OCCULT SENSES IN BIRDS BECK. 441 



north of the spot. This roost, above the Speedwell farms, always 

 had fifty to a hundred birds about it, and the vultures apparently 

 stayed near the South Mountain. I have rarely, if ever, seen vultures 

 ranging in the Little Conestoga Valley during the winter before or 

 since the incident. 



The second was that the dog was invisible from any part of the 

 sky. The sink hole was 6 or 7 feet deep, with an opening of about 

 3 feet. The shaft, inclined toward the south, went down at an angle 

 of about 45°, and the walls were so irregular with projecting rocks 

 and soil that the carcass at the bottom was completely hidden from 

 view. 



Under the existing conditions it is difficult to account for the find- 

 ing of the carrion by either eye or nose sense in the vultures. The 

 dog being invisible and there being no vultures in the neighborhood 

 when it was thrown into the hole, sight could scarcely have been 

 involved; and the possibility of a freshly killed dog at the bottom 

 of a 6-foot hole giving off enough scent in midwinter to attract birds 

 miles away is out of the question, even after eliminating the fact 

 that the sense of smell is but poorly developed generally among 

 birds. 



Assuming the correctness of the theory of a food-finding sense as it 

 exists to-day in certain species, the imagination naturally runs back 

 to the earlier stages in the evolution of these species. Given by 

 nature the right to life — if life can be maintained, and the first 

 essential of continued existence, food — it is perhaps logical and it 

 is certainly well supported by analogies, that chance superiority in 

 food finding would develop into something of permanent value in' 

 the species, and that the sense thus evolved would be the determin- 

 ing factor of survival among a host of related forms many of which 

 succumbed in the struggle for existence. And it is reasonable, too, 

 that this food-finding sense should have been most highly evolved 

 during centuries of widespread forest areas, and that it should have 

 persisted up to the present times in those species which were high 

 soaring and carrion feedingj for logically, among the Eaptores where 

 hunting and killing powers were lacking, subsistence depended upon 

 food that must have been, almost invariably, concealed as well as 

 fortuitous. 



Again assuming that two leading essentials for the maintenance 

 of the species — rinding food and finding the home — had been as- 

 sisted by specialized senses, it should follow that the third promi- 

 nent factor — mating — had been similarly safeguarded. 



While there is no convincing evidence at hand in support of a 

 definite mate-finding sense among vertebrates, there are many baffling 

 incidents of field observations which would find explanation in such a 

 theory. 



