This is interesting about ravens in Pennsylvania, especially the last comment. Good Birding.
-----Original Message----- From: Bird discussion list for Pennsylvania [mailto:[email protected]] On Behalf Of Scott Weidensaul Sent: Friday, February 02, 2007 8:32 AM To: [email protected] Subject: Re: [PABIRDS] Questions about Raven Flocks (Fulton Co) 2/01 In his wonderful book "Ravens in Winter," New England biologist=20 Bernd Heinrich found that winter raven flocks tended to be made up of=20 young birds, which use the force of numbers to overwhelm and displace=20 resident pairs from carcasses and other food sources. Vagrant=20 immatures and nonbreeders may also form winter roosts of up to a=20 hundred birds (raven roosts of more than 2,000 have been recorded in=20 the West), usually near a food source like a deer carcass. As for migration, the conventional wisdom is that ravens are=20 nonmigratory, although the fact that sometimes enormous numbers of=20 juveniles form communal roosts and flocks suggests they are, at a=20 minimum, dispersing from somewhere. Ravens are frequently seen at=20 hawkwatches up and down the Appalachians, but so far, no one that I'm=20 aware of has tried to determine if any of these birds are true,=20 regular migrants, if they're dispersing juveniles, or if they're=20 local birds simply using the ridges to moves across their often large=20 territories. (Some years ago I was building a database of known raven=20 nests, with the hope of one day wing-tagging chicks to follow their=20 fall movements via hawkwatchers -- an idea I've never had time to=20 implement.) In a 1922 paper on the breeding habits of the last ravens in=20 northern Pennsylvania, Richard Harlow said that "it will be but a few=20 years before it follows the Wild Pigeon into the list of extinct=20 Pennsylvania species." Nice to see how wrong he ultimately proved to=20 be. Scott Weidensaul Schuylkill Haven, PA >On January 14th I had a fairly large flock of Ravens here in Clinton=20 >County. There were at least 8 and possibly as many as 11. (The=20 >flock was along a cut for a power line that curved and it was not=20 >possible to see the whole flock at once.) The ravens weren't=20 >particularly vocal or active. The just seemed to be hanging out=20 >together. > >Peace, > >Jeff > >Jeff Schaffer > >________________________________ > >From: Bird discussion list for Pennsylvania on behalf of Dan Snell >Sent: Thu 2/1/2007 9:39 PM >To: [email protected] >Subject: [PABIRDS] Questions about Raven Flocks (Fulton Co) 2/01 > > > >Today during a Winter Raptor Survey, I had the good fortune to run into a >soaring flock of vocal ravens. At first I thought I had a kettle of Turkey >Vultures, but upon closer examination these were definately corvids!! >Excited, I stopped the car immediately, rolled the windows down- and >listened...and we watched the aerial antics. > >There were a total of TWELVE Ravens: some were soaring extremely high and >moving quickly eastward, one Raven was chasing a Red-tailed Hawk (which I am >not sure why the hawk was in the middle of the kettle formation.), flying at >a lower elevation were three definate pairs (synchronized flying and >tumbling). The sounds we heard included the throaty gutteral call, croaks, >and also a few "bell" sounds. > >In Fulton County, I RARELY see a flock of this size. The site location was >along a high ridge road near the Maryland border. One side was a forested >precipitous drop to a creek (that feeds the nearby Potomac River). The other >side had small hay fields with heavily forested mountains in the backdrop. > >Seeing something like this made me wonder: >Is anyone else currently seeing any amounts (flocks larger than two) of >ravens in PA? >Did I just witness pair formation (like some sort of aerial turkey lekking >grounds) and the others were just driven away.. >Or maybe a local migration of Ravens just occurred...... >What do the birders in the northern tier of counties see with winter >population dynamics of Ravens... > >Even though I should be working on "work projects", this really has me >intrigued... > > >Dan Snell >Shippensburg, PA >Southcentral Pennsylvania > >_________________________________________________________________ >Valentine's Day -- Shop for gifts that spell L-O-V-E at MSN Shopping >http://shopping.msn.com/content/shp/?ctId=3D8323,ptnrid=3D37,ptnrdata=3D= 24095 &tcode=3Dwlmtagline
