I have been copied on a posting made by Mr. Heil dated May 25, 2007 which
cast aspersions on the Baker et al (2004) study.  The study includes models
of population changes for the Red Knot rufa subspecies.  Per Dr. Peck's
well-written and appropriate response, NJ Audubon and its many conservation
partners who are working to protect the Delaware Bay shorebird stopover,
correctly reference the Baker et al study to substantiate the high risk of
extinction.  It is truthful to state that population models for the Red Knot
rufa subspecies demonstrate that the population could be at or near
extinction circa 2010.  No one pretends population models are a crystal
ball, but it provides a useful temporal context in which to categorize
probability of extinction.  To date, I have not read or seen any
publications or presentations claiming that the Red Knot rufa subspecies is
anything other than highly imperiled.



According to leading scientists from the Wader Study Group, prior to the
overharvest of horseshoe crabs the Delaware Bay was one of the top four most
important stopover locations in the world.  Both the Baker et al (2004) and
Morrison et al (2004) articles document the rapid decline of Red Knots on
the Delaware Bay and discuss a causal link of the decline to the overharvest
of horseshoe crabs.  Furthmore, as Dr. Peck wrote, other species such as the
Ruddy Turnstones, Sanderlings and Semipalmated Sandpipers are also
exhibiting declines in weight gain rates and population.



While Mr. Heil may doggedly attack the strong science of Baker and his
co-authors, I would rather welcome all to join us in restoring the Delaware
Bay shorebird stopover site to its former resplendent, intact condition
hosting nearly 1 million individuals from 9 shorebird species.



Below are excerpts from the two cited studies which I feel help establish a
baseline for discussion:



1. In a recent publication in the Proceedings of the Royal Society of London
(2004), Dr. Baker et al. made the following findings and conclusion, "From
1997-2002 known survivors in Delaware Bay were heavier at initial capture
than birds never seen again, annual survival of adults decreased by 37%
between May 2000 and May 2001, and the number of second year birds in
wintering flocks declined 47%...  Population size in Tierra del Fuego
declined alarmingly from 53,000 to 27,000 in 2000-2002, seriously
threatening the viability of this subspecies. Demographic modelling predicts
imminent endangerment and an increased risk of extinction of the subspecies
without urgent risk-averse management."



2. Similarly, Dr. Morrison et al. (2004) reported in Condor that "Surveys of
the North American race of the Red Knot (Calidris canutus rufa) on its main
wintering areas on the coasts of Patagonia and Tierra del Fuego (Argentina
and Chile) showed a dramatic decline in the wintering population: totals in
2003 were about 30 000 compared to 67 500 in the mid-1980s.  Numbers at the
principal wintering site, Bahia Lomas, fell by approximately 50%, from 45
300 in 2000 to 22 000-25 000 in 2002-2003.  Numbers at peripheral sites on
the coast of Patagonia declined dramatically, decreasing 98% compared to
numbers in the mid-1980s. Possible reasons for the declines are discussed.
Banding studies in Delaware Bay have shown that in recent years an
increasing proportion of Red Knots is unable to gain sufficient weight for
migration to the breeding grounds.  This is likely due to reductions in
their main food resource, eggs of the horseshoe crab Limulus polyphemus.
The resulting increase in mortality could account for the magnitude and
severity of the declines we observed."



Citations



Baker, Allan J., Patricia M. Gonzalez, Theunis Piersma, Lawrence J. Niles,
Ines de Lima Serrano do

Nascimento, Phillip W. Atkinson, Nigel A. Clark, Clive D.T. Minton, Mark K.
Peck, and Geert

Aarts. 2004. Rapid population declines in red knots: fitness consequences of
decreased refueling

rates and late arrival in Delaware Bay. Proc. R. Soc. Lond. B (2004) 271,
875-882



Morrison, R.I. Guy, P. Kenyon Ross and Lawrence J. Niles. 2005. Declines in
wintering populations

of Red Knots in Southern America. The Condor. 106:60-70.

Sincerely,
Eric Stiles, Vice President for Conservation and Stewardship
New Jersey Audubon Society
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