44 PROCEEDINGS OE THE ACADEMY OP 



the body is very gradual. At this season the feet were simply 

 orange-3'ellow, not vermilion, and the bill was dusky-shaded 

 throughout. Some of the year's young had nearly perfect wing 

 and tail featliers ; but the mantle showed dusky mottling, with 

 some blackish areas upon the wing-coverts ; while younger still 

 were marbled and otherwise beautifully variegated with gra}', 

 light brown, &c. In all the young, the feet were yellowish, more 

 or less obscured ; and the bill mostl,y black, with yellow or orange 

 on the basal part of the under mandible ; it was smaller than that 

 of the old, not so horny, and more obtuse. 



Sterna Forsteri. 



Chiefly migrant, but also winter resident. Compared with the 

 last, there is, I think, a difference in the migrations, &c., something 

 like that I have endeavored to show in the case of the Ammodromi^ 

 this being the more northerly species of the two, migrating earlier 

 in the spring and later in the fall, and wintering where 8. Wilsoni 

 does not ; of the breeding I can say nothing from personal obser- 

 vation. A few Forster's terns come back in August ; the}" become 

 abundant the following month, and there is little or no decrease 

 of their numbers until December, when a part go further south, to 

 return the latter part of March, and the rest remain. It is one 

 of the most plentiful terns on the harbor in October and ^N'ovem- 

 ber, when it may be distinguished at any reasonable distance with 

 ease ; Wilson's tern being the only one at all resembling it, and 

 this being marked in the manner just indicated. Forster's at this 

 season has the crown white, the occiput blackish, and a remark- 

 ably distinct black transocular fascia, better marked than in any 

 other species of ours. In this plumage it is unquestionably S. 

 havelli, Aud., as I pointed out some years since. The bill is nearly 

 as in summer, but not so bright ; the feet are orange instead of 

 red. This plumage was finished in all of a number of old birds 

 shot the second week in September. The young of the year can 

 also be distinguished from the young of hirundo at ordinarj^ g^^n- 

 shot range. The whole head is white, faintly washed with brown- 

 ish, except the transocular fascia, which is pure black, and very 

 sharply defined ; but nearly all the feathers of the crown have 

 dusky bases, that will increase during the fall and coming winter, 

 until the condition above noticed is attained. The eye-stripe is 

 i^ inch long and about ^ an inch wide, reaching from the lores 



[May 9, 



