Sunday, November 18, 2012

And you Thought Bird ID was Hard...

A Harlequin Darner-- Or is it??
I was looking through some old photos today when I came across a few shots I had taken of a dragonfly last June. It landed on my leg while I was birding at the Daniel Webster Audubon in Marshfield, MA. I could tell that it was darner, and with the help of the book narrowed the ID down to one of two extremely similar species-- Harlequin Darner or Taper-tailed Darner, the two "pygmy darners" of the East.

I concluded that this bug was probably a harlequin darner based mostly on the fact that they are more common, and I had never seen Taper-tailed before, but I realized that I was pretty much impossible to be certain.

But now I have a new dragonfly book, so I thought I would test it out, and seem if I could clinch the ID one way or another. The book (Dennis Paulson's excellent "Dragonflies and Damselflies of the East) said that Harlequin Darners have more than one bridge crossvein on their wings. It also mentioned that Harlequin Darners often land on people's clothing when they are approached, which offered more circumstantial evidence that this was a Harlequin. However, I wanted to be certain, so, using the appendices in the guide, as well as this blog post about pygmy darner ID, I began to try to puzzle out my dragonfly.

The photo above was the best that I took of it, but it isn't at a good angle, so I used one that showed a better view of the top of the wings:


Now the key field mark is found on the wings, so I zoomed in there a bit:

And a bit more. Still not quite enough:

Once I zoomed in this far, I could finally see the bridge crossveins, and be sure of the ID. There are two veins, so it is indeed a Harlequin Darner, Gomphaeschna Furcillata. 

A bit closer look at the veins in question:

And here are some arrows to help. The inner (left) vein would not be present were this a Taper-tailed Darner.
It's always frustrating to have to leave something unidentified, especially if I have photos, so it was satisfying to finally clinch this identification. It isn't that hard, once you know what to look for. Ok, it is a little difficult, but it's not impossible, and that's a start!

Wednesday, November 7, 2012

Cackler and Crossbills


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.
I've tried to find a Cackling Goose many times, with no luck, so it was great to finally see one, and for all of the field marks to so clearly match up to the field guides (which is not always the case in tricky IDs)
A closer look
The next morning, with tips from fellow young birder Jacob Drucker, I headed to the Quabbin Reservoir area to look for waterfowl and winter finches. I got some cool waterbirds, like Horned Grebe, some distant Scoters, a Common Loon, and some more common ducks like Bufflehead, Common Merganser, Ring-necked Duck, and Hooded Merganser. I also saw two Bald Eagles, which is always nice.
The Reservoir
The real targets were the winter finches, the collective name for a group of finches that breed in Canada and move south in the winter, usually erratically and unpredictably. Some years are "irruption years" with some species found seemingly everywhere, while other winters they could be completely absent. This winter is shaping up to be a very good winter for finches, particularly my three target species at Quabbin-- White-winged Crossbill, Red Crossbill, and Evening Grosbeak.
The reservoir again. Really pretty spot.
At the parking lot at Goodnough Dike, I heard the telltale calls of a roaming flock of crossbills, and after a few frustrating minutes, they flew into view, foraging at the top of the red pines surrounding the parking lot. They were Red Crossbills, one of two north american crossbills, and the one that I had never seen before. A fascinating bird, they have evolved a unique feeding strategy and bill shape-- the tips of their bills cross, and they insert their bills into the scales on pinecones, open the bill to force open the scales, and grab the seed with their tongue.

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:

video

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.