Swallows learn to open an automatic door to get access to their preferred nesting site.

"When the University of Victoria in Canada opened a new campus bike centre in the parkade located under the University Centre last November, motion-activated doors were installed to discourage swallows from nesting in the new facility. But when the swallows returned to their familiar nest sites a few weeks ago, they were undeterred by this peculiar impediment: they quickly learned how to open the doors by flying in front of the infrared motion detector, as you see in this video."

Via Tai Wiki Widbee