Eight Seabrook Island Birder (SIB) members were among the 12 lucky registrants for the Seabrook Island Natural History Group’s (SINHG) fall trip to visit the Kiawah Island Bird Banding on Cap’n Sams Spit. Every August, Aaron Given from the Town of Kiawah Island sets up twenty-five 40’ mist nets on Captain Sam’s Spit where, over the next couple of months, he collects birds for banding, measuring, and weighing. Our trip on October 1, was the peak migration time for all sorts of songbirds including vireos, warblers, catbirds, chickadees, etc.
Our group gathered at Beachwalker Park and enjoyed Sanderlings on the beach at sunrise as we walked towards the Spit. Aaron Given took us along the meandering paths beside the mist nets. He removed some birds from the nets as we went and some of us were lucky to hold the bags of the captured birds.
Once we got to their workstation, Aaron explained the process as each bird was identified, banded, measured, weighed, aged and studied for fat content of each bird. This data was all recorded in a ledger that would subsequently be entered in a database and shared globally.
While we were there, the following species were identified: Gray Catbird, Swainson’s Thrush, Common Yellowthroat, Yellow-breasted Chat, Black-throated Blue Warbler and Red-eyed Vireo.
For banding, a metal ring with a unique number is attached to each bird’s leg. This is done with special pliers and the unique number becomes the bird’s “name” in the database. The metal rings come in different sizes to not disturb the birds. At the nets, Aaron’s team efficiently pre-sorts the birds as they are placed in the bags which allows the same size bands to be used consecutively.
A special ruler is used to measure the length of the bird’s wing.
The birds don’t seem to mind being put head down into a PVC pipe to allow the bird to be weighed. Different PVC pipe sizes are used based upon the size of the bird.
To age the bird, the naturalists examine primarily the wing feathers. A hatch-year’s feathers are gradually replaced with sturdier feathers. By examining the feathers, the naturalists can tell which feathers have been replaced and then know if they are hatch-year or after. If the feathers don’t provide a definitive answer, the head can be misted with water to see how extensive the scull has developed.
The birds can consume a great deal of fat in a single night of migration. The amount of fat on a bird would vary based upon how much was gained prior to migration, any special conditions the bird faced during migration (wind, weather, etc.). While they are resting on Kiawah during migration, they eat berries and insects to regain fat to continue their journey. Some birds may be on Kiawah for only a day, others for a few nights and some for all winter. To identify the level of fat on a bird, the naturalist blows on the birds chest. The bird’s skin is rather translucent under the feathers so by blowing on the feathers, the skin is seen and through it, the degree of fat, rated 0 to 5.
Once all these studies are done, the birds are released to eat, gain weight and continue their journey. If they should fly into the nets again on the same day, they are released immediately rather than subject them to more stress. If a bird is “recaptured”, its number is recorded and new data is gathered to ascertain how the bird’s health has changed since its previous capture.
-Submitted by Judy Morr
(Image credit: Dean Morr)