MOST people know that the “cuckoo lays its eggs in another bird’s nest.”
The few will say that the cuckoo does nothing of the sort, that she will lay her egg on the ground somewhere, and then carry it either by beak or foot to the selected nest, deposit it there, and fly away. They will say (once I said the same thing) that “it never actually lays in another nest.” They are wrong, in one case, at any rate.
This spring a hedge-sparrow built its nest in the rough edge of a pile of faggots. In the course of time four pale blue eggs appeared, and one morning very early a large bird flew down to it. She must have remained there for some time, for as I strolled past when the sun was just rising above the hills she flew off the nest. I knew by the flight that the bird was a cuckoo. Below the pile of faggots, on the ground, lay the scattered remains of the eggs, and the cuckoo, before laying her solitary egg in the nest, had apparently sucked all four of them.
I feared that the hedge-sparrows would desert the nest, which now surely was but an empty mock, with its one alien egg. In the ordinary way one will find the cuckoo’s egg amongst the others, in some cases exchanged for one belonging to the nest. When the young cuckoo is hatched, he displays great irritation if anything touches his back, and will not rest till the other occupants of the nest, whether eggs or fledgelings like himself, are cast out. The parent birds show an indifference to these unfortunates, and all their efforts are for the intruder.
Thus I was considerably surprised to find that the female sparrow was sitting on the strange egg. Had I, before the tragedy, taken the four eggs away, and placed instead an egg of a robin or a thrush, it is practically certain that it would have been ignored. Both parent birds were near when the female cuckoo was laying her egg, and kept flying round the nest, accompanied by a robin who may have been, like myself, a curious spectator in this domestic affair.
Five weeks afterwards the young cuckoo was many times the size of his wretched foster parents, and throughout the long days of June they worked in the hedges, seeking caterpillars, grubs, and spiders for their querulous nestling.
The migration of the young cuckoo in August is helped by a most interesting series of ingenious frauds. The old cuckoos depart for the south in July, and the younger birds making their way independently, day by day, are directed only by instinct. But the baby cannot feed itself (or probably will not, being a born parasite), and the poor little pair of birds who have slaved for it will not follow him when the wanderlust comes into his blood. The method of cadging a meal is as extraordinary as it is utterly callous.
The cad will fly ten or twelve miles a day in a southerly direction. At intervals he cries in an infantile, screaming voice. There is bound to be near a pair of birds with young, and should they hear the cry, they leave their own children and go and feed the wide-mouthed impostor. No small birds, with fledgelings, appear to be able to resist the call. They go and feed him. The fact that the young cuckoo bears a resemblance to a kestrel hawk, both in flight and colour, makes their charity all the more mysterious. Down to the south he wanders, his wings getting stronger every day, until the time comes when the sea shines in the distance, and his long journey begins. And throughout the days of his English stay, he lives on the foolish and charitable ones among the smaller, insectivorous birds.
Sometimes he is a positive blackguard. One year (1914) I found a cuckoo’s egg in a tiny nest of a common wren. When hatched, and only after much difficulty, he hoisted out all his companions, or squashed them, until he broke the nest (round like a ball, and with the hole about an inch or so in diameter in the side) and squatted insolently on top of it. The wrens, with their upright, barred little tails ever jerking with pride, fed him incessantly. The female worked so hard, and the cuckoo was so greedy, that eventually the top of her head was devoid of all feathers, and made quite raw by the beak of her wonder-child. But she was very brave, and was apparently quite indifferent to the risk she ran of one day disappearing altogether. I have often wondered if cuckoos have the power of projecting into other birds the maternal love, or instinct, that is so obviously deficient in themselves. This seems to be the logical conclusion to draw, even if it be incomprehensible to the man who in human life thinks in terms of matter and the individual, instead of the spirit and the species.
1916.