USA: Biologists from PRBO Conservation Science, USA, tracked the migration trends of golden-crowned sparrows using geo-tags. Their study published in the journal PLoS ONE, revealed for the first time the exact migration route of this small songbird to its breeding sites in coastal Alaska. They observed that each bird, which weighs approximately 30 grams, migrated from 1600 to 2400 miles one-way to their breeding grounds.
PRBO scientists attached small tags that record day length to sparrows wintering in and near Point Reyes National Seashore before they headed north on spring migration. When the birds returned the following fall, four tagged birds were safely recaptured, the tags were removed and the data was downloaded to a computer.
“This study is helping to unravel the mystery of bird migration and answer the age old question of where birds go, which helps protect habitat along their entire migratory journey,” said lead author, PRBO’s Dr. Nat Seavy.
Each bird, which weighs approximately 30 grams, migrated from 1600 to 2400 miles one-way to their breeding grounds. Their individual breeding locations spanned approximately 750 miles along the coast of Alaska, and their north migration averaged only 29 days while southbound migration averaged nearly twice that (53 days).
“Until now, all we knew was that these birds bred far to the north and undertook one of the longest migrations of all songbirds that winter in central California. We’re very excited to finally pinpoint exactly where some of our Golden-crowned Sparrows breed,” explained Diana Humple, PRBO’s Palomarin Field Station Manager and a co-author of the study.
Today we are facing unprecedented changes in land-use and our climate” noted Nat Seavy. “The information in this study will help us understand where our migratory birds may be vulnerable to these changes, and what we can do to help protect them and the ecosystems on which they—and we—depend.”