Feathers and friction

As swallows return to the skies, their springtime nesting collides with construction season and human habitats

The writer Robert Wilson Lynd once quipped that “in order to see birds it is necessary to become a part of the silence.”

With the first day of Spring sprung, it takes little silence to notice the sights and sounds of nature on the wing in Oklahoma. Bridges and culverts are being frequented by cliff swallows, porches and entryways are attracting barn swallows, and Purple Martins are visiting birdhouses. This coincides with the breeding season, the presence of bugs and warmer weather.

The U.S. Fish and Wildlife Service (USFW) lauds swallows for doing an ecological service to humanity through insect control. The Purple Martin, North America’s largest swallow, has even helped Griggsville, Illinois, curtail its mosquito problem and earn the community a designation as the Purple Martin Capital of the nation.

But not all feathered guests are welcome, especially when it interferes with construction projects, agricultural operations and drive-thru lanes.

The Oklahoma Department of Transportation has published a paper that spotlights this conflict with two overlapping events in the state: nesting season for swallows and prime construction season. Both occur from April 1 to August 31, each year.

Due to the Migratory Bird Treaty Act of 1918, it is a violation of federal law to harm these birds through habitat modification or degradation — essentially anything that hinders behavior.

According to the National Audubon Society, Purple Martins increasingly nest specifically in man-made birdhouses; this practice dates to the Choctaw and Chickasaw tribes hanging hollow gourds within their villages in Alabama. The increased presence of roadways and bridges also provides an abundance of artificial nesting sites for cliff swallows to build in communities; barn swallows tend to nest in areas of isolation.

So what is a homeowner to do?

USFW outlines possible solutions based upon specific criteria: a nest is being built, a nest is built and/or eggs or brooding (feathered) young are present.

First, if a nest is being built, get rid of old nests to discourage reuse, and remove the introduction of new nests; then, put physical barriers in place to prohibit further use. In nuisance wildlife control terms, this is exclusionary work and can include bird spikes.

Second, if a nest is built, for cliff swallows wash away mud structures between visits from the birds; there must be no eggs present to legally use this remedy. Also, utilize audible deterrents (noise), and/or visual deterrents (spinners, balloons, and decoys).

Third, if eggs or a brood are present in an established nest, let them be.

Swallows can produce two clutches of young per year, with clutch sizes between three and five eggs each. All total, from incubation to fledging, 31 to 41 days is needed for young to leave a nest. Note that these offspring can visit the nest for weeks before then leaving for good.