Silence of the Songbirds--used some of the money from the book and a grant from National Geographic to hook up a teeny tiny "geolocator" on 14 Wood Thrushes and 20 of us Purple Martins in Pennsylvania in 2007, and then recaptured 5 of the thrushes and 2 martins last summer and took off the geolocators and retraced their trips to the tropics and back. She found that our overall migration rate was two to six times more rapid in spring than in fall.
Well, DUH! In spring we're headed north for sex and nesting and all that. In fall what do we have to look forward to? Just one more hot tropical winter eating bugs.
One martin took 43 days moseying down to Brazil during fall migration, but in spring he or she returned to the breeding colony in only 13 days, probably panting all the way, if you know what I mean ;-)
"We were flabbergasted by the birds' spring return times. To have a bird leave Brazil on April 12 and be home by the end of the month was just astounding. We always assumed they left sometime in March," Stutchbury said. All I can say is she doesn't know what it feels like to go from July all the way through the fall and winter with absolutely no sex, and no hope of any fooling around till you get back to Pennsylvania in the spring. No wonder we're in a hurry!
Anyway, you can read all about this on the Birder's World website. But you might have to read between the lines to understand the whole thing--people refer to sex as "the birds and the bees" apparently because they don't do it themselves. Poor things.