Aug. 29, 2013 — Scientists have studied bird migration for centuries, but it remains one of nature's great mysteries. How do birds find their way over long distances between breeding and wintering sites? Is their migration route encoded in their genes, or is it learned?
Working with records from a long-term effort to reintroduce critically endangered whooping cranes in the Eastern U.S., a University of Maryland-led research team found evidence that these long-lived birds learn their migration route from older cranes, and get better at it with age.
Whooping crane groups that included a seven-year-old adult deviated 38% less from a migratory straight-line path between their Wisconsin breeding grounds and Florida wintering grounds, the researchers found. One-year-old birds that did not follow older birds veered, on average, 60 miles (97 kilometers) from a straight flight path. When the one-year-old cranes traveled with older birds, the average deviation was less than 40 miles (64 kilometers).
Individual whoopers' ability to stick to the route increased steadily each year up to about age 5, and remained roughly constant from that point on, the researchers found.
Many migration studies are done in short-lived species like songbirds, or by comparing a young bird to an older bird, said UMD biologist Thomas Mueller, an expert on animal migration and the study's lead scientist. "Here we could look over the course of the individual animals' lifetimes, and show that learning takes place over many years."
No comments:
Post a Comment