Wednesday, 8 November 2017

Re: [cobirds] More Red Crossbill Info

Christian,
 
Thanks for the link to the crossbill update on eBird; I hadn't seen this article yet and it is a topic that is of keen interest for me, and you are right, it is a good one.  Like you, I have been into and recording crossbills for years now as they represent the most fascinating "evolution in progress" stories that we are getting to witness at this point in time. 
 
Given the projections in the article of an invasion year in the East and South of North America, I wanted to throw in a brief status report from up here in the Panhandle of North Idaho.  Red Crossbills are generally abundant up here, but have been largely absent for the past eighteen (18) months or so, and I have yet to hear even one since returning from Denver about three weeks ago.  Our cone crops seem to be in decent shape, with ornamental spruces in town at least fairly heavily laden – hoping the White-wingeds make a good showing at some point – so not entirely sure what's going on.  Anyway where this may come into play for Colorado birders this year is that our regular Red Crossbill types up here, Ponderosa (type 2), Hemlock (type 3), and Douglas-fir (type 4), have gone somewhere, so keep your ears (and recorders) open when encountering a flock.  Nick's post about a mix of Red Crossbills earlier this week is a good case in point.
 
Good Birding,
Doug
Denver…but Coeur d'Alene, ID at the moment.

From: Christian Nunes <pajaroboy@hotmail.com>
To: "cobirds@googlegroups.com" <cobirds@googlegroups.com>
Sent: Tuesday, November 7, 2017 10:02 PM
Subject: [cobirds] More Red Crossbill Info

As others have noted on the forum, there's a perceptible Red Crossbill incursion occurring across the region this fall. I'd like to stress the importance of recording crossbill calls. A simple voice memo from a smart phone can be uploaded and analyzed with free software (e.g. Ravenlite) or simply uploaded to eBird where a spectrogram will be produced automatically. If the recording is of high enough quality, the shape of the crossbill's call notes can be seen without any extra manipulation. 

The recent eBird article on crossbill types is by far the most succinct and useful resource yet published on the web. By comparing the shape of the call notes on a spectrogram, the identification of precise types becomes almost easy. 
ebird.org
As one of the most striking differences in bird occurrence from year-to-year in many northern regions of the world, finch irruptions are often exciting events.
Type 2 (Ponderosa Pine) and Type 5 (Lodgepole Pine) are the common breeding types in CO, and Type 4 (Douglas-fir) are irruptive. Other types wander into the state less frequently, most notably Type 3 (Western Hemlock). Several others are possibilities (maybe Types 7 & 10?), but we'll never document them without good recordings. 

Some recent observations and recordings of Type 4 (Douglas-fir) crossbills from CO:

http://ebird.org/ebird/view/checklist/S40332272 (Nick Komar and Walter Wehtje, Lake Loveland)

Documentation of Type 3 (Western Hemlock) by Steve Mlodinow at the Eaton Cemetery:


Happy listening,

Christian Nunes
Lyons, CO



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