Monday, August 21, 2006

haliaeetus leucocephalus

Some photos of Inwood's bald eagles (click to enlarge). One bird has already crossed the Hudson and is headed north; the others are expected to follow soon.

A bald eagle perched above the Harlem River in Manhattan. The Broadway Bridge and the Bronx are in the background.

An eagle in flight over the tidal basin.

This is one of the birds "branching" a few weeks ago. Before they're able to really fly, bald eagles typically spend a few weeks hopping around branches and getting a feel for how their wings work.

Friday, August 11, 2006

The tree that grows in Brooklyn (and anywhere else it cares to)

Ailanthus Altissima doesn't get the respect it deserves. Also known as the Tree of Heaven, this tree is the preeminent pioneer species in urban ecosystems. You'll find it growing in the cracks of street pavement, on the edges of parking lots, on the eaves of neglected buildings, and almost anywhere else where there's more than a thimbleful of dirt. Once you know what to look for (see photo at left), you'll see it everywhere in New York.

The Tree of Heaven in its typical habitat. Yep, that's heaven. Not quite what you expected, is it? Creative Commons photo by spike55151 on Flickr.

Ailanthus is almost perfectly adapted to urban living. A mature tree can produce hundreds of thousands of seeds, which scatter in the wind and lodge themselves in precisely the same nooks and crannies where loose bits of dirt collect. The tree's powerful root growth is strong enough to break up concrete and pavement. Thus, Ailanthus trees are important pioneer species in the transformation of vacant lots: their roots break up impervious surfaces and loosen compacted soils so that other, less hardy plants can follow afterward. In Williamsburg, there are dozens of old parking lots that Ailanthus trees have helped to transform into grassy savannas.

In spite of all this, some people think that Ailanthus trees are "weeds." They call Ailanthus "invasive" (it's native to China), they moan about cracks in their precious concrete infrastructure, and they claim that the trees have a "strong, offensive odor" (a quote from the National Parks Service Alien Plant Working Group, which has a desperado-style outlaw poster about Ailanthus here). Like it or not, though, Ailanthus is here to stay. So save yourself some hassle and appreciate this tree.

Thursday, August 10, 2006

Last chance to see these birds...

Though we expect them to return someday, Inwood's bald eagles are due to leave New York City any day now.

In the meantime, they're becoming excellent flyers and are really fun to watch. The Rangers, including yours truly, are putting on daily eagle programs at 2 pm, and sometimes at 11 am as well. The birds are easy to find, so we can almost guarantee that participants will be able to see a bald eagle. In New York City.

Click here for directions to Inwood Hill Park and the nature center.

Sunday, August 06, 2006

What's in the water

We received this message from the Parks' Natural Resources Group late last week:

"We had a bona fide manatee sighting in the Hudson River heading North. This particular animal has been making his way north up the coastline with sightings reported first at 23rd Street and then later at 125th (40.81826 N - 73.96201 W). On both occasions it was observed at the surface adjacent to the bulkhead and appeared to be heading further north up the river. As you can imagine, we are very anxious about hearing about our wayward visitor... The animal has been described as approx. 10 feet in length and has barnacles on its dorsal surface. If you could both spread the word to anyone who may be in the vicinity to keep their eyes open. We are looking for photo-documentation of the animal and wish to be advised of any sightings immediately."

Since manatees' range is usually limited to peninsular Florida, and occasionally as far north as Virginia, this particular animal is either: a) a psychopathic vagrant (use caution) or b) a manatee real-estate agent, getting in early on the New York waterfront's global-warming transformation into a sub-tropical mangrove swamp.

Friday, August 04, 2006

Heat island

Streetsblog posted this satellite image of NYC earlier today (courtesy of NASA's Earth Observatory). They remarked on the obvious difference in temperatures between parks and urbanized areas. I'd also like to point out the streets (like 125th St. in Harlem and Flatbush in Brooklyn) that show up clearly as white-hot lines through neighborhoods. Thank internal combustion engines for that phenomenon: cars, trucks, and buses can heat up the air immediately around them by dozens of degrees on a hot day if they're idling in traffic with the a/c on.

I rode my bike to work in Central Park on Wednesday, day one of the recent heat wave. Busy streets full of traffic, like Park Avenue in Midtown, were substantially warmer than adjacent streets with less traffic, and Belvedere Castle in Central Park was the least hot of all (the weather station there still reported 101 degrees of Fahrenheit yesterday).

Air conditioning hurts the situation as much as it feels good, since a/c units blast waste heat outside in order to make a building or a vehicle cooler. I was therefore not overjoyed when I rode past a large department store whose open doors were refrigerating an entire city block on my way home that afternoon. I'm pretty sure you can make out that building's HVAC unit as the bright-white pixel west of Roosevelt Island on the map above.

Wednesday, August 02, 2006

The Central Park S'more Inferno

This past weekend, a few of us Urban Park Rangers helped out at a Backpacker magazine campout on Central Park's Great Lawn. The campers, mostly 30-something adults with a few young families, hiked to the 120-foot summit of the Great Hill from various subway-station trailheads in the northern end of the park. Once there, they received freebie sleeping bags and other prizes from the magazine and its sponsors, as well as a catered dinner, before a ranger-led night hike.

As one of the participants put it, "it wouldn't be a camping trip if something didn't go wrong." But the immaculately landscaped setting of Central Park, where every last rock was placed by the well-laid plans of Olmstead and Vaux, and every plant is planted and pruned by an army of gardeners, there seemed to be little room for the unexpected. We (the rangers) would stay up in shifts to guard the campsite against roaming vagrants, bathrooms nearby would be open all night, and the freshly-mown lawn that lay under our tents is a barren wasteland for roaming critters. It was slightly warm for outdoor sleeping, but that can hardly be termed as something going wrong. But if it were, then we discovered a solution at 2 am.

That's when the goddamn lawn sprinklers went off. One of them emerged from the ground beneath my tent, which made for a damp and loud wake-up call. In the next hour, as soon as one sprinkler went dry, another sprung up elsewhere. Eventually, every tent on the hill was either awake, wet, or relocated.

Luckily, most people seemed amused by the ordeal. Or so it seemed to me as I wandered around in early-morning stupor, trying and mostly failing to redirect the jets of water away from the tents. A real camping experience? In Central Park, it was.