I was in Western Massachusetts last weekend to look at colleges, and of course, got some birding in too.
After looking at Williams on Saturday, I saw that there was a report on ebird of a Cacking Goose on the power canal in Turner's Falls, MA, which was pretty much on my route, so my dad and I went to check it out. We got to the canal, and began the tricky task of sorting out the single Cackling Goose from the 700+ very similar Canada Geese.
Until a few years ago, there was only one brown goose in the U.S. with a black neck and white chinstrap-- the ubiquitous Canada Goose, which had a number of subspecies that varied strongly in size and other field marks. Then research suggested that the smaller western subspecies were actually a distinct species, and the Cackling Goose came into existence. It's rare but regular on the East coast.
Back to the power canal, where there were lots and lots of Canada Geese. Some looked sort of small, but I decided that they were just small canadas. But when I spotted a tiny goose with a squared, blocky head, tiny bill, and white ring at the base of the neck, I knew I had my bird.
|Through iPhone and binoculars. It's the small one in the middle.|
|A closer look|
|The reservoir again. Really pretty spot.|
Another interesting thing about Red Crossbills is that their are one of the most taxonomically complicated species in North America (or anywhere). Research has found that there are at least ten different "types" of Red Crossbill, each of which gives a slightly different call note, and is adapted to feed on a different type of conifer. The extent to which they interbreed, if at all, is not really known, but it is quite possible that each of the "types" is actually a full species. If not, they are at least potentially evolving species, and it's interesting to try to figure out the distribution and habits of each of the types. For a great article on crossbill taxonomy, go to http://ebird.org/content/ebird/news/red-crossbill-types.
With this in mind, I tried to record the crossbills with my phone, figuring that I could try to identify them to type that way. I sent the recording to Matthew Young, the crossbill expert at Cornell's Lab of Ornithology and the author of that article, and he confirmed what I suspected-- these birds were Type 3 Red Crossbills (aka the Western Hemlock Crossbill). There was a twist, though: he said that there was one bird in the recordings that didn't sound like the others, and was actually a Type 10 Red Crossbill (Sitka Spruce Crossbill).
So I listened to the recordings that I had made again, and eventually picked out a short segment that had two distinctly different calls in it. See if you can hear the difference between the first three notes and the last one:
Even better than listening to the recording, however, is looking at a spectrogram, which is a visual representation of the sound. I used Raven lite, a program that the Cornell Ornithology Lab created, to generate a spectrogram for that recording. I compared my spectrogram to the samples in the article I linked to above, and bingo. The first three are perfect matches to the Type 10 spectrogram, and the last one is a perfect match for the Type 3 spectrogram
|Click to see large. The calls are at the .25, .4, .6, and 1.2 marks|
So in all I got two lifers, good birds, and some pretty cool identification/taxonomy/evolution stuff. Not bad for one weekend.