せぐろかもめじゃなかったです
背黒鴎じゃなかったです
seguro kamomejanakattadesu

Noun
Desu Copula

The polite, past negative form of せぐろかもめ

1. Wasn't a black-backed gull.

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana