1,017. Designating Birds for Use on Yom Tov

Shvisas Yom Tov 2:6

If one designates both black birds and white birds for use on yom tov, then on yom tov he finds white birds where the black ones were and vice versa, he may not take them because it is possible that his designated birds flew away and these are other birds altogether. Whenever there is a doubt as to whether or not birds have been designated, they are prohibited. If one designated two birds and found three, they are all prohibited for use. If he designated three and found two, they are permitted for use. If one designated birds that were in a nest but he found them in front of the nest, he may take them as long as they were the only birds in the nest and they are not able to fly. Even if there is another nest within fifty cubits at a diagonal angle, the birds are permitted because birds that waddle will only travel in a straight line to their nests.

Shvisas Yom Tov 2:7

Regarding fish in large ponds, animals and birds in corrals, and anything else regarding which one would say to bring a net in order to catch it – all of these are muktzeh and may not be caught on yom tov. If one did catch it on yom tov, it may not be eaten. Anything that can be caught without a net is considered to be designated for use. Such animals may be caught and eaten on yom tov. Similarly, if a wild animal makes its home in an orchard near a city, its young that are not hard to catch need not be specially designated because one already has in mind to take them.