I agree with Tony that Ravens are difficult to id and that social behavior is not really a good character to assess them. I have seen many flocks of hundreds to over a thousand Common Ravens (called floaters - juvenile and non-breeding adult groups) and these are quite common, especially where their populations are doing extremely well (which is much of the West). Territorial ravens (nesting pairs), either species from what I know, are fairly stand-offish and keep others out of their territory, though I have read that Chihuahuan Ravens may nest closer to each other, about 300 yards apart (likely a function of food availability more than anything).
I like to use several characteristics together to come to the conclusion, but I like to hear their call combined with tail characteristics, etc. before I make the call. I have seen several ravens in the Fort Collins to Longmont area that I believe were Chihuahuan, but have only have been convinced twice (once more than the other) that I was actually looking at a Chihuahuan Raven. It is always a tough call, even with the less wedge-shaped tail, size, etc. because you typically don't get to look at the nasal bristles, under feathers, and hear their call. I might add that Chihuahuan Ravens and crows can be tough too because the Chihuahuan is somewhere between the range of the other two, though in the case of the latter, it is typically easier to discern from behavioral characteristics. I believe we have at least a few Chihuahuans in the northern Colorado area, but I will be the first to say "Good luck!" Tom Hall Livermore, CO -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to cobirds@googlegroups.com. To unsubscribe from this group, send email to cobirds+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
