Most recordings containing "distress" in their title will be from commercial predator-calling sources, who own the copyrights to--and are unlikely to relinquish for free-- what they'd rather sell. While there are a lot of other interesting wildlife tracks available for download, there's darned few high-quality prey sounds legally available for the taking. If you happen to find them posted, chances are high that someone has ripped them from the original copyrighted source.
FWIW, FindSounds does not search for .mp3 tracks at all (it looks as though it might even pre-date the .mp3 format!) and has a 2MB limit file length. But you can always covert whatever .wav or .au sounds you find to .mp3, using a sound editor like GoldWave.
LionHo