224 
Mackay, Notes on Certain Water Birds. 
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waters between Woods Holl and Naushon Island, Mass. On 
March 13, 1S94, during a strong southwest wind, they all 
departed and were not observed afterwards. Mr. Edwards had 
saved the contents of the stomachs of some Eiders which were 
shot on February 11 and 15, which I saw; they consisted of 
sculpin spawn, in perfect condition, in small masses stuck 
together, and black mussels ( Modiola modiolus') ground up to 
the consistency of fine sand and black in color. Four female 
King Eiders (S. spectabilis) were taken there on February 20, 
1894, and the contents of the stomachs saved, which I also saw, 
consisted entirely of Tritea trivittata in good quantity and 
condition. 
Such a very large collection of Eiders, in so restricted a 
locality as the one above mentioned, can only be explained by 
the great abundance of the black mussel which these birds first 
discovered in the winter of 1892-93. These beds of mussels had 
increased to such an enormous extent that some of them, which 
were attached one to another, are said to be five feet or more in 
thickness. Only such masses are able to survive under the 
peculiar conditions which exist there, due to the great pressure 
of water which rushes with great force through this narrow 
passage or strait, connecting Buzzards Bay with Vineyard Sound. 
When the birds were disturbed by the steamboats which passed 
daily they would fly out into the Sound, where they would 
remain awhile, returning later. Although considerably harassed, 
and many shot, it apparently produced little effect on them, for 
they refused to forsake so attractive a feeding ground, and con- 
tinued to frequent it. I have little doubt that they will again 
appear in the same large numbers if the food supply continues in 
this locality next season. 
Auk XT. July. 1864 p. 228-24 
