Rookery Nook
The Life of the Rook. By G. K. Yeates. (Philip Allan. 10s. (d.) THERE is a branch of knowledge which may be called omi- thomythology. Time was when it comprised a large section of ornithological science. Our ancestors believed in the Roc, and drew valuable moral lessons from the behaviour of the parent pelican, who may still be seen in heraldic representa- tions, "in her piety all proper," feeding her young with blood
-from her own breast. And did not a monk testify that he had seen with his own eyes young barnacle geese extruded from barnacles that grew upon the branches of trees ? Was it not thought until quite recently that Birds of Paradise, like Queens of Spain, had no legs ? And did not Gilbert White himself believe that swallows passed the winter in the mud of ponds ?
One might have thought that with the relentless growth of science, ornithomythology would now be entirely defunct, but such is far from being the case. It is possible that the belief of most sportsmen, that woodcock will transport their young through the air, is erroneous, and as certain as certitude of a negative proposition can be made that the cuckoo, in spite of the testimony of many witnesses, never deposits its egg in a fosterer's nest with the aid of its beak.
The rook still holds a high place in this field. It is still believed by most laymen that rooks will hold courts of justice, or at least attack and mob an offender guilty of taking "what isn't his'n " in the shape of twigs from another bird's nest ; and by some ornithologists as well as probably by all /aymen that a flock of rooks when feeding will post sentinels.
Mr. Yeates, in this excellent book, not only helps to dispose of these legends, but gives us some understanding of the facts on which they have arisen. He shows, as others have before him, that it is possible to cause " sentinel " rooks to fly off in alarm without the flock being in any way disturbed ; and suggests that the so-called sentinels are merely birds which have temporarily satisfied their hunger and are roosting in their preferred perch on a tree until their crops are a little less full. This is merely a suggestion ; but with the other matter he goes further. He finds no evidence of the mobbing of stick-thieves by the other rooks ; he shows, however, that mobbing does exist, but that it is directed against attempts
at illicit sexual relations. Mating occurs only on the nest, Sometimes " strange " males (which in certain cases Mr. Yeates can make quite sure are not the rightful mates of a sitting hen) will descend on a nest and attempt to mate with the occupant : and this ia:then the cause of an uproar, not only on the part of the aggrieved hen bird, but of many neigh- bouring rooks. Mating petween the two birds of a pair, although it causes some interest and excitement among the neighbours, never leads to mobbing. This is an extremely interesting observation which needs following up by students
of animal behaviour.
There is a great deal more of value in the book, which gives
a detailed account of the Rook life throughout the cycle of the year. The detailed account of the role of food-giving by the rook to the hen in courtship, and of the subsequent emotional reactions of the hen to the food-giving when it is no longer a ceremony but her sole source of food while incu7 bating, is of great interest, and illustrated by an admirable
photograph.
. The only serious criticism is in reference to Mr. Yeatek interpretation of the fact that during the food-giving cerer rnonial the female adopts the attitude of the chick when being fed by its parents. I will quote his own words :
"If it is not too rash to put a bird's thoughts into print, it seems to me that the whole reasoning might be set down on such lines as follows : the gift of food is part of courtship : the end of courtship is mating : the result of mating is the chick. The swiftly moving mind of a bird—or so it seems to me—takes in at one glance the whole of this process, with the result that the female, when fed by her mate, plays the part of the chick."
How, in the name of Lloyd Morgan, a bird which is breeding for the first time could be expected to know that a chick was to be the ultimate outcome of courtship, seems not to have been reflected on by Mr. Yeates (who elsewhere, be it noted, takes an extremely sensible view of the range and limitations of the intellectual and emotional capacities of his subjects).
This book, with its wealth of observation and its excellent tree-top photographs, is a model of what bird-photographers should aim at. It can be recommended to all who are inter- ested in the queer subtleties of animal behaviour as well as
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