NORTHERN GRACE'S WARBLER 365 



half of the egg immaculate. Occasionally eggs are speckled all over ; 

 and some are marked with blotches. Generally the drab spots are in 

 the majority, when the fewer brown spots, which are often as dark 

 as to appear almost black, are more prominent. The measurements of 

 38 eggs average 16.9 by 12.7 millimeters; the eggs showing the four 

 extremes measure 18.2 by 13.1, 18.0 by 13.3, 14.8 by 12.7, and 15.4 by 

 11.7 millimeters (Harris). 



Young. — Nothing seems to have been published on incubation or 

 on the development and care of the young. 



Plumages. — Kidgway (1902) describes the young male in first 

 plumage as "above plain grayish hair brown or drab-gray, the 

 feathers ash gray beneath the surface ; sides of head similar but rather 

 paler; malar region, chin, and throat pale brownish gray, minutely 

 and sparsely flecked with darker, the chest similar, but with rather 

 large roundish spots of dusky ; rest of under parts dull white streaked 

 or spotted with dusky gray medially, dull grayish laterally." 



Swarth (1904) writes of the postjuvenal molt: 



A young male taken July 13tli is in the brown streaked plumage, but yellow 

 feathers are beginning to appear along the median line of the throat and upper 

 breast, and the yellow superciliary stripe is also beginning to show. Another, a 

 little older, has the streaks of the lower parts restricted to the sides and flanks, 

 and the yellow markings nearly perfect. A male taken on July 30th, which has 

 just discarded the juvenile for the winter plumage, dilTers from the autumnal 

 adults in having the white of the under parts more strongly tinged with buff; 

 and whereas the adult has the back decidedly streaked, though the markings are 

 overcast by the brownish edgings to the feathers, in the juvenile these markings 

 are but imperfectly indicated. 



Apparently, the nuptial plumage is assumed by wear alone, for no 

 available specimens show any signs of prenuptial molt and both young 

 birds and adults in the fall are much like the spring birds, but browner 

 and with the markings obscured by brownish tips that probably wear 

 away before spring. 



Young birds and females have duller colors than the adult males and 

 are browner in the fall than in the spring. Adults doubtless have a 

 complete postnuptial molt in late summer. 



Behavior. — Grace's warbler is a bird of the pines, spending most 

 of its' time in the towering tops of the tallest trees. It is sometimes 

 seen in other conifers such as hemlocks and spruces, but very seldom 

 on or even near the ground. Dr. Wetmore (1920) says : "Usually they 

 were found in the tops of the Yellow Pines where they worked about 

 rather leisurely, exploring the smaller limbs and at short intervals 

 pausing to sing. * * * Occasionally one was' found working 

 about through the oak undergrowth at times coming down almost to 

 the gi'ound. The flight was undulating and rather quick and jerky." 



