The bluebirds of happiness: Mashomack’s 20-year old-project brings birds back

Bluebirds are a near-universal symbol of happiness. Ask anyone who has volunteered to monitor Mashomack’s Nest box Trail, and they’ll describe the joy of seeing tiny blue eggs in a tightly woven grass nest, or a brilliant blue tree swallow diving for a floating feather to add to his nest.

These volunteers helped bring back the population of native birds who were almost eradicated by the hand of man 40 years ago.

Eastern Bluebirds are New York’s State Bird, and were so common in the early 20th century that they outnumbered robins. By 1970 the population of bluebirds in New York had fallen by 92% due to DDT and the loss of habitat that came with development.

In 1972, DDT was banned in the U.S. and across the Northeast, bird-lovers began to erect and monitor groups of nest boxes to replace the habitat lost to development, and bring back the Eastern Bluebird.

The Nest box Trail Project came to Shelter Island when Tom Damiani began erecting and maintaining boxes, and in 2001, Mashomack starting participating and organizing volunteers.

For many years, the volunteers were led by Dr. Bill Zitek, a local veterinarian, and later by Linda Hacker, with the support and encouragement of Mashomack’s naturalists, including Cindy Belt and Rebecca Kusa.  

Eastern Bluebirds have always been the focus of Shelter Island’s nest box project, but as more was learned about how bluebirds and tree swallows can successfully nest near each other, nest boxes were erected in pairs to encourage both tree swallows and bluebirds to breed at most sites.

From spring through summer, the nest boxes are monitored by a group of volunteers who go out into the woods and fields every week or so from late March through August to check the boxes and record what they find for bluebirds and their nest box neighbors, the tree swallow.

They note when these migratory birds arrive, when the birds start building nests, as well as the dates of first eggs, hatching and numbers of fledglings.

Alongside the successful nests are failures caused by competition from predators such as raccoons and snakes as well as house wrens and house sparrows. Volunteers record the inevitable damage and mortality they find; unhatched and broken eggs, dead hatchlings and parents and abandoned nests.

In 2001 the Mashomack nest boxes numbered 34, grouped in pairs to allow Bluebirds and Tree Swallows to nest alongside one another. There were 15 Eastern Bluebirds fledged that year and 52 tree swallows. By 2017, 61 nest boxes were monitored at Mashomack.

The number dropped to 30 during the pandemic when the volunteer program was inactive. The number of fledged bluebirds shot up in 2020 to 82, and 106 tree swallows fledged.

This year, with 30 nest boxes, 37 bluebirds and 71 tree swallows successfully hatched and fledged, nearly twice the number in 2001 when the program began. The results this year, and every year are included in the New York State and the national population surveys.

Twenty years of gathering and analyzing data has taught us a lot about two of our most-loved native migratory birds, and how we can encourage them to live here in spite of increasingly intense development.

We’ve learned many things over years of tending the nest boxes, but the most important, and most applicable to the lives of Shelter Island humans, is this; if you provide housing for creatures you want more of, they will build a nest, have young, and bring the community a lot of happiness.