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Figure
1. The black-billed magpie is
a black-and-white, pigeon-sized bird with an unusually
long tail. |
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Magpies and jays are in the Corvid family, which
includes ravens and crows. These social birds are bold and gregarious,
and adapt well to living around humans. Many feel that corvids rank
among the most intelligent of birds. The black-billed magpie
(Pica pica, Fig. 1) is easily distinguished from other
birds by its striking black-and-white color pattern. It has an unusually
long tail (at least half its body length) and short, rounded wings
that show flashes of white in flight. The feathers of the tail and
wings are iridescent, reflecting a bronzy-green to purple. The juvenile
magpie is similar to the adult, but has less iridescence and a shorter
tail.
Magpies are typically found close to water in open
areas near scattered trees and thickets east of the Cascade Mountains.
Since the mid 1900s, when they were regularly trapped
or shot, magpies have increased in abundance. They are now common
birds of rural, suburban, and even city parks and gardens.
Facts
about Washington Magpies
Food and
Feeding Behavior
- Black-billed
magpies are resourceful opportunists. They flip items over to
look for food, follow predators with hopes of scavenging scraps,
pick insects from the backs of cattle and sheep, and steal food
from other birds.
- Magpie
diets include mostly animal matter: insects, small mammals,
small wild birds and their hatchlings and eggs. They also eat
seeds, fruits, and nuts.
- Magpies
often congregate on recently killed large animal carcasses and
eat many road-killed small mammals and birds. They can use scent
to find food—an unusual trait for birds, which generally
have very little sense of smell.
- Food may
be stored in trees, shrubs, and in shallow pits magpies dig
in the ground.
Reproduction
and Family Structure
- Adult
magpie pairs stay together year-round and for life unless one
dies, in which case the remaining magpie finds another mate.
- The breeding
season for magpies is from late March to early July.
- The female
incubates six or seven eggs for 16 to 18 days. The male feeds
the female throughout incubation.
- Young
fly three to four weeks after hatching, feed with adults for
about two months, and then fly off to join other juvenile magpies.
- Magpies
form loose flocks throughout the year; winter congregations
may include several hundred individuals.
Nest and
Roost Sites
- Black-billed
magpies nest once a year, but will re-nest if their first attempt
fails.
- Magpies
nest individually or in loose colonies, frequently toward the
top of deciduous or evergreen trees or tall shrubs.
- Nests
are built by both sexes over a 40- to 50-day period. Old nests
are repaired and used, or a new nest is built on top, with older
nests reaching 48 inches deep by 40 inches wide.
- Nests
are loose accumulations of branches, twigs, mud, grass, rootlets,
bark strips, vines, needles, and other materials, with branches
and twigs constituting the base and framework. The nest cup
is lined with fine rootlets, grass, and other soft material.
- Nests
almost always contain a hood or dome of loosely assembled twigs
and branches, and usually have one or more side entrances.
- Other
bird species, including small hawks and owls, often use old
magpie nests.
Mortality
and Longevity
- During
the first half of the 20th century, black-billed magpies were
considered detrimental to game-bird populations and domestic
stock, and were systematically trapped or shot. Many also died
from eating poison set out for coyotes and other predators.
- In 1933,
1,033 magpies were shot in Washington’s Okanagan valley
by two teams of bounty hunters.
- Today,
adult magpies have few predators, although large hawks occasionally
take some. Nestlings die from starvation, adverse weather, and
attacks by raccoons, owls, and other animals.
- Pesticides
used on livestock are of some concern, since magpies perch on
livestock and eat those pests that are being poisoned.
- The life
span of a magpie in the wild is four to six years.
Viewing
Magpies
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Figure
2. Black-billed magpies are typically found close to water
in open areas near scattered trees and thickets. (Drawing
by Elva Hamerstrom Paulson.) |
The magpie
is probably the most conspicuous bird seen throughout interior
areas of the Pacific Northwest (Fig. 2). Where they are not harassed,
magpies can be extremely bold; when harassed, they become elusive
and secretive.
During the
breeding season, magpies are often seen in areas that combine
woods or thickets for nesting, water for drinking and bathing,
and open areas for feeding.
During the
nonbreeding season, particularly winter, magpies are most numerous
in environments influenced by people, such as livestock feedlots,
barnyards, roadsides, garbage dumps, railway loading yards, and
grain elevators. Individual magpies may wander widely.
Magpie migration
is mainly elevational, from low to high, although some north-south
movements occur. Where winters are severe, all magpies leave the
high country.
Magpies are
not swift fliers and elude predators and danger by flitting in
and out of areas with trees or diving into heavy cover.
If you locate
a colony of magpies, find a spot where you can view an expanse
of trees and meadow with binoculars. Sit down and wait. It won’t
be long before the magpies will ignore you and go about their
daily activities. If you notice that your presence is annoying
the birds, you are too close. Back away, sit down quietly, and
wait for them to return to the area.
Nest Sites
Magpies build
huge, domed nests. In the winter when deciduous trees are bare,
the large nests are easily seen. Because of their size, you may
first think they are hawk nests, but look for the telltale dome,
an adaptation that protects the young from predators.
Roost
Sites
From midsummer
through fall and winter, magpies gather together in the evening
and form communal roosts. Roosts are located in dense thickets
of shrubs and trees near major food sources. The birds use deciduous
thickets until the arrival of colder temperatures, at which time
they move into conifers. Sometimes old magpie nests are used as
night roosts.
The portions
of food magpies can’t digest are bundled into compact “pellets”
and later regurgitated. Pellets are usually found under or near
the roost.
Tracks
and Trails
A magpie’s
tracks show four medium-wide toes, three facing forward and one
back. The claws are long and their marks are detached from the
footprint.
Like virtually
all other corvids, magpies walk with a strut, and hop quickly
when rushed. The walking stride is about 6 inches and a tail print
may be visible.
Calls
Typical calls
include a rapid, nasal mag? mag? mag? or yak yak yak.
Preventing
Conflicts
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Figure
3. Protect fruit crops with flexible bird netting. Secure
the netting at the base of the shrub or tree to prevent birds
from gaining access from below. (Drawing by
Jenifer Rees.) |
Magpies help
control pest insects such as grasshoppers and tent caterpillars,
and also “clean up” dead animals and garbage scattered
by other animals. Other species of birds and mammals often use
unoccupied magpie nests.
Although
magpies prey on songbirds and their young, research suggests that
they do not ordinarily have a significant impact on songbird populations.
However, because magpies are intelligent, opportunistic, and at
times congregate in large numbers in close proximity to humans,
conflicts can occur.
Perhaps the
magpie behavior that is most annoying to farmers and ranchers
is the picking of wound sites on the backs of healthy horses and
livestock under certain conditions. However, this is not a common
occurrence, except possibly during severe winters when food for
magpies is scarce.
The following
are suggestions on how to prevent and remedy problems that might
arise. In cases where these methods are not practical, contact
your local wildlife office.
Eating
Fruits and Vegetables
Protect fruit
crops with flexible bird netting, which can be purchased in a
variety of lengths and widths at garden and hardware stores; professional
quality materials and hardware are available from bird-control
companies and over the Internet. Secure the base of the shrub
or the tree to prevent magpies from gaining access from below
(Fig. 3). Individual small branches containing fruit can be protected
with an onion sack or similar mesh covering.
Row crops,
such as strawberries, can be completely covered during the fruiting
season. If the netting is to be used for several harvest seasons,
it may be worth the extra effort to construct a frame to support
the netting.
Scare devices,
such as pie tins and commercially available Mylar balloons or
Mylar scare tape, are known to provide temporary protection. Suspend
balloons at least 3 feet above trees or bushes, or from lines
between posts. Use tethers at least 3 feet long.
Attach red
and silver “bird-scare tape” to stakes and stretch
it 18 inches above the areas that need protection. Twist the tape
several times before attaching it to stakes so that the visible
interval of red/silver is 16 inches. The tape should move freely,
so that when a slight breeze blows it will flash in the sun. The
space between tapes will have to be no more than 5 feet to be
effective.
Because most
birds will fly into a strawberry patch, land on the ground between
the plants and eat the ripe strawberries from there, scare devices
placed above the patch are not effective. Instead, place the scare
tape between the rows. The tape should sag slightly but should
not be less than 3 inches or more than 5 inches from the ground.
Scare devices
need to be moved weekly (daily if possible) so magpies don’t
become accustomed to them; they are also most successful if put
in place before the birds become a problem. Always harvest ripe
fruit immediately.
Protect germinating
corn plants and other crops with bird netting until plants are
about 8 inches tall. Large plastic trash bags attached to 6 to
7 foot wooden stakes, along with the above-mentioned scare tactics,
can be used in areas with lots of air movement (Fig. 4). Cracker
shells and propane cannons may be needed in larger plantings.
Ultrasonic devices are not effective at frightening magpies.
Lawn Damage
Because new
lawns are well irrigated during the growing season, worms and
grubs collect under the sod, attracting magpies—and skunks
and raccoons. If small sections are being damaged, lay chicken
wire over the area and secure it with stakes, stones, or by some
other means. Another technique is to utilize the scare tactics
described above.
Small Farm-animal
Damage
Freeroaming
chickens, ducks, and pigeons and their eggs and young are susceptible
to magpie predation.
Housing domestic
birds in a durable, completely covered coop will exclude not only
magpies but also hawks and owls. The structure can be constructed
by attaching 1-inch chicken wire or bird netting to a solid framework.
Where a complete
and permanent enclosure isn’t practical or desirable, escape
cover should be provided. Birds have natural defenses at the sight
of a predator and will quickly squeeze under a nearby building,
old car, shrub, or other area. Escape cover can be made of planks,
plywood, or chicken wire placed over logs, rocks, or bricks. It
should be at least 7 x 7 feet wide and long and the cover should
be 12 inches off the ground.
Please understand
that you cannot expect to fully protect free-range birds from
magpies and an occasional loss of a bird is to be expected.
Magpies
at Feeders
Magpies are
attracted to suet feeders and their aggressive habits can deplete
food supplies and keep smaller birds from approaching. Because
magpies have trouble clinging upside down, a suet feeder that
requires the birds to clasp the feeder in this position will discourage
magpies. Your local bird specialty store can also give you information
on feeder designs to deter these birds.
Communal
Night Roosts
The communal
night roosts of magpies create accumulations of droppings with
the potential to spread disease. When and where this poses a health
risk to the public (as deemed so by a Public Health representative)
or cannot be tolerated, steps need to be taken to remedy the problem.
Options include making the area temporarily off limits, routinely
cleaning up the soiled area underneath the roost, or dispersing
the flock by making the roost site undesirable to magpies. Large-scale
intervention strategies should be undertaken with the guidance
of the Department
of Agriculture.
Methods
to disperse magpies from a night roost include:
Harassment
Techniques
Harassment
techniques include visual and audio stimuli and an assortment
of other approaches to make magpies uncomfortable enough to move
elsewhere. If possible, act quickly when large numbers of roosting
magpies are detected. The birds will be more willing to abandon
a roost site they have not been using long. Note: Most harassment
techniques are effective only for a short time and the public
may not like them because they cause magpies to move elsewhere—such
as a neighborhood park or someone’s backyard containing
large trees.
Visual
scare devices include Mylar tape, eye-spot balloons, scarecrows,
and laser devices. Visual harassment devices can provide effective
short-term control, especially when they are used in combination
with auditory devices.
Audio
scare devices include hazing with pyrotechnics such as cracker
shells, blanks, and propane cannons.
When using
any auditory scare device, change the area from which it is emitted,
daily if possible. When using pyrotechnics, try to elevate them
above the roost site.
Magpies scare
most easily when they are flying. They are most difficult to scare
when perched in the protection of their roost. Therefore, audio
devices should begin to be used when the first birds come in to
roost, usually an hour and a half before dark. The same group
of magpies may circle around and come toward the roost many times,
so scaring efforts need to continue until it gets dark.
Scaring should
stop with darkness or the magpies will become accustomed to the
sounds. If using recorded alarm calls, play them only 10 to 15
seconds per minute when the birds are coming in. When most of
the birds are perched, play the call continuously until dark.
If possible, early morning scaring should be used in conjunction
with evening scaring, and should begin as soon as the first bird
movement is detected in the roost, often just before daylight.
Success may
not be achieved for several nights and will entail continuous
efforts every evening and every morning. Because the magpies may
attempt to establish temporary roosts in other unsuitable locations,
scaring efforts may be needed elsewhere until the birds move to
an acceptable area. If magpies are disturbed in their new roost
site they will move back to the old one. Be prepared to resume
efforts if they return.
Modify
the Night Roost
Modifying the
structure of the magpies’ night roost can discourage the
birds from using it. This includes thinning up to 50 percent of
the branches of roost trees, or removing trees from dense groves
to reduce the availability of perch sites and to open the trees
to the weather. A tree service company can remove tree limbs (Fig.
5).
Other Techniques
Other techniques
to disperse magpies include using 4-inch mesh bird netting to
create a barrier between the roost and the magpies; spraying magpies
with water from a high-pressure hose (some cities have used a
fire hose); installing a 360-degree sprinkler up in the roost
tree; and lighting up the interior of the roost with bright fluorescent
lights.
Lethal
Control
For information
regarding shooting magpies, see “Legal
Status”.
Public
Health Concerns
Magpies and
jays are not a significant source of any infectious disease that
can be transmitted to humans or domestic animals. Contact the
Washington Department
of Health for precautions to be taken when working around
large concentrations of magpie droppings.
Legal
Status
Magpies are
protected under the Migratory
Bird Treaty Act. However, under the Code of Federal Regulations,
“a Federal permit shall not be required to control . . .
magpies, when found committing or about to commit depredations
upon ornamental or shade trees, agricultural crops, livestock,
or wildlife, or when concentrated in such numbers as to constitute
a health hazard or other nuisance . . .”
Additional
Information
Books
Ehrlich,
Paul R., et al. The Birder’s Handbook: A Field Guide
to the Natural History of North American Birds. New York:
Simon & Schuster, 1988.
Nehls, Harry
B. Familiar Birds of the Northwest: Covering Birds Commonly
found in Oregon, Washington, Idaho, Northern California, and Western
Canada. Portland, OR: Audubon Society of Portland, 1989.
Peterson,
Roger Tory. A Field Guide to Western Birds. Boston. Houghton
Mifflin, 1990.
Washington, DC: National Geographic Society, 2002.
Udvardy,
Miklos D. F. Audubon Society Field Guide to North American
Birds—Western Region. New York: Alfred A. Knopf, 1977.
Internet
Resources
Prevention
and Control of Wildlife Damage
Seattle
Audubon’s Birds of Washington State
Wildlife
Control Supplies
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