Starlings
General Starling Facts
Habitat
Starlings nests are built into house cavities and can accumulate material that is unsightly and may be a fire hazard.
Diet
They have a wide-range for food, but they do prefer insects. Some people think that starlings are tearing up lawns and gardens, when in reality they are eating the insect pests and doing homeowners huge favors.
Notes
Starlings are pest birds. They have bird mites, and nose cone bugs that infest structures. They cause a lot of sound issues and bird droppings problems. They come in as many as two or three or thousand. Once they have infested an area or developed a roosting site, they can create hundreds of pounds of waste per night. These birds can be controlled through various repellants and sound irritant techniques.
Identification
Starlings are robin-sized birds weighing
about 3.2 ounces (90 g). Adults are
dark with light speckles on the feathers.
The speckles may not show at a
distance (Fig. 1). The bill of both sexes
is yellow during the reproductive cycle
(January to June) and dark at other
times. Juveniles are pale brown to
gray.
Starlings generally are chunky and
hump-backed in appearance, with a
shape similar to that of a meadowlark.
The tail is short, and the wings have a
triangular shape when outstretched in
flight. Starling flight is direct and swift,
not rising and falling like the flight of
many blackbirds.
Range
Since their introduction into New York
in the 1890s, starlings have spread
across the continental United States,
northward to Alaska and the southern
half of Canada, and southward into
northern Mexico. They are native to
Eurasia, but have also been introduced
in South Africa, Australia, New
Zealand, and elsewhere.
Habitat
Starlings are found in a wide variety of
habitats including cities, towns, farms,
ranches, open woodlands, fields, and
lawns. Ideal nesting habitat would
include areas with trees or other structures
that have cavities suitable for
nesting and short grass (turf) areas or
grazed pastures for foraging. Ideal
winter habitat would include areas
with structures and/or tall trees for
daytime loafing (resting) and nighttime
roosting; and grazed pastures,
open water areas, and livestock facilities
for foraging.
Food Habits
Starlings consume a variety of foods,
including fruits and seeds of both wild
and cultivated varieties. Insects, especially
Coleoptera and Lepidoptera
lawn grubs, and other invertebrates
total about one-half of the diet overall,
and are especially important during
the spring breeding season. Other
items including livestock rations and
food in garbage become an important
food base for wintering starlings.
General Biology,
Reproduction, and
Behavior
European starlings were brought into
the United States from Europe. They
were released in New York City in
1890 and 1891 by an individual who
wanted to introduce to the United
States all of the birds mentioned in
Shakespeare’s works. Since that time,
they have increased in numbers and
spread across the country. They were
first observed in Nebraska in 1930, in
Colorado in 1939, and in California in
1942. The starling population in the
United States is estimated at 140
million birds.
Starlings nest in holes or cavities
almost anywhere, including tree cavities,
birdhouses, and holes in buildings
or cliff faces. Females lay 4 to 7 eggs
which hatch after 11 to 13 days of incubation.
Young leave the nest when
they are about 21 days old. Both parents
help build the nest, incubate the
eggs, and feed the young. Sometimes 2
clutches of eggs are laid per season,
but most of the production is from the
first brood fledged.
Although starlings are not always
migratory, some will migrate up to
several hundred miles, while others
may remain in the same general area
throughout the year. Hatching-year
starlings are more likely to migrate
than adults, and they tend to migrate
farther.
Outside the breeding season, starlings
feed and roost together in flocks. Starling
and blackbird flocks often roost
together in urban landscape trees or in
small dense woodlots or overcrowded
tree groves. They choose trees or
groves that offer ample perches so that
all may roost together. In colder
weather they choose dense vegetation
such as coniferous trees or structures
(such as barns, urban structures) that
provide protection from wind and
cold. Fall-roosting flocks are relatively
small (from several hundred to several
thousand birds), but because they are
spread over large geographic areas,
they can cause widespread nuisance
problems. In contrast, winter-roosting
flocks are large (sometimes exceeding
1 million birds), but are often confined
to a few acres (ha). Some of the winter
roosting areas are occupied by starlings
year after year. Each day
they may fly 15 to 30 or more miles (24
to 48 km) from roosting to feeding
sites. During the day when not feeding,
they may perch in smaller groups
inside farm buildings or in other
warm, protected spots in and around
urban structures.
Damage and Damage
Identification
Starlings are frequently considered
pests because of the problems they
cause, especially at livestock facilities and near urban roosts. Starlings
may selectively eat the high protein
supplements that are often
added to livestock rations.
Starlings may also be responsible for
transferring disease from one livestock
facility to another. This is of particular
concern to swine producers. Tests
have shown that the transmissible
gastroenteritis virus (TGE) can pass
through the digestive tract of a starling
and be infectious in the starling feces.
Researchers, however, have also found
healthy swine in lots with infected
starlings. This indicates that even
infected starlings may not always
transmit the disease, especially if starling
interaction with pigs is minimized.
TGE may also be transmitted on boots
or vehicles, by stray animals, or by
infected swine added to the herd.
Although starlings may be involved in
the spread of other livestock diseases,
their role in transmission of these
diseases is not yet understood.
Starlings cause other damage by consuming
cultivated fruits such as
grapes, peaches, blueberries, strawberries,
figs, apples, and cherries. They
were recently found to damage ripening
(milk stage) corn, a problem primarily
associated with blackbirds.
The growing urbanization of wintering
starling flocks seeking warmth and
shelter for roosting may have serious
consequences. Large roosts that occur
in buildings, industrial structures, or,
along with blackbird species, in trees
near homes are a problem in both rural
and urban sites because of health concerns,
filth, noise, and odor. In addition,
slippery accumulations of
droppings pose safety hazards at
industrial structures, and the acidity
of droppings is corrosive.
Starling and blackbird roosts located
near airports pose an aircraft safety
hazard because of the potential for
birds to be ingested into jet engines,
resulting in aircraft damage or loss
and, at times, in human injuries. In
1960, an Electra aircraft in Boston collided
with a flock of starlings soon
after takeoff, resulting in a crash landing
and 62 fatalities. Although only
about 6% of bird-aircraft strikes are
associated with starlings or blackbirds,
these species represent a substantial
management challenge at airports.
One of the more serious health concerns
is the fungal respiratory disease
histoplasmosis. The fungus Histoplasma
capsulatum may grow in the
soils beneath bird roosts, and spores
become airborne in dry weather, particularly
when the site is disturbed.
Although most cases of histoplasmosis
are mild or even unnoticed, this disease
can, in rare cases, cause blindness
and/or death. Individuals who are
weakened by other health conditions
or who do not have endemic immunity
are at greater risk from histoplasmosis.
Starlings also compete with native
cavity-nesting birds such as bluebirds,
flickers, and other woodpeckers,
purple martins, and wood ducks for
nest sites. One report showed that,
where nest cavities were limited, starlings
had severe impacts on local
populations of native cavity-nesting
species. One author has speculated
that competition with starlings may
cause shifts in red-bellied woodpecker
(Melanerpes carolinus) nesting from urban
habitats to rural forested areas
where starling competition is less.
some areas starlings pull sprouting
grains, particularly winter wheat, and
eat the planted seed. Starlings may
damage turf on golf courses as they
probe for grubs, but the frequency and
extent of such damage is not well
documented.
Legal Status
European starlings are not protected
by federal law and in most cases not
by state law. Laws vary among states,
however, so check with state wildlife
officials before beginning a control
program. In addition, state or local
laws may regulate or prohibit certain
control techniques such as shooting or
the use of toxicants.
Damage Prevention and
Control Methods
Exclusion
Close all openings larger than 1 inch
(2.5 cm) to exclude starlings from
buildings or other structures. This is a
permanent solution to problems inside
the structure. Heavy plastic
(polyvinyl chloride, PVC) or rubber
strips hung in open doorways of farm
buildings have been successful in some
areas in excluding birds while allowing
people, machinery, or livestock to
enter. Hang 10-inch (25-cm) wide
strips with about 2.0-inch (5-cm) gaps
between them. These strips might also
be useful for protecting feed bunks.
Netting over doorways may also
exclude birds from buildings, but
would be easily torn by machinery or
livestock.
Where starlings are roosting or nesting
on the ledge of a building, place a
wooden, metal, or plexiglass covering
over the ledge at a 45o angle to prevent
use. Metal protectors or porcupine
wires (Nixalite® and Cat Claw®)
are also available for preventing roosting
on ledges or roof beams.
Nylon or plastic netting is another
option for exclusion. Exclude
starlings that are roosting inside open
farm buildings by covering the underside
of the roof beams with netting.
Netting is also useful for covering fruit
crops such as cherries or grapes to prevent
bird damage, and studies show it
to be a cost-effective method of protecting
higher-value grapes in commercial
vineyards. For wine grapes
harvested one time per season, tractormounted
rollers can facilitate installation
and removal of netting draped
directly over vines. Some New York
vineyards have used this method for
five years with the original netting still
in good condition. For table grapes
harvested by hand several times per
year, a frame can be used to hold the
netting above the vines so it doesn’t
interfere with the frequent harvests. A
practical tip: if protecting the total
vineyard is impractical, protect varieties
that receive the most damage,
those that ripen early or are otherwise
highly attractive to birds (for example,
small, dark, sweet grapes.)
Where starlings compete with other
birds for nest boxes, proper nest box
construction helps. For bluebird boxes,
use a round 1 1/2-inch (3.8-cm) hole or
a rectangular slot, 4 inches (10 cm)
wide by 1 1/8 inches (29 mm) high, to
allow bluebirds in but keep starlings
out. Starlings are discouraged by
horizontal wood duck nest boxes
made from a 24-inch (61-cm) section of
12-inch-diameter (30.5-cm) stove pipe.
The ends are made from wooden
circles, and the entrance hole on one
end is semicircular and 4 inches (10
cm) high by 11 inches (28 cm) wide.
Other nest box features such as interior
dimensions and color, amount of light
allowed into the box, and box placement
appear to have potential for
discouraging starlings while encouraging
preferred cavity-nesters.
Cultural Methods and Habitat
Modification
Livestock Facilities
Starlings are
attracted to livestock operations by the
food and water that is available to
them. Feedlots offer an especially
attractive food source to starlings during
winter when snow cover and frozen
ground impede their normal
feeding in open fields or other areas.
The snow cover and frozen ground
increase the likelihood as well as the
severity of damage.
Some livestock operations are more
attractive to starlings than others.
Operations that have large quantities
of feed always available, especially
when located near a starling roost, are
the most likely to have damage problems.
Research results emphasize the
importance of farm management practices.
These practices limit the availability of
food and water to starlings, thus making
the livestock environment less
attractive to birds. The following practices
used singly, but preferably in
combination, will reduce feed losses,
the chance of disease transmission,
and the cost and labor of conventional
control measures.
1. Clean up spilled grain.
2. Store grain in bird-proof facilities.
3. Use bird-proof livestock feeders.
These include flip-top pig feeders,
lick wheels for liquid cattle supplement,
and automatic-release feeders
(magnetic or electronic) for costly
high-protein rations. Using covered
feeders prevents starling access and
contamination of the food source,
and the banging of the lift-top lids
as pigs use the feeders may frighten
starlings and keep them uneasy.
Avoid feeding on the ground
because this is an open invitation to
starlings.
4. Where possible, feed livestock in
covered areas such as open sheds
because these areas are less attractive
to starlings.
5. Use feed forms that starlings cannot
swallow, such as cubes or blocks
greater than 1/2 inch (1.3 cm) in
diameter. Minimize use of 3/16
inch (0.5 cm) pellets; starlings consume
these six times faster than
granular meal.
6. When feeding protein supplements
with other rations, such as silage,
mix them well to limit starling
access to the supplements.
7. Where possible, adjust feeding
schedules so that exposure of feed
to birds is minimized. For example,
when feeding once per day, such as
in a limited energy-feeding program
for gestating sows, delay the feeding
until late in the afternoon when
foraging by starlings is decreased.
Feed cattle at night if possible. Starlings
prefer to feed early to midday
and in areas where feed is constantly
available. Feeding schedules
that take these factors into account
minimize problems.
8. Starlings are especially attracted to
water. Drain or fill in unnecessary
water pools around livestock operations.
Where feasible, control the
water level of livestock waterers to
make them unavailable or less
attractive to starlings.
Tree Roosts
When roosts occur in a
small number of landscape trees near
homes or along streets, thinning
branches from the trees used by birds
will usually disperse them. Roosts in
tree groves or woodlots usually occur
in dense, overcrowded stands of
young trees. Remove about one-third
of the trees to improve the tree stand,
especially if marked by a professional
forester, and to disperse the birds.
Such thinning successfully dispersed
roosts from research woodlots in Ohio
and Kentucky, and from at least two
problem-roost situations in Nebraska.
In dense cedar thickets, bulldozing
strips through the roost to remove
one-third of the habitat has also been
successful in dispersing birds. Soil disturbance,
however, may be hazardous
if soils harbor fungal spores of the
human respiratory disease histoplasmosis.
For further information on
roost dispersal, see Bird Dispersal
Techniques.
Frightening
Frightening is effective in dispersing
starlings from roosts, small-scale fruit
crops, and some other troublesome
sites. It is useful around livestock
operations that have warm climates
year-round, and where major concentrations
of wintering starlings exist. In
the central states, starlings concentrate
at livestock facilities primarily during
cold winter months when snow covers
natural food sources. At this time, baiting
and other techniques are generally
more effective than frightening. In addition,
frightening starlings may disperse
birds to other livestock facilities,
a negative point that should be considered
if disease transfer is a concern.
Frightening devices include recorded
distress or alarm calls, gas-operated
exploders, battery-operated alarms,
pyrotechnics (shellcrackers, bird
bombs), chemical frightening agents
(see Avitrol® below), lights (for roosting
sites at night), bright objects, and
various other stimuli. Some novel visual
frightening devices with potential
effectiveness are eye-spot balloons,
hawk kites, and mylar reflective tape.
Ultrasonic (high frequency, above 20
kHz) sounds are not effective in frightening
starlings and most other birds
because, like humans, they do not hear
these sounds.
Harassing birds throughout the
evening as they land can be effective in
dispersing bird roosts if done for three
to four consecutive evenings or until
birds no longer return. Spraying birds
with water from a hose or from sprinklers
mounted in the roost trees has
helped in some situations. Beating on
tin sheets or barrels with clubs also
scares birds. A combination of several
scare techniques used together works
better than a single technique used
alone. Vary the location, intensity, and
types of scare devices to increase their
effectiveness. Two additional tips for
successful frightening efforts: 1) begin
early before birds form a strong attachment
to the site, and 2) be persistent
until the problem is solved. For a more
detailed discussion of frightening techniques,
see Bird Dispersal Techniques.
Avitrol®. Avitrol® (active ingredient:
4-aminopyridine) is a Restricted Use
Pesticide available in several bait formulations
for use as a chemical frightening
agent. It is for sale only to
certified applicators or persons under
their direct supervision and only for
those uses covered by the applicator’s
certification.
Avitrol® baits contain a small number
of treated grains or pellets mixed with
many untreated grains or pellets. Birds
that eat the treated portion of the bait
behave erratically and/or give warning
cries that frighten other birds from
the area. Generally, birds that eat the
treated particles will die. Avitrol® baits
are available for controlling starlings at
feedlots and structures. At the dilution
rates registered for use at feedlots,
there is a low but potential hazard to
nontarget hawks and owls that might
eat birds killed by Avitrol®. It is therefore
important to pick up and bury or
incinerate any dead starlings found.
Around livestock operations, Avitrol®
is sometimes used where the goal is to
frighten or disperse the birds rather
than to kill them. However, many
birds may be killed, and data are lacking
on whether the results of Avitrol®
use at feedlots occur because of frightening
aspects or from direct mortality.
Three Avitrol® formulations are
labeled for starling control at feedlots
(Pelletized Feed, Double Strength Corn
Chops, and Powder Mix). The formulation
most appropriate for a given
situation may vary, particularly if large
numbers of blackbirds are mixed with
the starlings. However, the Pelletized
Feed formulation is generally recommended
for starling control because
starlings usually prefer pellets over
cracked corn (corn chops). The Double
Strength Corn Chops formulation is
probably best for mixed flocks of starlings
and blackbirds. Because Avitrol®
is designed as a frightening agent,
birds can develop bait shyness (bait
rejection) fairly quickly. Prebaiting for
several days with untreated pellets
may be necessary for effective bait consumption
and control. If starling problems
persist, changing bait locations
and additional prebaiting may be
needed. If any Avitrol® baits are to be
used, contact a qualified person
trained in bird control work (someone
from USDA-APHIS-ADC or Cooperative
Extension, for example) for technical
assistance.
Repellents
Soft, sticky repellents such as
Roost-No-More®, Bird Tanglefoot®,
4-The-Birds®, and others consist of
polybutenes, a nontoxic material that
can be useful in discouraging starlings
from roosting on sites such as ledges,
roof beams, or shopping-center signs.
It is often helpful to first put masking
tape on the surface needing protection,
then apply the repellent onto the tape;
this increases effectiveness on porous
surfaces and makes removal easier.
Over time, these materials lose their
effectiveness and have to be replaced.
Recent research has found that flavoring
used in grape soft drinks, dimethyl
anthranilate (DMA), and methyl
anthranilate (MA) repel starlings from
livestock feed at rates that do not affect
cattle. Although subsequent field trials
showed that DMA may not be costeffective
in some situations, results
have indicated that MA has potential
for cost-effective starling repellency.
Research is ongoing to improve the
cost-effectiveness of this compound
and to develop its potential for managing
starlings at livestock facilities and
possibly for repelling birds from fruit
crops.
Toxicants
When using toxicants or other pesticides,
always refer to the current
pesticide label and follow its instructions
as the final authority on pesticide
use.
Starlicide
A chemical compound
developed for starling control during
the 1960s by the Denver Wildlife
Research Center is now commercially
available as a pelletized bait. It is sold
under the trade name Starlicide Complete
(0.1% 3-chloro p-toluidine hydrochloride).
Starlicide is a slow-acting toxicant for
controlling starlings and blackbirds
around livestock and poultry operations.
It is toxic to other types of birds
in differing amounts, but will not kill
house (English) sparrows (Passer
domesticus) at registered levels. Mammals
are generally resistant to its toxic
effects.
Poisoned birds experience a slow, nonviolent
death. They usually die from 1
to 3 days after feeding, often at their
roost. Generally, few dead starlings
will be found at the bait site. Poisoned
starlings are not dangerous to scavengers
or predators. However, to provide
good sanitation and to prevent
the spread of diseases that the birds
may carry, pick up and bury or incinerate
any dead starlings.
It is important to use fresh bait, as the
current formulation of Starlicide Complete
loses effectiveness in storage. Bait
kept on hand from one winter to the next
may lose some of its potency, and bait
kept for 2 years may not work at all.
How to Use. Field tests in both the
western and eastern United States
have established guidelines for using
Starlicide. For the best success in a control
program, we recommend the following
steps:
1. Observe birds feeding in and around
the livestock operation. Note the
number of starlings and when and
where they prefer to feed. The best
time for observing is usually during
the first few hours following sunrise
when birds are seeking their morning
meal.
2. Determine what species of birds are
feeding. If any protected birds, such
as doves, quail, pheasants, or songbirds,
are present, do not apply
toxic bait. For assistance or advice
on bird identification or nontarget
risk assessment based on the situation,
contact your local Cooperative
Extension office, USDA-APHISADC
office, or the state wildlife
agency.
3. Prebait, for best results, with a nonpoisonous
bait to accustom starlings
to feeding on bait at particular locations.
Place the prebait in areas
where the starlings concentrate to
feed, but where it will not be accessible
to livestock or other nontarget
animals. The best prebait is a highquality
food that resembles the toxic
bait in color, size, and texture. If
such prebait is unavailable, use a
good quality feed such as that normally
fed to livestock.
Prebait for 1 to 4 days until the
birds readily feed on the prebait. If
good consumption is not obtained,
move the prebait to another location
where starlings are concentrating to
feed.
4. Apply prebait and bait on cold days
when snow covers the ground. This
timing is more effective because
starlings become stressed for food
and concentrate in livestock feeding
areas.
5. Place prebait and bait in containers to
ensure proper bait placement and to
protect it from the weather (Fig. 9).
Black rubber calf feeder pans work
well. They do not tip easily, their
dark color does not frighten birds,
and bait is openly exposed. Empty
farm wagons, feeder lids turned
upside down, wooden troughs, or
other containers may also work.
Avoid brightly colored or shiny
containers or ones that might tip
and spill bait. At night, the containers
can be covered to protect the
bait from the weather. However,
they must be uncovered at dawn so
that starlings can feed as soon as
they arrive. At feedlots where large
numbers of starlings (more than
100,000) are involved, and where
large quantities of feed are available
on the ground, broadcasting bait in
alleyways as per label directions is
recommended.
6. Apply toxic bait after starlings feed
readily on the prebait by removing
all prebait and replacing it with the
toxic bait. Consult the label directions
for the amount to use (1
pound [0.45 kg] of Starlicide Complete
used properly will kill about
100 to 200 starlings). The total number
of starlings using a farm over a
long period of time may greatly
exceed the numbers observed on a
given day, so continue baiting for at
least 2 or 3 days or until bait consumption
diminishes. Bait should
be available to the starlings at all
times when they are present.
Good bait acceptance may be more
difficult to obtain in warm-weather
climates such as in the southernmost
states. If this occurs, and the
Starlicide Complete bait is not
eaten, an alternative may be to use
Starlicide Technical (98% active
ingredient) applied to baits such as
french-fried potatoes, small fruits,
or livestock feed according to label
directions. The french fries and
fruits may be more attractive to
starlings, but they can spoil rapidly.
Generally, livestock feed makes an
acceptable bait because starlings are
accustomed to feeding on it.
Starlicide Technical can be used
only by or under supervision of the
USDA-APHIS-ADC for control of
blackbirds and starlings at livestock
operations. Contact them for help.
7. Remove bait after bait consumption
diminishes. Observe any birds
arriving at the feedlot during the
next 2 to 3 mornings after baiting.
Reduced bird numbers at this time
indicate control, as most birds will
die at the roost. If starlings continue
to be present, or if they gradually
return in increasing numbers, wait
until a number of birds are regularly
returning to feed at the area.
Then apply prebait and toxic bait
(Steps 4 to 6) as before. Do not leave
Starlicide baits exposed for prolonged
periods because this may
cause bait shyness (bait rejection),
and may also increase hazards to
protected bird species.
8. Group baiting may increase effectiveness.
Consider coordinating control
efforts with your neighbors. Several
persons baiting at the same time
will produce better control because
starlings may forage over a large
geographical area and may change
feeding sites from day to day. Notify
local wildlife officials of your
plans so that if large numbers of
starlings are removed, the officials
will be able to explain the die-off.
Contact USDA-APHIS-ADC officials
about the possibility of using
roost control procedures if a large
roost is associated with the damage
problem.
9. Cautions: Starlicide is poisonous to
chickens, turkeys, ducks, and some
other birds. Never expose bait
where poultry, livestock, or nontarget
wildlife can feed on it. Do not
repackage pesticides into anything
other than their original containers.
Read and follow all label directions.
Toxic Perches. Toxic perches are
perforated metal tubes 24 or 27 inches
(61 or 69 cm) long containing a wick
saturated with a contact toxicant that
enters the feet as the birds perch on the
tube. They can be safely and effectively
used in certain industrial and other
structural roost situations where they
do not present hazards to nontarget
birds and avian predators such as
hawks and owls. All killed birds
should be picked up immediately and
buried or burned because of potential
hazards to other wildlife.
The active ingredient in toxic perches,
fenthion (Rid-A-Bird Perch 1100 Solution),
is federally registered as a
Restricted Use Pesticide for use in
these perches. Fenthion is rapidly
absorbed through the skin and should
be used with caution to avoid spillage
and exposure to the handler. It is toxic
to humans, birds, fish, and aquatic
invertebrates. For additional information
on fenthion, refer to Pesticides.
Agents for Roost Control. Roost
control has been used to reduce starling
damage at livestock feedlots and
in urban areas where there are human
health and sanitation concerns. A
recent study indicates, however, that
roost control with wetting agents (no
longer registered) may not consistently
provide long-term reduction of birds
at feedlots, despite mostly favorable
results in reducing urban problems.
The presence of other roosting populations
near the treated roost may be an
important factor. At urban sites having
mild winter climates, the accumulation
of bird carcasses can produce a severe
odor and fly problem if carcasses are
not picked up or buried at the site
soon after roost treatment. Bulldozing
sites is the most efficient method to
bury carcasses, but soil disturbance
during this process may present human
health hazards from dissemination
of histoplasmosis spores. Such
roost control should be considered
only as a last resort when other alternatives
are not likely to solve the problem
in livestock and urban roost
situations.
Currently, the only material registered
for roost control is Starlicide Technical,
which is used for baiting at or near
roost sites in areas where starlings congregate
before roosting. This method is
currently registered for use in only a
few states and only under supervision
of USDA-APHIS-ADC personnel. A
federal registration is pending.
Although this method of roost control
is labor-intensive, it has been effective.
Fumigants
Fumigation is generally not practical
for starling control, and no fumigants
are registered for this purpose.
Trapping
Trapping and removing starlings can be
a successful method of control at locations
where a resident population is causing
localized damage or where other
techniques cannot be used. An example
is trapping starlings in a fruit orchard.
Two types of traps, nest-box and
decoy traps, are commonly used. Nestbox
traps are successful only
during the nesting season, whereas
decoy traps are most effective
during other times when the birds are
flocking. Nontarget birds captured in
traps should be immediately released
unharmed.
Decoy traps for starlings should be at
least 5 to 6 feet (1.5 to 1.8 m) high to
allow for servicing and can be quite
large (for example, 10 feet [3 m] wide
by 30 feet [9 m] long). A convenient
size is 6 x 8 x 6 feet (1.8 x 2.4 x 1.8 m)
(Fig. 11). If desired, the sides and top
can be constructed in panels to facilitate
transportation and storage. In
addition, decoy traps can be set up on
a farm wagon and thereby moved to
the best places to catch starlings. Place
traps where starlings are likely to congregate.
Leave a few starlings in the
trap as decoys; their feeding behavior
and calls attract other starlings that are
nearby. Decoy birds in the trap must
be well watered (which may include a
bird bath) and fed. A well-maintained
decoy trap can capture 100 or more
starlings per day depending on its size
and location, the time of year, and how
well the trap is maintained. Euthanize
captured starlings humanely such as
by carbon dioxide exposure or cervical
dislocation.
Shooting
Shooting is more effective as a dispersal
technique than as a way to
reduce starling numbers. The number
of starlings that can be killed by shooting
is very small in relation to the
number of starlings usually involved
in pest situations. Shooting, however,
can be helpful to supplement and
reinforce other dispersal techniques.
For more detail on dispersal, see Bird
Dispersal Techniques.
Economics of Damage
and Control
Consumption of livestock feed by starlings
can at times be a substantial economic
consideration. Data reported in
1968 from Colorado feedlots estimated
the cost of cattle rations consumed
during winter by starlings at $84 per
1,000 starlings. Current feed costs and
the associated losses would certainly
be much higher. A 1967 report
indicated that 1 million starlings at a
California feedlot resulted in losses of
$1,000 per day because of food consumption
and contamination, and
starling interference with cattle feeding
activity. Another report estimated
Remove old trigger mechanism
and cut through at this point.
that starlings in Idaho consumed 15 to
20 tons (13.5 to 18 mt) of cattle feed
per day. A 1978 study in England
estimated that the food eaten by starlings
in a calf-rearing unit over three
winters was 6% to 12% of the food presented
to the calves. Two other studies
in England since then found 4% losses
and negligible damage, respectively.
Producers who wish to estimate feed
losses to starlings at their facilities can
do so using one of two methods. The
following equation, which was developed
from data in Colorado, estimates
the cost of feed consumed per day:
Cost of feed ration consumed per
day = estimated starlings (to the
nearest 1,000) x fraction of birds
using trough x cost of feed ration
per pound (0.4536 kg) x 0.0625
pound (0.02813 kg) consumed
per starling per day.
A second method, which may be
applicable to most geographic areas,
precludes the need of estimating starling
populations. It requires the operator
to observe the feed troughs several
times during the day and estimate the
number of starlings entering the
troughs per day. From this estimate
the cost of the feed ration consumed
per day can be estimated with the following
equation:
Cost of feed ration consumed per
day = estimated starling entries
into troughs x 0.0033 pounds
(0.0015 kg) consumed per starling
entry x cost of feed ration
per pound (0.4536 kg).
These losses projected over a 3- to
4-month damage season can assist in
evaluating the costs and benefits of
proposed control measures.
Feed contamination from starling
excreta may not be an economic loss
for cattle or pig operations. In 2 years
of testing at Western Kentucky University,
neither pigs nor cattle were
adversely affected by long-term exposure
to feed heavily contaminated with
starling excreta. As compared to controls,
no significant differences were
observed in weight gain or feed efficiency
(ratio of weight gain to weight
of feed offered). In addition, there
were no observed differences in feed
rejection or disease incidence. These
results indicate that there is no economic
justification for starling control
based solely on feed contamination.
However, the effects of livestock water
contamination from starling excreta
have not been well studied.
Starling interference with livestock
feeding patterns may have economic
importance. A study in England
reported that calves in pens protected
from starlings showed higher growth
rates and better feed conversion than
those in unprotected pens. This protection
led to an increased profit margin.
The difference observed, however,
might have been caused by starlings in
the unprotrected pens consuming the
calf food, especially the high protein
portion, rather than by actual
interference with the calf feeding.
The costs associated with starlings in
the spread of livestock disease may at
times be substantial. For example, during
the severe winter of 1978-1979, a
TGE outbreak occurred in southeast
Nebraska, with over 10,000 pigs lost in
1 month in Gage County alone. Starlings
were implicated because the TGE
outbreak was concurrent with large
flocks of starlings feeding at the same
facilities. More recent data show that
starlings are capable of carrying this
disease in their feces. The role of starlings
in disease transfer, however,
needs further study.
Bird damage to grapes in the United
States was estimated to be at least $4.4
million in 1972; starlings were one of
the species causing the most damage.
Starlings, as well as many other
species of birds, also damage ripening
cherry crops. A 1972 study in Michigan
found 17.4% of a total crop lost
to birds. A 1975 study in England
estimated damage at 14% (lower
branches) to 21% (tree canopy) of the
crop; similar 1976 data showed less
damage. Starling damage to winter
wheat in a study of 218 fields in three
regions in Kentucky and Tennessee
averaged 3.8%, 0.5%, and 0.4% respectively,
with the most serious losses
(more than 14%) occurring where
wheat was planted late and fields were
within 11 miles (16 km) of a large starling
roost.
Human health and safety problems
associated with urban starling roosts
include concerns about the disease
histoplasmosis and about aircraft-bird
collisions. Although serious problems
occur only infrequently, they can have
grievous consequences where loss of
human life and/or permanent disability
may occur. Moreover, equipment
repair and replacement costs associated
with aircraft-bird collisions can be
substantial. For example, the costs of
aircraft-bird collisions in the United
States are estimated to be at least $20
million per year to commercial aircraft
and $10 million per year to Air Force
aircraft. These consequences mandate
a thorough understanding of urban
roost situations and timely roost management
where the potential for
human health and safety problems
exists.
On the beneficial side, starlings eat
large quantities of insects and other
invertebrates, especially during spring.
Many of these invertebrates, such as
lawn grubs, are considered to be pests.
This benefit, however, is partially offset
by the fact that starlings often take
over nest cavities of native insecteating
birds. As trends move toward
lower pesticide use and sustainable,
low-input turf and agricultural systems,
the role of starlings and other
birds may become more important.
Research is needed to further understand
potential positive impacts of
starlings and to learn how to maximize
potential benefits while minimizing
problems.
Although starlings are frequently associated
with damage problems, some of
which clearly cause substantial economic
losses, the economics of damage
in relation to the cost and effectiveness
of controls are not well understood.
Several factors contribute to this: (1)
Starlings are difficult to monitor
because they often move long distances
daily from roost to feeding
areas, and many migrate. (2) Effectiveness
of controls, particularly in relation
to the total population in an area, is
difficult to document. For example,
does population reduction in a particular
situation reduce the problem or
merely allow an influx of starlings
from other areas, and how does this
vary seasonally or annually? In addition,
does lethal control just substitute
for natural mortality or is it additive?
(3) The economics of interactions with
other species are difficult to measure.
For example, how much is a bluebird
or flicker worth, and what net benefits
occur when starling interference with
native cavity-nesting birds is considered?
(4) Other factors such as weather
and variation among problem situations
complicates accurate evaluation
of damage and the overall or longterm
effectiveness of controls. These
points, as well as others mentioned in
this chapter, are examples of factors
that must be considered in assessing
the total economic impact of starlings.
Clearly, to minimize starling-human
conflicts we need a better understanding
of starlings and their interactions
with various habitats and control
measures.
*The above information was taken from a University of Nebraska Web site with
express permission of Stephen Vatassel, wildlife damage project coordinator. |
