Friday, October 16, 2009

Fall Transition

I love living in a place where I can observe profound seasonal changes. During the summer my energy levels are at their apex. It used to disturb me when autumn rolled around and things seemed to slow to a crawl. As a birder, however, I find it fascinating watching some animals increasing their activities, just when many of us humans are considering hibernation.

I'm still taking regular bike rides to Jacob Riis Park, but I've given up on swimming in the ocean. At one point, I had the silly notion that I'd be able to swim until November. My last plunge was on September 20th and I don't think I'll be jumping back in any time soon. I took a ride out on October 4th and a strange, warm haze blanketed the entire beach. The water, sand and sky merged into a horizonless, abstract image. I could hear birds along the coast, I just couldn't see them. Anyone foolish enough to go swimming would have had a difficult time figuring out which direction was Queens and which was Bermuda.

I guess some changes are inevitable so, with some ambivalence, I said "Goodbye" to summer and packed my beach gear away until next year. Earlier in the season we had some ridiculously warm weather, so I was able to continue wearing my Tevas while I watched the warblers and other neotropic songbirds waving goodbye to NYC as they moved on south. Although I haven't posted much over the last two months, I have been able to get out and do some local birding. In late September I took a trip out to the Ridgewood Reservoir with my friend Heydi. There were still a decent number of warblers moving through the area and sparrows were just beginning to arrive. The highlight of the day was finding a Black Swallowtail Butterfly caterpillar. It was the first time I'd ever seen one outside of a field guide. The caterpillar's black, green and orange markings were even more vivid in life than the photographs were able to capture. Also, I felt compelled to touch the fat little thing and can report that it was very much like squeezing a marshmallow.

During my hazy Riis Park trip I also walked through an undeveloped area of Fort Tilden, behind the baseball fields. It is usually a good spot to find birds, but on that particular day, it was better for insects. The dried seedpods of dozen of Milkweed plants were crawling with Milkweed bugs. I guess, like everything else in this world, it was the timing. A week later and the black and red insects were all gone. Like other creatures in nature, the black and red colors are meant to warn potential predators to stay away. Milkweed bugs feed on the Milkweed plant and compounds found in the sap are concentrated in the body of the insect and make them taste bad to birds and other animals. I'm not certain if they are actually poisonous.

The fall migration progresses in a fairly predictable series of stages. Early in the season insects are still abundant as the temperature is still relatively warm and days are still pretty long. During this period mostly insectivores are moving through NYC. Swifts, flycatchers, vireos, swallows and wood-warblers. A little later on, as it gets cooler, bird that eat fruits and seeds begin to replace the insect eaters. In addition, waterfowl that overwinter in NYC begin to arrive along the coast and at inland lakes and ponds. It should also be noted that the predators (hawks and falcons) have been following these birds since the beginning of the migration. Within the last week to ten days sparrows have started working their way through the city. First were large flocks of Chipping Sparrows, then Song and Swamp Sparrows, finally, a tremendous number of White-throated Sparrows have appeared along the wooded stretches within all our parks. I took a long ride earlier in the week, just to find sparrows, but I'll save that for a sparrow-specific posting.

Last Saturday I went birding in Green-Wood Cemetery. I've been exploring the tops of the ridges, trying to figure out a good birding route along the cemetery's high points. There were birds everywhere, especially Chipping Sparrows and Palm Warblers. Flowering Dogwoods were loaded with ripe fruits and the robins and flickers were all jostling for prime feeding perches. I also spotted a few Baltimore Orioles and several Scarlet Tanagers. At this time of year Scarlet Tanagers are no longer scarlet. Their wings and tail are still black, but the head and upper parts are olive green and the lower part of the body is yellow. I suppose the first scientists to observe the Scarlet Tanager saw it in winter (basic) plumage because they gave it the specific name "olivacea". I was walking up a ridge opposite Horace Greeley's monument when I spotted a dead Scarlet Tanager in the grass. The bird seemed to have died very recently and there were no noticeably signs of trauma. It hadn't completely molted its scarlet plumage and there were scattered red feathers on its breast, belly, undertail coverts, flanks and rump. I felt bad because he nearly made it through the year.

Marge and I spotted a massive Cooper's Hawk flying around the cemetery tormenting the flicker flocks. This large accipiter was almost as large as the resident Red-tailed Hawks and was clearly targeting the yellow woodpeckers. The vocalizations that I normally hear flickers making sounds like a loud, "wika, wika, wika" or, "klee-yer". Whenever the Cooper's Hawk made a dive towards a flock some would made a noise that sounded more like a panicked screech. I haven't found that vocalization described in any of my field guides. Anyway, as we were walking the ridge above the Historic Chapel I spotted the remains of one of the Cooper's Hawk's meals - a Northern Flicker wing. Strange that there was only one wing.

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