By Scott Ford, DVM, DABVP (Avian)
This summer I am made a few trips up to the north part of Puget Sound (western Washington state) to volunteer with the Washington Department of Fish and Wildlife while they captured and banded scoters. This is part of an ongoing project to characterize the population and learn more about their physiology, feeding, and needs during the critical annual molt cycle. This information will be important to determining why scoters are declining and coming up with the best methods for managing them.
When I helped out on July 30th, we captured 57 surf scoters. These were captured in 3 sets of a specially-modified submerged net. The way it works, in a nutshell, is that three or four smaller boats go out to the shallow areas of the bay where the ducks are gathered. The ducks cannot fly well, if at all, while they are molting their flight feathers. However, they still dive well and they gather in shallow bays to feed on a variety of invertebrates that live on the bottom and amongst the sea grass. While a few of the boats gently herd and concentrate the flock, another boat deploys a long submerged net. The net has a weighted bottom end which sinks about 4 or 5 feet below the surface. The top end floats. Decoys are also included in the set to help identify the location of the net and to possibly attract birds. As the ducks are concentrated in front of the net, a pyrotechnic is shot off to startle the birds to dive. When they are caught in the net, their natural buoyancy brings them to the surface with the lightweight net. The net is then hauled in and birds are extracted and placed in breathable mesh bags for transport back to the processing station. The technique is very successful and has a good safety record for the birds.
The processing station is a boat that is outfitted with pet carriers where the birds can wait their turn with less stress. Since scoters are rarely on land, the carriers are modified with mesh hammocks to prevent injuries to the breast, feathers, and feet. During processing, a USFW band is applied. In addition, a variety of measurements are collected including the length of the beak, lower leg, wing, feathers, body weight, and measurement of the cloacal bursa. This last measurement, when combined with appearance of the bird, can help determine age.
After all the measurements are taken, the bird is released back into the bay. In a few cases, temporary radio transmitters are attached to the back of the bird to help with foraging studies. The transmitters allow ground-based researchers to monitor diving behavior (how long, how often, and what times of day), which usually corresponds to feeding activity. Knowing when and where the birds feed can help us understand what the ducks need and help in habitat management decisions.
If you would like to know more, check out the project?s website at http://home.comcast.net/~scoterbanding/. They also need volunteers each year and you do not need any special experience or training. It?s a great opportunity to meet interesting people and to get involved in important wildlife conservation and research.