Ko. 486] 



NOTES AND LITERATURE 



including (1) spring migration; (2) courtship and mating; (3) nest 

 building; (4) egg laying and incubation; (5) care of young; and (6) 

 fall migration. Some birds, like the robin and blue bird, pass through 

 two or three reproductive cycles before the fall migration. Tlie fish 

 hawks and eagles which repair their oki nests in the autumn do not 

 act in "anticipation of spring" but exhibit a recurrence ot" ilie iu',stin<j: 

 instinct, due to beginning a new cycle which is never finished, ^'oimi: 

 birds may be abandoncnl in the fall when the migratory impulse »>v(m-- 

 laps the parental instinct. jiduit r()l)in lias been seen to offer a 



string to its fully gr()\\ n youno-. and try to cram it down the throat of 

 a fledgling. Later the old bird llcw with the string into a tree. This 



the cowbird's egg, which it does so j)erfectly. It indicnics rather that 

 the reproductive cycle has been broken 1)\ tear, and a new one i> 

 begun, in these rare cases the old nest beinjr n taiufd a- a site n» hinld 

 upon. The herring gull also will bury it. u hm n. . ^. Ir ha- 1.. vu 

 interrupted through iVur. 



followed in th,>.f(Mn-.Kal..f ( onll.al^l(iv.■^^■nI■..l(>oyl,van.■xIra(.^linarv 

 /J//^^/,»v all,<ih,nH„s,^ ' It Mate, that "afn-r iIh' .'l-^ arc drj-o^nd 

 they arc nsually unardcd for a lime by the male, who fi^'his and (h'lv,- 



himself eats some of the eggs, bnt on' accouiU of the sKmn.-.. of hi^ 



is onlv guarding his own food supply: the origin of tlie l)roodiiig 

 habit in this case .seems to he the feeding habit." If .)ne d..nbts that 



Journ. of Comp. Neur., 1907, vol. 27. pp. ](»7 1!>S. 



