Quite a formidable list of birds have reared offspring at Regent's Park, and even more have succeeded in doing so at Whipsnade. In fact, the Zoo has had good fortune in breeding birds 4 Of practically every group save the birds of prey. In the last year or two, many species of pheasant, including the rare Rheinhardt's Argus, have hatched young in the pheasantries, where also budgerigars, love birds and macaws have bred; Stanley cranes have reared healthy young on the north bank; sacred ibises and several species of gulls have bred in the great and southern aviaries; in the Bird House young doves, pigeons and glossy starlings are among those which have been successfully brought to maturity.
In the last three years at Regents Park and Whipsnade the public has been able to see two of the most remarkable exercises in nest building performed by any members of the animal kingdom—the nidification of the trumpeter hornbill at Regent's Park, and that of the brush turkey at Whipsnade. Few people realize that the majority of forest and wood-living birds are hole-nesters, though such as have witnessed the nest-building of the nuthatch must realize to what high degree the art of hole-nesting can be brought.
But the hornbills outstrip the nuthatch in the art of nest-making, and of all the woodland birds have the most complicated and fantastic breeding habits. In most hornbills the female is literally walled up in her hole for a period of several months. In many species this period is over a hundred days, and in some may be as much as 175, The male bird supplies mud to the female, who receives it and does her own plastering. When the wall is complete, only a vertical slit remains for her beak. While in the nest, the female lays, incubates, feeds the young on supplies brought by the male, and herself goes through a complete incult. She seldom leaves until the young are nearly able to fly, and, when she does, the young may sometimes plaster themselves in for a further period.
During the last three years at the Zoo a pair of trumpeter hornbills, provided with a nest-box, went through part of their breeding cycle, and the female underwent voluntary imprisonment for well over two months. Mud was supplied by the keepers and brought to the female by the male in jhe usual manner, Unfortunately, in no year was the cycle entirely completed, and, though eggs were seen in 1939, no young were hatched,
Text read from the printed page and cleaned; old type leaves the occasional error.