BIRDS: Hawks and Owls
Fig. 1. Raptors,
representative of those that may cause damage by preying
on poultry and other birds, pets, and other animals: (a)
the goshawk (Accipiter gentilis), (b) red-tailed
hawk (Buteo jamaicensis), and (c) great horned
owl (Bubo virginianus).
Hawks and owls are birds
of prey and are frequently referred to as raptors— a
term that includes the falcons, eagles, vultures, kites,
ospreys, northern harriers, and crested caracaras. Food
habits vary greatly among the raptors. Hawks and owls
are highly specialized predators that take their place
at the top of the food chain. Some are responsible for
the loss of poultry or small game. In the past, raptors
were persecuted through indiscriminate shooting,
poisoning, and pole trapping. The derogatory term
chicken hawk was used generically to identify raptors,
especially hawks, but has fallen out of usage during the
past two decades. Recently, many people have developed a
more enlightened attitude toward raptors and their place
in the environment.
People who experience
raptor damage problems should immediately seek
information and/or assistance. “Frustration killings”
occur far too often because landowners are unfamiliar
with or unable to control damage with nonlethal control
techniques. These killings result in the needless loss
of raptors, and they may lead to undesirable legal
actions. If trapping or shooting is necessary, permits
should be requested and processed as quickly as
possible. Always consider the benefits that raptors
provide before removing them from an area; their
ecological importance, aesthetic value, and
contributions as indicators of environmental health may
outweigh the economic damage they cause.
Identification and General Biology
There are two main groups
of hawks: accipiters and buteos. Accipiters are the
forest-dwelling hawks. North American species include
the northern goshawk (Accipiter gentilis), Cooper’s hawk
(Accipiter cooperii), and sharp-shinned hawk (Accipiter
striatus). They are characterized by distinctive flight
silhouettes—relatively short, rounded wings and a long
rudderlike tail. Their flight pattern consists of
several rapid wing beats, then a short period of gliding
flight, followed by more rapid wing beats. Accipiters
are rarely seen except during migration because they
inhabit forested areas and are more secretive than many
of the buteos.
The largest and least
common, but most troublesome, accipiter is the goshawk
(Fig. 1). It is a bold predator that feeds primarily on
forest-dwelling rodents, rabbits, and birds.
Occasionally, it is attracted by free-ranging poultry or
large concentrations of game birds and can cause
depredation problems. Its breeding range is limited to
Canada, the northern United States, and the montane
forests of the western United States. Spectacular autumn
invasions of goshawks occur at irregular intervals in
the northern states. These are probably the result of
widespread declines in prey populations throughout the
goshawk’s breeding range. Cooper’s hawks will
occasionally cause problems with poultry; sharp-shinned
hawks are rarely a problem because of their small size.
The buteos are known as
the broad-winged or soaring hawks. They are the most
commonly observed raptors in North America. Typical
species include the red-tailed hawk (Buteo jamaicensis),
red-shouldered hawk (Buteo lineatus), broad-winged hawk
(Buteo platypterus), Swainson’s hawk (Buteo swainsoni),
rough-legged hawk (Buteo lagopus), and ferruginous hawk
(Buteo regalis). All buteos have long, broad wings and
relatively short, fanlike tails. These features enable
them to soar over open country during their daily
travels and seasonal migrations.
The red-tailed hawk (Fig.
1) is one of our most common and widely distributed
raptors. Redtails can be found over the entire North
American continent south of the treeless tundra and in
much of Central America. They demonstrate a remarkably
wide ecological tolerance for nesting and hunting sites
throughout their extensive range. Typical eastern
redtails nest in mature forests and woodlots, while in
the Southwest they often nest on cliffs or in trees and
cacti. Their diet, although extremely varied, usually
contains large numbers of rodents and other small
mammals. Redtails occasionally take poultry and other
livestock, but the benefits they provide in aesthetics,
as well as in the killing of rodents may outweigh
depredation costs. Other species of buteos rarely cause
Owls, unlike hawks, are
almost entirely nocturnal. Thus, they are far more
difficult to observe, and much less is known about them.
They have large heads and large, forward-facing eyes.
Their flight is described as noiseless and mothlike.
There are 19 species of owls in the continental United
States. They range in size from the tiny, 5- to 6-inch
(12-to 15-cm) elf owl (Micrathene whitneyi) that resides
in the arid Southwest, to the large, 24- to 33inch
(60-to 84-cm) great gray owl (Strix nebulosa) that
inhabits the dense boreal forests of Alaska, Canada, and
the northern United States.
The great horned owl (Bubo
virginianus, Fig. 1) is probably the most widely
distributed raptor in North America. Its range extends
over almost all the continent except for the extreme
northern regions of the Arctic. These large and powerful
birds are considered to be the nocturnal complement of
the red-tailed hawk. Great horned owls generally prey on
small-to medium-sized birds and mammals and will take
poultry and other livestock when the opportunity
presents itself. They are responsible for most raptor
Damage and Damage Identification
The most troublesome
raptors are the larger, more aggressive species, such as
the goshawk, red-tailed hawk, and great horned owl. The
majority of depredation problems occur with free-ranging
farmyard poultry and game farm fowl. Chickens, turkeys,
ducks, geese, and pigeons are vulnerable because they
are very conspicuous, unwary, and usually concentrated
in areas that lack escape cover. Confined fowl that are
chased by raptors will often pile up in a corner,
resulting in the suffocation of some birds. Reproduction
may also be impaired in some fowl if harassment
For years, game farms have
dealt with raptor depredation problems. Large
concentrations of game farm animals are strong
attractants to predators. Operators should consider the
prevention of predation as part of their cost of
operation. Other depredation problems include the loss
of rabbits at beagle clubs, the loss of homing and
racing pigeons, and occasionally the loss of farm or
household pets. Cooper’s and sharp-shinned hawks
occasionally prey on songbirds that are attracted to
feeding stations. This should be viewed as a natural
event, however, and control of the raptors is not
There are occasions when
raptors cause human safety and health hazards. For
example, concentrations of raptors at airports increase
the risk of bird-aircraft collisions and loss of human
life. The vast majority of aircraft strikes involve
gulls, starlings, and blackbirds, but a few raptor
strikes have been documented. It is interesting to note
that falconers with trained hawks have been used to
clear airport runways of other birds so that airplanes
can land. Although raptors are usually secretive and
choose to avoid human contact, they occasionally nest or
roost in close association with humans. At such times,
noise, property damage, and aggressive behavior at nest
sites can cause problems.
Poultry and other
livestock are vulnerable to a wide range of predators.
Frequent sightings of hawks and owls near the
depredation site may be a clue to the predator involved,
but these sightings could be misleading. When a
partially eaten carcass is found, it is often difficult
to determine the cause of death. In all cases, the
remains must be carefully examined. Raptors usually kill
only one bird per day. Raptor kills usually have bloody
puncture wounds in the back and breast from the bird’s
talons. Owls often remove and eat the head and sometimes
the neck of their prey. In contrast, mammalian predators
such as skunks or raccoons often kill several animals
during a night. They will usually tear skin and muscle
tissue from the carcass and cut through the feathers of
birds with their sharp teeth.
Hawks pluck birds, leaving
piles of feathers on the ground. Beak marks can
sometimes be seen on the shafts of these plucked
feathers. Owls also pluck their prey, but at times they
will swallow small animals whole. Many raptors
(especially red-tailed hawks and other buteos) feed on
carrion. The plucked feathers can often determine
whether a raptor actually killed an animal or was simply
“caught in the act” of feeding on a bird that had died
of other causes. If the feathers have small amounts of
tissue clinging to their bases, they were plucked from a
cold bird that died of another cause. If the base of a
feather is smooth and clean, the bird was plucked
shortly after it was killed.
Raptors often defecate at
a kill site. Accipiters such as the goshawk leave a
splash or streak of whitewash that radiates out from the
feather pile, whereas owls leave small heaps of chalky
whitewash on the ground.
Hawks and owls regurgitate
pellets that are accumulations of bones, teeth, hair,
and other undigested materials. These are not usually
found at the kill site, but instead accumulate along
with whitewash beneath a nearby perch or nest site.
Fresh pellets, especially of owls, are covered with a
moist iridescent sheen. They can be carefully teased
apart and examined to learn what the hawk or owl had
been eating. Owls gulp their food and swallow many bones
along with the flesh. These bones are only slightly
digested and persist in the pellets. A pellet that
contains large bones, such as those from the leg of a
rabbit, is undoubtably from a great horned owl. Hawks
feed more daintily and have stronger digestive juices
than owls. Thus, hawk pellets contain fewer bones.
All hawks and owls are
federally protected under the Migratory Bird Treaty Act
(16 USC, 703-711). These laws strictly prohibit the
capture, killing, or possession of hawks or owls without
special permit. No permits are required to scare
depredating migratory birds except for endangered or
threatened species (see Table 1), including bald and
In addition, most states
have regulations regarding hawks and owls. Some species
may be common in one state but may be on a state
endangered species list in another. Consult your local
USDA-APHIS-Animal Damage Control, US Fish and Wildlife
Service (USFWS), and/or state wildlife department
representatives for permit requirements and information.
Prevention and Control Methods
solution to raptor depredation is prevention.
Free-roaming farmyard chickens, ducks, and pigeons
attract hawks and owls and are highly susceptible to
predation. Many problems can be eliminated by simply
housing poultry at night. They can be conditioned to
move into coops or houses by feeding or watering them
indoors at dusk. If depredation persists, durable fenced
enclosures can be constructed by securing poultry wire
to a wooden framework and covering the enclosure with
poultry wire, nylon netting, or overhead wires (Fig. 2).
A double layer of overhead netting separated by a 5-to
6-inch (12- to 15-cm) space may be necessary to keep
owls away from penned birds. Large poultry operations
rarely have depredation problems because most practice
Table 1. Federally
endangered or threatened raptors.
Name: California condor (Gymnogyps
californianus) Status: Endangered Where Endangered: US
(California and Oregon), Mexico (Baja California).
Name: Bald eagle (Haliaeetus
Status: Endangered and
Where Endangered: US
(Conterminous states except Michigan, Minnesota, Oregon,
Washington, and Wisconsin)
Where Threatened: US
(Michigan, Minnesota, Oregon, Washington, and Wisconsin)
Name: American peregrine
falcon (Falco peregrinis anatum)
Where Endangered: Nests
from central Alaska across northcentral Canada to
central Mexico. Winters south to South America.
Name: American peregrine
falcon (Falco peregrinis tundrius)
Where Threatened: Nests
from northern Alaska to Greenland. Winters south to
Central and South America.
Name: Peregrine falcon (Falco
peregrinis) Status: Endangered Where Endangered:
Wherever found in wild in the conterminous 48 states.
Name: Hawaiian (lo) hawk (Buteo
solitarius) Status: Endangered Where Endangered: US
Name: Everglade (snail
kite) kite (Rostrhamus sociabilis plumbeus) Status:
Endangered Where Endangered: US (Florida)
Name: Palau owl (Pyroglaux
[=Otus] podargina) Status: Endangered Where Endangered:
West Pacific Ocean: US (Palau Islands)
Habitat modification can
make an area less attractive to raptors. Hawks and owls
often survey an area from a perch prior to making an
attack. Eliminate perch sites within 100 yards (90 m) of
the threatened area by removing large, isolated trees
and other perching surfaces. Install utility lines
underground and remove telephone poles near
poultry-rearing sites. Cap poles with sheet metal cones,
Nixalite®, Cat Claws®, or inverted spikes. Improve
rabbit escape cover at beagle clubs by constructing
brush piles and cutting large trees to increase the
density of shrub and ground cover. An abundance of
rabbits will often attract raptors. Clubs should release
only as many rabbits as are needed for an outing. Hawks
and owls that roost in buildings can be frightened away,
or live trapped and removed. Close off all entryways
after the birds are out of the building. Common barn
owls are endangered in some states and rarely, if ever,
cause damage to poultry. Their use of farm buildings,
where sanitation problems associated with droppings pose
no threat, should be encouraged. Consult your local
wildlife agency for information on barn owls in your
There are many techniques that can be used to scare
hawks and owls from an area where they are causing
damage. Some are inexpensive and easy to use, while
others are not. The effectiveness of frightening devices
depends greatly on the bird, area, season, and method of
application. Generally, if birds are hungry, they
quickly get used to and ignore frightening devices.
Frightening devices are usually a means of reducing
losses rather than totally eliminating them. Landowners
who use them must be willing to tolerate occasional
losses. Increasing human activity in the threatened area
will keep most raptors at a distance. The most common
and easily implemented frightening device is a shotgun
fired into the air in the direction of (not at) the
raptor. Scarecrows are effective at repelling raptors
when they are moved regularly and used in conjunction
with shotgun fire or pyrotechnics.
Pyrotechnics include a
variety of exploding or noise-making devices. The most
commonly used are shell crackers, which are 12-gauge
shotgun shells containing a firecracker that is
projected 50 to 100 yards (45 to 90 m) before it
explodes. Fire shell crackers in the direction of hawks
or owls that are found within the threatened area. An
inexpensive open-choke shotgun is recommended. Check the
gun barrel after each shot and remove any wadding from
the shells that may become lodged in the barrel. Noise,
whistle, and bird bombs are also commercially available.
They are fired from pistols and are less expensive to
use than shell crackers, but their range is limited to
25 to 75 yards (23 to 68 m). Your local fire warden can
provide information on local or state permits that are
required to possess and use pyrotechnics. The electric
pole shocker is a device developed by R.W. Schmitt of
Sheboygan, Wisconsin, to protect game farms and poultry
operations (Fig. 3). It has proven very effective in
several different settings in Wisconsin. Each unit
consists of a ground wire running 1 inch (2.5 cm) from
and parallel to a wire that is connected to an electric
fence charger. Install electrical shocking units on top
of 14- to 16-foot (4- to 5-m) poles and erect the poles
around the threatened area at 50- to 100-foot (15- to
30-m) intervals. When a raptor lands on a pole, it
receives an electric shock and is repelled from the
immediate area. Other perching sites in the area should
be removed or made unattractive. Energize the shocking
unit only from dusk until dawn for owls and during
daylight hours for hawks. The electric pole shocker
keeps raptors from perching within a threatened area but
does not exclude them from nesting in or using a nearby
area. Most hawks and owls are highly territorial. A pair
that is allowed to remain will aggressively defend the
area and usually exclude other hawks and owls. Thus,
farmers may actually find it beneficial to coexist with
a pair of hawks or owls that have learned to avoid an
area protected by pole shockers.
Fig. 2. A complete enclosure can protect fowl and
livestock from hawk and owl predation.
Fig. 3. The electric pole
(1) uninsulated (exposed) 12-gauge (0.28-cm) copper,
ground, and hot wires (no connection from ground to hot
wire) (2) insulated wire to ground (3) insulated wire to
fence charger (4) 14- to 16-foot (4- to 5-m) post (5)
mounting screw (6) 1-inch x 6-inch (2.5- x 15-cm)
self-insulating plastic pipe (7) 3/4-inch (0.2-cm) sheet
metal screws with plastic expansion sleeve or tubing
between head of screw and plastic pipe
Repellents and Toxicants
or toxicants are registered or recommended for
controlling hawk or owl damage. In years past, raptors
were killed by putting out carcasses laced with poison.
This practice led to the indiscriminate killing of many
nontarget animals. Concerns for human safety also
prompted the banning of toxicants for raptor control.
Trapping and Relocating
must obtain a permit from the US Fish and Wildlife
Service and usually the local state wildlife agency to
trap any hawk or owl that is causing damage. Trapping is
usually permitted only after other nonlethal techniques
have failed. Set traps in the threatened area where they
can be checked at least twice a day. If possible,
experienced individuals or agency personnel should
conduct the trapping and handling of captured birds.
The Swedish goshawk trap
is a relatively large, semipermanent trap that can be
used to capture all species of hawks and owls (Fig. 4).
It consists of two parts: a 3 x 3 x 1-foot (90 x 90 x
30-cm) bait cage made of 1-inch (2.5-cm) mesh welded
wire. A trap mechanism consisting of a wooden “A” frame,
nylon netting, and a trigger mechanism is mounted on the
bait cage. A hawk or owl dropping into the trap will
trip the trigger mechanism and be safely trapped inside.
Pigeons make very good lures because they are hardy,
easily obtained, and move enough to attract hawks and
owls. Other good lures include starlings, rats, and
mice. For detailed information on the construction and
use of Swedish goshawk traps, see Meng (1971) and
Kenward and Marcstrom (1983).
The bal-chatri trap is a
relatively small, versatile trap that can be modified to
trap specific raptor species (Fig. 5). Live mice are
used to lure raptors into landing on the traps. Nylon
nooses entangle their feet and hold the birds until they
are released. The quonset-hut type bal-chatri was
designed for trapping large hawks and owls (Berger and
Hamerstrom 1962). The trap is made of 1-inch (2.5-cm)
chicken wire, formed into a cage that is 18 inches long,
10 inches wide, and 7 inches high at the middle (46 x 25
x 18 cm). The floor consists of 1-inch (2.5-cm) mesh
welded wire with a lure entrance door and steel rod
edging for ballast. The top is covered with about 80
nooses of 40-pound (18-kg) test monofilament fishing
line (Fig. 5). Pigeons, starlings, house mice, and other
small rodents can be used as lures. The trap should be
tied to a flexible branch or bush to keep a trapped bird
from dragging the trap too far and breaking the nylon
Spring-net traps are ideal
for catching particular hawks or owls that are creating
a damage problem (Fig. 6). Square spring nets, hoop
nets, and the German “butterfly trap” have all been used
successfully. A trap is baited by attaching the
partially eaten carcass of a fresh kill or a stuffed
bird to the trigger bar. The trap should be camouflaged
by covering the frame and folded net with leaves and
feathers from the kill. For detailed information on
spring-net traps see Kenward and Marcstrom (1983).
hawks and owls can be trapped safely using the sliding
padded pole trap because of their tendency to perch
prior to making an attack (Fig. 7). Erect 5- to 10-foot
(1.5- to 3-m) poles around the threatened area where
they can be seen easily and place one padded steel
trap (No. 1 1/2) on top of
each pole. The jaws must be well padded with surgical
tubing or foam rubber and wrapped with electrician’s
tape. Run a 12-gauge steel wire through the trap chain
ring and staple it to the top and bottom of the post.
This allows the trap to slide to the ground where the
bird can rest. Some states prohibit the use of pole
Fig. 4. The redesigned,
modified, and improved Swedish goshawk trap developed by
Transportation. If necessary, landowners can safely
handle and transport hawks and owls. The key to
successful raptor handling is to control the bird’s
feet. The talons can easily grasp a careless hand and
inflict a painful injury. There is significantly less
chance of injury from the wings and beak. The safest
approach, regardless of the type of trap, is to toss an
old blanket or coat over both the bird and trap. The
darkness will calm Select a box that is large enough for
the bird to stand upright in. Holes should be punched
near the bottom of the box to supply fresh air and keep
the raptor from struggling toward any cracks of light
coming from the top of the box. Carry only one bird per
box. Tape an old rag or towel to the floor to provide a
good gripping surface to keep the bird from slipping. If
a burlap bag must be used to transport the bird, tie the
bird’s legs together with a nylon stocking to keep it
from footing someone during transport or release. If
possible, ask a local bird bander to attach a leg band.
Banding information can be very useful to the research
and management of raptors.
Transport the bird as
quickly and comfortably as possible.
should be restrained before they are transported to
reduce the chances of injury to both the bird and
handler. The best transport container is a stout,
covered cardboard box. Minimize excess handling, and
above all, keep the bird calm and cool. More birds die
most of overheating during shipment than of any other
cause. Transport the bird as far away from the trapping
site as possible. Some biologists believe that 20 miles
(32 km) is sufficient, but raptors have been known to
travel up to 200 miles (320 ) km after release. If a
bird is trapped in the fall, help it along its way by
transporting it southward birds and make them less able
to defend themselves. Reach in carefully with your bare
hands and grasp the bird’s lower legs. Control the feet
to avoid getting “footed.” Pull the bird out of the trap
so that it is clear of any object on which it could
injure itself. Fold the wings down against the body and
hold them securely. Check the bird for any signs of
external injury, such as cut feet or legs, excessively
battered feathers, or scalping (the splitting of the
skin over the forehead). If the bird is injured, have a
local veterinarian examine it, or in extreme cases,
transport it to the nearest raptor rehabilitation
Fig. 6.Automatic spring-net trap in set position; inset
All hawks and
owls are protected by federal and state laws. There are
cases, however, in which they can create public health
and safety hazards or seriously affect a person’s
livelihood. Contact your local USDA-APHIS-ADC office
first if you are interested in obtaining a shooting
permit. The USFWS and state wildlife agencies may issue
shooting permits for problem hawks and owls if nonlethal
methods of controlling damage have failed or are
impractical and if it is determined that killing the
offending birds will alleviate the problem.
Permittees may kill hawks
or owls only with a shotgun not larger than 10-gauge,
fired from the shoulder and only within the area
described by the permit. Permittees may not use blinds
or other means of concealment, or decoys or calls that
are used to lure birds within gun range. Exceptions to
the above must be specifically authorized by USFWS. All
hawks or owls that are killed must be turned over to
USFWS personnel or their representatives for disposal.
of Damage and Control
In 1985, we conducted a
national survey of US Fish and Wildlife Service and
Cooperative Extension personnel. Nearly all noted that
the economic damage caused by raptors is minimal on a
national scale, but can be locally severe if depredation
occurs on fowl or livestock that are relatively valuable
and vulnerable. Cost estimates of damage ranged from $10
to $5,000 per report and from $70 to $94,000 per year.
The severity of raptor problems is influenced by several
factors, including prey and carrion abundance, weather,
time of year, husbandry methods, vegetative cover, and
topography as well as density and local distribution of
We wish to thank
Fran and Frederick N. Hamerstrom for their comments on
early manuscripts and information regarding the handling
of raptors. Reviewers included Richard H. Behm, James L.
Ruos, Leroy W. Sowl,
V. Dan Stiles, and Richard
Winters. Eldon L. McLaury reviewed the manuscript and
provided legal information.
Figure 1 by Elva
Hamerstrom Paulson, from Hamerstrom (1972).
Figure 2 from Salmon and
Figure 3 by the authors.
Figure 4 from Meng (1971).
Figure 5 from Berger and
Figure 6 from Kenward and
Figure 7 from US
Department of Interior, Bulletin 211-1-77.
For Additional Information
Berger, D. D., and F. Hamerstrom. 1962. Protecting a
trapping station from raptor predation. J. Wildl.
Hamerstrom, F. 1972. Birds
of prey of Wisconsin. Wisconsin Dep. Nat. Resour. 64 pp.
Hamerstrom, F. 1984.
Birding with a purpose. Iowa State Univ. Press, Ames.
Heintzelman, D. S. 1979.
Hawks and owls of North America. Universe Books, New
York. 197 pp.
Karlbom, M. 1981.
Techniques for trapping goshawks. Pages 138-144 in R. E.
Kenward and I. Lindsay, eds. Understanding the goshawk,
Internat. Assoc. Falconry Conserv. Birds of Prey.
Kenward, R. E., and V.
Marcstrom. 1981. Goshawk predation in game and poultry:
some problems and solutions. Pages 152-162 in R. E.
Keward and I. Lindsay, eds. Understanding the goshawk.
Internat. Assoc. Falconry Conserv. Birds of Prey.
Kenward, R. E., and V.
Marcstrom. 1983. The price of success in goshawk
trapping. Raptor Res. 17:84-91.
Meng, H. 1971. The Swedish
goshawk trap. J. Wildl. Manage. 35:832-835.
Newton, I. 1979.
Population ecology of raptors. Buteo Books, Vermillion,
South Dakota. 399 pp.
Peterson, L. 1979. Ecology
of great horned owls and red-tailed hawks in
southeastern Wisconsin. Wisconsin Dep. Nat. Resour.
Tech. Bull. 111. Madison. 63 pp.
Salmon, T. P., and F. S.
Conte. 1981. Control of bird damage at aquaculture
facilities. WML No. 475. US Dep. Inter. Fish Wildl. Serv.,
Washington, D.C. 11 pp.
US Fish and Wildlife
Service. (no date). Raptor control-protecting livestock
from hawk and owl predation. US Dep. Inter. An. Damage
Control Bull. 211-1-77.
Scott E. Hygnstrom Robert
M. Timm Gary E. Larson
PREVENTION AND CONTROL OF
WILDLIFE DAMAGE — 1994
Division Institute of Agriculture and Natural Resources
University of Nebraska -Lincoln
United States Department
of Agriculture Animal and Plant Health Inspection
Service Animal Damage Control
Great Plains Agricultural
Council Wildlife Committee