C2 Mackay, Terns of Muskeget Island. Man- 



the autumn, and seem to drop from the clouds when they appear 

 in the spring. By September 30 there were comparatively few 

 Terns remaining, these being around the rips at the openings. 

 On October 2 Mr. Sandsbury wrote me there were no Terns in 

 sight from his house on Muskeget Island proper. I saw a few 

 single Terns resting on the water, and flying about, as I passed 

 through the Sound on October 3. 



Since my former article I have made some further attempts to 

 solve the problem of the cause of certain differences between what 

 I have called the reddish legged and flesh-colored legged chicks of 

 Sterna hirundo (see Auk, Vol. XII, p. 44). I found these chicks 

 in evidence again this summer in about the same proportion as 

 last season, say one-third red-legged birds and two-thirds with 

 flesh-colored legs. As far as my observations go the differences 

 between them appear to be fairly constant up to the period of 

 their being able to fly, which is as far as I have been able to 

 observe them. Hoping to obtain some further evidence, I kept a 

 number of each kind in separate coops on Muskeget. None of 

 them, however, lived over ten days, and most of them died inside 

 of a week. They were fed on lobsters and clams. I then took a 

 small series of selected chicks, had them sexed, made up into 

 skins, and forwarded to Washington for Mr. Robert Ridgway's 

 inspection, together with some other Terns' skins. He pronounced 

 them ,5. hirundo, as did Mr. William Brewster later. This point 

 being thus' settled I would say that there are here apparently two 

 kinds of chicks which differ in actions and in appearance. The 

 red-legged are brighter, more active, and neater looking. Those 

 with flesh-colored legs are lethargic and more stupid. Their bills 

 are stouter and larger, and all in all they are a coarser looking 

 bird, and I think a good many of them are hatched earlier than 

 the red-legged birds. Under such conditions, is it not possible 

 that there may be two varieties of S. hirundo, with differences 

 which may be constant during youth, but which become undis- 

 tinguishable in the adult birds ? 



The downy young of the Roseate (S. dougatti) may be distin- 

 guished by their upper parts being gray, white, and black, inter- 

 mixed in longitudinal streaks ; under parts whitish ; bill pinkish 

 flesh color, with black tip; legs and feet black. As they advance 



