Mike's comments reminded me of a blog I wrote for the ABA a little while ago. My main point was that we can perhaps use uncertainty as a "field mark"; not being sure can help support an identification. I think the Ross's/Snow question is a good example of this; when you have to ask yourself which one it is, you've got your answer. The blog post is available here: http://blog.aba.org/2011/07/ive-got-it-narrowed-down-to-two.html Blake Mathys --------------------------------- http://blakemathys.com/ --------------------------------- > Date: Mon, 5 Dec 2011 09:31:04 -0500 > From: [log in to unmask] > Subject: Re: [Ohio-birds] Snoss's geese > To: [log in to unmask] > > Greetings... I suppose the Snow and Ross's Goose issue and the > Canada/Cackling Goose issue probably produce some sightings and > reports that could go one way or the other, depending on the observer > and his or her knowledge and experience. There are a number of species > groups that the same could be said of. Some of the gulls come to mind. > > Jay Stenger pointed out to me that one useful thing about the Sibley > Guide that is sometimes overlooked is that Sibley provides average > weights for the different species in pounds, ounces, and grams. > Sometimes it's helpful to get a sense of the weight or "heft" of > particular species. Sometimes it's not. But in the case of Snow Goose > (Lesser's at an average of 5.3 pounds; Greaters at 7.4 pounds) and > Ross's Geese (2.7 pounds), I think the difference is enough that if > one is faced with a question of whether it's a Snow or Ross's Goose, > it's quite possible that given how relatively dainty a "true" Ross's > Goose should be, the question almost answers itself: if we have to ask > the question, it's probably not a pure or true (or however one wants > to define it) Ross's Goose. The same would seem to be useful, but not > diagnostic, for Canada/Cackling. > > I'm not saying it's the only way or the best way, but it's one way > that I've found helpful from time to time. > > Take care, > ---Mike Busam > Butler County > > ______________________________________________________________________ > > 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] ______________________________________________________________________ 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]