Conventional wisdom has always held that a "nor'easter" (a storm with strong northeasterly winds) should bring a flight of pelagic seabirds close to the New Hampshire shore for land-bound birders to enjoy. Based on my own observations during numerous storms over the past several years, I am beginning to question this position. It has been my observation that better flights of pelagic species are seen from the New Hampshire shore during storms with southeasterly winds.
Let me cite a few examples to back up this radical idea. On Saturday, October 21, 1995, my wife and I were scheduled to lead a field trip along the New Hampshire seacoast. A low pressure system and frontal line were approaching New England from the mid-west. The wind started to blow out of the east on Friday and by Saturday morning a steady 20-30 mph southeast wind was howling. Observing from Pulpit Rocks, an elevated bluff along the rocky shore in Rye, we tallied 5000 Northern Gannets, four Manx Shearwaters, and two Parasitic Jaegers.
On August 21, 1997, a coastal low pressure system with 15-20 mph southeasterly winds produced a flight of 28 Greater Shearwaters, nine Manx Shearwaters, 35 Northern Gannets, two Wilson's Storm-Petrels, six Laughing Gulls, and one Black-legged Kittiwake.
On September 29, 1997, a trough of low pressure along the coast with modest southeasterly winds at 10-15 knots brought 1898 Northern Gannets to the New Hampshire shoreline, but no jaegers or shearwaters. Although the wind direction was favorable, it was not quite strong enough to really move pelagic seabirds.
On October 27, 1997, a storm with moderate ESE winds pushed 29 Red-throated Loons, 65 Northern Gannets, 20 Greater Shearwaters, and 52 Oldsquaw in to the New Hampshire coast.
On November 1, 1997, a low pressure system with strong southeasterly winds produced a flight of 480 Northern Gannets, 122 Greater Shearwaters, an unidentified jaeger species, and several Black-legged Kittiwakes.
In contrast, on November 8, 1997, a low pressure system with strong northeasterly winds produced only a handful of Northern Gannets and no jaegers or shearwaters on the New Hampshire coast. This same storm produced many notable birds at nearby Cape Ann, Massachusetts, including 503 Greater Shearwaters, one Manx Shearwater, five Leach's Storm-Petrels, 1252 Northern Gannets, eight Pomarine Jaegers, one Parasitic Jaeger, 781 Black-legged Kittiwakes, 3 Dovekies, 128 Razorbills, and 10 Black Guillemots.
Another noríeaster struck on November 22, 1997, with 20-30 mph northeasterly winds, but produced only two dozen Northern Gannets and no other species of note on the New Hampshire coast.
My theory on this phenomenon is that birds which are feeding at Jeffrey's Ledge and Stellwagen Bank are blown in toward the New Hampshire coast by strong southeasterly winds. Conversely, Cape Ann fairs well on northeasterly winds since birds are swept off Jeffrey's Ledge and pushed toward Cape Ann. Jeffrey's Ledge is a relatively shallow ledge situated about 15 miles off the New Hampshire coast, northeast of Cape Ann. Stellwagen Bank is another offshore ledge that runs roughly from the tip of Cape Cod about halfway to Cape Ann.
Which type of storm is more likely to produce the favorable southeasterly winds? Since low pressure systems have a counterclockwise wind rotation about them, storms that take an inland track are more likely to produce southeasterly winds along the New Hampshire coast. Whereas an offshore storm track typically produces northeasterly winds. It usually takes sustained winds of at least 20 miles per hour to move seabirds in close to shore.
Monitoring your local weather forecast can be a big help. With modern weather forecasting it is possible to receive one or two days notice about approaching storm systems, including predictions of the expected wind direction and velocity. Television weather maps will show frontal lines approaching, low pressure systems, and the direction and speed of the wind. If you can learn to interpret the weather and its effect on birds, you can tailor your birding trips to be in the right place at the right time to record rarities.
Locations along the New Hampshire seacoast that provide good vantage points for storm birding include Pulpit Rocks, Ragged Neck, Seal Rocks, and Jenness Beach in Rye, North Hampton State Beach, and Bicentennial Park in Hampton.
These observations fall far short of a valid scientific study. The results can be skewed by such factors as the date when a storm occurs, the strength of the storm, the relative abundance of birds offshore while a storm is passing, and migration movements of birds caught by a storm. Another host of variable factors is introduced by the observer, such as length of time dedicated to observing during each storm, the spot chosen to observe from, and even the optics used. While I make no claims as to the scientific validity of my hypothesis, this is a fascinating area of birding that warrants more study in the future.
Table of storm dates with wind direction, velocity and sightings:
Species Recorded -------->