Birds in Barns, Arenas and Hay Storage in Western Montana

Which birds move into barns and arenas?

Penn State Extension's guide to birds around farm buildings names four species that cause most of the trouble in and around barns: pigeons, European starlings, house sparrows and house finches. The first three are introduced species. Pigeons nest on ledges, rafters and beams. Starlings and house sparrows are cavity nesters that use holes in walls, drain pipes, gaps under eaves and the spaces behind rafters.

Barn and cliff swallows are the other regular tenants, and they are a separate case with separate rules. We cover them in our guide to swallows nesting on Montana buildings and will not repeat it here.

Winter changes the picture. A Utah State University Extension publication prepared with USDA APHIS Wildlife Services notes that in colder weather starlings roost in barns and other structures that give protection from wind and cold, and Cornell Cooperative Extension adds that starlings are drawn to the food and water at livestock operations particularly during the winter months.

What do birds do to feed, water and livestock health?

Penn State Extension states the concern plainly: birds may consume and contaminate food and water, potentially transmitting diseases to livestock and poultry. Cornell's 2025 dairy fact sheet says starling droppings in feedlots, dairies and poultry farms can lead to food safety concerns, and names Shiga toxin-producing E. coli and Salmonella as examples.

The Utah State publication reports that starlings have been documented to transfer disease between livestock facilities. Its example is transmissible gastroenteritis in hogs, a virus that it says can pass through a starling's digestive tract and reach hogs through droppings on feed. The same publication is careful to add that the virus also travels on boots, vehicles and newly added animals, so birds are one route among several.

On avian influenza, Cornell reports that the highly pathogenic strains have rarely been found in starlings to date and that Canada geese and other waterfowl are much more likely to carry them. None of this is a diagnosis. If animals are sick, that is a question for your veterinarian.

What do droppings do to hay, tack and equipment?

Whatever sits under a roost gets coated: the top tier of a haystack, the tractor parked in the same bay every night, saddles on an open rack, arena footing under a truss. Penn State notes that accumulated droppings are messy and can corrode farm equipment, that nests often plug drains and gutters, and that birds may damage insulation. The Utah State publication also says the acidity of droppings can corrode metals.

There is a human health side to old accumulations as well. Dry scraping and sweeping put dust in the air, which is why our bird dropping cleanup uses wet methods, protective equipment and contained disposal.

Which barn birds are protected?

The U.S. Fish and Wildlife Service's published list of birds the Migratory Bird Treaty Act does not apply to includes the rock pigeon, and the same notice explains that house sparrows and European starlings belong to bird families the Act does not cover. That is the federal position. Utah State's publication advises checking with the state wildlife agency before any control program, because state and local rules can differ, and in Montana that agency is Fish, Wildlife & Parks.

Everything else in the rafters should be treated as protected. Penn State points out that the house sparrow is the only sparrow that is not protected, which makes identification the first step, and the Fish and Wildlife Service states that all swallows are protected and that nests with eggs or chicks may not be touched without a federal permit. House finches are native to the West and fall on the protected side too. The details are in which birds you can remove in Montana.

How do you keep birds out of a building with open sides?

You do not try to seal the whole structure. You take away the part the birds want, which is the overhead framing. The Internet Center for Wildlife Damage Management says roosting in a tool or machinery shed, barn or similar building can be permanently prevented by screening the underside of the rafter area with netting, and that panels can be cut into the net and fitted with fasteners so lights and equipment above it can still be serviced. Penn State and Utah State give the same advice.

That is the core of our barn bird control work: tensioned netting and exclusion under trusses and purlins, so the arena or hay bay stays open at ground level and closed where it counts. Gaps matter as much as nets. Cornell and Utah State say to close openings larger than one inch to keep starlings out, and Penn State sets the figure at half an inch, which is the size that also stops house sparrows.

Ledges and beam tops that cannot be netted can be fitted with a cover angled at 45 degrees or more, a method Penn State, Utah State and ICWDM all describe. Penn State cautions that spike strips are not effective against small birds such as house sparrows, because the birds fit between the points and nest there.

What about doors that have to stay open?

Cornell and Utah State both describe heavy vinyl or rubber strips hung in open doorways of farm buildings, which let people, livestock and machinery through while keeping birds from flying in. Cornell's specification is strips ten inches wide hung no more than two inches apart. Utah State notes that netting across a doorway can also work but may be torn by machinery or livestock, which is worth knowing before anyone nets the main door of an arena.

How much do spilled feed and open water matter?

A great deal. Penn State calls the abundant food supply one of the primary reasons birds gather at livestock facilities. Its daily list is short: clean up spilled grain, store grain in birdproof containers, use covered feeders where possible, and keep waterers at a level that is too deep for a bird to stand in but too low to reach from the rim.

Cornell adds a few more: feed in covered areas, use cubes or blocks larger than half an inch, which it says starlings cannot manage, and drain standing water that serves no purpose. Exclusion without feed management leaves a flock with every reason to keep testing the building.

Do scare devices work in a barn?

Not for long, and some not at all. Utah State states that ultrasonic devices are not effective frightening tools, because birds do not hear those frequencies. Cornell describes frightening devices generally as having limited effectiveness, and notes that sticky repellents on beams and ledges are quickly fouled by dust and dirt, which limits their use on most farms. Around horses, noise makers bring their own obvious problems. Our guide on whether bird scare devices work goes through the evidence.

Where to start

Walk the building at dusk and note where birds are going in and where they settle, then look at the floor in the morning to see what is under them. Note any mud nests, because those change the timing. That short survey is most of what we need to scope a job, and it is the same first step we take on every bird mitigation project.

More species and building guides are collected in the Montana Bird Control Guide.

Call HJ Property Care & Tree Service at (406) 215-7319 or request a bird assessment and we will identify the species, the access points, and what will actually stop them.

More resources