Why are leg bands used?
Marking birds with color bands and a U.S. Fish and Wildlife Service uniquely numbered metal band enables researchers to follow individuals from year to year, estimate their age, identify breeding partners, measure their success as parents, and determine migration routes and wintering sites. Accurate observation of band colors and their arrangement on the legs permits us to positively identify individuals without recapturing them.
How are bands applied?
Bands are placed around the tarsus of each individual; they move freely on the legs. If plastic color bands are used, one is placed above the metal band on the tarsus, and up to two color bands are placed on the other tarsus. Occasionally, a color band has two colors, and is referred to as a split band; these splits occur horizontally. Eventually most color bands fade, wear out, and fall off, leaving only a metal band. Color bands have been known to last more than ten years.
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Banding of the Great Lakes population began in 1993. Adults are banded with aluminum USFWS bands and 3 color bands to uniquely identify the individual. Chicks are banded with aluminum USFWS bands and a single color band to identify the hatch site. Since initiation of banding, a concerted effort has been made to band nesting adults and their offspring. Approximately 1500 PIPLs have been banded since 1993. These banding efforts have proven invaluable for creating effective management and recovery plans for this population.
Banding enabled the following observations:
- The Great Lakes population appears to be self-sustaining and isolated from the Great Plains and Atlantic populations. Adults and offspring return to breed in successive years.
- Between 1997 and 1999, there were at least four cases of close inbreeding, including brother-sister and parent-offspring pairings; three occurred in 1999.
- PIPLs exhibit mate and site-fidelity in consecutive years. Site fidelity, but not mate fidelity, is associated with previous reproductive success.
- Great Lakes PIPLs winter across much of the southern coastal United States and possibly Cuba. They have been reported in North and South Carolina, Georgia, Florida, Louisiana, and Texas. This information has been vital for identifying winter Critical Habitat as required by the Endangered Species Act.
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