Tuesday, November 24, 2015

Specific-hope Flycatcher

Ed Gaillard: birds &emdash; Western Flycatcher, Central Park

Rarity season continues: a week or so ago, some experienced birders spotted a small flycatcher in Central Park's Ramble, near the Boathouse cafe. The bird was a member of the genus Empidonax, which all have eyerings and wingbars, and are notoriously hard to identify as specific species with certainty. It had a yellow wash on the breast and belly, and they identified it as a Yellow-Bellied Flycatcher.

Some days later, other birders re-found the bird. They say that it had a very large eyering, and the eyering was kind of teardrop-shaped, and then the game was on. By Friday, the area was flooded with birders--because, you see, that kind of eyering is a hallmark of a "Western Flycatcher", and so the bird was thousands of miles out of its normal range, a screaming rarity that everyone list-making birder wanted to see, the second (or maybe first) record of this kind of bird in New York State.

Cool! Elena and I were planning to meet some friends for a walk in the Ramble on Saturday. Our friends aren't really birders, but they're interested, and we got to show them three excellent species. We easily found the continuing Great Horned Owl, and the Red-headed Woodpecker who is settled in for the winter. Then we joined the mob of bird paparazzi looking for the flycatcher.

We got a couple of nice, though brief, looks at it--little greenish-backed bird with messy plumage, distinctive eyering, feathers on the crown very spiky, basically rather rumpled from its wild journey across the country. And all the mobbing birders also got good looks at the scruffy little vagrant, and many photos were taken. Excellent.

There's just one problem. "Western Flycatcher" isn't a species. It's officially two species, Pacific-Slope Flycatcher and Cordilleran Flycatcher, and--remember I called the Empidonax flycatchers notoriously hard to identify? These two are almost completely impossible to separate, except by the region they nest in. Which in this case is no help. Until the late 1980s, they were considered one species, and a lot of people think that the split is poorly-founded. Even if you have a bird of each species in your hand, the are simply no physical characteristics to tell them apart.

This could not stand. Birders, list-making birders, especially rarity-chasing birders ("twitchers") want--no, need--a species ID.

So the crowd watched and watched, on into Sunday. More photos were taken. The bird wasn't vocalizing--the call is usually a good way to separate empid species. In this case the calls are almost identical, but if they got a recording, a sonogram might tell which kind we had. Eventually, it called, and they recorded it. And a careful observer saw the bird poop and collected the output; maybe they can analyze its DNA from that. I'll let you know if I hear any results.

I slept poorly Sunday night and was up early, so I went to the park before work. I ran into Corey Finger of the 10,000 Birds blog, and we watched the little bird for a while. It was fairly cooperative--I was finally able to get some photos (my view on Saturday was too brief).

Ed Gaillard: birds &emdash; Western Flycatcher, Central Park

For myself, I'm happy to just call it "Western Flycatcher". But who knows, it might turn back into a species, if the American Ornithological Union ever has second thoughts about the split.

Sunday, November 15, 2015

Rarity season

In November, after the bulk of migration is over, the rarities start to show up. Some are lost birds, blown off course or young and inexperienced at migrating. Some are northern birds on the move for winter food sources. Some are young birds of sedentary species, dispersing in search of their own territory.

Ed Gaillard: birds &emdash; Great Horned Owl, Central Park

A Great Horned Owl showed up in Central Park on Sunday (11/1). I didn't know about it until after sunset--I had gone up to Inwood Hill Park, which was quiet, though I did see one nice bird:

Ed Gaillard: birds &emdash; Vesper Sparrow, Inwood Hill Park

This Vesper Sparrow was fairly confiding, foraging on the soccer field south of Spuyten Duyvil Creek, and occasionally retreating to a small fenced-off area of tall grasses. Anyway, I went home afterwards and took a nap, and woke to find owl reports on my Twitter stream.

The last Great Horned Owl in Central Park was in April of 2012, and only stayed one day. So I thought I was out of luck. But to my surprise, there was a Twitter report early Monday morning that the owl was still there. It was sleepy and turned away from observers, so it wasn't a great look even though it was not hidden at all, high in a huge sweetgum tree. Then I had to go out of town on business for three days, but on Friday, the owl was still there! and awake in the morning.

Ed Gaillard: birds &emdash; Great Horned Owl, Central Park

It moved around a bit--at one point it leaned forward as if interested in flying out at something. Or more likely it was just pooping.

Another excellent bird in the park is a Red-Headed Woodpecker. It's a first-year bird, so its head hasn't turned red yet.

Ed Gaillard: birds &emdash; Red-Headed Woodpecker, Central Park

It's been there for a couple of weeks now, and looks like it's settling in for the winter. The bird has been excavating a roost hole in a snag, and caching acorns in locust trees. I hadn't known that Red-headed Woodpeckers stored acorns.

This weekend, strong winds from the west blew in some very interesting birds--Franklin's Gulls and Cave Swallows--but I haven't had any luck in spotting any.

I can't resist showing off one more owl photo.

Ed Gaillard: birds &emdash; Great Horned Owl, Central Park