Bird Control Options (and non-options)
In the last issue of TFGV, I outlined the reasons that European starlings
are such successful immigrants to North America and such persistent pests
in grapes and tender fruit. Starlings are by no means the only birds that
can cause problems in grape and fruit production; other species frequently
cited as pests include robins, grackles, mockingbirds, waxwings, and blackbirds,
as well as a host of unlikely, but occasional fruit feeders such as goldfinches
and even gulls. There are behavioural differences between different types
of birds, but regardless of the species involved, the goal of growers
is to keep them from damaging fruit and grapes. When planning a bird management
strategy, refer to the OMAF factsheet Bird Control on Grape and Tender
Fruit Farms, Order No. 98-035, and always remember the fundamentals of
bird management:
- Start early before birds establish a pattern of fruit feeding on your
farm
- Using a variety of methods is much better than one single approach;
no method listed below is a stand-alone solution to the problem
- Unpredictability is the key to successfully disturbing birds - vary
devices, timing, and placement for best results with acoustical devices
- Communicate your plans with nearby neighbours to mitigate disputes
- Physical exclusion using nets is the most successful method to keep
birds from feeding on grapes
Physical exclusion (i.e. netting)
Pros: best single method of reducing bird feeding on grapes; effective,
reliable and not subject to bird acclimation (i.e. they can't "get
used to it"); economically feasible over life of netting; best of
all neighbours love nets compared to other bird scaring methods; research
to best timing of net draping underway and if there are other advantages
with training, or disadvantages with growth
Cons: significant cost outlay at first with on-going operating
costs
Propane cannons
Pros: effective, familiar and reliable; easy to service; relatively
cheap; best uses well - known (never fire at less than 3 minute intervals,
move around vineyard frequently, randomized rotating multi-shots units
work best, newer programmable units can be turned off at low feeding times
such as middle of the day)
Cons: Frequent noise complaints; theft or vandalism of units increasing;
acclimation of some birds if not moved around or random
Electronic sound devices
Pros: effective and reliable; generally less irritating to neighbours
than cannons; devices that mimic distress calls may also attract hawks
which repel pest birds
Cons: not everyone finds them less irritating; distress calls mostly
work only on the species mimicked
Whistling or pyrotechnic pistol cartridges
Pros: effective; no firearms acquisition certificate (FAC) needed
Cons: disturbing to some neighbours; require your presence to use
Shotguns
Pros: none
Cons: not generally effective and not as effective as pyrotechnic
units; require FAC; disturbing to neighbours; will not reduce population
of birds significantly; knowledge of legalities under Fish and Wildlife
Conservation Act regarding nuisance wildlife needed
Scare-eye balloons
Pros: effective on some species
Cons: not effective on robins or waxwings
Streamers and flashtape
Pros: cheap; relatively easy to install
Cons: yellow fine for blackbirds but red/silver needed for other
species; useless if not maintained properly
Flashing lights and mirrors
Pros: effective against starlings; solar powered units available
that require little maintenance besides frequent moving around vineyard
Cons: lights good at dusk and dawn only; mirrors only good in sunshine
Hawk silhouettes, stuffed owls, etc.
Pros: more realistic units on market now; cheap and easy to deploy
Cons: only effective for a short period of time; require very frequent
moving
Falconry
Pros: effective if sustained activity
Cons: expensive if hiring a service; birds of prey are not pets
and require significant investment in time and training for falconers;
long-term commitment necessary
Chemical repellents
Pros: nice idea in theory
Cons: no such product registered; no products used on other crops
(e.g. turf) that would not adversely affect flavour of grapes
Personal presence in vineyard (i.e. driving ATV etc. around)
Pros: none
Cons: not very effective for time and energy expended; not feasible
in large vineyards; potentially dangerous; physically exhausting as must
be constant presence to be effective
Trapping
Pros: none
Cons: expensive to construct traps; must separate and free all
migratory birds and non-nuisance birds (hence legal liability issues are
important) within 24 hours; must understand all responsibilities and applicable
directives under the Fish and Wildlife Conservation Act; nearly constant
maintenance of traps needed; must "seed" traps with some live
and cared-for birds (must provide water etc. for trapped and "seed"
birds); very low return for energy and money expended; American crows,
brown-headed cowbirds, red-winged blackbirds, common grackles, starlings
and house sparrows may be trapped and killed; will not greatly affect
local bird numbers
Poison and adhesives
It is illegal to use poison and adhesives to kill, injure or capture
wildlife.
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