A handful of miles south of Sacramento, 6,550 acres of protected land sits inside the boundaries of the Stone Lakes National Wildlife Refuge. It is a crucial link in the Central Valley's natural landscape corridor and the Pacific Flyway for migratory birds. Every two weeks a group of experienced, dedicated volunteers gather on a weekday morning to band birds. I was fortunate to be able to observe a recent session.
Bird banding involves much more than simply fitting an aluminum band inscribed with a unique number on a bird's leg. As much information as possible about the bird is collected: species, age, sex, weight. Measurements are taken of the wing, tail and beak; any deformities are noted. There may be other research data being collected; on this day, a UC-Davis post-doc student was obtaining cloacal swabs to test for the presence of E.coli and salmonella bacteria on the birds.
The welfare of the bird is the top priority during the banding session. Banders go through a lengthy educational and permitting process. Weather conditions, temperature, time of day, frequency of checking the nets, the amount of time handling the bird are all considered during the operation. For example, it is often difficult to sex a bird outside of its breeding cycle; not a lot of time is wasted trying to figure it out.
Migratory birds face unique stresses. Data obtained during a banding session (along with data collected if a bird is recaptured, resighted, or harvested during game season) help us understand population dynamics, expansion or contraction of colonies and territory, habitat requirements, and the annual cycles of nesting, molting, and migration. Conservation and management of avian populations and habitat, along with general education of the public, depend upon accurate and reliable data being collected, shared and published by banding operations like this one at Stone Lakes NWR.