My experience with Cardinals and windows indicates vulnerability to deception by reflected images. Might the "fish feeder" have thought it was feeding a Cardinal? -----Original Message----- From: Upper Valley Birders [mailto:[log in to unmask]] On Behalf Of David L. Webb Sent: Saturday, May 26, 2012 9:36 AM To: [log in to unmask] Subject: Re: [UVB] chickadee feeding robins --- You wrote: I have never heard of that happening before, where one species of bird helps another species raise nestlings?! It seems like it would be a horribly maladaptive thing to do, wasting all that energy instead of either trying to re-nest or just relax for the rest of the summer to try again next year. It seems so odd that it tried to build a nest out in the open in the sun when I thought Chickadees were only cavity nesters, too. I wonder if there is something seriously wrong with the poor little bird's brain. Maybe it's not that unusual and I've just never heard of it before. (?) Does anyone have any other examples of it happening that they know of? --- end of quote --- I don't know how common such behavior is, but it does occur. I read an article some years ago (I believe in _Smithsonian_) that mentioned a cardinal that had lost its brood and was feeding carp in a pond! The fish came to the surface, opened their mouths wide, and the cardinal hovered over and dropped them tidbits of food. While I wasn't able to find the article online (it appeared years ago, before the internet), I did find this, which even has a video: <http://www.a-home-for-wild-birds.com/cardinal-and-goldfish.html>. Really amazing! Best wishes, David Webb