Tiny little backpacks with geolocator units that used light to determine location. Traced the path of several species as they headed south to Brazil and then home again.
...the songbirds flew much quicker than expected — more than 311 miles (500 km) a day compared with previous estimates of 93 miles (150 km) per day. And the birds zipped back to North America in the spring about two to six times faster than the fall trip. For instance, one purple martin took 43 days to reach Brazil in the fall, but returned to its breeding colony in the spring in just 13 days.
I've done that on some vacations. You roam around for weeks and weeks until you decide it's time to go home and then it's deadhead all the way! We once did that from Estes Park in Colorado to Morristown, NJ after spending 5 weeks on the road. Made it back to NJ in 36 hours INCLUDING a 3 hour stop at Cabela's original store in Sydney, Nebraska.
But these birds have a bit more on the mind: SEX!
Stutchbury said the songbirds have more incentive in the spring to chug back to North America where they compete for the best real estate for snagging the highest quality mates.
In fact, the birds took lengthier rest stops during their fall journeys to wintering grounds. The purple martins stopped for three to four weeks in the Yucatan before continuing to Brazil. And four wood thrushes took a one- to two-week break in the southeastern United States in late October before crossing the Gulf of Mexico. Two of the wood thrushes (including one that stopped over in the southeastern United States) stopped on the Yucatan Peninsula for two to four weeks in the fall.
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So ... they're not only faster than we thought, but smarter, too!
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