Hi All, Bill Whan's comments regarding Robin observations and occurrences were right on the money. I just want to add a little more information that might also help explain recent observations of large groups of Robins in the state. One of the things to consider is that up until recently much of the winter has been relatively mild with little to no snowfall through much of the state. The recent onset of snow and cold (in some cases subzero temps.) have covered many wild food sources. This may be causing Robins to congregate in more urban and suburban areas to take advantage of the urban heat island effect that these areas have; typically being several degrees warmer than surrounding rural areas. As a result it may also be giving the impression that there are suddenly a lot more Robins around. Bill's observation that birds don't eat English Ivy fruits until after a good freeze is true for many kinds of winter berries, both native and ornamental. These winter fruits typically have a small amount of fat in them, as well as a little carbohydrate. Additionally, many winter fruits are protected by secondary compounds that make them distasteful and, in some cases, toxic to many kinds of animals. For some fruits it's thought that freezing helps to lessen the content of the secondary compounds and makes it easier for birds to eat them. The recent freeze is probably allowing birds to exploit many of these fruits now. Some fruits, like those on the American Cranberrybush (Viburnum opulus) are produced in mid to late fall but aren't eaten until much later. During the winter the sugar concentration in the berry seems to increase which may be related to freezing, but American Cranberrybush fruits also contain a secondary compound called chlorogenic acid. When birds, like Cedar Waxwings, eat berries from American Cranberrybush it lowers their pH and causes their bodies to become acidic (which can be problematic-if you like to cook, think about how Ceviche is made). To counter the effect of the acid birds must eat something that will neutralize the acidity. What they turn to are catkins from Cottonwoods. The catkins contain protein which is broken down during digestion into ammonium and the ammonium neutralizes the acid. As a result some winter berries will persist into spring until their dietary complement will become available. As Bill mentioned many of the Robins that are here currently may be moving southward, and part of the reason we may have so many now is that we have had an influx of Robins from further north inter-mixing with some of our resident Robins that, up to now, have not seen the need to head southward. As the number of Robins begins to decline keep an eye on any berry bushes that have retained their berries. Typically, a resident male will try to last through the winter and defend one of these bushes from other over-wintering frugivores like mockingbirds and Robins from further north. It's thought that these males are trying to protect a food source for their own use during the winter, but also a source of food that may attract females when they return during the spring. This, in turn, may help the male find a mate. Thanks, Casey Casey Tucker Education Specialist Audubon Ohio 692 N. High St., Suite 303 Columbus, OH 43215 614-224-3303 (phone) 614-224-3305 (fax) [log in to unmask] www.audubonohio.org ______________________________________________________________________ Ohio-birds mailing list, a service of the Ohio Ornithological Society. Our thanks to Miami University for hosting this mailing list. Additional discussions can be found in our forums, at www.ohiobirds.org/forum/. You can join or leave the list, or change your options, at: http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS Send questions or comments about the list to: [log in to unmask]