716 REPRODUCTION AND MIGRATION IN BIRDS 



1932 Experiments in bird migration. III. The effects of artificial light, 



castration and certain extracts on the autumn movement of the American crow 

 (Corviis brachyrhynchos). Proc. Natl. Acad. Sci. U. S., ^.^'^l^'^^\.,.^^ 



Serventy, D. L./and A. J. Marshall. 1957. Breedmg periodicity m Western 

 Australian birds: with an account of unseasonal nestings in 1953 and 1955. 



Skutch.' r R %5a The nesting seasons of Central American birds in relation 

 to climate and food supply. Ibis, 92, 185-222. f u- a.. o« 



Thomson, A. L. 1950. Factors determining the breedmg seasons of birds, an 

 introductory review. 76/5, 92, 173-84. . , j ■ ,u- m t7Q 



Voous, K. H. 1950. The breeding seasons of birds m Indonesia. Ibis, 92, li^ 



Wagner H. O., and E. Stresemann. 1950. Uber die Beziehungen zwischen 



Brutzeit und Okologie mexikanischer Vogel. Zool. Jahrb., 79, 273-308. 

 Weise, C. M. 1956. Nightly unrest in caged migratory sparrows under outdoor 



Wh:ttm! E: a S.' Fa'itors'm'Jdifying egg production with special reference 

 to seasonal changes. /. Agr. Sci., 23, 383-418. • u, fot 



Winn H S 1950 Effects of different photoperiods on body weight, tat 

 deposition, molt, and male gonadal growth in the slate-colored junco. 

 Doctoral dissertation. Northwestern University, Evanston, 111. 



Wolf son, A. 1940. A preliminary report on some experiments on bird migra- 

 tion. Condor, 42, 93-99. ... r^ ^... aa ot,1 63 



194^ Regulation of spring migration in juncos. Condor 44, 23 /-o^. 



; 1945. The role of the pituitary, fat deposition, and body weight in 



bird migration. Condor, 47, 95-127. ^ j i *u c 



1947 Summation of day lengths versus increasing day lengths as 



the external stimulus for gonadal recrudescence and fat deposition in 

 migratory birds. Anat. Record, 99, 89. . 

 L. 1952a. Day length, migration, and breeding cycles m birds. Sci. 



_i^'^''/952b. -nii^occ^urrence and regulation of the refractory period in the 

 gonadal and fat cycles of the junco. /. Exptl. ZooL, 121 311-26. 

 ^ 195^c The cloacal protuberance-a means for determining breeding 



condition in live male passerines. Bi'd-Banding, 23, \ 59-65 ■ 



. 1953. Gonadal and fat response to a 5:1 ratio of hght to darkness m 



the white-throated sparrow. Condor, 55, 187-92. 



__ 1954 Production of repeated gonadal, fat, and molt cycles within 

 one year in the junco and white-crowned sparrow by manipulation of day 



J!!?^'-I95f lsiT^oi'f Vefrtt^^^^ period in the gonadal cycle of juncos 

 exDOsed to ^0-hour photoperiods. Anat. Record, 122, 454-55. 



Wolfson A and H. S%inn. 1948. Summation of day lengths as the external 

 stimulus for photoperiodic responses in birds. Anat. Record, lOI, 7U-/1. 



