FW 353 Group 10 Class Project
Created by:
Mikayla Seamster
Economics/Management & Challenges
Erika Dinkler
Diseases
Todd Carroll
Ecosystem Associations & Population Ecology
Carley Leonard
Food & Cover
Signatures:
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Table of Contents
I.
II.
III.
IV.
Northern Pintail (Anas acuta)..........................................................................................3
A. Ecosystem Associations…………………………………………………………..4
B. Population Ecology……………………………………………………………….4
C. Food and Cover…………………………………………………………………...5
D. Diseases…………………………………………………………………………...6
E. Economics/Management…………………………………………………………..9
F. Challenges………………………………………………………………………..10
G. References………………………………………………………………………..12
Eastern Cottontail (Sylvilagus floridanus).....................................................................15
A. Ecosystem Associations………………………………………………………….16
B. Population Ecology………………………………………………………………16
C. Food and Cover…………………………………………………………………..16
D. Diseases…………………………………………………………………………..18
E. Economics/Management…………………………………………………………21
F. Challenges………………………………………………………………………..22
G. References……………………………………………………………………….23
Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii)...............................................26
A. Ecosystem Associations………………………………………………………….27
B. Population Ecology………………………………………………………………27
C. Food and Cover…………………………………………………………………..28
D. Diseases…………………………………………………………………………..29
E. Economics/Management…………………………………………………………30
F. Challenges……………………………………………………………………..…31
G. References……………………………………………………………………..…33
Red-tailed Hawk (Buteo jamaicensis).............................................................................35
A. Ecosystem Associations………………………………………………………….36
B. Population Ecology………………………………………………………………36
C. Food and Cover…………………………………………………………………..37
D. Diseases…………………………………………………………………………..38
E. Economics/Management…………………………………………………………40
F. Challenges………………………………………………………………………..41
G. References………………………………………………………………………..43
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Northern Pintail
Anas acuta
(Game Species)
Prepared by:
Mikayla Seamster
Erika Dinkler
Carley Leonard
Todd Carroll
3
Ecosystem associations
Northern pintail are nearctic birds and are native to the Prairie Pothole Region of North
America, along the northern American border from Alaska all the way to western Greenland
(Ducks Unlimited). During the summer, pintail populations may migrate south to central or
southwest America, and sometimes to parts of Mexico (“Northern Pintail”). They winter
throughout most of the United States and south through Mexico to northern South America (Bird
Species and distributions in Yukon-Charley Rivers National Preserve). Along the eastern coast
of the United States, migrations typically follow two distinct routes: the eastern corridor and the
western corridor. The eastern corridor connects Florida and the North Carolina Outer Banks with
Northern Canada as it passes through the northeastern states. The western corridor passes
through most of the midwest and serves as a pathway between Manitoba and the southeast
United States (Howell and Wilson, 14-19).
Like most waterfowl, common nesting grounds for the northern pintail include lowland
moors, marshes, brackish wetlands, ponds, lakes, and some rivers. Nests are typically built in
dense vegetation about half a mile from the water, in areas with appropriate levels of cover
(Austin and Miller).
Population Ecology
Originally one of the most abundant ducks in North America, the northern pintail has
recently been suffering from a noticeable decline since the 1950s. In 2009, there was only
reported to be around 3.2 million ducks, which is just about 60% of the 5.5 million that the North
American Waterfowl Management Plan had intended (Ducks Unlimited). The Northern Pintail
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typically breeds in the spring or summer, producing an average of 7 to 9 eggs each season.
Incubation of the eggs lasts about 23 days, and after hatching, the ducklings are instantly led to
the water. Fledging requires about 45 days, after which the hen will regrow flying feathers and
take off, leaving her offspring behind (EOL: Encyclopedia of Life).
The offspring, both males and females, reach maturity after roughly one year, though
their lifespan usually lasts only about 267 months (Robinson). Northern pintails typically build
one nest for breeding, but if the nest is destroyed for whatever reason, they are likely to build a
new one. However, the newer clutch will not be as large as the original, and the ducklings have a
significantly lower survival rate (Howell and Wilson, 14-19).
Food and Cover
The northern pintail is an omnivore and is known to eat a variety of different things,
which include: grains, seeds, weeds, aquatic insects, crustaceans and snails (The Cornell Lab of
Ornithology). The grains that they consume the most are rice, wheat, barley and oats. The seeds
they enjoy include alkali and hardstem, bulrush seeds, and a weed called the sago pondweed.
Two other types of food they typically consume are cladocera and widgeon grass (The Reagents
of the University of Michigan).
Northern pintails must seek cover in order to avoid predators or other dangers and to
protect themselves from the elements. During the day, northern pintails are notorious for using
large expanses of shallow, open habitats. The wetlands in which they reside not only offer
plenty of food, but they also provide good visibility to avoid predation. At night, northern
pintails often seek habitats with greater, more robust cover. During nesting, northern pintails
seek cover that is considered sparser (Fredrickson and Heitmeyer 1991).
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The main reason why northern pintails must seek good cover is to avoid predation. Some
of the known predators of northern pintails include: humans, bobcats, coyotes, crows, magpies,
gulls, striped skunks, ground squirrels, red foxes, badgers, raccoons, Eurasian badgers, kit foxes,
skunks, gray foxes and American badgers (The Reagents of the University of Michigan).
Cover is not the only technique that northern pintails use to avoid predation. They also
have particular nesting behaviors that help their populations to survive. For example, northern
pintails nest much earlier and in more open areas than other species of duck so their nests suffer
less from predation (Tesky 1933). They also protect their brood by flying at an intruder or by
pretending to be injured and leading the predator away from her brood (Nature Works).
Diseases
Diseases can have huge impacts on species; some diseases can cause serious mortality
events, while others only cause small problems for individuals. Environmental conditions, a host,
and an agent are the three aspects necessary for a pathogen to infect a host. Once infected, the
host has the disease. Northern pintail breeding populations have decreased from more than 10
million in 1957 to about 3.5 million by 1964 due to diseases. Northern pintail can be affected by
various parasites including Cryptosporidium, Giardia, tapeworms, blood parasites, and external
feather lice. They are a dominant species in series wildlife mortality events including avian
botulism, avian cholera, and avian influenza, including H5N1 (Avian web). New castle disease
has also been a huge problem for an isolated northern pintail population in Japan (Sakai, K., et
al. 2007). A few of the diseases that have large impacts on waterfowl populations, including
northern pintail are described below.
Avian botulism is caused by the bacteria, Clostridium botulinum. This bacteria is found
in the soil and produces toxins when temperatures are warm, there is a protein source, and no
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oxygen. Decomposing vegetation can help provide perfect conditions for the bacteria to activate
and produce the toxins. The toxins produced by the bacteria can be categorized into different
types; waterfowl are impacted by type C and sometimes by type E. Invertebrates are not affected
by the toxin, and in fact, they store it in their bodies. Avian botulism occurs when waterfowl eat
invertebrates or ingest the toxin directly. An avian botulism outbreak can occur when maggots
feed on animal carcasses and end up ingesting the toxin. Then, waterfowl come along and eat the
maggots and become infected with the toxin, resulting in avian botulism. Ducks especially are
susceptible to this type of avian botulism outbreak and they can be infected by the toxin after
eating only three or four infected maggots. Avian botulism is a neurological disease and it
prevents muscles from receiving the proper messages from the nervous system. As a result,
waterfowl and other birds are unable to use their wings and legs properly and they also lose
control of their third eyelid, neck muscles, and other muscles. If waterfowl cannot control their
neck muscles and hold their heads up, then death is imminent. Death can also result from water
deprivation, predation, or respiratory failure. Wildlife managers have to removecarcasses quickly
from the area to help reduce the bacteria found there. They can also alter the water depth during
hot weather to reduce or flood watershed areas which will increase the deaths of invertebrates,
which in turn, will remove a protein source for the bacteria. Birds that have already been infected
by the toxin can be offered fresh water, shade, and cover from predators to help them recover
(United States Geological Survey, Avian Botulism 2013).
Avian cholera is caused by the bacteria, Pasteurella multocida. It can infect birds and
mammals; however there are different strains that infect them. Wild birds, like waterfowl, are
most commonly infected by one strain, type 1. Avian cholera can be transmitted by the bacteria
being spread via bird-to-bird contact, contact with secretions or feces of infected birds, by
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ingestion of food or water which contains the bacteria, or by aerosol transmission. Bacteria can
remain viable in the soil for up to four months. Avian cholera causes large die-offs in waterfowl
species. Large flocks of birds with poor body condition, lethargic birds, birds suffering from
convulsions, birds swimming in circles, birds exhibiting erratic flight, among other signs can be
evident of avian cholera in a wild bird population. When the disease has been detected in a
population, prompt action has to be taken by wildlife managers to collect carcasses to reduce the
amount of bacteria in the area and to try to reduce the spread of this highly contagious disease
(United States Geological Survey, Avian Cholera News 2013).
The public became concerned with avian influenza in 2009 when there was a worldwide
pandemic of the H1N1 flu virus. H1N1 in humans is similar to the strains that are endemic in
pigs and birds, thus avian influenza. For humans, the H1N1 strain that caused such a ruckus in
2009 is now considered a regular seasonal flu strain. However, avian influenza still infects bird
populations, including the northern pintail and there is the possibility that this strain cause be
passed to humans. Humans may contract avian influenza by direct or indirect contact with
contaminated environments or by handling birds that are infected (Avian web). Another concern
is migratory bird species, such as the northern pintail spreading diseases to other areas of the
world where the disease may not be currently present. This has occurred when birds, in particular
the northern pintail, have carried avian influenza from Asia to North America as they have
migrated. New castle disease in Japan has infected an isolated population of northern pintails. It
is believed that this disease originated in the Middle East and spread to Japan as northern pintails
or other migratory bird species migrated to Japan. This disease is currently trying to be contained
because it can affect many different species of migratory birds and therefore, could be spread to
various areas of the world via migration (Koehler, A.V., et al. 2008).
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Economics/management
Northern pintail are medium-sized ducks with long, thin necks, pointed tails and a
distinctive silhouette. (All About Birds). Northern pintails are one of the most popular waterfowl
species hunted. During hunting season, hunters spend a lot of money on hunting license, sporting
goods and travel arrangements near migration flyways which adds a considerable amount of
revenue to towns’ economy (Robinson 2002). There are multiple agencies and laws that work
together to manage for wildlife species like the northern pintail. Management of Federal
Migratory Bird Hunting and Conservation Stamps commonly known as duck stamps are pictorial
stamps produced by the U.S. Fish and Wildlife Service. They serve as a hunting license and an
entrance pass into national wildlife refuges where admission is charged. Ninety-eight cents of
every dollar generated from the sale of Federal Duck Stamps goes directly to the purchase or
lease of wetland habitat for protection in the National Wildlife Refuge System. It has been called
one of the most successful conservation programs ever introduced and is a great way to conserve
America’s natural resources (Federal Duck Stamp Office 2013).
Managing to promote meadow and salt marshes, open grasslands and steppe habitats will
provide adequate forage and cover areas for northern pintail. Intertidal coastal wetlands and
floodplains favored by the species need to be protected from development and agricultural
modification (European Commission 2007-2009). Simple site-based management of hunting
disturbance can have a dramatic effect on local distribution and abundance. The EU management
plan addresses minimizing disturbance and effects of habitat loss, degradation and pollution to
insure protection measures are applied in a coordinated fashion throughout flyway areas.
Richkus also found that raptors were a primary cause of mortality for female pintails. Managing
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to provide nesting with overhead concealment or reducing perch sites for raptors may decrease
the risk of avian predation of pintails (Richkus 2005).
Changing climate can pose threats to waterfowl like northern pintail by altering
freshwater systems like wetlands and raises the salinity when there is less rainfall. Saline
wetlands are less useful for raising young water birds because they do not possess a developed
salt gland to excrete concentrated salt from the bloodstream (Hixon 2011). “Slightly more than
one-third (36%) of the 165 wetland breeding species in the U.S. show medium or high
vulnerability to climate change” (Wetlands). The prairie Pothole region contains millions of
shallow depression that fill with water in the spring and provide breeding habitat for millions of
ducks and migratory birds. As the climate warms, many ponds could dry up or be wet for shorter
periods (Global Warming and Waterfowl). Also if there is an increase in precipitation it will
decrease salinity and will decrease food availability for adult breeding birds. Northern pintail are
vulnerable to changes in water level because it can cause alterations to the distribution of
breeding habitats (Hixon 2011).
Challenges
Northern pintail face many challenges through their life history and some of these include
being threatened by wetland habitat loss on its breeding wintering grounds, petroleum pollution,
wetland drainage, changing wetland management practices, being hunted for sport, lead
poisoning from lead shot ingestion and many diseases including avian botulism and avian
influenza (Birdlife International 2013). Runge found that pintails are moving more northward
probably in result of change in habitat and has resulted in lower reproduction, decreased carrying
capacity and a decrease in sustainable harvest potential (Runge 2005). Clark et al. states that the
northern pintail population has remained below the North American Waterfowl Management
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Plan (NAWMP) goal of 5.6 million birds for the last decade. They have also failed to respond
positively to improved wetland conditions on Canadian Prairies. Uncertainty of relative influence
on land use changes, harvest and disease impacts, and breeding population redistribution on
overall population dynamics creates problems to try and manage for northern pintail (Clark et al.
2009). Another challenge is trying to protect a species globally. Northern pintails migrate all
over the U.S. and are common visitors to Central America, the Caribbean and northern Colombia
(Northern Pintail). So when trying to promote or manage for a species you may have to work
together with other countries or state agencies to establish law and regulations to benefit the
species.
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References
All About Birds. Northern Pintail. The Cornell Lab of Ornithology.
http://www.allaboutbirds.org/guide/northern_pintail/id. Accessed 20 Nov. 201.
"Anas Acuta: Northern Pintail." Facts about Northern Pintail (Anas Acuta). EOL:
Encyclopedia of Life. Web. 20 Nov 2013. <http://eol.org/pages/1048943/details>.
Austin, J.E. and Miller, M.R. (1995). Northern pintail (Anas acuta). In: Poole, A. (Ed.) The Birds
of North America Online. Cornell Lab of Ornithology, Ithaca.
http://bna.birds.cornell.edu/bna/species/163/articles/introduction.
Avian web. n.d. Northern pintail aka pintail. http://www.avianweb.com/pintailducks.html
Accessed 16 September 2013.
Bird Species and Distributions in Yukon-Charley Rivers National Preserve. Northern Pintail
(Anas acuta).
http://science.nature.nps.gov/im/units/cakn/relatedwebsites/YUCH_Bird_Inventory_Web
site/species_descriptions/nopi_description.htm. Accessed 21 Nov. 2013
European Commission. 2007-2009. Management plan for pintail (Anas acuta).
http://ec.europa.eu/environment/nature/conservation/wildbirds/hunting/docs/pintail.pdf.
September 18, 2013
Federal Duck Stamp Office. 2013. What are Duck Stamps? U.S. Fish & Wildlife Service.
http://www.fws.gov/DuckStamps/Info/Stamps/stampinfo.htm Accesses 18 Nov. 2013
Fredrickson, Leigh H., and Mickey E. Heitmeyer. 1991. Waterfowl Management Handbook.
U.S. Department of the Interior, Washington, D.C, USA.
Global Warming an Waterfowl. Impacts to Waterfowl by Flyway. National Wildlife Federation.
http://www.nwf.org/Wildlife/Threats-to-Wildlife/Global-Warming/Effects-on-Wildlife-andHabitat/Birds-and-Waterfowl.aspx. Accessed 19 Nov. 2013
Hixon, A. Mark, Gregory, V. Stanley, Robinson, W. Douglas. 2011. Ch. 7. Oregon's Fish and
Wildlife in a Changing Climate. Oregon, USA. http://occri.net/wpcontent/uploads/2011/04/chapter7ocar.pdf. Accessed 18 Nov. 2013
Howell, Doug, and Jim Wilson. "Tracking an Enigma." Wildlife in NC. n.d. 14-19. Print.
http://www.ncwildlife.org/portals/0/Learning/documents/WINC/Sample_08/sample_feb0
8a.pdf.
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Koehler, A.V., et al. 2008. Genetic evidence of intercontinental movement of avian influenza in
a migratory bird: the northern pintail (Anas acuta). Molecular Ecology 17: 4754-4762.
Nature Works/ Northern Pintail-Anas acuta.
http://www.nhptv.org/natureworks/northernpintail.htm. Accessed 21 Nov. 2013
"Northern Pintail." Northern Pintail Facts, Figures, Description and Photo. Ducks Unlimited.
Web.18 Sep 2013. http://www.ducks.org/ThePintail.
Northern Pintail. Ultimate WF 360 Waterfowling. Ducks Unlimited.
http://www.ducks.org/hunting/waterfowl-id/northern-pintail. Accessed 19 Nov. 2013.
Richkus, D. Kenneth, Rohwer, C. Frank, Chamberlain, J. Michael. 2005. Survival and CauseSpecific Mortality of Female Northern Pintails in Southern Saskatchewan. Journal of
Wildlife Management. 69(2):574-581. http://www.bioone.org/doi/abs/10.2193/0022541X(2005)069%5B0574%3ASACMOF%5D2.0.CO%3B2. Accessed 19 Nov. 2013.
Robinson, J. 2002. "Anas acuta" (On-line), Animal Diversity Web.
http://animaldiversity.ummz.umich.edu/accounts/Anas_acuta/. Accessed September 18,
2013.
Runge, C. Michael, Boomer, G. Scott. 2005. Population Dynamics and Harvest Management of
the Continental Northern Pintail Population.
http://www.fws.gov/migratorybirds/NewReportsPublications/AHM/Year2005/NOPI%2020
05%20Report%202.pdf. Accessed 21 Nov. 2013
Sakai, K., et al. 2007. Characterization of Newcastle disease virus isolated from northern pintail
(Anas acuta) in Japan. Journal of Veterinary Medical Science 69: 1307-1311.
Tesky, Julie L. 1993. Anas acuta. In: Fire Effects Information System. U.S. Department
ofAgriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences
Laboratory. http://www.fs.fed.us/database/feis/animals/bird/anac/all.html. Accessed 18
Sept. 2013
The Cornell Lab of Ornithology. All About Birds.
<http://www.allaboutbirds.org/guide/northern_pintail/lifehistory>. Accessed 16 Sept.
2013.
The Regents of the University of Michigan. 2013. Northern Pintail: anas acuta.
<http://www.biokids.umich.edu/critters/Anas_acuta/>. Accessed 16 Sept 2013.
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United States Geological Survey National Wildlife Health Center. 2013. Avian Botulism.
http://www.nwhc.usgs.gov/disease_information/avian_botulism/ Accessed 17 November
2013.
Wetlands. The State of the Birds. 2010 Report On Climate Change.
http://www.stateofthebirds.org/stateofthebirds2010/habitats/wetlands-1. Accessed 19
Nov. 2013.
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Eastern Cottontail
Sylvilagus floridanus
(Game Species)
Prepared by:
Mikayla Seamster
Erika Dinkler
Carley Leonard
Todd Carroll
15
Ecosystem associations
The eastern cottontail is found all over the eastern coast of the United States. It is found
completely statewide in North Carolina, and its range extends from New York and North Dakota
all the way south to Columbia and northern Venezuela. It spreads westward out to Nebraska, but
can be found in scattered areas of Oregon and Arizona (Mikita). Although native to the state it
was not as widespread prior to European settlement (Eastern Cottontail Rabbit).
Having such a large range across North America, eastern cottontails are suitable for many
diverse habitats. Eastern cottontails have been found in deserts, plains, hardwood forests,
farmlands, pastures, and hedgerows (IUCN). Individual eastern cottontails typically live in fairly
small home ranges of about 1.5 - 7 acres, and they rarely leave except during breeding seasons
(Trent and Rongstad, 1974).
Cottontails are generally considered pest animals in most rural areas. In the summer, they
can cause serious damage to crops and farmland. It can also transfer bacterial diseases like
tularemia if one is not careful. However, eastern cottontails are very popular game species and
bring in incredible amounts of money each year (EOL: Encyclopedia of Life).
Population Ecology
In general, eastern cottontail populations are on the rise, though not in all areas. For
example, the population in Virginia has actually decreased over the past 50 years, possibly due to
early successional habitats, like forest edges, being converted to farmland (IUCN).
Eastern cottontails are polygynous, meaning the male takes multiple mates, and have
litters of about five offspring roughly three or four times a year. Breeding typically takes place in
the spring and summer seasons, between February and September. Females and males both reach
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maturity after about two or three months, and they have lifespans of about three to five years
(Mikita).
In captivity, however, there have been cottontails that have lived over nine years. In the
Tulsa Zoo, one organism in particular lived to be 8.3 years old, and another was estimated to be
over 10 years old (EOL: Encyclopedia of Life).
When mating, male rabbits compete with other competitors and will perform a “dance”
with the chosen female. The male chase the female around, until she eventually stops and bats at
him with her front paws. The males then jumps straight into the air, and the female confirms it by
following suit (NatureWorks).
Food and Cover
The eastern cottontail is an herbivore and eats a variety of green leafy vegetable and
woody plants. During the spring, summer and autumn months their diet contains mostly native
and introduced grasses like orchard grass, timothy, redtop, bluegrasses, wheat grasses, Korean
lespedeza, common lawn grasses and Indian rice grass. Various fruits including wild
strawberries are eaten during these months as well. During the winter, eastern cottontails will eat
mostly woody plants like buds, blackberry bark, sumac, witch-hazel, oak, dogwood and willow
(Eastern Cottontail 1999).
The type of cover that eastern cottontails typically utilize consists of brushy areas, fields
or woods, small pine stands, shrubs, tangled vines, briers and tall grasses, all of which offer some
type of protection. Eastern cottontails are predated quite often so any area that offers good
hiding places is a good place for these rabbits to be. In cold weather, eastern cottontails will take
cover in old burrows made by other species, like woodchuck burrows (Fairfax County Pubic
Schools).
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Eastern cottontails have many natural predators. Red and gray foxes are two of the most
significant predators with diets composed of 50% eastern cottontail. Bobcats are also significant
predators and eastern cottontails make up 75% of their diet. Some other predators include:
coyotes, dogs, domestic cats, skunks, owls, hawks, snakes and even red squirrels have been
reported to hunt young cottontails (Eastern Cottontail (Sylvilagus floridanus) 2013).
The Eastern cottontail is known as “the protein pill of the Animal Kingdom” (Saunders
1988) and is a major part of the diets of many predators. One reason that these cottontails get
predated so often has to do with their reproductive behaviors. Females produce multiple litters
of 4-5 rabbits and their gestation period is approximately 28-30 days. The kits make short
excursions out of the nest at 16 days of age and disperse from the nest two weeks later. Usually
by the summer after their birth in the spring they are able to breed. Their generation periods are
so short and there are so many born into each generation that naturally they would get predated
more often (Eastern Cottontail (Sylvilagus floridanus) 2013).
Diseases
Studies have been conducted to learn more about ectoparasites, as well as endoparasites
in wild eastern cottontail rabbit populations in the southeastern United States. One study,
conducted between 1964 and 1978 collected 399 eastern cottontails in 11 different southeastern
states. The two most common types of arthropods found on these animals were ticks and fleas.
Ticks were found on the animals throughout most of the year, but were more prominent during
the late spring and the summer. Ticks can be vectors of other diseases including tularemia,
Rocky Mountain spotted fever, tick paralysis, and bovine anaplasmosis. Three individuals from
this study were infected with tularemia. Tick attachments sites can also cause abscesses and
lesions, which were documented on some individuals. Flea infestations were more common in
the winter and spring and lower in the summer. These flea infestations were highest in the spring
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and were shown to be directly related to the breeding pattern of eastern cottontail rabbits. Tick
and/or flea infestations can cause anemia and may result in the death of a weak individual
(Andrews, C.L. 1980). Another study was conducted from the fall of 1966 to the spring of 1967
which looked at the effects of endoparasites on wild eastern cottontail rabbit populations. During
this time, 260 eastern cottontail rabbits were collected from 8 different southeastern states.
Various endoparasites were found including stomach worms, gut nematodes and other
nematodes, and tapeworms. The study concluded that, for reasons unknown, eastern cottontail
rabbits who reside in the southeast are more likely to be infected with endoparasites then eastern
cottontail rabbits living in other regions of the United States (Andrews, C.L., and W.R.
Davidson. 1980).
An ectoparasite which is not deadly to eastern cottontail rabbits and other lagomorphs,
but is a problem for hunters, is “wolves”. “Wolves” are the larval stage of a bot fly that infects
eastern cottontail rabbits. A bot fly will lay its eggs on the fur of lagomorphs, the eggs will then
hatch and the larvae will bore into the skin of the rabbit. The larvae will remain under the skin
while they develop until they are about 1 ½ inches long. Once they reach this size, they will
burrow out of the rabbit’s skin and fall to the ground. They will then burrow into the ground
where they will remain through the pupal stage. Later, they will emerge as adult bot flies.
Infestations in the southeastern United States are greatest during May, June, August, September,
and October. “Wolves” are problematic for hunters because even though the larvae are in the
skin and do not affect the meat, most hunters will discard a rabbit with this ectoparasite (Virginia
Department of Game and Inland Fisheries).
A deadly disease that affects eastern cottontail rabbits is tularemia. Tularemia is a
bacterium, Francisella tularensis, which is spread to rabbits by a vector, such as fleas, ticks, or
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other biting insects. Tularemia can infect all different species of wildlife and has been found in
over 150 species. It is a can cause huge problems in population numbers because it can kill large
numbers of individuals in a population. It is often hard to detect tularemia in a population of any
wild species, because most of the time infected individuals are not found until they are dead or
dying. However, the disease has been detected earlier in eastern cottontail rabbits. Infected
eastern cottontail rabbits have been known to run slower which makes them easier to catch.
Other symptoms include odd behavior, muscle spasms, staggering, rubbing their noses and
forefeet into the ground, and acting as if they are tame. Necropsy shows the most typical signs of
white spots throughout the liver. Tularemia is considered a zoonotic disease because it can be
transmitted from wildlife to humans. Tularemia can be transmitted to humans via environmental
exposure including being bitten by an infected arthropod, handling infected live or dead animals,
consuming infected food or water, or via aerosols. Symptoms in humans include fever, chills,
joint and muscle pain, weakness, and swollen and painful lymph nodes. Sores will develop at the
site of the arthropod bite. If left untreated, it can be deadly to humans. There are about 200 cases
of human tularemia in the United States every year (Indiana Department of Natural Resources).
A news report from February 2013 says that two men in North Carolina were infected with
tularemia after rabbit hunting in the eastern part of the state (Lallanilla, Marc. 2013).
Rabies is a zoonotic virus that can infect any mammal. Eastern cottontail rabbits are not a
primary source of rabies in North Carolina; however it is possible for them to have the virus.
Raccoons, skunks, foxes, and bats account for the majority of rabies vector species in the United
States; and raccoons are the primary vector in North Carolina. Rabies affects the central nervous
system of mammals and symptoms can include the animal acting very aggressive, unusually
friendly, paralysis, stumbling or disorientation. Rabies is deadly in wildlife and can be deadly to
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humans if left untreated. If a human comes into contact with a rabid animal, vaccinations are
necessary to prevent the human from contracting the rabies virus (New York State Department of
Environmental Conservation. 2004).
Economics/management
Sullivan states that due to eastern cottontails relatively stable population they are a major
economic importance of prey to many top furbearer predators including bobcats, coyotes, foxes,
and red wolves. Based on a survey of hunters during a recent hunting season, it was estimated
that hunters harvested approximately 382,500 rabbits in North Carolina (Additional
Information). Eastern cottontails are also a prominent game species hunted for sport, meat, and
fur (Mikita 1999). Research shows that in 2006, the total economic effects of fish and wildliferelated recreation was estimated at $4.3 billion (Southwick Associates, Inc. 2008). So promoting
these species may increase wildlife recreation and hunting and provide economic benefits.
Habitat can be improved by promoting old fields and shrublands containing woody and
herbaceous plants will provide escape cover for eastern cottontails from hawks or owls (Teff).
Creation of artificial cover in the form of brush piles is beneficial to eastern cottontails. Fire
management will encourage herbaceous and shrub growth after timber harvest can also improve
cover (Sullivan 1995). Promoting vegetative cover including natural thickets such as lespedeza,
blackberry, honey suckle, and fallow areas will provide protection from predators (Yarrow
2009). Yarrow states that promoting transition zones between forest and agricultural fields will
also provide more food and cover. Providing travel lanes across or into fields accomplished by
leaving undisturbed strips to turn natural vegetation should be maintained by mowing, disking,
or burning on one side of each strip every two or three years in early spring will allow access to
different habitats (Yarrow 2009).
21
Climate change may have little effect on eastern cottontail’s economic value and
management due to their abundant range and rapid reproduction rate. However, if climate change
affects their microhabitats like decreasing forage materials due to excess drought , it may affect
their life histories (McKelvey et al. 2008). Contributors like habitat fragmentation may increase
a species vulnerability to climate change. For instance if eastern cottontail habitat is fragmented
and they are limited to a select area, they be unable to move to another area to escape from an
area climate change has made unsuitable (Lumpkin 2011).
Challenges
Although abundant, eastern cottontail is sensitive to change in habitat and this has caused
significant population declines in parts of its range (Eastern Cottontail (Sylvilagus floridanus)
1999). Some local populations of eastern cottontail may be negatively affected by changes in
land use and removal of hedges and fence rows as well as by the increasing use of herbicides to
kill many weeds that the species feeds on. Eastern cottontails are harmed or killed by mowing,
plowing, burning and often killed on roads (Eastern Cottontail (Sylvilagus floridanus)). Eastern
cottontails can do considerable damage to flowers, vegetables, trees, and shrubs any time of the
year and in places ranging from suburban yards to rural fields and tree plantations. So, vegetable
and flower gardeners, farmers, and homeowners who are suffering damage may have very little
to say in favor of eastern cottontails and usually want to eradicate them. (Craven 1994).
22
References
Additional Information. Ruffed Grouse. North Carolina Wildlife Resource Commission.
http://www.ncwildlife.org/Learning/Species/Birds/RuffedGrouse.aspx. Accessed 21 Nov.
2013.
Andrews, C.L. 1980. Ectoparasites collected from eastern cottontails in the southeastern United
States. Journal of Medical Entomology 17: 479-480.
Andrews, C.L., and W.R. Davidson. 1980. Endoparasites of selected populations of cottontail
rabbits (Sylvilagus floridanus) in the southeastern United States. Journal of Wildlife
Diseases 16: 395-401.
Craven, R. Scott. 1994. Cottontail Rabbits. Internet Center for Wildlife Damage Management.
http://icwdm.org/handbook/mammals/CottontailRabbits.asp. Accesses 18 Sept. 2013.
Eastern Cottontail Rabbit. Department of Natural Resources. Ohio.gov.
http://www.dnr.state.oh.us/Home/species_a_to_z/SpeciesGuideIndex/easterncottontailra
bbit/tabid/6606/Default.aspx. Accessed 21 Nov. 2013
Eastern cottontail (Sylvilagus floridanus). ARKive. Eastern cottontail threats.
http://www.arkive.org/eastern-cottontail/sylvilagus-floridanus/. Accessed 18 Nov. 2013.
Eastern Cottontail (Sylvilagus floridanus). 1999. No.4 Fish and Wildlife Habitat Management
Leaflet. http://www.tn.gov/twra/pdfs/cottontail.pdf. Accessed 20 Nov. 2013.
"Eastern Cottontail - Sylvilagus floridanus." NatureWorks. New Hampshire Public
Television, n.d. Web. 20 Nov 2013.
http://www.nhptv.org/natureworks/easterncottontail.htm.
Eastern Cottontail. United States Department of Agriculture. 1999. Washington D.C.,USA.
Saunders, D.A. 1988. Eastern Cottontail floridanus Allen. Adirondack Ecological Center.
1-266.
Fairfax County Public Schools. Eastern Cottontail Sylvilagus floridanus.
http://www.fcps.edu/islandcreekes/ecology/eastern_cottontail.htm.
Indiana Department of Natural Resources. n.d. Fact sheet: Tularemia in cottontails.
23
http://www.in.gov/dnr/fishwild/files/fw-Tularemia_fact_sheet.pdf. Accessed on 17
November 2013.
Lallanilla, Marc. 2013. Rabbit fever strikes two N.C. hunters.
http://www.nbcnews.com/health/rabbit-fever-strikes-two-n-c-hunters-1C8539089.
Accessed 17 November 2013.
Lumpkin, Susan, Seidensticker, John. Rabbits: The Animal Answer. 2011. Book.
http://books.google.com/books?id=V6Lb3fVKg3oC&pg=PA176&lpg=PA176&dq=global+
warming+effects+on+eastern+cottontails&source=bl&ots=QvS3aYbDFX&sig=m2eQoaM
kk3xBUKfCbCe9DTnjQ8g&hl=en&sa=X&ei=triNUvnEJaavsASMyIHoAQ&ved=0CDgQ6
AEwAg#v=onepage&q=global%20warming%20effects%20on%20eastern%20cottontails
&f=false. Accessed 19 Nov. 2013.
McKelvey, S. Kevin, Perry, W. Rodger, Mills, Scott. 2008. The effects of Climate Change on
Mammals. Climate Change Resource Center. USDA-Forest Service.
http://www.fs.fed.us/ccrc/topics/wildlife/mammals/. Accessed 19 Nov. 2013.
Mexican Association for Conservation and Study of Lagomorphs (AMCELA), Romero Malpica,
F.J. & Rangel Cordero, H. 2008. Sylvilagus floridanus. In: IUCN 2013. IUCN Red List
of Threatened Species. Version 2013.1. www.iucnredlist.org. Downloaded on 18
September 2013.
Mikita, K. 1999. "Sylvilagus floridanus" (On-line), Animal Diversity Web.
http://animaldiversity.ummz.umich.edu/accounts/Sylvilagus_floridanus/. Accessed on 18
Sept. 2013.
New York State Department of Environmental Conservation. 2004. Ch 4: Section 4: What you
need to know about wildlife diseases. http://nwco.net/044-wildlifediseases/4-1-2symptoms.asp. Accessed on 17 November 2013.
Southwick Associates, Inc. 2008. The 2006 Economic Benefits of Hunting, Fishing and Wildlife
Watching in North Carolina.
http://www.ncwildlife.org/portals/0/Hunting/Documents/2006NCEconomicImpacts.pdf.
Accessed on 18 Nov. 2013.
Sullivan, Janet. 1995. Sylvilagus floridanus. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
http://www.fs.fed.us/database/feis/animals/mammal/syfl/all.html. Accessed 18 Sept.
2013.
24
“Sylvilagus floridanus: Eastern Cottontail.” Facts about Eastern Cottontail (Sylvilagus
floridanus). EOL: Encyclopedia of Life. Web. 20 Nov 2013.
< http://eol.org/pages/976910/details#benefits >.
Teff, C. Brian. Chapter 4. Managing Shrublands and Old Fields.
http://www.state.nj.us/dep/fgw/pdf/mgtguide/ch04_managing_shrublands.pdf. Accessed
21 Nov. 2013.
Trent, Tracey T.; Rongstad, Orrin J (1974). "Home range and survival of cottontail rabbits in
southwestern Wisconsin". Journal of Wildlife Management 38 (3): 459–472.
doi:10.2307/3800877. JSTOR 3800877.
Virginia Department of Game and Inland Fisheries. n.d. Eastern Cottontail (Sylvilagus
floridanus). http://www.dgif.virginia.gov/wildlife/rabbit/eastern-cottontail.asp. Accessed
17 September 2013.
Yarrow, Greg. 2009. Cottontail Rabbit Biology and Management. Extension Forestry & Natural
Resources. Clemson Cooperative Extension.
http://www.clemson.edu/extension/natural_resources/wildlife/publications/fs8_cottontail
%20rabbit.html. Accessed 18 Sep. 2013
25
Rafinesque’s big-eared bat
Corynorhinus rafinesquii
(Endangered Species)
Prepared by:
Mikayla Seamster
Erika Dinkler
Carley Leonard
Todd Carroll
26
Ecosystem associations
Rafinesque’s big-eared bat is most commonly found in the southeast United States. Its
full range extends from Florida up north to Indiana, and as west as Texas and Louisiana. In
North Carolina, they are found almost statewide (Arroyo-Cabrales & Ticul Alvarez Castaneda).
Like most other bats, they live primarily in caves openings and hollow trees in temperate forests.
They are also native in urban environments, having been found in abandoned buildings and
under large bridges (“Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii)”).
In an example of top-down food web management, Rafinesque’s big-eared bats also have
a major role in controlling insect populations in their area. They feed on insects that are typically
harmful to human crops and other pests like mosquitoes (Reyes, 2002).
Population Ecology
Not much is understood about the reproduction process of Rafinesque’s big-eared bats.
From what scientists have gathered, the bats mate in the fall, but the average length of gestation
is unknown. However, they typically give birth in the summer, so its expected to be roughly ten
months. The typical litter size is only one offspring that reaches independence after about three
weeks and live for around ten years in the wild (“Rafinesque’s Big-eared Bat (Corynorhinus
rafinesquii)”).
The proper conservation status of Rafinesque’s big-eared bat is currently being debated.
According to the U.S. Federal List, the bats are considered “Threatened,” but the IUCN Red List,
the leading authority on animal conservation and threatened species, labels the bat of “Least
Concern” (Arroyo-Cabrales &Ticul Alvarez Castaneda). Though the species isn’t exactly
considered endangered, the population has never been recorded as above 10,000 individuals. No
statistics have been gathered over the entire range, but some states (Georgia, West Virginia,
South Carolina, and Tennessee) have reported decline. Alabama, Arkansas, Illinois, and North
27
Carolina also suspect decline, whereas Indiana and Ohio go so far as to suspect extirpation of the
species in their states (“Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii)”).
Food and Cover
The Rafinesque’s big-eared bat is an insectivore that eats mostly moths but also will eat
mosquitoes, beetles and flies (Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii)).). These
bats use their large ears and echolocation to find their prey. They listen for the echoes of the
high-frequency sound waves they emit that bounce off the insects to distinguish what size, shape
and distance away they are (Texas Parks and Wildlife).
The stereotype of bats taking cover in caves is true for the Rafinesque’s big-eared bat, but
they also roost in other dark, hidden places such as buildings, old mine shafts, wells, hollow
trees, areas behind loose bark, and crevices in rock ledges. This bat uses complete darkness as
cover while it hunts at night time and uses a mild form of torpor during the winter to conserve
energy. Females maintain separate roosts in the spring and summer to protect their young
(Georgia Museum of Natural History 2008).
The main predators of the Rafinesque’s big-eared bat include snakes, raccoons, opossums
and cats (Texas Parks and Wildlife). One of their strategies to reduce predation has to do with
their color. They have adapted to have a cryptic coloration so they can blend in with their
environmental and remain undetected. However, their coloration does not always help them
against predators. When they torpor during the water, they are most susceptible to predation
because it takes them several minutes to wake up and they are unable to make a quick getaway
(Regents of the University of Michigan 2012).
28
Diseases
White-nosed syndrome is the most prominent disease affecting bats in the northeastern
United States at this time. It was first detected in February of 2006 in a cave in Albany, New
York. Since then millions of insectivorous, hibernating bats in 22 different states in the
northeastern and southeastern United States, including North Carolina, as well as in five
provinces in Canada have been affected by the disease. The fungus that causes the disease is
Geomyces destructans. This is a white fungus causes powdery conidia and hyphae on the skin of
the muzzle, ears, and wings of bats. It can affect many different species of bats and populations
have declined approximately 80% since the first discovery of the disease. Bat populations that
have been affected by White-nosed syndrome will not increase quickly because most of the
species only have one pup per year. White-nosed syndrome has not been found in Rafinesque’s
big-eared bat, however, this is a hibernating species found in the colder climates of North
Carolina, so it could be at risk of disease (United States Geological Survey National Wildlife
Health Center 2013).
Biologists continue to research White-nosed syndrome to learn more about how it affects
bats, how it is spread, and if there are any treatment options to help the declining bat populations.
One thing that biologists have found is that the disease causes bats to come out of torpor too
soon. White-nosed syndrome causes loss of body fat, so it could be that bats become hungry
during the winter and come out of torpor in order to find food. Bats that come out of torpor too
soon fly to their deaths when the leave the cave. Other symptoms of the disease include scarring
and damage to their wings, which can impede flight, and death. White-nosed syndrome occurs in
Europe, but the bats there are immune to the disease. A controversial theory among biologists
concludes that White-nosed syndrome was introduced to the United States by European
29
vacationers visiting U.S. caves. The exact path of disease transmission is not known, but bat-tobat transmission is the most likely cause (United States Geological Survey Fort Collins Science
Center. 2012).
Winter torpor is a type of hibernation that bat species, including Rafinesque’s big-eared
bat, use to survive the winter in the cold climates where they are found. Some species, like
Rafinesque’s big-eared bat, use a shallow type of torpor and wake up on some nights to forage
for food. A study was done to learn more about this behavior in Rafinesque’s big-eared bat. They
put temperature-sensitive radio-transmitters on 24 individuals and put PIT-tags on 128
individuals. Their movements were measured during the winter months between 2010 and 2012.
The study found that Rafinesque’s big-eared bats only stay in torpor for short periods of time and
they are relatively active during the winter, unlike most bats in North America who hibernate.
The data showed that the bats switched roosts fairly regularly during the winter torpor. The
conclusion of the study shows that Rafinesque’s big-eared bats may be less susceptible to Whitenosed syndrome because they are active during the winter (Johnson, J.S., et al. 2012).
Economics/management
Rafinesque’s big-eared bats provide economic benefits by helping to control insect
populations and feed on insects that can be harmful to agriculture (Reyes 2002).Cavity-roosting
species generally require patches of forests containing old timber, but these habitats have been
declining in southeastern United States (Trousdale 2005). Promoting silviculture that retains
snags and reduces clutter between stands will promote habitats for Rafinesque’s big-eared bats
(Lack et al. 2007). Overall reproduction cutting methods of between aged and even-aged
methods have implication for bats especially with regard to roosting and management of
foraging habitats (Lack et al. 2007). Protection of large hollow trees in lowland areas, especially
30
near water is essential to preserve this species. Artificial roosts may provide crucial alternatives
in areas where hollow trees and abandoned buildings have been removed (Rafinesque).
Trousdale captured and radio tagged 25 bats and they only lead to 14 trees and most of
these were alive and relatively large with a mean DBH of 79.4 cm and mean height of 18.5 m.
Tree roosts were also rare in the area and Rafinesque’s showed roost fidelity to particular areas
of forest. Rafinesque's big-eared bats are also known to switch roosts every 2.1 days and alters
fidelity by roost type (Trousdale 2008). Therefore, management of dead trees but also patches of
large trees would benefit this species where there is low amount of old timber in forests and
would allow them to switch roosts when needed. Promoting the quality young pine stands is also
essential. Mezel found that big-eared bats home range size was 93.1 ha even though there were
large areas of bottomland hardwoods, foraging actively occurred in young pine stands and only
9% of forage occurred in bottomland hardwoods.
Evidence of climate change is prevalent. Flowers are blooming earlier, lakes are freezing
later and animals are altering their migratory patterns. These effects can change closely linked
associations such as timing of hatching insects with the arrival of migratory predators and alters
vegetation that species have evolved to depend on (Climate Change 2007). Bats are very
sensitive to temperature due to their small size and large surface area. They choose roosting and
hibernating sites within a very narrow range of temperature, wind, speed, and humidity and with
climate change altering these conditions it can affect reproduction condition and seasonal needs
(Hellmann et al. 2009).
Challenges
Rafinesque’s big-eared bats face many challenges some of them being habitat loss by
clearing of swampland forest, hollow tree removal during certain forest management practices,
31
and decreasing numbers of abandoned buildings to create roosts. Insecticide applications and
commercial logging also have damaging effects on populations. Bats are very intolerant of
disturbances either natural or human and will abandon roost or hibernation site if disturbance
occurs (Arroyo-Cabrales 2008). Challenges also arise to the rapid spread of diseases including
the famous fungal disease, White-nose syndrome.
32
References
Arroyo-Cabrales, J. & Ticul Alvarez Castaneda, S. 2008. Corynorhinus rafinesquii. In: IUCN
2013. IUCN Red List of Threatened Species. Version 2013.1.
http://www.iucnredlist.org/details/17600/0 . Downloaded on 19 September 2013.
Climate Change. 2007. Trinity River National Wildlife Refuge. U.S. Fish & Wildlife Service.
http://www.fws.gov/refuge/Trinity_River/what_we_do/climate_change.html. Accessed
19 Nov. 2013.
Georgia Museum of Natural History. 2008. Rafinesque’s Big-eared Bat Corynorhinus
rafinesquii.
http://naturalhistory.uga.edu/~GMNH/gawildlife/index.php?page=speciespages/species_
page&key=prafinesquii. Accessed 18 Sep 2013.
Lack J. Michael, Haynes, P. John, Kurta, Allen. 2007. Bats in Forests. Conservation and Management.
Online Book. Pg. 177-237.
http://books.google.com/books?hl=en&lr=&id=TOwkWu0eV4oC&oi=fnd&pg=PR9&dq=Bats+i
n+Forests.+Conservation+and+Management&ots=RAZQ1l6nap&sig=nHwZUvidbyfiJXjc6FMUB1L2pE#v=onepage&q=Bats%20in%20Forests.%20Conservation%20and%20Mana
gement&f=false. September 18, 2013
Menzel, A. Michael, Menzel, M. Jennifer, Ford, W. Mark, Edwards, W. John, Carter, C.
Timothy, Churchill, B. John, and John C. Kilgo. 2001. Home Range and Habitat Use of
Male Rafinesque’s Big-eared Bats (Corynorhinus rafinesquii). The American Midland
Naturalist. 145(3):402-408. http://www.bioone.org/doi/abs/10.1674/00030031(2001)145%5B0402:HRAHUO%5D2.0.CO%3B2. Accessed 19 Nov. 2013
Hellmann, J.J., et al., 2010. Climate change impacts on terrestrial ecosystems in metropolitan
Chicago and its surrounding, multi-state region. Journal of Great Lakes Research.
http://changingclimate.osu.edu/assets/pubs/sm-chicago-2010.pdf. Accessed 19 Nov.
2013.
Johnson, J.S., et al. 2012. Frequent arousals from winter torpor in Rafinesque’s big-eared bat
(Corynorhinus rafinesquii). PLoS One 7(11).
Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii). Texas Parks and Wildlife Department,
Austin, Texas, USA. http://www.tpwd.state.tx.us/huntwild/wild/species/rafinesque/.
Accessed 19 Nov. 2013.
33
Regents of the University of Michigan. 2012. Corynorhinus rafinesquii Rafinesque’s big-eared
bat. < http://animaldiversity.ummz.umich.edu/accounts/Corynorhinus_rafinesquii/>.
Accessed 18 Sep 2013.
Reyes, E. 2002. "Corynorhinus rafinesquii" (On-line), Animal Diversity Web.
http://animaldiversity.ummz.umich.edu/accounts/Corynorhinus_rafinesquii/. Accessed
September 18, 2013 at
Texas Parks and Wildlife. Rafinesque’s Big-eared Bat Plecotus rafinesquii.
<http://www.texasthestateofwater.org/screening/pdf_docs/fact_sheets/rafinesques_bigeared_bat.pdf>. Accessed 18 Sep 2013.
Trousdale, W. Austin, Beckett, C. David, Hammond, L. Shea. 2008. Short-Term Roost Fidelity
of Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii) Varies With Habitat. Journal of
Mammology, 89(2):477-484. http://www.jstor.org/stable/25145117. Accessed 19 Nov.
2013.
Trousdale, W. Austin, Beckett, C. David. 2005. Characteristics of Tree Roosts of
Rafinesque'sbig-eared Bat (Corynorhinus rafinesquii) in Southeastern Mississippi. The
American midland Naturalist. 154(2):442-449. Published by: University of Notre Dame.
http://www.bioone.org/doi/abs/10.1674/00030031(2005)154%5B0442:COTROR%5D2.0.CO;2. Accessed 19 Nov. 2013.
United States Geological Survey Fort Collins Science Center. 2012. White-Nose Syndrome
Threatens the Survival of Hibernating Bats in North America.
http://www.fort.usgs.gov/wns/. Accessed 18 September 2013.
United States Geological Survey National Wildlife Health Center. 2013. White-nosed syndrome
(WNS). http://www.nwhc.usgs.gov/disease_information/white-nose_syndrome/.
Accessed on 17 November 2013.
34
Red-tailed Hawk
Buteo jamaicensis
(Nongame Species)
Prepared by:
Mikayla Seamster
Erika Dinkler
Carley Leonard
Todd Carroll
35
Ecosystem associations
Red-tailed hawks span almost the entire continent of North America and can typically be
found anywhere in the mainland United States. Their range extends from deep south in Mexico
to the southeastern corner of Alaska. Breeding typically occurs in the north, in central Canada,
though their residential area consists of most of the United States and central Mexico. Red-tailed
hawks can be occasionally found in southern Mexico, but this range is not considered to be for
breeding and is possibly used as a migration destination during the winter (Ridgely et al.).
Much like the eastern cottontail which was described above, red-tailed hawks are suitable
for a variety of habitats, given its wide range. They are typically found in deserts, scrublands,
grasslands, and prairies. They can be found in both temperate and deciduous forests, and can
often be found in urban parks (Ridgely et al.)
Red-tailed hawks are known for their high standing in their food webs, and they are
considered to be very important predators. They maintain the populations of rodents and other
small mammals, though they tend to be antagonistic with other bird species. Red-tailed hawks
can commonly be seen being swarmed by smaller birds, and its not uncommon for a red-tailed
hawk to steal for from other raptors or even have its own food stolen (Ridgely et al.).
Population Ecology
Red-tailed hawks usually mate and lay eggs in the spring. Hawks are monogamous,
meaning they mate with only one other individual, and they lay about 3 eggs per season. The
eggs hatch in about 28 - 35 days. After that, the fledging process requires about another 44 days,
and the offspring will become independent after about ten weeks. Both females and males
become sexually mature at around three years of age, and they live together during a lifespan of
about 30 years (Arnold, 2002).
36
Food and Cover
Red-tailed hawks, like many other hawks and other raptors, eat mainly small mammals
such as voles, mice, rats, rabbits, snowshoe hares, jackrabbits and ground squirrels. They often
eat other birds as well including pheasants, bobwhites, starlings and blackbirds. Snakes and
carrion are also included in the diet. The prey of a red-tailed hawk typically weighs anywhere
from less than an ounce to more than 5 pounds (The Cornell Lab of Ornithology).
Red-tailed hawks prefer tall trees as their form of cover. Tall trees offer protection from
predators, a sturdy base for a nest, and a good vantage point for hunting and seeking food. They
are not species specific when it comes to trees and will sometimes use other means of cover if
tall trees are not present. Red-tailed hawks have been spotted using cacti and utility poles
instead (Standiford and Tinnin 2013).
Although red-tailed hawks are predators themselves, there are still some species of
animals out that that hunt this species for food. The known predators of red-tailed hawks include
raccoon, great horned owl and red fox. Corvids have been known to hunt eggs and nestlings
(Regents of the University of Michigan 2012). During the early 20th century, red-tailed hawks
were hunted by humans because they were perceived as a predator of livestock. The shooting
declined in the mid 20th century but these hawks are still suffering illegal persecution in the
mixed-woodland plains of far eastern Canada (Wildscreen 2013).
Red-tailed hawks are very numerous and their populations have been increasing steadily
as they have expanded their range after the mid 20th century (Wildscreen 2013). They are not
terribly prone to predation but it does still happen every once in a while. During nesting, redtailed hawk pairs are very territorial and act aggressively towards predators or other animals near
their nest to avoid predation. The females are more aggressive around the nest while the males
37
are more territorial about boundaries and often scan the perimeter searching for intruders. Most
of the predation of these birds occurs to eggs and nestlings (Regents of the University of
Michigan).
Diseases
Red-tailed hawks, along with all raptors and other birds can have ticks, feather lice, and
feather mites. However, the most significant disease issues with red-tailed hawks and other
raptors are the diseases that they can get from eating prey that are vectors or carriers of certain
diseases. Red-tailed hawks can contract Salmonellosis, Trichomoniasis, and Aspergillosis from
their prey (Mass Audubon). Salmonellosis is a bacterium that is found in the intestines of
infected raptors. “A recent Spanish study found that 13/310 (4.19%) wild, free living raptors
were positive for Salmonella” (Tizard, Ian). A study done in North America found only two fecal
samples out of 105 were positive for Salmonella, and both of these samples were from red-tailed
hawks. (Tizard, Ian). Trichomoniasis infects raptors when they eat infected doves or pigeons.
This disease is caused by a protozoan and causes a necrotic mass to grow in the esophagus; this
mass will eventually cause death because it blocks the esophagus. Necropsies on raptors infected
with Trichomoniasis reveal that liver and abdominal lesions are present (Michigan Department
of Natural Resources. 2013). Aspergillosis is more common in captive raptors than in wild
populations, but red-tailed hawks are one of the three species that is most susceptible. This
disease is caused by a fungus that infects humans, mammals, and birds. Being exposed to spores
and immunodeficiency can cause a raptor to become infected with the disease. Aspergillosis
affects the respiratory system and can cause symptoms such as depression, anorexia, diarrhea,
and open beak breathing. Treatments can be effective in some cases as long as the disease is
38
recognized early in the individual; individuals in advance stages of the disease will not survive
(Abundis-Santamaria, Edgar).
A study was conducted in Kansas to determine the effects on red-tailed hawks of voles
affected with Frenkelia microti tissue cysts. These tissue cysts form in the brains of voles and the
voles are a large part of the red-tailed hawk diet. The study looked at various rodents in the diet
of red-tailed hawks to see the impact of the voles. This study was the first to conclude that redtailed hawks serve as a host for Frankelia microti. Frankelia microti is a species of parasitic
protozoa that will infect the gastrointestinal tract of raptors and tissues in rodents. Rodents are
the intermediate host for the parasite because the parasite will decyst within the stomach of the
rodent and then move to the liver. The rodent is then eaten by a raptor and the cysts release
spores into the raptor, thus, infecting the raptor (McKown and Upton, 1992).
Another study was conducted on 13 red-tailed hawk carcasses and 11 Cooper’s hawk
carcasses to determine which ones tested positive for West Nile virus (WNV). “In red-tailed
hawks, the kidney (38%), cerebrum (38%), cerebellum (38%), and eye (36%) were the organs
most commonly containing WNV antigen” (Wunschmann, 2004). The study concluded that
West Nile virus can be fatal for both red-tailed hawks and Cooper’s hawks. West Nile virus
causes inflammation of the brain and spinal cord, which in many cases is fatal; this virus can
infect humans, birds, and horses. The virus was first detected in the United States in 1999,
however it had been in Africa since 1937. There was a pandemic in the United States in 2002
when WNV spread throughout the U.S. sickening and killing numerous raptors, birds, humans,
and horses. WNV is spread by mosquitos, but birds serve as a host. Signs of WNV in raptors can
be broken down into three different phases. Phase one includes the raptor showing signs of
depression, anorexia, weight loss, sleeping, pinched off blood feathers, and an elevated white
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blood count. Phase two includes the above signs along with head tremors, liver necrosis,
blindness or lack of awareness, clumsiness, weakness, aggression, high fever, paralysis,
excessive sleeping, and detached retinas. The third and final phase includes all of the above signs
as well as more severe tremors, seizures, and finally death. There is no treatment for this virus,
however, raptors in phase one and two will likely respond to supportive care, which includes
giving the bird fluids, proper nutrition, and a warm place to recover, and will not proceed to
phase three. After a raptor has had WNV and recovered from it, they may be free of the virus, or
they may be asymptomatic carriers of the virus. The vaccine that was created for horses has been
used in some captive raptor situations without negative side effects, so that is a possibility to
keep WNV from affecting captive raptors; this vaccine would obviously not be possible in
protecting wild raptors from contracting West Nile Virus (Shimmel, Louise. 2013).
Economics/management
Since red-tailed hawks are great at pest control (Arnold 2002), managing them will be
beneficial to many farmers by allowing crops to prosper and keeping small mammal populations
under control. Increasing habitat of patchy woodland and open areas will increase red-tailed
hawk habitat (Arnold 2002). Tesky states that managing stands with 500 to 100,000 over story
trees per acre with not more than 40% of trees 20 cm is recommended for red-tailed hawks.
Snags and unusable trees for timber harvests should be retained as perch sites during
management based silviculture. Clearcutting may be beneficial by providing foraging habitat but
is often detrimental to nesting sites if done before or during the breeding season which occurs
from March to May. Prescribed fire can be beneficial to enhance habitat by creating snags and
also by increasing the prey base (Tesky 1994). Since red-tailed hawks usually nest in tall trees in
or at forest edges, promoting edges in woodland areas will be beneficial.
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Climate change effects on red-tailed hawks is largely unknown. Survival and productivity
may be affected by shifts in preferred prey abundance, distribution across ranges, and migration
patterns (Battistone 2012). Climate change is expected to create drier conditions in the
southeastern plains and more moisture in the northeastern plains. Changes in moisture and
temperatures may cause disruptions in insect populations (Migratory Birds 2013). This could
cause a trophic cascade since some small animals feed on insects, a decrease or alteration in
insects may affect small mammal population therefore altering the availability of the small
mammal prey to red-tailed hawks.
Challenges
The greatest threats to red-tailed hawks include gun shots, collision with automobiles,
human interference with nesting activities and lead poisoning (Arnold 2002). They also suffer
threats from pesticide contamination, diseases, parasites, and predation especially by great
horned owls (Battistone 2012). Red-tailed hawks have surprisingly increased in population over
most of their range due to habitat fragmentation of forests into small woodlots and increased
forest edge (Tesky 1994). Since red-tailed hawks are a predatory species on small mammals they
pose a threat to small pets such as puppies or rabbits in urban areas which may cause rouse in
affected owners. Red-tailed hawks pose a serious threat to aviation and are rated the 10th biggest
threat to air crafts out of 25. “From 1990-2003, red-tailed hawks were responsible for 24.5% of
reported raptor strikes to civil aircrafts and together with vultures represented a loss of
approximately $7 million to the United States aviation (Red-tailed hawk 2013). These damaging
results lead to increased want to manage against red-tailed hawk populations but lukily they are
protected under the Migratory Bird Treaty Act and therefore, can only be hunted with a special
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permit issued through the United States Department of Agriculture and United States Fish and
Wildlife Service (Red-tailed hawk 2013).
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