しろはらとうぞくかもめじゃありませんでした
白腹盗賊鴎じゃありませんでした
shirohara tōzokukamomejārimasendeshita

Noun
Desu Copula

The polite, past negative form of しろはらとうぞくかもめ

1. Was not a white-bellied pirate gull.; Was not a white-bellied gull thief.

Past/Perfective
Negative
Polite
Terminal Form
Usually Written in Kana