VARYING FECUNDITY IN BIRDS 185 



bird does not sit down and ejaculate about them and strong on the wing ; 



" Kismet," feebly awaiting the period and to fulfil this desire they succeeded 



of migration. She feels desolate with- in resisting for a time their extraor- 



out her young around her ; either she dinarily powerful instinct to migrate, 



has a superhuman sense of race duty. There are a few further rules which 



or else she desires the company of her are useful, and these may be stated 



offspring in the sunnier climes to which more briefly. 



she will soon be hurrying. At any (i) The effect of the breeding season 



rate she immediately begins bustling is to maintain the numbers of each 



about, and in a week she will have species at an equable level. Neither 



another nest in an apparently safer increase or decrease are met with, 



spot, even if the duties run her peril- unless there is a notable change of 



ously near the date when her migra- conditions. 



tory instincts annually become clamor- (2) By August the numbers of each 



ous. In a dell near Bristol one year species are at least treble what they 



I made the acquaintance of two separ- were in April. 



ate pairs of nightingales nesting close (3) These numbers are subsequently 



together. A bird-stuffer from the reduced to the normal, as follows : 



neighbouring city had more than the (a) In the case of migratory species, 



usual cunning of his kind, if not more curtailment is effected by the hard- 



than usual greed, and he found and ships and dangers of the two journeys, 



emptied both nests when the eggs (ft) In the case of resident species, 



were nearing the hatch. Both birds many succumb to extreme cold and 



built second nests, and laid new exposure and starvation during the 



clutches, and again he utterly despoiled winter months. 



them ; but the third time they were (c) All bird flesh is heir to certain 



too cunning for him, and safely reared ills, accident, the preying of the car- 



the last nests. The young birds nivora, winged or footed, and at the 



were so late in taking wing that all the hands of the gamekeeper, collector, 



nightingales I knew of in the surround- and small boy bully. These losses, 



ing country-side had apparently gone, however, probably do not compare 



Clearly whatever the principle at the with (a) and (&). 



bottom of it the birds were unsatis- The various species may now be con- 



fied till they had young ones flying sidered in more particular detail. 



