What's Happening on the Hudson River in April
Spring is announced by blooming flower beds, songbirds singing, and light green leaves emerging on trees. The sugar maple sap run has dried up as the growth cycle starts anew. Yellow forsythia and pinkish-white magnolia are in resplendent beauty; their blooming is a pretty reliable bioindicator of the arrival of shad and herring spawning runs in the Hudson. The name of another early bloomer, shadbush, attests to the connection of its flowering with the shad runs. The river herring of April is the alewife, arriving early in the month and ascending tidal tributaries to spawn. Striped bass are also moving upriver, though in a more leisurely fashion, as their spawning season is not until May. By April's end, trophy stripers will be reported from the Tappan Zee to Troy. Seekers of striped bass use fresh-caught, live alewives and blueback herring. Hudson River tributaries will also be active as suckers, smallmouth bass, white perch, yellow perch, minnows and catfish all stream into them by the millions to spawn.
With all these fish in the water, especially at low tide, our wading birds return in April. Great blue herons, black-crowned night herons, green herons, bitterns, and their white cousins the great egrets and snowy egrets add grace, elegance, and deadly spear-fishing skills to the tidemarshes. They stalk the schools of killifish and minnows moving like clouds through the shallows. Osprey and harriers hunt from the air over backwaters and bays, along with double-crested cormorants, seeking larger prey, like menhaden, goldfish, and gizzard shad. It is not unusual to see a bald eagle dive-bombing them to steal a fish.
Eagles and other birds of prey are starting families in April. By the start of the month egg-laying begins; when the clutch is complete, the adults will share the task of keeping the eggs warm for the month before they hatch. Then the real work begins.
Songbirds are out to impress this month. Returning migrants travel thousands of miles, often ending in the very same backyard they chose in years past. However, new challengers for territory or females are always appearing, stimulating these birds to compete with their songs. The black-capped chickadee adds a sweet and soft fee-bee song in addition to its namesake call. Don't confuse this song with the more nasal fee-bee trademarked by the eastern phoebe. This newly-returned vocalist seems reluctant to stop and sing, as its constantly-bobbing tail attests. The bird utters swift bursts of song between flights after flying insects. In fields near wet woodlands, the nasal peent of the American woodcock penetrates the evening twilight. This rarely-seen bird becomes the star of the stage when he's trying to find a mate, and the male's estatic circling courtship flight is a must-see. Specialized whistling wing-feathers declare his love from a darkening sky, but only a skilled observer will be able to locate the bird on the ground.
Harbor seals have been moving into the estuary in increasing numbers of late, following incoming schools of migrating fish. Seals can be spotted dozing on rocks, jetties, and even piers, digesting their latest feast. However, view them from a distance. It is illegal to harass, kill, or possess any marine mammal (dead or alive) in the US. Seals can also give a serious, bacteria-laden bite, despite those big, sad, "come hither" eyes. Other marine mammals that occasionally visit the estuary include harbor porpoises and, rarely, bottlenose dolphins. Any sighting of seals or dolphins should be reported to the Riverhead Foundation's 24 hour Hotline at (631) 369-9829.