220 CALIFORNIA ACADEMY OF SCIENCES. 



that the adult male is red, the female yellowish, and the 

 young dusky gray, but whether the yellow plumage of 

 the male is simply a mark of immaturity or a seasonal 

 difference, I have not been able to determine. 



(6.) The red-winged blackbirds (Agelaius) present 

 some interesting features in the changes of plumage. 

 Not only does the male differ from the female in summer, 

 but both sexes also change in winter, and the plumage 

 of the young resembles but is not identical with that 

 of the female. 



The uniform black of the males is in winter broken 

 up by rusty terminals to the feathers, while the brown 

 and gray streaks of the female become duller in winter, 

 and the white tinge on the lower parts less marked. The 

 changes in the red wing-patch are shown in Plate XII. 

 The adult males in summer are colored with a patch of 

 brilliant red or crimson. In winter it is yellowish much 

 broken up with dusky and black mottlings. The wing 

 patch of the adult female Agelaius phwniceus and A. 

 guhernator in summer plumage is a pale reddish tinge 

 greatly interrupted with mottlings, while the wing patch 

 of the summer female of A. tricolor is a dull crimson, 

 mingled with bluish black mottlings. The last figure 

 represents the adult female in winter, or young, phase 

 of the shoulder marking, the color being there a plain 

 unmodified brown. The various stages of transition 

 from the unspecialized to the most highly developed 

 phase are thus to be found in this group by studying the 

 variations of age, sex and season. 



The third division includes those, forms in which the 

 adult male is, at all seasons of the year, unlike the 

 female. Instances where the female is more conspicu- 

 ously colored than the male are very rare, and I do not 

 think there is any example of this group among North 

 American land birds. The phalaropes form one of the 



