About those birds

The location they were at is the Mission of San Juan Capistrano, which is known for its yearly influx of swallows. They arrive at the same time each year. There was a song about it, back in the '40s, "When The Swallows Come Back To Capistrano." Later in the film, as Garfield is saying goodbye to her, she mentions the place by name. The birds are/were a big tourist attraction and had no fear of people. So, the birds were not trained; the filmmakers got lucky. Whether this is still going on or not, I don't know, but back then, it was a big deal. Hope that helps.