BIRDS WHICH SHARE NESTS

Evening Star, Issue 19951, 22 August 1928, Page 9

BIRDS WHICH SHARE NESTS

CO-OPERATIVE SITTING More than ouo sort of egg is sometimes found in a bird’s nest (says a writer in the ‘ Manchester Guardian'), but one must bo wary about too readily accepting this as a natural state of affairs, for boys are apt to play pranks “to see what’ll happen.” I myself in my inquisitive youth put a pair of blackbird’s eggs into tho nest of a thrush, taking away two of her four, so that the same number remained. She did not seem to mind, for she raised the brood as though they were all her own. But, now and then, thrushes do mate with blackbirds, the eggs lookl- - more like those of tho latter, and the nest, too. Once tho thrush which has made tho customary mud cup has begun to lay, she does not object to the lining of the intertwined dead grasses which tho. blackbird’s Instinct tells him to introduce. Such eggs are usually fertile, and a hybrid is produced. Robins have been known to share a nest with a pair of blackbirds—though heaven knows how much hard fighting has preceded this apparent compromise in a feud to secure the coveted site. Such nests have two cups, side by side, each with its own eggs. When a, squabble of this sort occurs the pair that has first secured the site, and established a nest, is occasionally evicted by a “claim-jumping” pair, the hen of which lays a carpet of moss and grass on the eggs already laid by the previous tenant, and proceeds to lay her own. There was a case at Weybridge a year or two ago of a robin taking over tho nest of a blackbird which had been killed by a cat, and sitting on tho blackbird’s orphaned eges as well as her own—but she probably regarded them merely as a nuisance, and they did not hatch. There have been cases of robins sharing a nest with water wagtails, laying their eggs all together in tho same cup and taking turns to sit. It is curious what a strong attraction certain nesting sites have for a number of different sorts of bird year after year. I have known a mass of twigs and grasses in a fork of an old ivy-covered oak that has beep tho homo successively .of owls, pigeons, jays, spnrrowhawks, and thrushes. More than once 1 have found wrens nesting ou the “ground floor” of such a large untidy mansion, fitting their neat little dome of moss into tho, cavo in the twigs a foot or two below the nest of a thrush or blackbird. A pair of blackbirds in Essex built last summer inside a twig ncsb recently vacated by a turtle dove.

Sparrows are prom) to seise the mud nests of martins under the eaves of a house and lay their eggs there among those of the evicted tenant. But though I have found the eggs of both in the same nest and seen the mother martin return when she found the coast clear during the temporary absence of the sparrow, the martin’s eggs were not there a, few days later; they lay below in bits on the garden path.