on as many species as possible, nest searchers would often abandon more difficult
searches, such as those for Winter Wren, and focus on other
species. By concentrating on Winter Wrens in 1995 and
making a special effort to learn the behaviors of this species
in previous years, we came close to finding 20 nests of the
difficult but fairly abundant Winter Wren in each treatment
that year.
Once an individual observer had found many nests, the act
of monitoring nests became a bigger time commitment than
searching for nests. Nests of most of our species took large
amounts of time to monitor. The contents of most cavity nests,
many enclosed nests, and high open-cup nests could not be
directly observed. As a result, observers used adult behavior
around the nest to determine nest activity and fate. For many
of our species, nest monitoring required from 30 to 60 min to
determine nest stage during each visit. Because of the amount
209
of time we had to spend monitoring each nest and the distance
and difficulty in the terrain among nests, any one observer
was able to monitor from 10 to 15 nests in a day in a 50-ha plot.
The amount of time it took to monitor nests in these cedar/
hemlock forests was not necessarily unusual for conifer forests. In a similar study examining the effects of salvagelogging on cavity-nesters in post-fire coniferous forests, one
person could successfully monitor 7 to 12 nests per day (SJH,
unpublished data). In addition, in cedar/hemlock forests, we
found many ultimately unused nests for four of our five focal
species. Each unused nest required as much time to monitor
as an active nest (nest fate again being determined from
observing adult behavior) and multiple visits were made to
each as if it were an active nest until we had clearly determined that it was inactive.
Within our study, we encountered constraints in all of the
above-mentioned areas leading to a tradeoff between finding
low numbers of nests for many species or focusing on selected
species. The main constraints were the low density of the
species for which we could find nests, inaccessibility of
replicate plots (none within driving distance of our housing
in April to mid-May), and our limited budget that determined how many people we could hire, house, and transport.
We eventually chose to focus on two species of concern to find
an adequate number of nests for those species in each
treatment each year. In addition, we decided to measure
other components of population health. Even with this focus,
it would be preferable to include more sites to increase the
number of nests monitored and the applicability of our
results beyond our two study areas. More replicates would
require more financial resources to hire more people. Ideally, we would have liked to have had six additional study
areas (3 of each treatment), with two 50-ha plots in each for
a total of 12 more plots, in order to adequately sample from
one to five focal species and address the question of whether
fragmentation affects these species.
Martin and Geupel (1993a) suggest that each field worker
can be in charge of two plots, although they do not consider
logistic differences among habitats. Because of the constraints listed above, we found that our habitat required one
person/plot to find most nests of the focal species in these oldgrowth forests and to monitor those nests. One person could
monitor nests successfully on 25 ha (one-half plot) in an 8- to
10-hr day. Thus we would need 16 field assistants for our
ideal expanded study. In addition, measuring other components of population health by colorbanding individual birds
requires at least one and preferably two additional field
assistants for each four, widely dispersed, 50-ha plots. To
implement a BBIRD study, Martin and others (1997) currently recommend at least four plots/treatment in any habitat and as many as eight plots/treatment in habitats with
low nest density. Based on the number of nests found in 1993
and 1994, we agree with Martin and others (1997) that 8
plots/treatment would be a reasonable approach in our lowdensity habitat. We would then be likely to obtain 20 nests/
treatment for most focal species each year.
Cavity- or enclosed-nesters might seem an ideal group to
focus on in old-growth coniferous forests. In general, we
were fairly successful in finding their nests. Cavity-nesters
and some enclosed-nesters, however, are also difficult to
study in that one cannot easily look into their nests without
special equipment (e.g., nest cameras) or technical climbing
210
equipment and experience. Without this special equipment
or experience, the researcher is left to guess nest fate based
on observational data, mostly obtained from watching
adult activity on the outside of the nest. In addition, when
contents cannot be directly determined and these nests are
watched from afar, the observer often has to spend from 30
minutes to 1 hr (sometimes greater than 1 hr for Pileated
Woodpecker), watching the nest to determine what activity
is actually occurring, making it difficult time-wise to monitor many nests, and leaving little time for additional nest
searching. Invariably, some nest cards must be thrown out
because nest fate is impossible to determine. Finally, because many cavity-nesters have large territories (especially woodpeckers), large areas must be surveyed to find
large samples of nests. In spite of the difficulties in studying them, cavity- and enclosed-nesters as a group are
critical to study; they are among those species that are most
likely to be negatively affected by silvicultural practices,
and therefore warrant considerable attention (Hejl and
others 1995).
BBIRD is a valuable program for a number of reasons,
including the fact that it is the only set of standardized
protocols for evaluating reproductive success of landbirds.
BBIRD also gives us a useful methodology for evaluating
the effects of forest management practices on bird populations. When using BBIRD methods or otherwise measuring
nesting success and when limited by constraints such as
ours, we suggest emphasizing one to five focal species. In
addition, if a researcher is uncertain what species are of
concern in the habitat of interest or for which species
observers will be able to find an adequate number of nests,
then we suggest either: (1) one season of community-level
BBIRD; or (2) one season of point counts and minimal nestfinding to determine the species of interest and those for
which nests can be found in adequate numbers to test
hypotheses. In following years, the researcher will be able to
use BBIRD methods to study all species or just focal species.
For example, based on point count results from the first year
of study, we would concentrate nest-finding efforts on species with greater than 0.20 individuals/count in future years
in cedar/hemlock forests. If focusing on a few species, then
we suggest colorbanding individuals of one to several of
those selected species. Colorbanding can help observers
focus searches on hard-to-find nests within a species, potentially resulting in a less biased estimate of nesting success
and predation and parasitism rates for that species.
Colorbanding also allows one to examine additional parameters related to population health for the selected species.
Acknowledgments ______________
We are indebted to all of the other nest searchers: E. A.
Beringer, D. S. Booth, T. M. Ferraro, C. K. Friers, K. L.
Hughes, J. S. Kramer, K. J. Kreisel, G. Mandujano Chavez, P.
McLaughlin, L. Ortiz, L. C. Paige, C. C. Patton, T. M. Platt, C.
Tejeda Cruz, J. J. Tewksbury, and L. Van Huis. We are
grateful to the Priest Lake Ranger District, Idaho Panhandle National Forests, especially Tim Layser, for logistic
support. We thank C. J. Conway, R. J. Cooper, T. E. Martin,
and D. Rosenberg for reviewing earlier drafts of this
manuscript.
USDA Forest Service Proceedings RMRS-P-16. 2000