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New England Seabirds


Leach's Storm-petrel

Oceanodroma leucorhoa

Leach's Storm-petrel photographed by Scott Surner on BBC 2011 Pelagic to Continental Shelf Edge.

Northern Hemisphere Breeder
Leach's Storm-petrel like all Ocenodroma is a Northern hemisphere breeder and therefore is busy during our summer. Migrates south during our winter.

In the north Atlantic breeds on offshore islands from Maine, Canada, Nova Scotia, and Newfoundland. A few pairs breed on Penikese Island south of Cape Cod. Regularly seen in Cape Cod Bay during the summer.  Take the Plymouth or Barnstable whale watch.  Also in Greenland and  at St. Kilda in Scotland.

In the north Pacific breeds on offshore islands from Japan to the Aleutians and Alaska and south to the Baja Peninsula.

Atlantic birds winter off the coast of Brazil. Occurs in all three oceans: Atlantic, Pacific, and Indian.

Leach's lays a single egg in shallow burrows 1 -3 feet in length. Both parents take turns incubating and both feed the chick, coming and going from the burrow only at night. Burrows can be collapsed by humans walking about over them and nests are disturbed by dogs and feral cats.

Young are fed by both parents by regurgitation.

When To See
Immature non-breeding birds can be seen offshore on the edge of the Continental Shelf and at Cashes Ledge in summer. Late fall, especially October, any Storm-petrel on Stellwagen Bank should be closely examined as it is probably Leach's rather than Wilson's Storm-petrel. Also seen from seawatches on Cape Cod during late fall and early winter. This bird is perhaps easier to see on west coast pelagics.

Hard to observe on the breeding grounds as it enters and leaves burrows at night and human presence disturbs nest by collapsing burrows.

Similar plumage to Wilson's Storm-petrel. Leach's is larger and has a forked tail. See the photograph by David Jones to the right. This photo was taken on the 2010 BBC pelagic south of Cape Cod. 

A small vertical dark band dividing the white rump is visible in this photo may not be visible on all birds. This dark divider is variable by age and subspecies.  See the article in American Birds.

Legs do not trail behind the tail when flying. Bill, legs and feet are black. White rump patch does not extend down around the rump.  Light band on wing reaches the leading edge of the wing.See pictures below.

These characteristics are hard to observe at sea. Appears longer winged, has a slower wing beat, and you do not see the legs trailing behind tail. Notice that the trailing edge of the wing has a definite angle. Wilson's shows a straight trailing edge.

Leach's Storm-petrels were feeding on suet chum.


This really nice photo by David Jones of Clamflats Photos.  See more of David's  photos at  Thanks for sharing.

Photo by Eric Masterson on Cashes Ledge August 2009.  Note forked tail and the light band  that reaches the leading edge of the wing.

Photographed by Eric Masterson on Fippenes Ledge June 2010. Forked tail is very visible, but notice that you do not see the dark band dividing the white rump patch. The light band on the upper wing certainly reaches the leading edge.



Photograph by Jeremiah Trimble of two Leach's Storm-petrels from the June 2010 BBC Continental Shelf Edge pelagic trip.

The forked tail is visible on the right bird.  The lack of wrapping of the white rump patch is visible on both birds.






Glen Tepke Leach's Storm-petrel


Two pictures of Leach's Storm-petrel taken by Glen Tepke. Both pictures show that the white rump patch does not extend down the sides of the rump. Notice the broad upper wing crescentic bars  that reach  the leading edge of the wing. Thanks for sharing Glen.

With hundreds of Wilson's Storm-petrels around a boat, Leach's can be picked out because of the slightly larger size, different wing shape, and different flight characteristics.


Glen Tepke Leach's Storm-petrel

Does not follow in the ship's wake. Occasionally follows trawlers (Harrison 2).  Attracted to beef suet chum floating on the water. Not as likely to patter feet on the surface of the water as Wilson's Storm-petrel. In light winds feeds by sitting on the water and moving forward using legs. (Flood and Thomas in British Birds 28 )
Jeremiah Trimble photograph of Leach's Storm-petrel sitting on the water.
This photo by Eric Masterson taken in August on Cashes Ledge shows a mixed flock of Wilson's and Leach's Storm-petrels  feeding on the surface. Eric called this photo 180 and it demonstrates the value of photographs in identifying storm-petrels.

The birds pattering on the surface are most likely Wilson's Storm-petrels while the birds sitting on the water are probably Leach's. The bird sitting just to the right of the center of the photo is most certainly a Leach's.  Notice that it looks larger.  The bird in the air over this bird also appears to be a Leach's because the tail appears notched and the broad upper wing crescent-shaped bar reaches the leading edge. This bar does not reach the leading edge of the left most bird nor the bird second from the top. These birds are Wilson's.

Photo by Eric Masterson taken in August on Cashes Ledge

Numbering the birds from left (1) to right (4).  Bird 1 is possible 2 birds.  Bird 2 is a Wilson's because the legs clearly trail the tail.  Bird 3 is Wilsons ( light band on wings does not reach the leading edge, tail not forked). Bird 3 legs are still dragging below so they do not appear behind the tail.  Bird 4 appears to be Leach's. (Forked tail, white rump patch does not wrap, legs do not trail.) Identification by Emmalee Tarry who readily admits to being wrong before.


Can you identify the two Storm-petrels in this photo by David Jones? 


Left bird is obviously a Wilson's Storm-petrel. Notice the feet trailing the tail and the white bar on the wings stopping short of the leading edge of the wing.  Right most bird appears to be a Leach's Storm-petrel. Notice the white bar of the right wing reaches the leading edge and the feet do not trail behind the tail.



Now how about this bird with the obvious split white rump patch photographed by Eric Masterson?  Is this Leach's or Wilson's Storm-petrel.

Looking past the split white rump patch notice that the white wing bar does not reach the leading edge of the wing, the trailing edge of the wing is rather straight, and most telling the feet trail the tail.  This bird is a Wilson's Storm-petrel.


New Reference regarding Leach's Storm-petrel in the Pacific Ocean

2009  Howell, Steve ; McGrath, Todd; Hunefeld, Terry; Feenstra, Jon   Occurrence and identification of the Leach's Storm-petrel (Oceanodroma leucorhoa) comples off southern California  North American Birds  Vol 63 (2009)- Number 4