I actually remember a SF short story where astronomers detected something looking like a giant bird coming from outer space into the solar system. It then appro

I actually remember a SF short story where astronomers detected something looking like a giant bird coming from outer space into the solar system. It then approached Mars, the planet cracked open and a baby bird came out. Next, both birds started heading for Earth... and people started drilling in a desperate attempt to kill whatever was under their feet... Unfortunately I don't remember the author.