” 
To 
WILSON’S STORMY PETREL. 5538 
DESCRIPTION. 
The plumage generally is sooty-brown, darker on the crown; primaries and tail 
brownish-black; wing coverts and inner secondaries ashy-gray ; rump, feathers of 
the sides adjoining it, and outer lower tail coverts, white; bill black; iris dark-brown; 
tarsi and feet black. 
The female differs only in being rather smaller. 
This is larger than Wilson’s Petrel, and has a much stronger bill: it may be 
readily known from it by its forked tail, and the interdigital webs being entirely 
black. 
Length, eight inches; wing, six and a half; tail, three; bill, two-thirds of an 
inch; tarsus, one inch. . 
HIS species is the most abundant of our Petrels. It is, 
in fact, the only one that breeds here; and all others 
may be regarded as wanderers. About the first week in 
June, in the latitude of the islands on the north-eastern coast 
of Maine, it pairs. Breeding in communities, it soon begins 
its nest. This is composed of weeds, short grasses, and 
small pebbles, which are arranged in a flat structure, at the 
end of a burrow constructed by the birds, or in the fissures 
and crevices of rocks on the islands off our northern coast. 
In this a single egg is deposited, which is of a pure-white 
color, with an obscure lilac ring around one end, consisting 
of fine confluent dots. It is nearly oval in form, and 
averages in dimensions about 1.30 inch in length and .96 
inch in breadth. A large number of specimens in my col- 
lection exhibit a variation of from 1.35 to 1.24 inch in 
length, and from 1 inch to .80 inch in breadth. These eggs 
soon become discolored and dirty, from the nature of the 
nest and the habits of the bird; but originally they are pure- 
white. Their shell is exceedingly fragile, and a little rough 
to the touch, like that of the eggs of all birds of this class. 
“THALASSIDROMA WILSONII.— Bonaparte. 
Wilson’s Stormy Petrel. 
Procellarza pelagica, Wilson. Am. Orn., VII. (1808) 90. 
Thalassidroma Wilsonii, Bonaparte. Syn. (1828), No. 308. Nutt. Man., II. 
(1834) 324. Aud. Orn. Biog., III. (1835) 486; V. (1839) 645. 0., Birds Am., VIL 
(1844) 223. 
Oceanites Wilsonii, Bonaparte. Cons. Ay. II. (1855) 199, 
