This is the 16886th most frequent Russian word.
сову
"Сову" means "owl" (in the accusative case) in English.
Here, 'сову' is the accusative form of the noun 'сова,' meaning 'owl,' used as the direct object of the verb 'увидел' (saw).
Я увидел сову в лесу.
I saw an owl in the forest.
The word 'сова' is in its nominative form, serving as the subject of the sentence and denoting the kind of bird being described.
Сова - ночная птица.
The owl is a nocturnal bird.
In this sentence, 'сову' again appears in the accusative case, as the noun 'сова' is the direct object of the action 'подкармливаем' (we feed).