740 tr.S. NATIONAL MUSEUM BULLETEST 23 7 part 2 



chestnut wings of Henslow's sparrow separates this species at all ages 

 from the grasshopper sparrow. 



The only other bird with which the grasshopper sparrow might be 

 confused is Leconte's sparrow (Passerherbulus caudacutus) . This 

 sparrow, however, inhabits prairie marshes, an environment too wet for 

 the grasshopper sparrow. Both adult and young Leconte's sparrows 

 are streaked, but the underparts are light yellowish brown instead of 

 cinnamon buff, and they lack the yellow before the eye and on the bend 

 of the wing. 



Enemies. — It is ironical that the grasshopper sparrow's greatest 

 benefactor is also his greatest enemy. This sparrow depends upon 

 man for maintenance of its habitat through grassland management, 

 but these fields are cut for hay. Haying usually begins in mid-June, 

 the height of this bird's nesting season. The nest usually escapes 

 destruction from mower blades, but some nests may be crushed by 

 implement wheels. If the nest escapes destruction by haying opera- 

 tions, it is exposed to weather and predators. Grass used for silage 

 is cut early, around the first of June. This is the height of nest build- 

 ing by the grasshopper sparrow. I have found that in fields regularly 

 cut for grass silage, resulting in early loss of cover, the population of 

 grasshopper sparrows is very low. The loss of cover later in the nesting 

 season does not result in abandonment of the field or the nest, if the 

 nest has not been destroyed. I have never noted grasshopper sparrows 

 leaving a field after haying, despite the loss of cover. This is in sharp 

 contrast to Henslow's sparrow, which leaves a field when the grass is 

 cut. 



Among the predators of the grasshopper sparrow are the skunk 

 (MejJhitis mephitis), weasels, spermophiles (Citellus spp.), foxes, and 

 cats. Cats take their toll of grasshopper sparrows, especially after 

 the hay is cut, although they probably catch fewer of these birds 

 than of other sparrows. Dogs at times discover grasshopper sparrow 

 nests accidently. 



W. H. Nicholson writes that hogs, snakes, spotted skunks (Spilogale 

 ambarvalis), and striped skunks seem to be the major enemies of the 

 Florida grasshopper sparrows. He states; "I have found 25 to 30 

 nests under construction; upon returning later I found practically 

 all of them destroyed by the above." 



As the nests are well concealed and the birds stay close to the 

 grass, hawks probably are insignificant as predators, except after the 

 hay is cut. Marsh hawks (Circus cyaneiis), though common in 

 grasshopper sparrow habitat, appear to have little influence on the 

 species. The grasshopper sparrow apparently pays no attention to 

 them, for I have observed males singing while marsh hawks were 

 hunting nearby. When, however, a sharp-shinned hawk (Accipiter 



