The Mid-Winter Meetings. 195 



The reproductive cycle is made up of a series of terms, representing discrete acts 

 or chains of actions in a definite succession. Eight or more terms may be recog- 

 nized, many of which, such as brooding and feeding the young, are recurrent within 

 the series. The cycle may be graphically represented by a series of tangent circles, 

 each one of which stands for a distinct sphere of influence, or subordinate series of 

 related impulses, named and numbered as follows: (i) Spring migration; (2) 

 courtship and mating (often attended by song); (3) selection of nesting site and 

 building nest (often accompanied by the fighting instinct); (4) egg-laying; (5) 

 incubation — including care of eggs, such as shielding, rolling, cleaning and cover- 

 ing (fear often completely blocked by brooding instinct); (6) care of young in 

 nest, subject to the following analysis: (a) feeding young, including capture and 

 treatment of prey, return to nest (pause), call-stimulus, testing reflex response of 

 throat, watching for reflex response (pause); {h) inspection of young and nest; (c) 

 cleaning young and nest; removal and disposition of excreta; {d) incidental care of 

 young and incidental behavior in this and other terms of cycle — brooding, shielding 

 or spreading over young whether sitting or erect, bristling and puffing, preening, 

 gaping, stretching and yawning, guarding and fighting; (7) care and incidental 

 education of young when out of nest; guarding, feeding, play, and other instinctive 

 acts; (8) fall migration. Beginning at 2, 3 or 4, according to circumstances, the 

 cycle may be repeated once or oftener within the season. 



The coordinated instinctive responses of the young begin in the sixth term, and 

 are mainly as follows: (6) Initial responses at moment of hatching or shortly after, 

 including grasping movements of limbs, elevation of head, opening of mouth, and 

 the swallowing reflex in response to contact of bill of old bird or of food in deep 

 part of throat; characteristic actions in muting following feeding, in response to the 

 attitude of inspection in adult; call-notes, pecking, and gaping, stretching, and 

 spreading in response to heat, flapping, fear and flight; (7) calling (teasing), follow- 

 ing, crouching and hiding, play, imitation, preying and flight; (8) fall migration. 



The formula of the reproductive cycle given above is a composite, which with 

 slight changes will apply to most of our common wild birds. In the most aberrant 

 cases of behavior, where the parental instincts have been reduced to a minimum as 

 in the cow buntings and the megapodes, the cycle ends abruptly at term 5, and in 

 the cowbird there is no attempt to either build a nest or to conceal the eggs. 



The Blending and Overlap of Instincts. By Francis H. Herrick, Western 

 Reserve University. 



There are many anomalous actions or peculiarities of behavior in wild birds 

 which have not been satisfactorily explained, although certain of them have been 

 long known. Some of the eccentricities of conduct referred to are the following: 

 (l). Repair of the old nest or the building of a new one at the close of the breeding 

 season; (2) omission of nest building, and dropping of eggs on the ground; (3) 

 leaving young to perish in nest, and starting on migration; (4) offering strings or 

 other objects to young in the place of food ; (5) building more than one nest including 

 the "cock nests" of marsh wrens; (6) rebuilding on the same site, producing super- 

 imposed nests or nests of from two to four "stories" "to conceal" foreign bodies, 

 such as the cowbirds' eggs in the nests of vireos and warblers. 



All of these curious actions receive much light, and in most cases are satisfactorily 

 explained by what we shall call the blending or overlapping of instincts. As shown 



