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Yellow Feet? Early field guides including the one from which the signature graphic of this web page was taken show Wilson's Storm-petrel with yellow webbing between the toes. This characteristic is almost never observed in the field without having the bird in hand as in this photo by Eric Masterson. Modern field guides do not usually show this characteristic as it is not really a field mark.

Digital photography changed everything.  Photographers took to the sea on pelagic trips and whale watches and they take hundreds of shots on each trip. We began to get some wonderful pictures that clearly show the yellow web.  The first I received came from Arthur H. Kopelman president and sponsor of the CRESLI pelagics.  He  captured this awesome photograph of a Wilson's Storm-petrel at  Veatch's Canyon, June 6, 2006      kopelman@optonline.net

From the July 19,2008 BBC Pelagic to the Continental Shelf edge, this great photo of Wilson's Storm-petrels by Scott Spangenberg  The bird on the left has its feet closed as usual, but the bird on the right is caught with both feet open giving us a clear look at the yellow web. Nice photo Scott. Yellow webs are not a field mark for the ordinary observer, but with a good photograph they are pretty definitive.  The only other Storm-petrel in our area to display yellow web is the White-faced Storm-petrel which is otherwise very distinctive.

When To See
Look for Wilson's Storm-petrel  from June to October on Stellwagen Bank and even in the harbor in summer.  The highest numbers are seen in July and early August. The bird is best observed on very calm seas when you can see it pattering on the water picking up bits of food on the wing.

Identification - Dark with white rump The first Storm-petrel you are likely to see in New England waters is the Wilson's Storm-petrel or WSP. Your identification problem will be to separate it from the three other dark with white rump Storm-petrels possible in our waters.  See Separating New England Storm-petrels. In this awesome photograph taken by Scott Spangenberg you can see the primary field marks of the WSP. Notice first the complete white tail band. The upper wings have light  crescent shaped  bands that do not reach the leading edge of the wing (2).  When flying the long legs trail behind the tail.(1).  Notice also the straight trailing edge of the wings in calm winds.(3)

Underside Ian Davis captured this view of Wilson's Storm-petrel which shows the underside as it banks toward the boat.  Notice that the wings are dark underneath and that the white rump wraps on either side of the tail.  Legs extend beyond tail. Photographed on the BBC 2007 June 30 pelagic. The close approach of this Storm-petrel and the thousands that swarm in our waters makes photographs like this possible.  Thanks for sharing.

Feeding Breeds in the southern hemisphere and migrates to the north Atlantic in our summer to feed on copepods and small crustaceans which it picks from the surface of the water on the wing as you can see in this photograph  by Jim Wallius. Feeds over the continental shelf. Follows ships and whales. Attracted to chum. Known to feed on oil from carcasses. About 20 birds were observed feeding near the carcass of a Right Whale by the Newburyport Whale Watch just outside the mouth of the Merrimack River. See Whales Always Lose.

Behaviors The most obvious Storm-petrel behavior is pattering their feet along the surface of the water when feeding.  This is best observed on a calm ocean.  Observe the angle of the wings when pattering.  Wilson's Storm-petrel, the wings are from the horizontal to a shallow V shape as seen in Chris Ciccone's photograph. Usually found in groups either resting on the ocean or feeding.

Here a Wilson's Storm-petrel patters on the ocean surface with wings  almost horizontal. Photographed by Leonard Medlock on the August 08 BBC Extreme Pelagic.

On my first pelagic trip to Monterey Bay in California, I was looking forward to identifying several new Storm-petrels.  The first flock spotted was far from the boat almost to the horizon.  I decided to wait for a closer flock.  But the next flock was far away as was the following flock and they didn't seem to respond to the boat's chumming.  I realized that other storm-petrels are not boat followers and  I had to work at identifying distant storm-petrels.  That's when I came to appreciate our wonderful little birdwatcher friendly Wilson's Storm-petrel.

Southern Hemisphere Breeder
Two subspecies "O.o.oceanicus breeds in South Georgia, Crozets, Kerguelen, Falklands, Tierra del Fuego, islands off Cape Horn , and perhaps also at Peter, Balleny and Bouvet Islands. O.o. exasperatus South Shetlands, South Sandwich , and most if not all suitable sections of Antarctic coastline." Harrison 1983 (2)

In the Antarctic Peninsula nests in cavities in glacial rubble, scree, and also in tunnels excavated by the birds under boulders. Usually enters and leaves the nest site at night. One egg per nest. Both parents incubate the egg and feed the chick.

Adults, eggs and chicks preyed upon by Skuas. (11). An even bigger danger is that the adult, egg, or chick become trapped in the burrow by a heavy snow storm. Researchers in Antarctica found mummified remains in burrows.

Dive?
Does Wilson's Storm-petrel dive? I have seen thousands of Wilsons and never saw a single bird dive under the water. Parmelee (10) descrbes an incident of Wilson's Storm-petrel "submerging to grasp rising oil droplets before the droplets could float to the surface and burst."