We asked participants in a recent cover survey to send questions that Contributing Editor Julie Craves could answer in her popular column Since You Asked in our upcoming December issue. The response was amazing! We received far more interesting questions than Julie could address in the December issue, so we're jumping right in and answering questions for her. We'll answer more on the blog and in future issues of our newsletter.Josée Lavigne of St.-Jean-sur-Richelieu, Quebec, asked: Why do grackles point their beaks at one another?I love questions about why birds behave in unusual ways. Before we get to the answer, here's a photo I found on Flickr that shows what Josée asked about:
Common Grackles tilt their bills up at each other on a tray feeder and deck railing in Holmdel, New Jersey. Photo by johnbird30The birds are not looking up at a passing airplane. Rather, they're tilting their heads back and bills up to show who's boss. It's a dominance display that ornithologists have given not one but three names over the years: the Bill Tilt, Bill Up, and Head Held Up Display. Males typically tilt their bills up when another male approaches, and after one bird tilts the longest and highest, the other bird will either leave or back down. Grackles of the opposite sex will also give the display to each other early in the breeding season before they find a mate, but paired birds never perform the display to one another.
Robert W. Ficken of the Cornell Lab of Ornithology described the display and many other grackle behaviors in a detailed 1963 paper in The Auk, the journal of the American Ornithologists' Union. "The Head Held Up threat, with its many variable components, presumably signals rather precisely the varying degrees of readiness to attack or escape," he wrote. "Such precision of expression would serve to reduce fighting, stress, and time wastage in a species where there is much close contact among individuals."Ficken's observations are as true today as they were half a century ago. --Matt Mendenhall, Associate Editor
Read more answers to readers' questions:
Ask BirdWatching Magazine: "What should I do about House Sparrows at my feeders that eat everything in a few hours?"Ask BirdWatching Magazine: "Do owls migrate?"Ask BirdWatching Magazine: "Is there a way to feed birds in bear country?"
Read Julie's answers to readers' questions in Since You Asked
Very interesting, and a great photo, too.