It's absolutely true; he never got the memo about turning into birds. Not that he would have believed it anyhow, not without seeing it. And even then? It's bad enough the Doctor consorts with humans, but even lower forms of life (let's conveniently forget the cheetah incident, and come to think of it, the goo snake as well)? The Master would honestly be perturbed by any explanation at this point.

He's tempted to fire at the bird, just to get it to do something (and to show the Doctor he's not to be toyed with). He's even reaching for the screwdriver. But it flies away and he clenches his fist around the weapon in utter frustration, watching the bird until it's no longer visible. He's about to turn around and resume walking when he realizes he's gotten his wish after all.

"I knew it." The Master shakes his head, smiles thinly. "I knew this had something to do with you."