Jeff et al., This sounds like a remarkable observation, and it far surpasses anything in my experience, even though I've seen Cassin's Finches in what I thought were large singing flocks at this time of year (dozens of birds, but still less than 100). However, the Birds of North America account of the species seems to indicate that something similar may have been recorded before. Here's the relevant text:
"Breeds semicolonially (~100–1,500 individuals, Samson 1976b<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib059>; nests ~25 m apart on average, Mewaldt and King 1985<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib040>). Spends remainder of year in flocks (e.g., Orr 1968<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib047>, Samson 1977<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib060>, Mewaldt and King 1985<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib040>). ... Breeding colony may remain more or less intact as coherent group through winter (Mewaldt and King 1985<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib040>). Apparently flocks in winter and during spring migration can be substantial (e.g., “large flock” on 31 May, Boulder, CO [Minot 1880<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib041>]; “large flock” on 19 Feb, Tucson, AZ [Scott 1887<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib062>]; flock of 39 birds, 2 Jan, Providence Mtns., CA [Johnson et al. 1948<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib031>]; congregations up to 5,000 in Dec in Colorado [Chapin 1958<http://bna.birds.cornell.edu/bna/species/240/articles/species/240/biblio/bib010> ])." It might be worth a field note for *Colorado Birds*. Nathan Pieplow Boulder On Mon, Mar 12, 2012 at 10:06 AM, Jeff J Jones <jjo...@jonestc.com> wrote: > While travelling back from San Luis Valley on Sunday, I stopped at a > location where I did an RMBO transect several years back – Brown’s Creek, > Chaffee County. It is off Hwy 285 and CR 270. You take it back to the foot > hills east of Antero Peak.**** > > ** ** > > I got out of my car near where the side road to Brown’s Creek is gated off > for the season and heard a cacophony of singing finches. I am used to this > racket to a certain degree at my home in Teller County – usually from a > combination of house and cassin’s finches along with pine siskins and > evening grosbeaks. The level of noise in this open ponderosa woodland, at > about 9,000’ elevation, was incredible. It was coming from about a quarter > mile away. So, I trudged across the snow to the edge of the noise in this > open woodland. *Cassin’s Finches *everywhere, singing. My home lot is > exactly an acre – so I have a good estimate of the size of an acre. For at > least 5 acres there were dozens of Cassin’s Finches per tree – all singing. > I expected to find pine siskins as well as perhaps other species, but all I > could find were Cassin’s Finches, exclusively! **** > > ** ** > > I attempted to estimate the number. I counted at least a dozen per > ponderosa (the ponderosas in this stand were of a homogenous young age; > perhaps 25-45 ft tall). In some, I could count upwards of 40+ per tree. > Then I counted the trees in the immediate half-acre in front of me. And > with an estimated avg of 20 per tree – I figured I had 400-600 Cassin’s > Finches just in the 25 trees in front of me (what I estimated to be a half > acre). 5 acres of this (again just an estimate) would put the number of > deafening *singing Cassin’s Finches at 4000-6000*! **** > > ** ** > > There was not a lot of movement-type activity among the birds; e.g. > chasing each other around, within or amongst the trees; simply mostly > sedentary singing. When my dog and I approached the edge too closely; those > in the immediate tree moved to a nearby tree and continued their singing > without complaints from the current residents of the new tree. I moved left > and right of this area in order to come up with my assessment of a total of > 5 acres; instead of walking into the heart of the concentration.**** > > ** ** > > I had never seen or *heard* anything like this from Cassin’s Finches. I > am quite familiar with this species, as I have lived in their breeding > habitat in Teller Co for 24 years now. And, while I do get them > congregating in my woods near my feeder, at times numbering 40-50; > 4000-6000 was a sight and sound to behold. You would not have been able to > hear someone talking to you at a normal level from 20 ft away. The temp was > about 41F, overcast, with not much breeze.**** > > ** ** > > Being reasonable and open for error, my estimate could be off by a factor > – but you have the process I used above. I left after about 20 minutes; > wishing I could stay and listen for hours. And they were still going at it. > They had not moved. I haven’t researched this yet to see if this is a known > phenomenon documented by others for this species; so wondering if anyone > else has seen such a thing of this magnitude from this species.**** > > ** ** > > *Jeff J Jones***** > > (jjo...@jonestc.com)**** > > Teller County - 8500' - Montane Woodlands**** > > ** ** > > -- > 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. > -- 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. 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