382 MENTAL EVOLUTION IN ANIMALS. 



and tlie natives thus discover her nest. In La Plata the 

 Furnarius builds a large oven-like nest of mud in as con- 

 spicuous a place as possible, on a bare rock, on the top of a 

 post, or cactus-stem ; * and in a thickly peopled country, with 

 mischievous boys, would soon be exterminated. The ojreat 

 Butcher-bird conceals its nest very badly, and the male 

 during incubation, and the female after her eggs are hatched, 

 betray the nest by their repeated harsh cries.t So again a 

 kind of Shrew-mouse at the Mauritius continually betrays 

 itself by screaming out as soon as approached. IsTor ought 

 we to say that these failures of instinct are unimportant, as 

 principally concerning man alone ; for, as we see instinctive 

 wildness directed towards man, there seems no reason why 

 other instincts should not be related to him. 



The number of eggs of the American Ostrich scattered 

 over the country, and so wasted, has already been noticed. 

 The Cuckoo sometimes lays two eggs in the same nest, leading 

 to the sure rejection of one of the two young birds. Flies, it 

 has often been asserted, frequently make mistakes, and lay 

 their eggs in substances not fitted for the nourishment of 

 their larva. A Spider J will eagerly seize a little ball of cotton 

 when deprived of her eggs, embedded as they are in a silken 

 envelope ; but if a choice be given her, she will prefer her own 

 eggs, and will not always seize the ball of cotton a second 

 time : so that we see sense or reason here correcting a first 

 mistake. Little birds often gratify their hatred by pursuing 

 a Hawk, and perhaps by so doing distract its attention ; but 

 they often mistake and persecute (as I have seen) any inno- 

 cent and foreign species. Foxes and other carnivorous 

 Ijeasts often destroy far more prey than they can devour or 

 carry away : the Bee Cuckoo kills a vast number more bees 

 than she can eat, and " unwisely pursues without interruption 

 this pastime all the day long."§ A queen Hive-bee confined 

 by Huber, so that she could not lay her eggs in worker cells, 

 would not deposit, but dropped them, upon which the 

 workers devoured them. An unfertilized queen can lay only 

 male eggs, but these she deposits in worker and royal cells— 

 an aberration of instinct not surprising under the circum- 



* Journal of Besearches, p. 95. 

 f Knapp, Journal of a Naturalist, p. 188. 



X These facts are given by Duges in Anns, des Sc. Nat., 2nd series 

 tome vi, p. 196. 



§ £ruce's Travels in Abyssinia, vol. v, p. 179. 



