Middleton Island, Gulf of Alaska: Nest Box #2, North End, 2024 (Photo: D. Costa).
The 2024 season marked the 16th year of the Tree Swallow (TRES) project on Middleton Island, a remote outpost in the Gulf of Alaska. Led by Shannon Whelan, the ISRC field station crew managed to keep a close watch on the TRES population, despite their busy schedule focused on seabird research.
Tree Swallow on Middleton Island, North End, Gulf of Alaska, 2024 (Photo: D. Costa).
In early spring, four new cedar nest boxes were installed to replace older ones that had either not survived the harsh winter or were unlikely to last another breeding season. These new and robust cedar boxes were generously provided by Audubon Alaska, which granted the ISRC the funds to purchase 10 nest boxes last year. The design, recommended by Chris Gates (treeswallows.com), was quickly built and shipped by Glenn Foote, arriving just in time for installation in the spring of 2023. Although two of these boxes were installed last year, they went unused by the swallows, making us eager to see if they would be occupied this year and add value to the project.
One of the new Cedar nest boxes (# 2, installed last year). Middleton Island - North end, Gulf of Alaska, 2024.
When the TRES arrived on the island in 2024, they found 19 available nest boxes, crafted from various materials as part of an ongoing quest to discover the best (sustainable, durable, and affordable) designs that could withstand Middleton's extreme weather.
The crew kept a vigilant eye out for the first TRES, which was sighted on May 23—a single bird soaring past the Chateau.
Results of the 2024 Season:
Nest box check results August 4-6, 2024 (S.Whelan):
The crew kept a vigilant eye out for the first TRES, which was sighted on May 23—a single bird soaring past the Chateau.
Results of the 2024 Season:
Nest box check results August 4-6, 2024 (S.Whelan):
During the nest box checks conducted from August 4-6, 2024, the crew observed that five of the boxes were occupied, and at least four of these led to successful fledging of young swallows. The new cedar boxes proved particularly successful: three out of the six new boxes were used by the TRES, all resulting in fledged young. Shannon also documented each nest box and its contents with photographs, showing the promising outcomes, packed together here in a slideshow:
Unfortunately, not all stories had happy endings—three large chicks were found dead in Box 20, likely victims of the island's notoriously bad weather. While it's unclear if any chicks managed to fledge from that particular nest, the abundance of droppings in other successful nests suggested that large broods were fledged this year.
Distribution of Tree Swallow nest boxes on Middleton Island and their status in 2024:
Unfortunately, not all stories had happy endings—three large chicks were found dead in Box 20, likely victims of the island's notoriously bad weather. While it's unclear if any chicks managed to fledge from that particular nest, the abundance of droppings in other successful nests suggested that large broods were fledged this year.
Distribution of Tree Swallow nest boxes on Middleton Island and their status in 2024:
Overview of nest box history:
Despite the challenges posed by the environment, the new cedar boxes appear to be a success. If they'll last long enough, their design will likely serve as a model for future nest box installations on Middleton Island.
Acknowledgements
A heartfelt thank you to Shannon Whelan, Scott Hatch and the ISRC team, Audubon Alaska, Chris Gates, and Glenn Foote for their invaluable contributions to the project.
