How I Spent the War
I managed to keep the animosity that I felt toward my father within bounds for the length of my weekend leaves. . She was smaller than I was, and when she hugged me in the living room she seemed to dissolve into tears between the piano and the ...
May 28, 2007
Cuckoos mimic hawks to fool small birds
Cuckoo.jpg Nick Davies and Justin Welbergen from the University of Cambridge decided to find out by comparing the way small birds respond to stuffed hawks and cuckoos. Species that are parasitized by cuckoos often evolve defences including the ability ...
March 28, 2010
In 1943, when I was a fifteen-year-old schoolboy in Danzig, I volunteered for active duty. What I did cannot be put down to youthful folly. It happened while I was serving in the Luftwaffe auxiliary—a force made up of boys too young to be conscripts, who were deployed to defend Germany in its air war. The service was not voluntary but compulsory then for boys of my age, though we experienced it as a liberation from our school routine and accepted its not very taxing drills. The Kaiserhafen battery became our second home. At first there were attempts to keep school going, but, as classes were too often interrupted by field exercises, the mostly frail, elderly teachers refused to travel the wearisome dirt road to our battery. We got to use our 88-mm. guns only two or three times, when a few enemy bombers were sighted in our airspace in the beam of the searchlights. We were proud to have shot down a four-engined Lancaster bomber. As a rule, however, service in the Luftwaffe auxiliary was dreary, though dreary in a different way from school. We were especially turned off by nightly guard duty and ballistics classes, which dragged on forever in the musty classroom barracks.
Several species of this large family are murderous slackers , who shun their own parental responsibilities by deceiving other birds into caring for their chicks. But this is not the only way that cuckoos fool other birds – they also mimic hawks. The resemblance between cuckoos and hawks (particularly sparrowhawks ) has been noted for millennia. The resemblance is uncanny enough that Pliny believed that cuckoos disappeared from Europe in the winter by transforming themselves into hawks, a theory that Aristotle rightly dismissed on the grounds that cuckoos lacked the formidable talons and... Hawks and cuckoos belong to two very different families of birds, so why do they look so similar. Non-parasitic cuckoos (and indeed, not all cuckoos leech off the parenting skills of other birds) provide an important clue, for they look much less than hawks than parasitic species. Their body shape helps them to make a controlled glide, which sparrowhawks use to launch surprise attacks, and cuckoos use to sneak up on a targeted nest. Alternatively, the cuckoos could be actively mimicking the hawks. The disguise could fool the cuckoos’ predators.