Slaty-backed Gull

Here the details of the Slaty-backed Gull named bird below:

SCI Name:  Larus schistisagus
Protonym:  Larus schistisagus Auk 1 p.231
Taxonomy:  Charadriiformes / Laridae / Larus
Taxonomy Code:  slbgul
Type Locality:  Bering Island and Petropaulski, Kamchatka, type from Bering Island.
Author:  Stejneger
Publish Year:  1884
IUCN Status:  Least Concern

DEFINITIONS

LARUS
(Laridae; Ϯ Great Black-backed Gull L. marinus) L. larus  rapacious seabird, probably a gull  < Gr. λαρος laros  voracious seabird, perhaps a gull; the Great Black-backed Gull, the largest member of the Laridae, breeds only on sea coasts, where it is a true predator; "69. LARUS.  Rostrum edentulum, rectum, cultratum, apice declive: Mandibula inferior infra apicem gibba.  Nares lineares, antice latiores.   ...   Pulli primi anni plurumque in his grisei sunt; unde speciei multiplicatio." (Linnaeus 1758); "Larus Linné, Syst. Nat., ed. 10, 1, 1758, p. 136. Type, by subsequent designation, Larus marinus Linné (Selby, Cat. Gen. Subgen. Types Aves, 1840, p. 48)" (Peters 1934, II, 313). Linnaeus's Larus comprised six species (L. tridactylus, L. canus, L. marinus, L. fuscus, L. Atricilla, L. parasiticus).
Synon. Adelarus, Atricilla, Blasipus, Bruchigavia, Caturates, Chroicocephalus, Cirrhocephala, Clupeilarus, Dominicanus, Einalia, Epitelarus, Gabianus, Gavia, Gavina, Gelastes, Glaucus, Hydropeleia, Ichthyaetus, Lambruschinia, Laroides, Lencus, Leucophaeus, Melagavia, Melanolarus, Microlarus, Misamichus, Ocyplanus, Pacificolarus, Plautus, Procellarus.

schistisagus
Late L. schistus  slate  < L. lapis schistos  fissile stone  < Gr. σχιστος  skhistos  cloven  < σχιζω skhizō  to split; L. sagum or sagus  cloak  < Gr. σαγος sagos  cloak.