Current Nature: Celebrating Spring With Our Tree Swallows

Libby Buck, Conservation Science And Land Steward At The Linda Loring Nature Foundation • Apr 14, 2024

Male Tree Swallow. Photo by Vern Laux

Guess who's back on island to kick off spring in style? That's right - the tree swallows have returned, and they're putting on quite the show across our island.

Around this time of year, these fantastic iridescent blue-green birds start showing up, fresh from their winter adventures down south in places like Florida and Central America. It's always exciting to see them flock together, almost like a migration party on our island. We are thrilled to have them back with us.

If you've never seen a tree swallow, picture this: a flock of small birds with shimmering feathers swooping through the air like tiny fighter jets, snagging bugs on the fly. Besides being delightful to watch, tree swallows help regulate the insect population and tell us a lot about the environment's health. Their return is like a springtime alarm clock, signaling that warmer days and blooming flowers are on the horizon.

2) First sighting of a Tree Swallow at the LLNF Property for the 2024 season. Photo by Seth Engelbourg

Tree swallows are cavity nesters, meaning they love nesting in tree holes and birdhouses, so keep an eye out, especially around our ponds and coastal areas—they love habitats known for flying insects. For the best chance of spotting them, head to spots like Linda Loring Nature Foundation, Coskata-Coatue Wildlife Refuge, or anywhere near Miacomet Pond. You'll hear their cheerful chirps and maybe even catch a glimpse of their fancy aerial displays.

Male Tree Swallow in flight. Photo by Lorri Howski/Macaulay Library

But there's more to these aerial acrobats than meets the eye. The Linda Loring Nature Foundation (LLNF) is conducting a vital study on these nesting birds, focusing on population ecology, conservation biology, and behavioral ecology. The LLNF team has placed over 50 nest boxes in strategic locations to study the nesting success of tree swallows. Over the past decade, tree swallows have predominantly occupied these boxes, underscoring their significance in our local ecosystem and the importance of the LLNF's work.

LLNF staff monitoring Tree Swallow nest boxes. Photo by Libby Buck

Why is it crucial to study these birds? Recent research from the Cornell Lab of Ornithology has revealed a significant decline in North American bird populations, with swallows among the top ten families experiencing losses. The LLNF Nest Box Monitoring project is a proactive initiative to protect and enhance these breeding birds, particularly tree swallows. By providing safe nesting spaces and closely monitoring their breeding success, the LLNF is playing a vital role in the conservation of these species.

Adult Tree Swallow incubating newly hatched chicks at LLNF. Photo by Libby Buck

This study has helped us understand the impact of climate change on bird behavior. As temperatures rise and rainfall patterns change, it can affect the timing of nesting, the number of chicks raised, and food availability for birds. Other researchers expect that nesting may occur earlier during warmer years, and that egg size may be smaller during years with higher precipitation. This is due to the sensitivity of insects, which are a primary food source for Tree Swallows, to changes in spring and summer temperatures and rainfall. By studying nesting patterns and climate data, the LLNF hopes to monitor these changes and contribute to broader conservation and climate research efforts.

As you enjoy watching tree swallows soar overhead this spring, remember that their presence here represents more than just a seasonal return—it's a chance to learn, protect, and appreciate the incredible wildlife that shares our island home.

Stay tuned for more editions of Current Nature, a bi-weekly column featuring seasonal topics, natural history information, and advice on the outdoors from the staff at the Linda Loring Nature Foundation.