I had no time for birding this weekend, mainly because I was leading two 3-hour workshops for teachers of English on Saturday. However, I did have time to read some fascinating interesting reports about bird migration.
We're learning more and more about the latter these days, because scientists have developed tiny geotracking devices that weigh less than 1 gram (0.04 ounces). This is enabling researchers for the first time to attach tracking devices to, and monitor the migration routes of, even very small birds.
One report detailed the 16,700-mile migration of four Ruddy Turnstones from Australia to the Arctic and back, and it included some amazing data about various stages of the birds' journey.
Traveling at an average speed of 31-34 mph, it took them only six days to fly one 4,700 mile leg four days to cover a 3,850 leg, and four more days to complete another 3,100 mile stage. That's pretty impressive for a bird that weighs in at around 250 grams (9 ounces).
Researchers are now planning to attach lightweight geotrackers to a range of small birds and so it won't be long before we start finding out more details of the migration journeys made by other shorebirds and even songbirds.
The new geotracking devices can normally be attached either to birds' backs or to their legs. In the case of the Turnstones, the researchers said they had no choice but to attach the devices to the birds' legs. Why? After spending the summer feeding in Australia, the birds were so fat and round that the backpack geotrackers kept falling off!