Photo copyright Richard White© 2002
Photo copyright Richard
White© 2002
Richard points out that no small shearwaters are known to breed on Ascension, although sub-fossil remains of Audubon's shearwater have been found and a bird identified as Audubon's was found in a burrow on an offshore stack in 1959. The bird has blue feet which seem to indicate a Little shearwater, as does the extent of the white on the undertail coverts. However, the dark feathering extends over the eye. The indent of white around the edge of the ear coverts is reminiscent of the larger Manx Shearwater. Measurements are at the upper range for boydi but are the undertail coverts too white for this species?
Measurements:
Head and bill 62.5 mm
Bill length 25 mm
Bill depth 8.5 mm
Bill width 12.2 mm
Tarsus 36.0 mm
Center toe 35.4 mm
Center claw 5.7 mm
Wing 191 mm
Tail 83 mm
Comments please!
Map borrowed from Barry
Weaver's excellent Volcano web site - check it out!
We had an interesting shearwater wash up at Cape May Point during a hurricane in the fall of 1998. The bird was at the small end for Audubon's, and had fairly striking bluish/purple legs, similar to those pictured in the photo. The undertail coverts were white, with the exception of the longest ones nearest the tail which were black. The face was slightly more white than on the bird pictured from Ascension. We toiled over it for quite some time and left the identification to those at the Philadelphia Academy of Natural Sciences. It turns out that it was an Audubon's of the race "loyermilleri", which can occasionally show leg coloration like this. Forgive me if I misspelled the subspecies name, I don't have a reference with me here. It is mentioned in Birds of the West Indies. I believe Louis Bevier dug up the reference. In any event, you can get more details on the bird, including photos and video stills from Shawneen Finnegan. It might be interest .
Brian Sullivan, Institute for Wildlife
Studies, San Diego, CA
I think it is just that - a Little Shearwater.
Don't be fooled by the lack of clear white above the eye - not all Littles
have this feature. Where it
is clearly seen - the identification is
certain but where not then Little cannot be ruled out. Without seeing the
whole bird - I am fairly certain
that is what it is.
I've handled Littles in the Madeira Islands
and have handled Audubon's in the Caribbean. The Cape Verde Little Shearwater
is now very much persecuted and numbers are declining annually. Contrast
this with the islands of the Desertas, Selvages and Porto Santo group (
all Madeira) where enforcement of protection and "National Park" status
has all but ended persecution and resulted in ever increasing numbers.
It is not surprising they should therefore look for new predator-free breeding
areas such that islands off Wales (UK) and now Ascension may be prospected,
although lacking colony stimulation.
Photos copyright of Bernard
Zonfrillo© 2002
Attached is a shot of 2 different Little
Shearwaters from the Desertas - as you can see - no clear white over the
eye. Many birds are like this and it may be a feature of age. The Ascension
bird is a little darker than my examples. The other shot is of a bird from
the Azores that shows a narrow white line over the eye. In fact I realise
that I do not have a shot of a "text book" Little with a large white area
around the eye! Those
individuals are in the minority! Plumage
is always a bit variable in shearwaters- some Manx have a clear neck-crescent
while others have nothing.
As regards separating the small Shearwaters - one very easy way to do it is to examine their feather-lice. There are clear differences between Little, Cape Verde (boydi) and Audubon's Mallophaga such that anyone finding a dead one (or alive for that matter) should go over it carefully and remove the lice with fine-point tweezers, placing them all in a small vial of alcohol. Never cross-contaminate them with other birds or other species. Then send them to me! Seabird lice are often host-specific such that they can not only pinpoint the bird species but also where it originated because lice also frequently evolve diagnostic subspecies. Seabirders should bear this in mind.
Dr. Bernard Zonfrillo, Ornithology
Unit, Division of Environmental & Evolutionary Biology
Glasgow University, Scotland
Dr. Richard Veit, College of Staten
Island, New York
We did have the Blue-footed shearwater you mentioned from
NJ here at the Academy. I think it has been prepared but may not
have been accessioned into the collection yet. At any rate I couldn't find
it, but the collection manager Nate Rice is in Australia at the moment
and he would know where it is. As I recall the thinking at the time was
that it was of the loyemillerri subspecies of Audubons. I think this
was orginally suggested by Louis Bevier who was working at BNA [Birds of
North America] at the time.
VIREO has 2 photos by Bob Pitman of an Audubon's on land, presumedly to nest from the Line Islands in the South Pacific which shows bluish legs, and 1 photo of an Audubons on land by Rick and Nora Bowers from Little Tobago Island which shows bluish tarsus and and 1 bluish "toe" with pink webbing.
Matt Sharp, The Academy of Natural Sciences, Philadelphia
Paul Scofield, Curator - Vertebrate
Zoology, Canterbury Museum, Christchurch, New Zealand
Dr. Bernard Zonfrillo, Ornithology
Unit, Division of Environmental & Evolutionary Biology
Glasgow University, Scotland
Photos copyright of Shawneen
Finnegan© 2002
I did go up to the Academy of Science and compared this bird directly with other Audubon's in the collection and it was a match. We decided that it was loyemilleri subspecies from Trinidad/Tobago area. The legs were blue, but the webs of the feet were pinkish. This bird had an ulcer on one of its feet that made it look much redder and purple around the affected area (see dorsal view).
Shawneen Finnegan, Tucson, Arizona
[Notice the limited dark feathering on
the undertail coverts of the Cape May specimen compared to Jamaica bird
shown above. Is this an artifact of the way the feathers are arranged or
a genuine difference? - AW]