118 Wilson's WAfiBtER. 



Male. Golden olive above, with the top of the head bluish black; 

 Forehead, sides of head, and under parts, gamboge yellow. 



Female. Similar to the adult male, sometimes scarcely different, but 

 often with the black of crown obscured by greenish tippings to more or 

 less of the feathers. Autumnal birds of both sexes are similar to the 

 spring dress. 



Dlmensions. Length, 5.00 ; stretch, 6.80 ; wing, 2.10 ; tail, 2.15; bilL 

 .35 ; tarsus, .7o. 



Comparisons. Somewhat like a Yellow Warbler, but with a more 

 slender form and more active habits ; also known by the black crown. No 

 other warbler has this marking in combination with the unstreaked under 

 parts. 



Nests and Eggs. Nests placed on the ground, composed of grass 

 and leaves, lined with fine grass and a few hairs. Eggs, usually four, 

 sometimes five, pure white, rather thickly spotted with reddish brown and 

 lilac. Dimensions, .60 by .48. 



General Habits. Although not a rare bird with us, 

 Wilson's Warbler is interesting because it is not as often seen 

 as many other of our warblers It is one of the late spring mi- 

 grants and often frequents willows and alders that grow along 

 streams, but it also sometimes occurs in the gray birches and 

 other low trees which border woodlands At first glance it 

 may be mistaken for a Yellow Warbler, but upon close obser- 

 vation it will be seen that Wilson's Warbler is much more 

 slender in form than that species, and rather more active, fre^ 

 quently darting into air in order to snap up some passing in- 

 sect. I have not often observed these birds feeding near the 

 ground ; on the contrary they appear to prefer the upper limbs 

 of the low^ growths which they inhabit. 



Breeding Habits. According to descriptions, this spe-' 

 cies always places its nest on the ground, concealed in a low' 

 thicket, often in a swampy place. The eggs are deposited 

 from the middle to the last of June. 



Song. Wilson's Warbler ordinarily gives a low warbling; 

 song, and occasionally a harsher series of notes like " zee zee 



