720 



REPRODUCTION AND MIGRATION IN BIRDS 



Table I (Continued) 



Species 



Fringillidae 

 Fringilla codchs 

 Pyrrhula rubicilla 

 Serinus canaria 



Carduelis elegans 

 Chloris Moris 



Loxia curvirostra 



Junco hyemalis 



Junco oreganus oreganus 

 Junco oreganus shujeldti 

 Junco oreganus thurheri 

 Junco oreganus pinosus 

 Zonotrichia leucophrys leucophrys 

 Zonotrichia leucophrys gambelii 



Zonotrichia leucophrys pugetensis 

 Zonotrichia leucophrys mittalli 

 Zonotrichia atricapilla 



Passerella iliaca 

 Melospiza melodia 



Sex 





c?, 9 



Reference 



d" 



Vaugien (1948) 

 Vaugien (1948) 



Takewaki and Mori (1944) ; Vau- 

 gien (1948) ; Kobayashi (1954c) 

 Vaugien (1948, 1956a,b) 

 Damste (1947); Schildmacher 

 (1956) 



Schildmacher and Rautenberg 

 (1953) 



Rowan (1925, 1926, 1938); Wolf- 

 son (1952a, 1953); Jenner and 

 Engels (1952) ; Engels and Jenner 

 (1956) 



Wolfson (1942) 

 Wolfson (1942) 

 Wolfson (1942) 

 Wolfson (1942) 

 Wolfson (1954) 



Earner and Mewaldt (1952, 1953); 

 Wolfson (1945) 



Wolfson (1945); Bailey (1950) 

 Wolfson (1942, 1945) 

 Miller (1948, 1949, 1951, 1954); 

 Wolfson (1945) 

 Wolfson (1945) 

 Wolfson (1945) 



mately as a logarithmic growth curve from resting weight (2 mg or 

 less) to about 200 mg (maximum weight is about 600 mg). Thus, 



logio PF, + logio I'Fo + ^/ (1) 



where Wo is the initial testicular weight in milligrams and Wt is the 

 weight after / days (Fig. 1 ). For photoperiods of the same duration, k 

 for first-year birds is about 1.16 times as great as for adults. Wo for 

 first-year birds is about 0.7 mg whereas it is about 2 mg for adults. 



Since equation ( 1 ) represents a fairly close approximation of testi- 

 cular growth as a function of time, the rate constant k is useful in 

 comparing birds subjected to various photoperiodic treatments. For 

 example, it is of importance (Farner and Wilson, 1957b) to examine 

 A: as a function of the length of the daily photoperiod (p) (Fig. 2). 

 It is to be noted that for values of p from about 9.5 to 18 hr, k 



