As unpleasant as the bird's racket is, the Batman's mostly able to tune it out now. He'll be leaving the door alone for now, in favor of talking more to Frisk.

Especially considering how concerning their explanation of the situation is. Batman thinks over the information: There are a lot of people who'd want to kidnap the Batman, some of whom probably could scrounge up a flying castle (unless Frisk's just confused on that point) but he's not sure who'd manage to snatch him without his notice, nor why anyone would be interested in kidnapping this particular child or any of the unknown someones that Frisk mentioned.

"Has there been a lot of fighting so far?" Batman asks, leaning forward so as to better look Frisk over. They didn't look hurt when he first spotted them, but he wasn't exactly checking for injuries.