Hey again from Ship Island, where the summer’s swelter presses ever-onward. Since our first hatching on 6/16, the crew here has put out over 500 bands on emerging chicks, but even this is just a small fraction of the total number of young birds growing up on Ship. With an average overall clutch size of 2.35 and over 680 breeding pairs of terns, there could be over 1,600 chicks swarming Ship Island right now! …And that’s ignoring all of the non-seabird species our tiny chunk of land in Blue Hill Bay plays host to. Of course, it’s just about impossible to catch and band them all; after barely 24 hours of life, the downy chicks will start making their first forays away from the nest bowl, making them quite difficult to locate and catch.
Lately, tern wrangling hasn’t been the only bird research conducted at Ship! Last week, we had a guest researcher and technician from the University of Maine come ashore with mist nets in tow. They are pursuing an ambitious project looking at character displacement and niche partitioning in multiple populations of coastal sparrows, from generalists like song sparrow (Melospiza melodia) and Nelson’s sparrow (Ammodramus nelsonii) to specialists like the rapidly-declining saltmarsh sparrow (Ammodramus caudacutus). We had a great few days of intellectual exchange; Kelby got to learn all about passerine capture and handling, and our guests had the chance to get immersed in an aggressive common tern colony!
No matter what kind of biological research with wild bird you are conducting, be it conservation/management, behavioral ecology, population demography, migration dynamics, or otherwise, there is one core action taken with the birds that is a constant across all of these disciplines: banding the bird.
With this in mind, I thought I’d take a moment to answer the single most common question I’m asked by laypeople when doing fieldwork: “why do you band birds in the first place?”
Like many questions, this one has both a short answer and a much longer answer. In its simplest form, bird banding serves one fundamental purpose: permanently mark an individual within a population.
An individual is typically marked with a federally-issued metal band that contains a unique combination of numbers (for example, most Ship Island bands this year lie somewhere between 1332-71600 and 1332-72000). Different countries issue different types of bands; here at Ship, we have resighted several common terns originally banded in Argentina. They have a totally different band format! There are hundreds of bird banding stations placed across the United States, Canada, and the neotropical wintering grounds of our many species; collaborative data collection from all of these stations gives us a detailed view of where birds are moving.
Federal bands aren’t even the only ones that you can use to mark birds; different varieties of field-readable bands allow researchers and birdwatchers alike to gather data on a bird without having to recapture it. A couple examples: the Refuge’s Arctic terns (Sterna paradisaea) receive metal field-readables with an alphanumeric code; numerous seabirds and waterfowl are labeled with colored field-readables with numbers or letters; songbirds everywhere are given colorful plastic color-bands in unique combinations to distinguish individuals.
These applications only brush the surface of all the research and management activities enabled by bird banding. If you think long enough about it, many more ideas spring to mind: hunters report banded ducks that they have taken; birders everywhere go out of their way to report field-readable bands; recapture data allow us to positively determine a bird’s age. The possibilities are nearly limitless, and all stem from the simple application of a small metal ring to a bird’s leg.
Back to the birds for me, now. The common terns on Ship are getting ready to fledge, and work presses ever onward.
Meredith @ Ship I.