Tree Swallows Part II: Banding the Birds

Today I had my first experience “processing birds,” a procedure that the Savannah Sparrow and Storm Petrel teams reference all the time. According to Nat Wheelwright, when tree swallows were in their heyday on the Island, the record for processing was 80 birds before breakfast. We are unlikely to beat that record this summer, with only four tree swallow adults that we know of on the Island. We approached the first box, marked N-26.1 on our map and painted in faded, peeling black on the box door. From the outside, it looked like just another weather-beaten structure that in my mind had become part of the landscape of the sweeping fields on the South of the Island. Nat revealed the hidden life inside when he put his palm over the entrance of the box, opened a side panel, and plucked a female tree swallow from her nest with practiced deftness.

Processing a female Tree Swallow

Processing a female Tree Swallow

Nat showed Hannah, Tracey, and me how to hold her by carefully gripping her neck between our peace fingers and cupping her body with the rest of our hand. She was warm, soft, and more solid than I had expected, and I could feel her entire body throbbing with her heartbeat. Though she obviously longed to return to her safe nest, she hardly struggled her entire time in captivity, earning her the name “Pacifica.” Nat explained that tree swallows are generally calm and easy to work with, which is one of the reasons that they have been so well studied on Kent Island.

The first step of processing was to band Pacifica to be able to identify her if she returns next summer, and so that other scientists who encounter her during her migration can also identify her. Nat banded one of her legs with an embossed metal band with a code that will be entered into a global database, and the other leg with a pink plastic band so we can easily spot her in the field. Next, Nat fully extended her wing and measured it, pointing out the subtle bands on her feathers that each mark a month of growth. He explained that the regularity of these bands also reveals some of the biological history of the birds, because an inbred tree swallow will have irregular bands.

Feather color is also an indicator of age, and her dusty, brown feathers showed that she was under a year old, a mother for the first time. The chicks of young birds are less likely to succeed, because their parents have less experience nest building, foraging, and dealing with bad weather, which can wipe out an entire generation. Despite the higher risk of failure, the future looks bright for Pacifica’s chicks as long as the weather holds. When we lifted her from the scale, she shot out of the toilet paper tube that had contained her like a cannonball, and flew straight to her nest to care for her chicks. Processing our second female, who we named Calypso in the hopes that she will stay on Kent Island in the future, went equally smoothly. In eleven days we will return to her nest to band her chicks, and hopefully we can finagle a way to trap the males, which are much more difficult to catch. While it is depressing that only two tree-swallow pairs remain on the Island, especially for Nat who saw the population at its height, as long as there is life there is hope, and watching it emerge is an amazing thing.

A Tree Swallow Nest Box (photo by Tracey Faber)

A Tree Swallow Nest Box
(photo by Tracey Faber)

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