Very fun - took me a while to figure out a few of the pairs. With BAR, initially I was stuck on EXAM and DENIAL, but I think the mechanism is actually finding the clue that each half of the birds could answer- and the clues for EXAM and DENIAL can't be answered by BAR- and not finding a synonym for half of the bird name. In some cases, it works both ways, but not all... once I figured that out, and focused on the clue part, I got it. Nice!