European Starlings Nesting in Vents, Soffits and Gaps in Montana

How do you know it is a starling?

The Montana Field Guide describes the European starling as a compact, stocky bird with mostly glossy black plumage showing purple and green iridescence, a short squared tail, pointed wings and a long bill, which is yellow in spring. After the fall molt the feathers carry whitish or buff spots. It is listed as a non-native species in Montana.

USDA APHIS Wildlife Services notes that starlings in winter often mix with blackbird flocks and get misidentified as blackbirds, although the two are not related. That matters, because native blackbirds are protected and starlings are not. The short tail and the triangular wings in flight are the quick field marks.

Why do starlings nest in vents and soffits?

Because they are cavity nesters and a building is full of cavities. Montana Fish, Wildlife & Parks (FWP) says starlings exploit any opening in buildings, such as dryer, range and bathroom vents and gaps around roofs and walls. APHIS lists vents, rafters, soffits, lampposts and signage bracing, and says urban and suburban starlings commonly use building exhaust vents as nest sites. The Montana Field Guide puts it most simply: nests can be found virtually anywhere a cavity can be found.

Both parents build the nest from long grasses and other vegetation, and APHIS says they may work in cloth, string, plastic and feathers. In a vent duct that is a plug. APHIS states that nests can clog vents and create unsafe venting conditions. The mechanics of clearing a dryer or bath fan line are covered in our separate guide to birds in dryer and bathroom vents. Larger cavities are in birds in the attic or soffit.

Are starlings protected in Montana?

No. FWP states that European starlings are not protected by federal or state law. APHIS says they are not protected by the Migratory Bird Treaty Act and that no state laws in the U.S. directly protect them. The U.S. Fish and Wildlife Service notice listing birds the Act does not apply to explains that the starling family is outside it, and Montana's wild bird protection statute names starlings, with their nests and eggs, among the birds it does not cover.

APHIS adds the practical limits: methods may be regulated by local ordinances, and owners should check with state and local agencies before starting any control program. The bigger risk is misidentification. A hole in a wall or a vent may hold a native bird instead, and FWP notes that starlings take over cavities from native hole-nesting species. A swallow, a bluebird or a flicker in the same opening is protected, and Montana bird nest removal law applies. Confirm the bird before touching the nest.

When do starlings nest?

APHIS gives the reproductive period as late March through early July, depending on latitude. A clutch is four to seven eggs, incubation takes about 13 days, and the young fledge roughly three weeks after hatching. APHIS adds that south of 48 degrees north two clutches are often attempted, and Missoula and the Bitterroot lie south of that line.

Site loyalty is the part that matters to a homeowner. APHIS reports that once a pair is established on a successful territory, one or both birds may return year after year. A vent that held starlings last spring is likely to hold them again unless it is closed.

What mess and noise should you expect?

Inside, the sound is scratching and the constant begging of nestlings. APHIS notes that both parents feed the young and may make up to 20 trips an hour, which is why a wall cavity seems to be busy from dawn. Outside, expect droppings streaked below the opening and nest material pushed out of the hood.

FWP says starlings have been associated with histoplasmosis, chlamydiosis, salmonellosis and West Nile virus, and that they whitewash buildings with their droppings. APHIS explains that histoplasmosis comes from inhaling spores of a soil fungus that thrives where bird droppings have enriched the ground. It also notes that most cases occur in the central, southeastern and mid-Atlantic states. Old nest material can also carry mites, which we cover in bird mites after nest removal. If you feel unwell after a cleanup, see a clinician.

Why do starlings mob barns and feedlots in winter?

Food and water. FWP says starlings consume and contaminate livestock feed and water, and cites an Alberta figure: a winter flock of 2,000 starlings can eat one to two tons of feed in a month and spoil another 500 to 1,000 kilograms. It adds that they may pick the high-protein portion out of supplemented feed. APHIS reports research at cattle feedlots linking the number of starlings on site with Salmonella contamination of feed and water troughs.

APHIS is emphatic that feed management comes first: use covered feeders or feed under cover, avoid putting feed on the ground, clean up spilled grain, and reduce unnecessary standing water. For the building itself it recommends netting the underside of roof beams to keep starlings out of barns and sheds, and heavy plastic or rubber strip curtains across doorways used by people, machinery and livestock. Our guide to birds in barns and arenas goes further.

How is starling exclusion done?

FWP calls exclusion one of the best choices for homeowners and is specific about materials: evict the birds and seal the entrance with hardware cloth or metal flashing. It warns that light materials such as nylon or plastic netting and window screen will not keep out determined starlings, which can tear them out. New Mexico State University Extension gives the gap size, advising that all openings greater than one inch be closed to exclude starlings.

On ledges and beams, APHIS recommends 45-degree coverings so there is nothing level to stand on, and FWP notes that a starling needs only about an inch of space to perch. For larger openings and open-sided structures APHIS calls netting highly effective if installed correctly. It also gives the warning that every installer should heed: birds trapped behind netting may die and decay. Nothing gets sealed until the cavity is confirmed empty. Vent covers must still let the appliance exhaust properly, so we fit screening made for the purpose.

When should exclusion be timed?

Because starlings are unprotected, the law does not set a nesting window for them the way it does for native birds. Timing is still worth getting right. The cleanest window is late summer through winter, after the last brood has fledged and before pairs claim sites again in March. Work done then closes an empty cavity.

If a nest is found in season, the first step is confirming the species. After that, because starlings are not protected, the nest does not have to be left until the end of the season, which matters when it is blocking a dryer or a bath fan. What does not work is hazing them out of a cavity. APHIS reports that starlings quickly habituate to visual and audio deterrents.

What should you do next?

Look at every vent hood, soffit return and gap at the roofline from the ground, and note which ones show grass or droppings. Our bird mitigation assessment confirms the species and the entry points, and bird nest removal covers clearing the cavity before it is screened. The rest of the species guides are 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.

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