This is the 14357th most frequent Russian word.
отловленные
"Caught" or "captured."
In this sentence, 'отловленные' (caught) serves as an adjective describing the birds that were caught for preservation and relocation.
Отловленные птицы были переселены в заповедник.
Caught birds were relocated to a nature reserve.
Here, 'отловленные' again acts as an adjective qualifying 'animals' and relates to the act of capturing them.
После долгой охоты он обдумывал судьбу отловленных животных.
After a long hunt, he pondered the fate of the caught animals.
The word 'отловленные' describes 'рыбы' (fishes), emphasizing that these were captured prior and are being displayed.