The species feeds mostly on squid, which comprises 87% of its diet in some studies; it will also feed on lanternfishes as they ascend to the surface at night, as well as on crustaceans.
The Schlegel's Petrel is classified as Endangered (EN), considered to be facing a very high risk of extinction in the wild.
Schlegel's Petrel in Chesh. {Brit. Birds, II.) Pemberton, R. Fulmar at Ince. {Lanes. Nat., p. 105.) Stubbs, F. J. Bird Notes from the Oldham District. {Nat.) Yates, J. M. St. J. Woodchat in Chesh. {Brit. Birds, II.) 1909. Coward, T. A. Black Grouse in Chesh. {Zool.) Idem by A. Newstead. {T.c.) Newstead, A. Ornitholog. Records from Chester since Jan. More