PARASITIC WEAVERBIRDS 53 



olive because of increase in width of these marginal parts. Feathers 

 of back between Pyrite Yellow and Warbler Green with blackish 

 shaft stripes, and tipped with Light Grayish Olive. Rump and upper 

 tail-coverts similar but with dark shaft stripes more reduced and 

 more completely hidden. Upper wing-coverts similar to feathers of 

 the back. Primaries and outer secondaries dark Brownish Olive, 

 externally narrowly edged with Warbler Green, and internally, on 

 the basal two-thirds, broadly edged with Drab Gray to Smoke Gray. 

 Inner secondaries and rectrices Fuscous Black, externally edged with 

 Warbler Green basally and with Light Grayish Olive on their more 

 distal portions. Cheeks, auriculars, chin, and throat Olive-Ocher, 

 slightly duskier and more olivaceous on sides of head than on chin 

 and throat, this darker tone extending down along sides of throat. 

 Breast as sides of neck but clouded with even duskier olivaceous tone. 

 Abdomen Olive-Ocher, darkening slightly on sides and flanks, which 

 are obscurely marked with dusky shaft streaks, and become slightly 

 paler on under tail-coverts. Under wing-coverts pale Olive-Bufi 

 becoming yellower on edge of wing. Iris dark brown. Bill dark 

 brown to blackish brown becoming much paler, brownish gray, on 

 basal and gonydeal portion of mandible. Feet grayish brown to 

 brown. Wings 64-71 (68) mm. Tail 40-46 (43.5) mm. Culmen 

 from base 12-13 (12.7) mm. Tarsus 16-18 (17) m.m. 



Adult male in worn plumage: Remarkably different from the 

 above, but the change is due wholly to abrasion. Grayish or Light 

 Grayish Olive edgings are worn off and cause the bird to appear light 

 Aniline Yellow to Pyrite Yellow, and make blackish shaft streaks of 

 upper parts much more noticeable and striking, less obscured by 

 paler margins of feathers. Feathers of breast have lost their dusky 

 olivaceous tinge, and under wing-coverts are yellower and less gra3dsh 

 in appearance. The more worn the plumage, the more strikingly 

 yellow with black dorsal streaks the bird becomes.^^ 



Juvenal male: Very different from adult. Narrow frontal line, 

 superciliary areas, lores, cheeks and am-iculars Clay Color. Feathers 

 of crown and occiput with fairly wide black shaft streaks, laterally 

 broadly edged and lipped wdth Clay Color. Feathers of back, rump, 



«5 Mackvvorth-Praed and Grant (1948) describe what they call an "Immature" plumage, which is chron- 

 ologically intermediate between the adult and the juvenal or nestling plumage. It is charactcrizod briefly 

 as similar to the adult male in tresh plumage, but generally darker on the anterior upper parts. The Aniline 

 Yellow on the forehead is restricted to a thin line. The crown and occiput are Orange Citrine to Medal 

 Bronze. The feathers have indistinct dusky shaft streaks. Other parts arc as in the freshly phmiaged 

 adult (description based on specimens that I assume corrps[iond with what Mackworth-Pracd and Grant 

 had in mind). Although the top of the head is darker than in most freshly plumaged adult male birds, 

 I am still doubtful that this condition is a real plumage stage, and not merely the dark extreme of the adult 

 plumage. Chapin (19,')4, p. 407) found that "even in the fresh feather the shaft of each barb Is bright yellow, 

 but the outer part of all the barbules is dusky and tends to mask the yellow color, giving the general clTect 

 of olive." While Cliapin's comments refer to unqucstiimably fully adult birds, I have examined forehead 

 feathers from these dark-headed "immatures" microscopically and find exactly what Chapin observed. 



526526—60 5 



