Tundra Swan Trax
Tundra Swan Study
The Virginia Department of Game and Inland Fisheries is cooperating with Cornell University and the Atlantic Flyway states of Maryland, Pennsylvania, and North Carolina in a study to better assess the migration patterns and winter ecology of tundra swans.
Specific objectives are to:
- 1) determine breeding areas, migration routes, and migration chronology of tundra swans,
- 2) determine site fidelity and population associations during the wintering period,
- 3) determine local movements and habitat use of tundra swans in Virginia, and
- 4) estimate survival rates for tundra swans in Virginia and the Atlantic Flyway.
This study will also be very useful in addressing management concerns such as human-swan interactions, trumpeter swan restoration efforts, current hunting regulations, and future population management strategies.
To conduct the study, swans are captured in each of the cooperating states and fitted with identifying markers so that their movements can be tracked. In Virginia, swans were trapped and banded in January-March 2001. In addition to leg bands, 100 swans were equipped with neck-collars, 20 female swans were equipped with conventional (VHF) radio transmitters, and 2 female swans were equipped with satellite transmitters. Radio transmitters were put only on females because they are most likely to return to their natal breeding areas. Neck-collars were put on both male and female swans.
Neck-collars were fitted around the swan's neck and sit at the base of the neck. They are colored gray with black letters. Neck-collars have been used on swans and geese for over thirty years and provide an easy method of bird identification. The collars can be observed at a distance of several hundred yards using binoculars or a spotting scope. Observers locate flocks of swans and scan the flocks to locate neck-collared individuals. The conventional transmitters are being used to provide information in addition to that from the neck-collar sightings. These transmitters emit a signal that can be detected with a receiver and antenna from a distance of up to 2 miles away on the ground and 5-10 miles away if tracking from an airplane. The neck-collars and conventional radio transmitters provide information on the local movements and habitat use by swans while they are in Virginia.
The satellite transmitters help provide information on long-distance movements when the swans leave Virginia. This includes migration routes and the location of staging, or stopover areas, and breeding locations. No direct fieldwork is required to track swans equipped with satellite radios. These transmitters emit a signal that is received by an ARGOS satellite orbiting the earth. The satellite then relays information on the location of the transmitter, along with date and time, to a data processing center back on the ground. Researchers from Cornell University obtain the data from the satellite company and then pass it on to Virginia and the other participating states.
Cooperating states were also successful in capturing and marking tundra swans this winter. Maryland put on 50 neck collars, 20 conventional radios and 2 satellite radios, Pennsylvania put on 100 neck-collars, 20 conventional and 5 satellite radios, and North Carolina put on 400 neck-collars, 80 conventional and 10 satellite radios. These cooperators are also monitoring neck-collared and radioed swans in their respective states.
Efforts to monitor spring migration are now underway. We have plotted the location of our satellite-equipped birds on our website and you can follow their migration paths and track them to their nesting locations. Other states are doing the same thing, so we will have a more complete picture of where all the marked swans are going and what differences might exist between different wintering areas. In addition, states in tundra swan migration and breeding areas, such as the Great Lakes Region and Alaska, are assisting in the project by looking and listening for marked swans. Several swans that we marked in Virginia this winter were located by cooperators from the Canadian Wildlife Service on the north side of Lake Erie during March and April.
Satellite equipped swans will be monitored throughout the year. Satellite radios should remain active for 18 months or more and could provide information on the annual life cycles of these birds into the winter of 2003. The conventional radio-transmitters have a battery life of 15-18 months and should still be active in the 2001-2002 fall-winter period. Searches for swans equipped with conventional radios will begin when birds start arriving in the fall and will continue throughout the winter. Plans are to trap and equip an additional 20 female swans with conventional radios and an additional 5 females with satellite radios in Virginia during the winter of 2001-2002. Swans fitted with conventional radios in winter of 2001-2002 will be monitored again in the winter of 2002-2003. Swans equipped with satellite radios in winter 2001-2002 should provide information into the winter of 2003-2004.