Likewise. Even when I'm sure I know the answer, it doesn't fit.
Example: 8 across has to be "cardinal", but that's not nearly enough letters, so let's try "northern cardinal" - still too short, unless you're including the space.
Including the space would allow 5 down to be "blue jay" (otherwise it would have to be "scrub jay"), but there's a problem: the "A" in "cardinal" isn't in the same square as the "a" in "jay". Maybe you wanted 8 across to be "northern cardinals"? If so you need to phrase the clue accordingly.
4 down is easy*, and puts the letter "g" in the intersection with 6 across. I looked up "mohoidea" (the clue for 6 across). There are only 3 species, and none of them have a "g" anywhere in their names (scientific, English, or Maori). In fact, none of them are the right length.
* I take that back, it's impossible to know whether you meant the one starting with a "P" or the one starting to with a "W".
I looked up the answer to 1 across, and it doesn't come close to the right number of letters.
2 down was clever - I'm sure I got the second word right, anyway.