We estimate that 30 – 38 pairs of Barn Swallows nested in the Fort River Boat House in 2020.
Of 98 adult swallows banded at Fort River in 2019, 27 were recaptured in 2020 (28%). This number is probably lower than the actual number present due to fewer banding days conducted this year during the pandemic. This return rate is similar to rates found in other studies of Barn Swallows. While a 28% return rate may not seem particularly high, remember that swallows banded in 2019 made two long migrations to and from South America before returning to breed in Massachusetts in 2020. And, because returning Barn Swallows don’t show perfect site fidelity, some individuals may have simply chosen to nest elsewhere in the area.
This Success Informs Future Conservation Actions
Aging barns occupied by Barn Swallows are a common feature in New England’s historical agricultural landscape, and sometimes these structures simply cannot be saved. Thanks to the help of collaborator Andy French, project leader at the Conte Refuge, we have learned important lessons about how to attract and relocate Barn Swallows into alternative structures where they can be protected in cases where occupied barns must be removed. Some of the steps that were taken included:
Collection of some nests after the breeding season to use in attracting swallows the following year to a different, more secure nesting location. A majority of nests built in 2020 were built on top of “seed” nests that had been harvested in 2019.
Placement of nesting structures, hung from the Boat House rafters, to provide nesting sites. Some of these structures also included defecation screens that prevented swallow droppings from raining down on equipment below—an important consideration for private landowners who often have to deal with bird damage to their tractors and other farm equipment.
Playback of Barn Swallow vocalizations was used in 2019 to advertise the availability of the Boat House site to pairs that were nesting in the nearby Bri Mar Stable. In 2020, we decided not to play audio recordings because Barn Swallows had already begun to move into the Boat House in 2019.
Next Steps for Aerial Insectivore Conservation
Mass Audubon also hopes to continue to contribute to a developing US Fish and Wildlife Service initiative aimed at conserving aerial insectivores (e.g., Barn Swallows, Cliff Swallows, Chimney Swifts, bats, etc.), pollinators that feed in fields and field edges, and grassland-nesting species in the Connecticut River Valley. If we are successful in securing funds, we hope to collaborate with the Conte Refuge in 2021 to deploy VHF nanotags on breeding Barn Swallows to learn more about the locations of important feeding areas with presumably healthy insect populations. This work would also include education activities, working with private landowners to maximize the conservation benefits associated with their farms, as well as conducting inventories of declining birds and other taxa. We’ll post more information about these efforts in future blogs.
Last summer, Mass Audubon’s Director of Bird Conservation, Jon Atwood, collaborated with Andy French, project leader at the Silvio O. Conte National Fish and Wildlife Refuge, to study Barn Swallows that were nesting in an aging horse stable destined for demolition during the non-breeding season. Approximately 40 pairs of swallows nested in the stable during 2019; an additional 4-7 pairs nested in an adjacent building, known as the Boat House, which the US Fish and Wildlife Service (USFWS) planned to set aside as a more long-term Barn Swallow nesting site and storage area. The aging horse stable was eventually demolished after the resident swallows had migrated to their South American wintering grounds.
The Barn Swallows are back!
We have good news to report! As hoped, the majority of swallows that nested in the stable in 2019 have returned and set up housekeeping in the Boat House. As of June 16 (still relatively early in the breeding season), 30 pairs were actively nesting in the Boat House, and four additional pairs had established nests in nearby artificial structures built for this purpose.
Last year Jon banded many (but not all) of the Barn Swallow adults so that we could tell if they returned to the site in future years. Of 51 birds that have been captured using mist nets in the Boat House in 2020, 22 (43%) had been banded as adults in 2019 in the stable. In other studies, researchers have found that return rates of breeding swallows to undisturbed nesting sites have ranged from 20% in Oklahoma to 42% in New York. Although most Barn Swallows do not return to where they were hatched, we have even captured 2 individuals that hatched from nests that were located last year in the horse stable.
A new kiosk gives an up close look at the birds
USFWS has placed video cameras in the Boat House, and visitors can watch the nesting swallows feed their young from an observation kiosk located near the start of the 1.2 mile long universally-accessible Fort River Birding Trail. Visitors may also be greeted by the families of Tree Swallows and Barn Swallows that are also nesting in the kiosk. The kiosk will eventually house a professionally-designed and fabricated exhibit with information about aerial insectivores.
This success will lead to other successes going forward
Not only does this success story provide a happy ending to the difficult management debate that swirled around the U.S. Fish and Wildlife Service’s decision to remove the horse stable, but these efforts have also paved the way for future conservation actions that can be applied to other situations. Aging barns occupied by Barn Swallows are a common feature in New England’s historically agricultural landscape, and sometimes these structures cannot be saved. Through the experience at Conte Refuge we have learned important lessons about how to attract and relocate Barn Swallows into alternative structures where they can be protected if occupied barns need to be removed.