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Stormy Petrels

May 27, 2010

It’s one of the most abundant species of birds in the world, with a total global population in the tens of millions, but how many birders in North America are really familiar with the Wilson’s Storm-Petrel?  The key to seeing just about any species of bird to get in its habitat, but therein lies the rub.  The Wilson’s Storm-Petrel’s habitat is not easily accessed.  The clue lies not in it’s rather pedestrian common name, an possessive honoring one of North America’s first and finest ornithologists, Alexander Wilson, but in the gentle flowing scientific moniker, Oceanites oceanicus, which spells it out rather explicitly.  The genus comes from Greek, the name of a mythological sea-nymph called Okeanus, from which was derived the term “okeanites”, referring to those who travel on the sea.  At this point the species name oceanicus seems a little redundant, but assigns a name both self-evident and evocative for a little bird for whom the sea is more favorable than the land.  Additionally, it provides a contextual standard for the two other Oceanites species, equally sea-going but limited to the Pacific Ocean and therefore not nearly as familiar to English speaking birders.

Those that never venture offshore are unlikely to see any Wilson’s Storm-Petrels except in the rare event of a strong summer storm that blows them close enough to land to see from the beach, but even then the encounter is like to leave one disappointed with a view that’s rarely more than a dark, bouncing dot on the broad expanse of ocean.  One has to make an effort to be sure, but it’s an effort well worth making to experience the species on it’s own terms in the salty windswept world it calls home.  Once you’re out there, the birds thank you for your trouble by putting on a show notable not just for their adept mastery of this unique domain, but for the sheer numbers of birds evident just beyond land’s horizon.  The pungent mixture of Menhaden oil and hunks of shark liver will draw them to you in spades.

Wilson’s Storm-Petrels arrive in North American waters in April, so it’s easy to consider them summer birds here.  But their world is opposite ours, their seasons backwards.  They nest on islands surrounding the Antarctic continent during the Southern Hemisphere summer, our winter.  These little birds in the Gulf Stream are newly arrived on their wintering grounds from thousands of miles south to fatten up for the upcoming year, a part of the unique community of bird species that can be found in the Gulf Stream this time of year.  Wilson’s Storm-Petrels are Antarctic nesters, but they share the ares with tropical nesting species like Black-capped Petrels, tundra nesting species like Arctic Terns and Jaegers, and the nesting birds of the eastern Atlantic like Cory’s Shearwaters and the rarer Gadfly Petrels.  All congregate here to take advantage of the upwelling of nutrients caused by the Gulf Stream running against the continental shelf, and all can be found together off the coast of North Carolina during this brief period of time in late May.  It’s an incredible assemblage.

So the Storm-Petrels here are a mix of adult birds and birds that just six weeks ago were eggs in the back of a burrow on a desolate Antarctic island.  There’s no immediately obvious way to tell them apart by plumage, as the uniformly dark brown, white-rumped Storm-Petrel pattern is the default for nearly the entire family of birds let alone individuals within one species.  But a little knowledge of molt cycles and suddenly an entire world opens up.  As soon as the adult birds leave their nesting islands they go through a wing molt where they retain the four outer primaries but lose the inner ones, giving them a distinctive wing shape that looks jagged and abrupt.  The young birds, by contrast, show a wing of entirely fresh feathers in the conventional roundish shape that helps to distinguish the Wilson’s from the other Storm-Petrels in the area.  Once you’re keyed into it, the difference is apparent on every bird you see.

Despite the fact that they’re exceedingly common out in the Gulf Stream, there’s still a novelty in being able to enjoy a bird with whom you rarely get to spend any substantial time.  To watch them congregate in flocks across the oil slick, turning into the wind and dropping their exceptionally long legs onto the surface of the water and pattering along on fluttering wings.  For that instant they don’t resemble birds so much as butterflies, a brittle structure made of paper and balsa wood fluttering above the vast ocean’s surface, hanging in the air to pick up a piece of flotsam imperceptible to you or I.

The impression lasts for just an instant, though, as the bird swiftly wheels around, catches the wind like one of those fighter kites and heads off in another direction.  Suddenly all fragility is gone, in it’s place is something far more robust, built to withstand the worst the sea can throw at it and born to ride the currents of air that carry just inches above the ocean’s surface which, of course, it is.

One of the biggest appeals of pelagic birding is the idea that anything is possible.  The ocean is nothing but one giant connected ecosystem and, even in the 21st century, range maps are really only our best guess as to what to expect and where.  The exciting truth is that any bird, no matter how unlikely, can show up just about anywhere if the wind and waves conspire to pull it towards that distant horizon.  But because the act of visiting this realm is extraordinary in and of itself, there’s value even in the relatively mundane.  How lucky are we that something as incredible as Wilson’s Storm-Petrels can ever be considered as such.

  1. May 30, 2010 10:12 am

    Nate, another beautiful post. Can’t help but think and worry about the Gulf Oil Spill, and its devastating impact on the wildlife, but in, and dancing above the sea.

  2. May 31, 2010 4:55 pm

    Awesome post! I would love to get a chance to see one of these at some point (never done a pelagic), but this post is an acceptable substitute for now 🙂

  3. July 1, 2010 9:12 am

    Entirely new to me that they are antartic breeders and the adults are going through a distinctive molt. I went on a pelagic trip last year – have to look at my pics of the WSP to see whether I can distinguish between young birds and adults. It always looked to me like they were not just walking but dancing on water. Beautiful!

  4. john falzon permalink
    July 22, 2010 10:25 am

    In Malta, the Stormy Petrel is called Kangu ta’ Filfla. Filfla is a very small uninhabited island few miles to thesouth of Malta where this bird loves of have its nest. It s said that on Filfla one may find thelargest Stormu Peterl cmmunit in the whole Mediterranean.


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