Posts tagged as:

horseshoe crabs

Vineyard Dowitcher ID

by Lanny McDowell on August 2, 2010

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If you want to delve  into the arcane business of confidently recognizing a Long-billed Dowitcher in the midst of short-billeds this time of year, and it’s still early, please go right ahead and let me know when you have a long-billed nailed down.  All the shorebird books take on this subject and, sort of like the fairly recent Gulls book, the more you read, the more confused and uncertain you are likely to become.  Less can be more.  Dump some of the plumage factors and go for structural comparison.  If you are lucky, really lucky, you will have one species beside the other and not a single bird, bill tucked and snoozing.

The reason for bringing this ID quandary (morass) to the fore is that I saw and photographed a dowitcher on July 29th out at the flats inside the opening of Tisbury Great Pond.  Its central tail feathers were rufous toward the tips, where the barring “should” have a white or light buffy color.  Most references do not mention this feature, but Paulson’s Shorebirds of North America does write about the rufous in the tail being an identifier for long-billed.

Well, in this case I do not happen to believe this, because in another shot taken of the same bird, the bill droops a bit in the last third of its length, which feature is mentioned as reliable for picking out a short-billed (versus a straighter bill for long-billed).  Since every set of comparisons for these two species seems to end up in the scrapheap of variability – except for voice, which all the writers embrace as distinctive – the tail feather ground color issue will be at home on the list of “may be a factor, but not reliable taken alone as a single distinguishing mark”.  In my book, anyway.

We all seem to want the elements that will offer us certainty, but like so many other BIG questions, sometimes the more you look, the less you know.  Not really fair, is it?

Check out the tail feather tips and the bill on this West Tisbury dow:

Dowicher showing rufous tipped rectrices


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Dows are Cool! Lan

State of the Union at Global Conservation Alliance

by Lanny McDowell on February 15, 2010

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Here is an update on where we stand right now.  By the way, the new name for our shorebird project within GCA is The Red Knot Survival Project.

I was just reading about non-profits and who gives to them, who the supporters are.  Well it turns out that 75% of the money donated comes from private individuals.  That is pretty astounding, and also encouraging.  As of this writing, Global Conservation Alliance has received money donations from various individuals, from one corporate contributor and from one conservation organization donor.

GCA members have traveled to Delaware Bay to work there the last two years, in 2008 and 2009; and we anticipate going back this year.  Our target dates are May 22 until June 1st.  The full moon, when horseshoe crabs gather in the most dense numbers to lay their eggs, because the higher tides of the full and new moons take them further up the beach, occurs on the 27th of May this year, right in the middle of our stay.  Also, it happens that the historical departure date for Red Knots leaving en masse for the Arctic occurs on some afternoon between the 27th and the 29th of May. [click to continue...]

shore bird photos up close & personal

by Lanny McDowell on June 17, 2009

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Take a course in good water and air
, and in the eternal youth of Nature you may renew your own.  Go quietly, alone; no harm will befall you.
John Muir

Especially when someone looking at bird photography sees a lot of detail in the avian subject, feathers in sharp focus or a shiny glint in the bird’s eye, he or she wonders how it is accomplished.  Often the viewer concludes, “Oh, well, the big lens!”   “What kind of glass are you using?” is the more camera-savvy question.  Guess what?  It can be the humongous and fast prime lens on the oversized gimbled tripod … on a bright sunny day … bird posed at the edge of the nest … shot from the sturdy platform of the observation tower in the well-managed nature sanctuary.  Nothing wrong with that.  Do whatcha gotta do, I say.

Here’s what I go for, though.  What I seek out and what rings my avian art bell is:   first of all, it almost does not matter what the species is;  [click to continue...]

Red Knots Endangered, just knot officially

by Lanny McDowell on December 19, 2008

 Here is an excerpt from the American Bird Conservancy’s report about the current status of Endangered Species Listing by the U.S. Fish and Wildlife Service, thanks to Betty Andersen:

Government Review Confirms Red Knot and Other Imperiled Bird Candidates Should Be Listed as Endangered Species

 
 

The U.S. Fish and Wildlife Service (FWS) has released its revised list of species that are candidates for listing under the Endangered Species Act (ESA). Designation as a candidate species is not a requirement for listing under the ESA, and FWS can, and regularly does, list animals and plants without first placing them on the Candidate List. As a result, The U.S. Fish and Wildlife Service (FWS) has released its revised list of species that are candidates for listing under the Endangered Species Act (ESA). Designation as a candidate species is not a requirement for listing under the ESA, and FWS can, and regularly does, list animals and plants without first placing them on the Candidate List. As a resultthe Candidate List is regarded by many conservationists as a stall tactic by FWS.

Candidate species are assigned a listing priority from 1 to 12 based on the magnitude of threats they face, the immediacy of the threats, and their taxonomic uniqueness (for example, full species have higher priority than subspecies). The species’ listing priority dictates the relative order in which proposed listing rules are prepared, with the species at greatest risk (listing priority 1 through 3) being proposed first. Significantly, in the 2008 list, FWS determined that the ranking for the Red Knot should be raised from 6 to 3.

The rufa Red Knot, a reddish-brown shorebird slightly larger than an American Robin, migrates annually from Tierra del Fuego to its arctic breeding grounds, stopping to rebuild critical energy reserves by feasting on horseshoe crab eggs in Delaware Bay.

Only 14,800 Red Knots were counted in 2007 at the species’ primary wintering areas, a 15% decline from 2006, and a 75% decline from 1985. The results of several scientific studies have shown that a major reason behind this decline is a fall in the number of available horseshoe crab eggs due to overfishing of the crabs themselves, which are used as bait in conch and eel fisheries. This led FWS to conclude in their candidate review that, “The primary factor threatening the Red Knot is destruction and modification of its habitat, particularly the reduction in key food resources resulting from reductions in horseshoe crabs…”

“The U.S. Fish and Wildlife Service has once again confirmed that the Red Knot is increasingly threatened with extinction and deserving of heightened conservation measures, particularly immediate reductions in the commercial harvest of horseshoe crabs, whose eggs comprise the knot’s primary food source,” said Darin Schroeder, American Bird Conservancy’s Vice President of Conservation Advocacy.

The increased priority ranking for the species from 6 to 3 may speed its listing, but this could still be years off. “Too often species languish on the candidate species list and are not afforded the protections of the Endangered Species Act that we know work very well,” said Schroeder. “We urge the incoming administration to expeditiously act to list the species as the scientific research warrants.”