HARRIS' SPARROW 1259 



I described it on its R-l return Feb. 13, 1964, as: "Typically immature 

 plumage — crown heavily veiled, eye-line wide and buffy, throat white 

 with only a few flecky lines radiating down from the dark chin, breast 

 dark splotched, tail heavily frayed but white edging showing slightly." 

 Victor Vacin has written me of a single similar "puzzler" among his 

 306 return records. 



Molt. — Certain characteristics are acquired gradually through the 

 winter. In immature birds the black fringe of the chin frequently 

 appears during December and January, and Swenk and Stevens 

 (1929) note it in some as early as October and November. In adults 

 the buffy edges of the black loral feathers wear off and leave the bird 

 dark-faced, not too unlike the black hood of the breeding plumage. 

 Dark flecks may appear in the superciliary stripe by early February. 



The prenuptial molt begins about the middle of March (earliest 

 Mar. 3, 1951) and continues through most of April. By April 25 

 young and old are indistinguishable in velvet black hoods, gray cheeks, 

 and fresh white feathers of chests and sides. The sequence of this 

 molt is from chin and forehead (if not already black) to throat, crown, 

 nape, and cheeks. New quills may appear in the chest and sides of 

 some birds several weeks in advance of other areas. In first-year 

 birds the superciliary stripe is frequently the last clue to immaturity, 

 remaining a patchy buff and black until April or early May. Last to 

 molt is the postauricular spot, which turns from brown to black. 



An individual bird completes the molt in about a month. One in- 

 dividual I handled daily throughout the spring showed no quills until 

 April 13; by May 9 this bird wore the full black hood, though still in 

 heavy quills. Individuals traced by Mrs. Nice (1929a) at Norman, 

 Okla., and a stray bird at Berkelej 7 , Calif., by Russell H. Pray (1950) 

 followed the same sequence. Young and old pass through the molt at 

 the same time. First signs of molt in the spring have been observed 

 some years in adult birds, in other years in immatures. While an 

 occasional old return may be in full breeding plumage before the end 

 of April, I also have notations on R-ls such as "molting head, chin, 

 throat" on May 3, and "almost through molt" on May 14. 



External sex differences. — Sex differences in plumage and 

 measurements are slight and overlap considerably. In general the 

 largest, stoutest, brightest birds are males and the smallest, most 

 drab are females. The crown tends to be wider in males, narrower in 

 females. A goodly number of intermediates cannot be sexed with 

 certainty by external examination, though familiarity with the species 

 increases awareness of minute differences. On my field cards I have 

 hazarded guesses for as many as possible, resexing at each repeat or 

 return. In some cases "immature females" have returned the next 

 year as large, plump, glossy "adult males," but more frequently the 



