Science: Cuckoo

The problem of the cuckoo was a step nearer solution last week, with the publication of Cuckoo Problems (H.F. & G. Witherby, Ltd., London), an authoritative treatise on the somewhat wayward habits of large European and Asiatic cuckoos which lay their eggs in the nests of other birds, leave their young to be brought up by foster parents.* Author: the 78-year-old dean of British ornithologists, Edward Charles Stuart Baker, C.I.E.; O.B.E.; F.Z.S.; M.B.O.U.; H.F.A.O.U.; H.F.H.O.U.; F.L.S.; J.P.

Ornithologist Baker’s interest in cuckoos began rather dramatically. “I was a very small boy,” he writes, “when I found my first Cuckoo’s egg in a Hedge-Sparrow’s nest in a Norfolk lane. [It was] a red letter day which synchronized with my first attempt to read The Origin of Species. Since then I have been filled with interest in Cuckoo’s eggs and Evolution.”

The cuckoo problem that most deeply engrosses Ornithologist Baker and others is: How does the cuckoo get the egg into the nest? This problem is posed by the fact that some wise birds build nests with obstructive entrances for the express purpose of keeping out cuckoos. The cuckoo has developed several methods for outwitting these isolationists. Cuckooists recognize a First, Second and Third Method. In the First Method the cuckoo simply squats down and lays her egg. The Second Method is somewhat more complicated, comes into play when the cuckoo is momentarily baffled by a nest built in a hollow tree or other enclosed space with an aperture too small for her to enter. In this case the cuckoo just hangs at the entrance of the hole (by clinging to the edge of the nest, a twig, or bark of the tree) and lets fly.

It is the extremely rare Third Method, a kind of fourth dimension among cuckoo problems, that is still controversial. The Third Method is used when a cuckoo encounters a nest with a very small or tortuous entrance. Unable to squat or cling, the cuckoo flutters to the ground, lays an egg, is thought by some to swallow it, then poke her long bill and neck into the nest opening, and regurgitate.

Like most cuckooists, Ornithologist Baker does not claim ever to have witnessed the Third Method, but he believes that he has.

“When bird nesting in Bihar [India],” he writes, “I was strolling alongside a high, dense cactus hedge when my attention was drawn to a bird [female cuckoo] flying up from behind over my head and settling on the ground about 25 paces beyond me. I ran up to within about ten paces, screened from her sight by a bush, and then saw she was sitting quietly on a small mound, back to me and quite motionless. Presently I saw her put her head down and her shoulders heave, as if she were being sick, and then immediately fly to a spot in the hedge a little farther on. Following her up I saw she had got to a nest of the Jungle Babbler and was sitting on the edge of it, but she flew away directly she saw me. In the nest I found three eggs of the Babbler and one of the Cuckoo. I never doubted for a moment but that the Cuckoo had carried her egg to the nest in her bill and dropped it in.”

Incensed last week was another British ornithologist, Edgar P. Chance, now resident in New Jersey. Ornithologist Chance is the author of The Truth About the Cuckoo. In India Author Chance took his remarkable moving picture of a cuckoo in the act of egg-laying, received £1,500 for it. He brushes off Ornithologist Baker’s study as academic. “Stuart Baker,” Chance explains, “is not steeped in cuckoos. Most of his knowledge of cuckoos comes from books.” Says Cuckooist Chance: “It is not Stuart Baker, but my name that you will find under Cuckoo in the 14th edition of the Encyclopaedia Britannica”

* Unlike the North American black-billedcuckoo {Coccyzus erythropthalmus) and yellow-billedcuckoo (Coccyzus americanus), whichbuild their own nests, rear their own young,but like the U.S. cowbird (Molothrus ater) ,which also farms out its young.