34 



The Canadian Field-Naturalist 



[Vol. XXXVI 



birds. 



They arrive at the cliff, mated, about the middle 

 of April, and a full clutch of eggs has been laid as 

 early as April 23 (1903). This was an unusually 

 early date, as May 1 is about the average date to 

 find the eggs of this species. 



While these hawks inhabit a cliff for many 

 years in succession, they have the habit of chang- 

 ing the location of their nesting site each year. 

 A most inaccessible part of the cliff is selected for 

 the rearing of their young, making it difficult for 

 the curious to intrude or trespass on their sacred 

 territory. Their habits and conduct are regular, 

 firmly fixed and subject to little variation. 



The male falcon selects a rampike, usually a 

 short distance back of the cliff where his home is 

 fixed, and this is used as a look-out station or 

 observation post; when not away on a foraging 

 expedition, he here maintains a constant vigil. 



The female attends to all the domestic duties 

 of the falcon home, but is spared the task of seek- 

 ing for food. This is the duty of the male who 

 never fails to secure an abundant supply. During 

 the period of incubation he is particularly atten- 

 tive in the matter of feeding his mate. The food 

 secured consists in the main of birds, which they 

 capture alive in true falcon style . . 



Anxious to secure a set of photographs of the 

 young hawks in the development stages of their 

 lives, I visited this particular cliff in the month 

 of June one year. Instead of finding, as I anti- 

 cipated, a brood of healthy and vigorous fledglings 

 ready to be brought into the field and scope of 

 the camera, I was greeted by the sight and un- 

 pleasant odor of four addled eggs. While dis- 

 appointed in the main object of my long trip and 

 expectations on this occasion, I was privileged to 

 witness a phase in the life of this particular species 

 which I had not previously seen or known from 

 observation and which compensated me for my 

 journey and efforts. 



In the vicinity of the addled eggs, the cliff was 

 covered with the remains of the feasts of the 

 falcon family. Distributed over the entire sur- 

 face I saw regurgitated pellets very similar in size 

 and shape to some that I found near the nest of a 

 Short-eared Owl in Cataraqui marsh a few years 

 ago. On close examination, I found that the 

 pellets contained hair and feathers and the small 

 skulls and teeth of the small short-tailed field 

 voles (Microtus pennsylvanicus) . At. the foot of 

 the cliff were the bodies of two young ground 

 hogs (Arctomys monex) which had been killed by 

 the falcons, but had not been used for food. In 

 all my experiences with these hawks, this was the 

 only occasion on which I found any evidence to 

 prove that mammals constituted any part of 



their food. I am now satisfied that mammals 

 form a very important part of the food of the 

 falcon. 



The mechanical or constructive faculty is 

 evidently absent in the falcon as no attempt 

 whatever is made to build a nest, the eggs being 

 deposited in the loose clay which forms the 

 capping of the cliff where they select their habita- 

 tion. Not infrequently the clutch contains one 

 or more addled eggs. On two occasions I found 

 the entire clutch addled. 



When the young falcons are hatched, they are 

 well covered with a soft white down and are able 

 to toddle about shortly after they leave the shell. 

 The lives of the parent hawks are evidently in 

 constant jeopardy. This is no doubt due to the 

 fact that they fall victims to the gun of some 

 farmer who has suffered from their destructive 

 propensities. 



A few days after the arrival of the falcons at 

 the cliff in 1914 (April) one of the parent birds 

 disappeared, but the unmated one remained in 

 the vicinity of the ledge until September. In the 

 spring of the following year the single bird return- 

 ed alone to the old home, where it remained a few 

 weeks, then disappeared never to return to the 

 place where the loss of its partner was sustained. 



When the eggs of the falcons are taken they do 

 not lay again the same year, but do not leave the 

 locality until the proper time for their migration, 

 returning at the usual time the following year. 

 In 1918 a most delightful and profitable oppor- 

 tunity came to me in a part of Frontenac County 

 which made it possible for me to continue my 

 observations of the falcon. The conditions 

 were more favorable than on my previous expedi- 

 tions. In 1920 I secured a set of photographs of 

 the young falcons, and was able to identify the 

 feather remains of the birds which had fallen 

 victims to the rapacity of their parents. 



On one occasion, I found falcon eggs in a most 

 unusual location. They were laid among ferns 

 close to some silver birch saplings on the open 

 ground on the top of a cliff. This clutch of eggs 

 is now in the collection of the Rev. C. J. Young, 

 M.A., Brighton, Ontario. 



Apparently the development of the young 

 falcon is phenomenally rapid. Different writers 

 on ornithology whose works I have read are 

 united in stating that the period of incubation is 

 one month. I am satisfied the period must be 

 somewhat shorter, probably about twenty-one 

 days. Later on, I hope to be able to settle this 

 question with a greater degree of accuracy. On 

 June 14 I found the young hawks with a heavy 

 growth of white down covering their bodies and 

 completely enveloping the feathers. On visiting 



