1266 U.S. NATIONAL MUSEUM BULLETIN 237 part 3 



The alarm note was a loud weenk, or wink, readily distinguishable from the 

 weaker zheek of Gambel's Sparrow and from the heavy tchup of the Fox Sparrow 

 (Passerella i. iliaca). The call which accompanied mating was a fine, rolling 

 chatter, similar to that given at such time by many other members of the sparrow 

 tribe. 



During late July and August (1934), when care of the young and 

 the fall molt are sapping the vitality of most northern birds, we heard 

 very little singing at Churchill. Seton (1908) notes that he "found 

 the species in full song September 3" at Great Slave Lake. On 

 migration during the fall they are generally silent. Thomas S. 

 Roberts (1879) states that at Minneapolis, Minn., "I have never heard 

 any song from them except on one occasion. That was in the fall, 

 when a bird in the plumage of the year uttered a low, continuous 

 warble as it sat on the top of a brush-pile. This was repeated many 

 times, and reminded one somewhat of the subdued singing of the 

 Tree Sparrow, often heard in the early spring." 



Swenk and Stevens (1929) comment that when the southbound 

 Harris' sparrows reach the region south of latitude 41°: 



* * * a region where the birds will linger in abundance from late September to 

 late October, * * * their whole vocal behavior changes. The autumn is ordinarily 

 a season when bird songs are conspicuous by their absence, but in the region 

 mentioned the Harris's Sparrow sings as sweetly, if not as fully and volubly, in 

 October as in May. It especially likes to sing in chorus in the evening, shortly 

 before nightfall. At this season the song commonly consists of one or two drawling 

 minor whistled notes, sometimes followed by a third note at a different pitch, all 

 relatively slow and subdued as compared to the spring song, and very like the 

 abbreviated songs of our other Zonotrichias at the same season. On bright days 

 during the entire winter its more or less abbreviated song may be heard. As 

 spring approaches the song becomes complete and more sustained. 



Enemies. — Nothing has been recorded of actual predation on the 

 nesting grounds. The North is blissfully free of many of our song- 

 birds' worst enemies — snakes, house sparrows, starlings, cowbirds, the 

 feral cat, small boys, agricultural practices, and that modern scourge, 

 pesticides. A list of potential predators known within the breeding 

 range of Harris' sparrow includes an occasional marsh hawk, peregrine 

 falcon, pigeon hawk, sparrow hawk, horned owl, northern shrike, red 

 fox, a few red squirrels, martens, and weasels. If the birds are as 

 clever at concealing their nests from natural enemies as from visiting 

 ornithologists, predation is slight indeed. 



During the winter Harris' sparrows may suffer some losses to cats, 

 boys with air guns, shrikes, and bird hawks of one kind or another. 

 The greatest destructive force to the species, however, is undoubtedly 

 weather. Storms during the migration and snow or ice that covers 

 the food supply probably account for more fatalities than all other 

 causes combined. 



