Songbirds Wear Backpacks For Science

Ornithologists have been wondering about the details of songbird migration for hundreds of years. Biologist Bridget J. M. Stutchbury has found a fascinating high tech solution to help answer this question: tiny solar powered backpack transmitters. The transmitters are about the size of your thumbnail, and rest right over the birds' hips, with loops fastening the backpack over the birds' legs.

Dr. Stutchbury and her colleagues have attached transmitters to 34 birds, although they were only able to collect the data from 7. One flaw in the system is that the biologists have to re-capture the birds and retrieve the backpacks in order to collect the data. (As opposed to larger wildlife tracking transmitters, which can send their data to researchers via satellite.)

The first round of transmitters were attached to purple martins. Dr. Stutchbury trapped the birds in Pennsylvania, attached the miniature backpacks, then observed the birds for several days to make sure that the birds' lives had not been affected by either the experience or the presence of the transmitters. After verifying that the birds continued with their day to day routines, Dr. Stutchbury's team waited for the birds to begin their round-trip migration to South America.

Last year on April 25th, the first be-backpacked purple martin returned to Pennsylvania. The sensor data from it and the six other purple martins revealed that the birds traveled far faster than ornithologists had expected. In some cases, the birds flew up to 370 miles per day. One female purple martin "flew almost 5,000 miles in 13 days, including 4 stopover days."

Dr. Stutchbury's team attached sensors to dozens more birds last summer. The birds should be returning to their origin site within a few months.