This is the 14267th most frequent Russian word.
острове
"Острове" is the prepositional case of "остров," meaning "island" (used after certain prepositions).
The word 'острове' is used here in its prepositional form, indicating the location where the subject was.
Я был на острове с друзьями.
I was on the island with friends.
Here, 'острове' again is in its prepositional case, used to denote a specific location, emphasizing the presence of animals.
На этом острове живёт много интересных животных.
There are many interesting animals living on this island.
'Острове' is in the prepositional case, used after the preposition 'по' to specify the area of the walk.