Whether you hate the mess barn swallows leave or enjoy being able to watch them up close, a Texas A&M AgriLife Extension Service expert encourages you to plan for these birds’ arrival now.
The migratory spring season for swallows started March 1 and barn swallows will typically enter the southern U.S. in mid-March to mid-April. 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 an overhang or covered ledge, and a supply of mud they deem the proper consistency for nest building. If your property meets these building requirements, odds are good swallows will be back year after year unless you intervene.
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, said if you don’t want barn swallows on your property, then you 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 your house or structure and the resulting bird droppings underneath isn’t appealing,” Tidwell said. “Too many nests can also become a health concern.”
Tidwell said nests by entryways may also be a nuisance when swallows act territorial and “divebomb” homeowners to protect their nest and young.
“Luckily swallows are not as aggressive as blue jays or mockingbirds and swallows won’t peck at your head like they will,” she said. “And often once swallows get used to your presence and know you aren’t going to harm the nest, they will stop swooping down on you as you come and go from your structure.”
How to prevent barn swallow nests
Tidwell shared advice for preventing the swallows many Texans consider unwanted and pesky guests.
- Use netting or wire mesh hung diagonally to cover areas where swallows could build nests — typically anyplace like an eave or where a roof and wall meet.
- Surfaces can also be covered with materials hung vertically to prevent birds from getting to their 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 you may see in a grocery store for workers in refrigerated areas.
- Knock down old nests that are empty. Birds will reuse nests from previous years if available.
- When you see a new nest starting to be constructed, 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, the law says you’ll be stuck with the nest until it is empty again.
What to avoid when preventing barn swallows
- No repellents are known to be effective.
- No toxicants are registered for use.
- Trapping is not allowed.
- Shooting is not allowed.
- Barn swallows are not easily frightened so trying to scare them away using any method is usually ineffective.
How to remove a barn swallow nest
Old, empty nests and the mud for nests birds are beginning to construct can be removed several ways.
- A pressure washer or hose.
- A pole.
- A scraper or chisel can be used, however if you are getting close enough to a nest to use those tools, protective gear should be used. Gloves and a mask should be worn — if you have a respirator or leftover N95s now is the time to put them to use.
- Use caution. Blood sucking parasites and mites can survive in nests long after the birds have left, even as long as three years. You do not want to come in direct contact with a nest potentially filled with parasites, mites and feces.
Four reasons why you might want to welcome swallows
- Swallows eat the insects that many people consider pests. Essentially, they are providing a free ecological service — catching insects for you. And the more mouths to feed, the fewer insects you’ll have.
- The proximity of nests to doorways and windows makes for easy bird watching.
- The educational experience of seeing the baby birds start as eggs then grow from hatchlings to nestlings to fledglings. At the juvenile stage, they will leave the nest. The birds have an extended breeding season, and two or more clutches are common.
- They’re just passing through. They’ll be gone when the weather gets chilly again.
With a breeding season starting late March, nests will soon be built and occupied. Now is the time to act—whether that means hanging out a welcome sign or discouraging the birds from taking up residence.
“Swallows have a tendency to return to previous nesting locations,” Tidwell said. “So, if you’ve had birds in the past, odds are good you’ll have them again.”