Riding the Wind

The wind had reversed direction and picked up speed since my last report on birds flying past the tip of Halibut Point. Then, the wind was coming briskly from the northeast and a good variety of birds were getting a boost from flying directly into it.

Sanderlings

Now on a very blustery day a different set of birds, and far fewer of them, was flying with the westerly wind, toward the east.

Common Eider

In both cases the birds were flying primarily from left to right but with different approaches to harnessing the wind. I had to speculate on whether they were seizing opportunities for intentional travel or simply making the best of elements forced on them.

Ring-billed Gull bucking the wind

Gulls were the exception to the pattern of the down-wind travelers. They patrolled both up and down the shoreline using the wind to hover and maneuver adroitly in all directions. Their ability to shape their wings and tail in broad, cup-like configurations helped keep them aloft.

Herring Gulls contesting a morsel

When they were in travelling mode, however, gulls harnessed the wind with preferences similar to other maritime flyers, wings straight, narrowed and extended.

Northern Gannet

Gannets are one of the most spectacular aerialists along the Halibut Point shoreline. The proportion of their long wing length to narrow width forms what is known as a high aspect ratio that facilitates maximum lift with minimum drag and turbulence, as the moving air creates a vacuum above the wing curvature.

Seasonal range of the Northern Gannet
All About Birds website, Cornell Ornithology Lab

Gannets are able to spend most of their lives far out at sea covering tremendous distances in pursuit of fish. They are most often seen along the New England coast in fall and winter.

Cory's Shearwater

The wings of shearwaters optimize the high aspect ratio principle to control and stabilize their flight near the water surface in all kinds of winds. They spend most of their life far from land but are occasionally pushed close enough to shore to be seen from our coast in late summer or early fall. When forced in by a gale like other seabirds they follow a counterclockwise loop around the edge of the Ipswich Bay to escape back out to sea past Halibut Point. 

Migratory range of Cory's Shearwater
BirdLife International, 31 May 2021

Cory's Shearwaters come to land for breeding in the Azores and Madeira, as well as the Canary Islands. Their pelagic migration journey follows an 8-shape pattern along the African and South-American coasts pursuing small fish on the surface and schools sometimes driven up by large marine predators such as dolphins and tuna. In summer they range up the continental shelf as far north as Newfoundland. They expertly benefit from dynamic soaring, as explained by Gloucester's Chris Leahy in The Birdwatcher's Companion to North American Birdlife, 2004.

Dynamic soaring

"Dynamic stability exploits the fact that winds blowing over the surface of the sea are slowed by the waves at the surface and gradually increase in velocity with altitude. Relatively heavy birds such as albatrosses, fulmars, and shearwaters with high aspect ratios (best for control and stability) can gain speed high in the fastest air and then plunge downwind; when they reach the slower air near the seas surface they then use their momentum to head up again, simultaneously turning into the wind, which blows them back aloft. The entire sophisticated maneuver is performed without a single flap."