756 U.S. NATIONAL MUSEUM BULLETIN 23 7 paet 2 



feeding and brooding the young and cleaning the nest. Daytime 

 brooding ceases on the fifth day after hatching. 



After the young leave the nest, both parents continue to carry 

 food to them. Though the flightless young never travel more than 

 a few yards from the nest area, for the first day or two the parents 

 seem to have diflaculty locating them, and hover on threshing wings 

 until a tip! call from a youngster guides them to earth. 



Plumage. — Cartwright et al. (1937) give the following description 

 of the Juvenal plumage: 



Loral region and forehead black sparsely tipped with buflf; crown black tipped 

 with buff, more buffy in the center, showing an indistinct median line; superciliary 

 line buff; auriculars buff tipped with black; malar region buff, nape and hindneck 

 black edged with buff; back black edged with pale buff, giving a scaly appearance; 

 rump black edged with ochraceous-buff ; upper tail coverts and rectrices the same; 

 scapulars black edged with buff, paler at the tips; primary and secondary coverts 

 greyish-black; throat and upper breast black widely edged with buflf, the same 

 pattern continuing along the sides; belly white tinged with buflf, paler toward the 

 vent; undertail coverts white; crural tracts whitish with black centers. The 

 general coloration of the juvenal is ochraceous buflf about the head, a mixture of 

 blackish and ochreish on the back giving a scaly appearance. The colors are more 

 intense than any plumage of the adult and the breast and side markings are 

 heavier. 



A thesis by R. R. Graber (1955) compares the juvenal plumages of 

 Ammodramus as follows: 



The two species of this genus, savannarum and hairdi are very much more alike 

 as juvenals than as adults. Adult bairdi bears a striking resemblance to the 

 savannah sparrow, Passerculus sandwichensis, and Ridgway (1901) placed the 

 species in a montypic genus, Centronyx, between Passerculus and Coturniculus ( = 

 Ammodramus) , stating that it was much closer to the latter. He did not mention 

 the juvenal plumage in his discussion of the relationship of the three forms, but 

 the characters of the juvenal support his view that bairdi and savannarum are 

 close. Certain patterns are common not to juvenal or adult savannarum but to 

 juvenal savannarum and adult and juvenal bairdi. I refer particularly to markings 

 on the chin and side of the head and the conspicuous ventral streaking. Juvenals 

 of both species have a scaled back-pattern. This pattern appears to be an 

 adaptive feature in prairie birds, but juvenal Passerculus does not have it, despite 

 the fact that Passerculus and Ammodramus are prairie associates in the many 

 areas throughout which their ranges overlap. 



A striking feature of the juvenal plumage in Ammodramus is its firm texture. 

 In this respect, the plumage is like that of the adult. This is particularly true of 

 bairdi, in which the juvenal plumage appears to be long-lived. The occurrence 

 of juvenal specimens and worn adults in Arizona has led to speculation concerning 

 a discrete southern breeding range. Among the many bairdi records listed by 

 Cartwright, Shortt and Harris (1937) were several southern records of juvenals. 

 In every case these were late August or September records. I have seen three 

 such specimens, worn birds in the early stages of the postjuvenal molt. Such 

 specimens are not reliable evidence of breeding, though stub-tailed juvenals would 

 be. The number of records of juvenals south of the known breeding range of 

 bairdi indicates that this species migrates often, and probably regularly, in juvenal 

 plumage. This is also true of Leconte's sparrow, Ammospiza lecontei, though the 



