to gladden us with his cheering “cuckoo.” Various species of insectivorous birds are made use of as foster-parents, and there is no doubt that much discrimination is exercised by the mother Cuckoo as to where and when to deposit her egg. The nests most favoured in this country are those of the Meadow Pipit, Pied Wagtail, Hedge Sparrow, Sedge and Reed Warblers, but over sixty different species of British Birds have been made use of at various times. Practically nothing is known as to whether Cuckoos pair, or if the female receives the attentions of several males, and the number of eggs laid by a single bird in the season is also doubtful, though about eight is said to be the number. Many interesting problems are thus still unsolved about one of our commonest birds, and if his character be not a very estimable one, we can but marvel at the workings of evolution which has enabled so curious and complicated a method of parasitism to be sufficiently successful to ensure the perpetuation of the race. It must be remembered that for the successful rearing of each young Cuckoo the mother has to find and recognise the nest of an insectivorous bird, and to lay her egg during the five days in which the foster-parent elect is laying her clutch. As regards the various stages of evolution that have caused the young Cuckoo to evolve as a murderer at his birth, and that have provided him with the means in the shape of a special hollow in his back, we know nothing, and can in the present state of our knowledge merely leave the problem in wonder and amazement. The male is clear greyish ash on the back and throat; tail feathers blackish with small white spots on the margin. Under parts whitish, with dark bars on the flanks. The young vary considerably and are generally dark brown, more or less barred with rufous on the upper parts. Length 13 in.; wing 8·5 in. THE GREAT SPOTTED CUCKOO Coccystes glandarius (Linnæus) On three or four occasions this bird has been obtained in England and Ireland. It is a native of North Africa and South Spain, where it breeds, migrating in winter to South Africa. Its eggs are almost always deposited in the nest of a Magpie, but other members of the Crow family are sometimes chosen. The general colour is greyish brown, most of the feathers tipped with white; under parts white. The crown is grey, with long pointed crest. Length 15·5 in.; wing 8 in. THE AMERICAN YELLOW-BILLED CUCKOO Coccyzus americanus (Linnæus) Some half-dozen examples of this American species have occurred on our western shores during the autumn migration. It is about the size of our Cuckoo, olive-brown above, and buffish white below. Each of the tail feathers are tipped with white. Length 11 in.; tail 6 in.; wing 5·40 in. THE BARN OWL Strix flammea, Linnæus