An invasive plant survey for NYSDEC (New York State Department of Environmental Conservation) has kept a colleague and me busy at the river's edge this fall. A late start has extended the field work beyond the end of the growing season. Last week Anita and I took to the water at Stockport Flats, a DEC nature sanctuary north of Hudson, to survey shorelines of Stockport Middle Ground Island and the mainland shore south of Stockport Creek. Invasive plants were the least of what we saw.
We had never canoed Stockport. We immediately discovered an exceptional diversity of aquatic, wetland and upland habitats. A low island divides the creek mouth in two, the north channel sluggish and marshy, the south channel brisk and rocky. West of the Amtrak bridge the water was so shallow the canoe scraped bottom in places, as we paddled across a broad delta of accumulated sediment. Approaching the big island the water deepened, but the paddle could touch bottom all the way to the island shore. We had never encountered this situation before in the Hudson estuary.
As we rounded a tiny, nameless island west of the creek delta, we spotted a huge bird standing on something in the outer shallows. Binoculars revealed a young bald eagle intently pulling at something with its hooked beak. The eagle soon took flight but went only a short distance southwest to land on another object. When we reached the spot where we'd first spotted the eagle we saw a rib cage sticking out of the water. It was a dead deer that the eagle had been eating. We headed north to Stockport Middle Ground Island, hoping our departure might encourage the eagle to return to its meal.
On the sandy south beach of the island, freshly emerged eastern comma butterflies flickered scarlet orange in brief flights, then dropped to the ground and disappeared. When these insects land, only their camouflaged hindwings show, blending in with dead wood and dry leaves. Around the outer corner of the broad beach was deep water against a precipitous sand cliff carved by wind and waves. Such abrupt contrasts, reminders of the extreme dynamics of the river, greeted us everywhere we went.
The island had the standard complement of Hudson shoreline invasive plants - black locust, bush honeysuckle, Asiatic bittersweet, tree-of-heaven (ailanthus), Japanese barberry, Japanese stilt grass. The notorious purple loosestrife, recently decimated over much of the region by beetles introduced to control the plant, persisted in the sandy shallows where daily tides flooded out the beetles. On higher ground it was scarce.
With the sun moving west we headed south to the mainland shore to see what invasives were there. Dodging the wakes of a big cargo ship and a loud speedboat we landed on a west-facing sandy shore much steeper than the island shore where we'd been in the morning. The landing spot had a clearing with a good sitting log and an old campfire. Invasives were here, but away from this disturbance, there were very few non-native plants. As we explored the shore farther south the trend held. Here was a rather rare thing - a low river shore with very few invasive plants. So much dredging and filling has gone on along the Hudson that it's hard to tell if the soils and vegetation are natural or not. But here the near absence of exotic plants suggested a history mostly free of human disturbance.
On our way south along the shore we had seen a turtle basking on a log, but only briefly before it slid into the water. Was it a map turtle, we wondered? Would it be on the log again when we headed back from the end of the survey transect? As we neared the log from the south we saw that the turtle had climbed onto its log again, so we approached slowly, concealing the movement of the paddle. This often works with turtles, though we're not sure why. This stealth action was our most successful yet, putting the canoe nearly within arm's reach of our quarry - a mossy-backed male map turtle - before he spooked and plunged in.
To end the day perfectly, as we approached the final bend before the railroad bridge, our eagle appeared again, flying and landing behind the trees at the point. As we rounded the turn, the eagle stayed perched in a cottonwood tree, watching us, framed by bare branches against the clear, blue autumn sky. ++