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CONDUCTED
UNDER: By: Dr. William S. Seegar SUMMARY As part of a continuing research program, field studies were conducted on the peregrine falcon, Falco peregrinus. Study sites were Assateague Island, MD/VA, and Padre Island, TX. This report focuses on the 34th annual study at Assateague Island. Between 24 September and 20 October the survey team expended 519 man-hours in the field, recording 572 sightings of peregrines and capturing 155 different individuals (table 1). Ten of the falcons captured were previously banded. The 572 sightings included 116 opservations of individuals previously captured during the survey, along with 4 recaptures. All sightings of resident peregrines were excluded from data presented here. During the survey 191 merlins (Falco columbarius) were observed. BACKGROUND The presence of peregrine falcons on Assateague each autumn was confirmed by falconers in 1938. Most of these were tundra peregrines (Falco peregrinus tundrius), a migratory Arctic nesting subspecies. Some few individuals of the subspecies Falco peregrinus anatum were also determined to occur on Assateague in the fall. These peregrines were known to breed on rock faces in the eastern United States. Catastrophic declines in global peregrine populations after the mid 1940s were attributed to widespread use of chlorinated hydrocarbons (such as DDT) as agricultural pesticides after World War II. Food chain contamination resulted in high levels of DDE (the principal metabolite of DDT) in the tissues of peregrines, which caused the formation of thin eggshells and increased reproductive failures. F.p. anatum was extirpated east of the Mississippi River and only remnant populations survived elsewhere in temperate North America. By the late 1960s F.p. tundrius was also in rapid decline and both subspecies received endangered species status in 1970. Diverse efforts were undertaken to study,
monitor and augment peregrine populations. Assateague Island, as a major
North American peregrine populations rebounded dramatically after the U.S. ban of DDT for agricultural use in 1972. Relying heavily on data from this study, the U.S. Fish and Wildlife Service (USFWS) in 1994 removed F.p. tundrius from the List of Endangered Species. F.p. anatum followed in 1999. METHODS Our study area on Assateague Island, MD/VA, consists of the following domains: Assateague Island National Seashore (National Park Service [NPS], MD/VA), Chincoteague National Wildlife Refuge (CNWR, USFWS, VA) and Assateague State Park (State of MD). During the survey period the island is traversed each day from sunup to sundown by two parties in four-wheel-drive vehicles. Only vehicle failure, high wind, flood tide, or other condition that would place peregrines or personnel in jeopardy constrains survey operations. The island is divided at the state line and each area to the north and south is surveyed in the morning by single vehicles, which switch sides of the island at midday. All raptors observed are recorded according to species, time, location and activity at time of sighting. An attempt is made to capture peregrines encountered that are not identified through color marking as duplicates, and that are found in areas conducive to trapping. Unbanded peregrines are fitted with a U.S. Geological Survey (USGS) lock-on band (size 6 for males, 7a for females) and processed according to current research protocols before release at the capture site. Past protocols have included recording weight and body measurements, collecting small feather snips, pollen samples from plumage, and 2cc blood samples, affixing color-coded alpha-numeric bands, and attaching conventional and pulse-coded transmitters. Since 1993 we have also deployed Platform Transmitter Terminals (PTTs) on a small sample of adult peregrines, which are tracked and located globally by polar orbiting satellites. Before each falcon is released the head is marked with red dye. This identifies the individual as one already sampled during the survey and precludes recapture attempts; it fades quickly over a four-week period. Recommendations and Acknowledgments
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focal point of
the autumn tundra peregrine migration, had been visited for the preceding
three decades by falconers, bird banders and scientists. In 1970 the
Department of the Army initiated a program to monitor the tundra peregrine
and to develop new technologies to assist in the study of highly migratory
threatened, endangered and sensitive species. The program rapidly expanded
to include research in diverse geographic regions to assess all aspects
of the natural history of the tundra peregrine, and specifically the
issues associated with global contaminants affecting their population
dynamics. The principals, now working under the Earthspan banner, have
developed new and innovative technologies to examine migration and wintering
biology. The results dramatically extend our knowledge of this macropredator
on migration and during its wintering period in the Neotropics.