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NORTH AMERICAN FAUNA 69 



tances but not driven beyond the territory boundary. The action 

 of the two birds reminded me somewhat of the well-known sexual 

 chase of Red-winged Blackbirds (Agelums phoeniceus) , when the 

 females arrive on the breeding grounds. 



During prenesting I observed a display by a paired male where 

 he assumed a posture similar to a female ready for copulation. 

 The posturing occurred when the male was perched about 3 feet 

 from the ground and was approached by the female to within 

 about 1 foot. When the female alighted near the male, he uttered 

 a faint twee-twee-twee that was barely audible from where I was 

 standing less than 8 feet away. The next day under similar cir- 

 cumstances, the same male extended his rump feathers only and 

 uttered the same faint notes. 



Also during prenesting, a paired male was observed to perform 

 a "moth" or floating" flight. I could not locate the female at the 

 time. 



Vocalizations 



During the courtship and mating period, a pair spends most of 

 the day foraging on the ground, usually within 30 feet of each 

 other and often only 2 to 3 feet apart. The male sings very little 

 during this period and is otherwise less vociferous than the fe- 

 male. He may do some sustained singing early in the morning, 

 usually before 7 a.m. I spent 3 consecutive days in the territory of 

 one male, and after 7 a.m. on these days he sang four, none, and 

 two primary advertising songs. During the day singing was more 

 subdued and appeared to be for the purpose of singnaling the 

 female when she was momentarily out of contact with the male. 

 Sometimes a song was incomplete, consisting only of the first, 

 second, or third notes. 



Vocalizations other than song are used by the pair to maintain 

 contact. "Chipping" by the female is the most obvious and fre- 

 quently used vocalization. Some females chip often enough for 

 the investigator to follow a pair during most of the day in habitats 

 where he can move about easily. 



The chipping of the female often differs from the conventional 

 alarm (chip) notes of both sexes. At times the chip note is more 

 subdued, more of a squeak, and toward the end of the vocal 

 performance the notes run together into a sort of muted chatter. 

 At that point the chipping has the ring of excitement, and has 

 attracted the male, who may attempt copulation. 



Sometimes a very faint chi/p (that I could barely hear at 20 

 feet) is used by both members of the pair. This is a single chip, 



