What's Happening on the Hudson River in March
Signs of spring appear in March, such as early flowers - snowdrops, crocuses, and daffodils. Day length increases by a minute or so a day. The vernal equinox marks the day of balance, when day and night are the same length. Tree buds swell as they gather nutrients from flowing sap, and in the case of sugar maples, sap runs may continue all month. Meanwhile, the Hudson is flowing with increased energy as well. Runoff from rain and melting snow will push the salt front downriver, usually from about River Mile 45 between Peekskill and the Bear Mountain Bridge down to River Mile 30, the Tappan Zee Bridge, by mid-April. However, Hudson Valley weather is defiant of smooth transitions, so do not pack away your snow gear just yet.
Winter's bald eagles, most visitors from Canada, are leaving; by month's end eagle numbers will have dropped about 75%, as only resident birds will remain. Our breeding pairs will be nesting by month's end; in the last few years there have been about two dozen eagle nests along the tidal Hudson. Adding in non-breeding adults and juveniles from recent years brings the "resident eagle" total well above 50 birds.
Backyard bird feeders are being mobbed now by large, raucous flocks of red-winged blackbirds and grackles. Other birds are moving north as well. Snow geese in high-altitude V-formations are often unseen because they are out of sight before their calls reach us down below. They do not usually land until they reach the upper Hudson from Thompson Island north to Fort Edward. There, mixed rafts of snow and Canada geese can be seen with smaller groups of mergansers, goldeneyes, scaup, wood ducks, pintails, and grebes.
The river water temperature is slowly rising through the 30s and into the low to mid-40s. Above the Tappan Zee Bridge, the striped bass bass fishing season typically opens in the middle of the month (it opens a month later below the bridge and in New York Harbor). Stripers, many having wintered in the broad shallows of the Tappan Zee, will be easy targets for anglers in the warming shallows of Croton Bay and all along the Tarrytown shoals. By month's end, the first river herring - alewives - will start working their way upriver from the sea. These fish are mostly early males scouting out the marshes and creeks for spawning grounds, a prelude to next month's rush of activity. Both striped bass and harbor seals zealously greet this prey fish.