Monday, July 28, 2008
Bird Banding at Beidler
During the last couple weeks, we have noticed some Prothonotary Warblers (Protonotaria citrea) foraging in an early successional mixed upland forest adjacent to the old-growth, bald cypress-tupelo swamp at the Audubon Center at Francis Beidler Forest. Every year in early July, it seems that Prothonotary Warblers become much more difficult to find along the boardwalk, even though most do not begin migrating south until mid-August. In fact, the boardwalk almost becomes a bird-free zone for nearly all species. This may simply be because the males have stopped singing and are less visible or perhaps their activity level drops after they have raised their young. However, after seeing some Prothonotary Warblers in the early successional upland forest last week, we began to wonder if perhaps that is where some of our in-swamp birds had relocated.
Audubon South Carolina’s Director of Bird Conservation, Jeff Mollenhauer, recently obtained a federal bird banding permit with a special permit to color band Prothonotary Warblers. Birds are typically banded on the leg with an aluminum band containing a unique 9-digit number to identify that particular bird. The band numbers and all of the information we collect on the birds is sent to the USGS Bird Banding Laboratory. If one of the birds we band is captured at another banding site or found deceased, the individual recovering the bird will send the band number and any updated information to the laboratory. From that contact, they can learn where and when the bird was banded and previously recaptured. The size of the band depends on the size of the bird. It's safe to state that the band is often so small that one would need to recapture the bird to read the number...even then only the youngest eyes could do so with ease. In order to allow visitors or staff to identify an individual Prothonotary Warbler from the boardwalk without having to recapture it, a series of plastic color bands are being placed on each bird's legs.
To answer our questions about which birds (specifically, the age and/or sex of Prothonotary Warblers) were using the upland habitat, we set up six mist nets along the edge of the early successional forest (see map). The mesh of mist nests are strong enough to capture the birds without injurying them, but fine enough that the net is invisible when viewed at a right angle. The images show a closeup of the net, a view down the length of the net, and finally the same net viewed at a right angle (use the sunlight spot on the path as a reference). Presto...it's invisible! Birds in the nets were carefully removed and placed in cloth bags to reduce the stress on the birds until their vital statistics could be taken. All captured birds were banded, but only the Prothonotary Warblers received the separate colored bands.
Our first attempt at banding birds in Beidler Forest turned out to be highly successful! We were able to capture and band two Prothonotary Warblers: one juvenile and one adult female. Both received a series of color bands and we will try to locate them again later this week. We were amazed by the number of birds using the early successional forest, particularly since the activity has been so low in the old-growth forest during the past few weeks. We also captured and banded: 1 Swainson’s Warbler (Limnothlypis swainsonii), 2 Kentucky Warblers (Oporornis formosus) [one twice!...slow learner], 1 Acadian Flycatcher (Empidonax virescens), 1 Blue-gray Gnatcatcher (Polioptila caerulea), 1 Northern Parula (Parula americana), and 3 Northern Cardinals (Cardinalis cardinalis). Many of the birds that we captured were birds that had hatched some time this year, which often required a quick look at a field guide. The Kentucky Warbler in the image was not impressed.
Additionally, we captured a Carolina Wren (Thryothorus ludovicianus) that managed to escape before being banded. As described in the pre-banding meeting, they are master escape artists and just so squirmy! Although General Francis Marion was equally as elusive, the Swamp Wren moniker never took hold!
Images by Mark Musselman
Posted by Swampy at 3:56 PM