Is there any story to the bird?

Question

A bird shows up a couple times in Portal 2. First, it turns out that Wheatley escaped using a bird's egg (not sure how...). Then, a bird (presumably the mother of the eggs) comes and attacks Wheatley, causing him to cry out "AHH! Bird! Bird!"

A while later, a bird starts eating potato-GLaDOS. You eventually find its nest and get it off of GLaDOS, but then you see it later on: "Bird! Bird! Kill it! It's Evil!"

Did Valve mean anything by including the bird? It's the only other animal apart from yourself. Is this the same bird that attacked Wheatley? How did it even get that deep into Aperture Laboratories? Do all robots have Ornithophobia?

Answer 1

Half-Life Wiki has an explanation for the bird in Portal 2:

The bird, a crow based on the caw she makes, is a minor antagonist in Portal 2 to the AIs Wheatley and GLaDOS. The bird attacks Wheatley after he used her eggs to break a door, and kidnapped GLaDOS while she was a potato. After this GLaDOS becomes incredibly afraid of birds, telling Chell to kill it. At the end of the DLC Peer Review co-op stage, the bird is chased out and locked out of Aperture by P-Body and ATLAS, though GLaDOS told them to abort the mission and run, because she had no plan. The bird's eggs are hatched by GLaDOS after this, with GLaDOS planning to raise them into little killing machines.