I had a lot of fun messing around with this game, nice work!
I too noticed that the crabs rarely spawn and was unable to absorb the bird power. Also, it's not really clear what the goal of the game is. Is it to climb as high as possible, make lots of babies, or become the dominant species? I'm not sure.
I played for a while (about 10 mins) but lost interest without a clear objective.
Anyway, thanks for making this little Gem. I look forward to watching it progress!