Birds are temporarily captured in fine cotton mist-nets that are strung between poles. Mist-nets resemble volleyball nets, but are much softer, finer, and harder for birds to see!

We remove the birds quickly from the nets and take care not to harm them.

We then bring the bird to be "processed" either at our bird banding laboratory at the Coyote Creek Field Station or at a temporary field site we are monitoring.

Birds are very "cost-effective" and relatively easy to monitor as the equipment and materials needed to band are neither heavy nor too expensive. The things most needed to band are highly trained banders, dedication, and teamwork!

Each bird is given a loose fitting, uniquely numbered identification band around its leg. This ID number is the key that allows us and other bird observatories to track this bird if it happens to be recaptured in the future. Only one band is placed on each bird-when a bird is recaptured, we simply read the number on its existing band, take measurements, and let it go.

We use several band sizes to fit the many different leg sizes found on various bird species. They are comfortable but not too loose so that they fall off. We don't have to worry about banding juvenile birds with a band that might become too small when they get older since birds don't normally leave the nest until they are fully grown.

Vital information such as feather molt, breeding status, weight, sex and age is collected. This information is crucial for the population biology work we do at the San Francisco Bay Bird Observatory.

Bird banders are highly trained to pay close attention to what they see while processing a bird. For example, a way to often tell the age of a bird is by observing its skull through the transparent skin on its head. Many birds grow a second layer of skull when fully mature that is separated from the first juvenile layer by a series of "columns" found between the two. Often, mature birds have little dots that can be seen on the top layer. These dots are the tops of the columns and if present can help us determine the bird's maturity level.

Initially, the information is recorded in the field while the bird is being processed. Our biologists and banders work quickly, so as to release the bird as soon as possible, but also carefully with attention to detail and accuracy. This is very important in maintaining the value and integrity of the information we collect while banding birds.

Once we band the bird and take the necessary information, we release the bird in the area we captured it.

The information is then transferred to the computer into a database that allows us to study the data we've collected and look at such things as the longevity of various species and habitat preferences for different birds.