GRASSHOPPER SPARROW 739 



it serves to announce her location, to maintain the pair bond, and to 

 signal both the male and the young that she is approaching the nest. 



Song falls into seasonal and daily patterns. The male sings the 

 grasshopper song from arrival until mid-August. The sustained song 

 is introduced approximately at the time of the females' arrival. 

 After pairing, the volume of song drops for a few days, but singing does 

 not cease entirely. The sustained song is confined mostly to evening 

 twilight; the grasshopper song is the common daytime song. During 

 the periods of egg laying and incubation the male sings both songs 

 frequently, especially in early morning and late evening, continuing 

 until darkness. Song wanes during June when the birds are busy feed- 

 ing young. Prior to renesting the sustained song is heard frequently 

 for several days before it wanes again. The trills of both male and 

 female are given from the period of pair formation to the completion 

 of nesting. 



The grasshopper sparrow does not have an extended morning 

 awakening song. When it wakes the bird may start to feed in silence, 

 or it may utter a few call notes, or snatches of the grasshopper or sus- 

 tained songs. Once the bird starts singing, it interrupts the song 

 sequence frequently with feeding. By mid-July the morning singing 

 has almost ceased, and daytime song is rarely heard, but in the cool of 

 evening, as feeding activity stops, twilight singing may still be heard 

 until darkness falls. At this period the sustained song with its greater 

 carrying power seems to be the most conspicuous, and for this reason 

 has been erroneously described as a postseason elaboration of the 

 regular song of the species. Night singing, particularly when the 

 moon is full, is a common habit with all races of the species. 



The call note of all races of the grasshopper sparrow most commonly 

 heard is a two-syllabled chi-lip or til-lie. Given by both sexes, the 

 call functions primarily as an alarm note; as such it varies in intensity. 

 When rapidly given in high intensity alarm, the notes suggest the slow 

 chcking of a fishing reel. Less frequently, especially under situations 

 of low intensity alarm, the call note is only a sharp tik. 



While feeding the grasshopper sparrow utters a single note tik or 

 chip. It is similar to the alarm note, but is higher pitched and less 

 sharp and vigorous. The food call of the young is a double note chi-ip 

 similar to that of the adult but with a more liquid quality. 



Field marks. — Adult grasshopper spaiTows are short-tailed, flat- 

 headed, and the only sparrows of the grasslands that lack streaks or 

 markings on the breast. Young birds of the year have streaked 

 breasts and are often confused with adult Henslow's sparrows, which 

 are more sharply streaked with black on the breast, sides, and flanks. 

 The young Henslow's sparrow with relatively unstreaked breast may 

 be confused with the adult grasshopper sparrow, but the distinctly 



