Tips provided to prevent barn swallow nests this spring

Whether a person hates the mess barn swallows leave or they enjoy being able to watch them up close, a Texas A&M AgriLife Extension Service expert encourages individuals to plan for these birds’ arrival now.

The migratory spring season for swallows started March 1. Of the eight species of swallows in North America, barn and cliff swallows are typically considered to be the most problematic since they build mud nests attached to houses, barns and other structures. 

Barn swallows tend to nest as single pairs, but cliff swallows can nest in colonies composed of up to several hundred pairs.

Swallows need a suitable surface to build a nest, typically on an overhang or covered ledge and a supply of mud they deem the proper consistency for nest building. If a property meets these building requirements, odds are good swallows will be back year after year unless someone intervenes.

Immediate intervention

AgriLife Extension’s Liz Tidwell, a small acreage wildlife program specialist in the Department of Rangeland, Wildlife and Fisheries Management in the Texas A&M College of Agriculture and Life Sciences-Uvalde, says if people don’t want barn swallows on their properties, they must immediately intervene before any nests are built and occupied.

The Migratory Bird Treaty Act, passed in 1918, makes it a federal crime to hunt, kill, capture, sell or otherwise hurt them, which includes destroying nests in use.

“The main reason people want to remove barn swallow nests is aesthetic. Having mud nests on the side of a house or structure and the resulting bird droppings underneath isn’t appealing,” Tidwell says. “Too many nests can also become a health concern.”

Tidwell also notes nests by entryways may be a nuisance when swallows act territorial and “divebomb” homeowners to protect their nests and their young.

“Luckily swallows are not as aggressive as blue jays or mockingbirds, and swallows won’t peck at a person’s head,” she says. “Often, once swallows get used to human presence and know we aren’t going to harm the nest, they will stop swooping down on people as they come and go from their structure.”

Preventing barn
swallow nesting

Tidwell shares advice for preventing swallows.

First, she suggests using netting or wire mesh, hung diagonally, to cover areas where swallows could build nests – typically any place such as an eave or where a roof and wall meet. Surfaces can also be covered with materials hung vertically to prevent birds from getting to preferred building sites.

Bird spike sticks and bird barriers can be purchased and installed to prevent birds from building nests.

For places where there is an open entry way, vinyl plastic hung in overlapping strips may be used. This is essentially a doorway curtain similar to what one may see in a grocery store for workers in refrigerated areas.

Tidwell also suggests knocking down old, empty nests, because birds will reuse nests from previous years if they are available.

“If an individual sees a new nest starting to be constructed, they should knock down the mud daily until the birds give up on their build. Once a bird starts spending time in the nest, even if it is not yet completed, laws say homeowners will be stuck with the nest until it is empty again,” she notes.

Things to avoid

When trying to prevent the building of barn swallow nests there are several things individuals need to avoid.

First, no repellents are known to be effective, and no toxicants are registered for use. Trapping and shooting are not allowed.

Additionally, barn swallows are not easily frightened so trying to scare them away using any method is usually ineffective.

Removing a nest

Old, empty nests and the mud for nests birds are beginning to construct can be removed several ways.

These include a pressure washer or hose, a pole and/or a scraper or chisel. However, when getting close enough to a nest to use those tools, Tidwell notes protective gear should be worn, including gloves and a mask. 

“If the person has a respirator or a leftover N95, now is the time to put them to use,” she says. 

She also encourages individuals to use caution, since blood-sucking parasites and mites can survive in nests long after the birds have left, even as long as three years. 

With a breeding season beginning in late March, nests will soon be built and occupied, so now is the time to act.

“Swallows have a tendency to return to previous nesting locations,” Tidwell concludes. “So, if a person has had birds on their property in the past, odds are good they’ll have them again.”

Susan Himes is an agricultural communications specialist for Texas A&M AgriLife Extension Service. This article was originally published by the Texas A&M AgriLife Extension Service on March 21.