Captilization does not matter.
Black-bellied Plover (with hyphen) will not return any instances of Black bellied Plover (without hyphen).
Wilsons Warbler (no apostrophe) will not return any instances of Wilson’s Warbler.
Use as simple a search term as possible.
Complicating the search term will return fewer results.
Try searching on nicknames, too.
When looking for Sooty Shearwater, for example, try terms such as “sooties”.