Wildlife Sidelights
Previously Undescribed Species Reported in the
Adirondacks
Heather Root, a graduate student at the State University of New
York’s College of Environmental Science and Forestry, has found high in old
Sugar Maples in Adirondack Park, three mites that had not previously been
described and a foliose lichen that had previously been reported only once in
New York. Mites are tiny arachnids
related to spiders. The lichen, a
folios (leaflike) lichen, had been reported
on
Long Island
in the 1960s. Root’s co-major
professor
Gregory McGee
believes that she and her field assistant Howard Prescott may be the first
people to study biodiversity in the forest canopy of the
Northeastern United States
.
The purpose of Root’s research was to find out if lichen and mite
communities differ in old and managed stands.
Her managed stands included selection system forests and reserve shelterwood
stands, both cut from old-growth forest. All
her stands therefore harbored big, old Sugar Maples. She found that the lichen
communities (and the mites that live in them) did not vary by type of stand
but that they did vary with the size of the trees.
Large trees had a greater variety of lichens, more unique assemblages,
and greater lichen cover than small trees.
Since Root examined only small areas, much may yet remain to be
discovered in the
Adirondack
canopy.
Sources:
Gregory McGee
, Personal Communication, 2006.
SUNY
College
of Environmental Science.
“80 Feeet Up, Tree
Top Inhabitants Pose New Questions.” [Press Release]
April, 24, 2006
.
--Posted April 27, 2006
_____________________________________________________________________________________________________________
Old Growth and the Ivory-Billed and Pileated Woodpeckers
(Summary by Robert M.
Davis of Frances Backhouse, “Survivor,” Audubon, Nov.-Dec.
2005, pp. 18-23.)
Within a few months of the sighting (still disputed), reported last
April, of an ivory-billed woodpecker in a swampy forest of Arkansas, the
Cornell Laboratory of Ornithology received almost 2000 messages describing
sightings as far north as Maine and Michigan. Since there are real
similarities of appearance between the ivory-bill and the pileated
but their ranges differ dramatically---the ivory-bill exists only in the
southeastern United States., while the pileated is
relatively common in the entire East and across the northern
United States and southern
Canada---probably all of these sightings were of the latter.
The classic contrastive description of species is that of the blueberry
and the elephant: the former is blue but the latter is gray. That of the
ivory-billed and the pileated woodpeckers is more
complex. Both are large and predominantly black, but the patterns of white on
the necks, backs, and wings, and the colors of the bills distinguish them from
one another. Also, both male and female pileated
woodpeckers have the bright red crest, but only the male of the ivory-bill has
this feature. Though their habitats may overlap, the pileated
prefers “deciduous and coniferous forests”, while the ivory-bill is
limited to “mature bottomland and swampy forests”.
Why has the ivory-billed woodpecker become nearly extinct while the pileated
has recovered and now thrives? As one would expect, the answer lies in the
relationship between their diets and their habitats. Most of the field
research on the ivory-bill was done by James Tanner of Cornell in the 1930s.
He found that this species’ diet consists especially of beetle larvae,
particularly of the long-horned beetle (cerambycid),
living under the bark of “large, recently dead trees.” These birds need
large amounts of good-quality food “within easy flying distance of their
nest.” Tanner calculated that, on average, an area of six square miles is
needed to support one pair of ivory-bills. On the other hand, one square mile
can support six pairs of pileated woodpeckers,
which find their diet of ants (especially carpenter ants) and beetle larvae
even in longer-dead trees and live trees.
The habitat required for the ivory-bill is found only in the Southeast,
and the primal forests on which it depends were almost completely cut between
1870 and the 1940s. While this destruction hurt the pileated
population also, it survived because its range and food supply are much more
widespread and because it can find its food and nesting sites even in
fragmented habitats. Nevertheless, the practice of too frequent burning and
too short a cycle of cultivation and cutting of lumber (15-25 years) would
endanger the pileated woodpecker, which depends on
larger, older snags, generally 35 years old or older.
--posted March 31, 2006
__________________________________________________________
The Plight of the
Florida Panther
(Summary
by Robert M. Davis of Abby Goodnough's “A Rare Predator Bounces Back
(Now Get It Out Of Here),” New York Times, March 14, 2006).
There are
about 100 Florida panthers, an endangered subspecies of the puma, in the area
of Big Cypress National Preserve, north of the Everglades. Although scientists
debate whether or not this feline still qualifies as a subspecies, especially
because of cross-breeding with the Texas puma in the 1990s, they agree that
the population must grow and needs more space to survive. In fact, the ideal
would be “three separate populations of at least 240 each”--an
unrealizable goal because of the dwindling amount of suitable habitat.
Moreover, already in 2006, six panthers have been killed: one by another
panther, five (including a female pregnant with four kittens) by automobiles.
Actual
cases of endangerment of humans or killing of domestic animals by Florida
panthers are few in number. The panther team leader of the Florida Fish and
Wildlife Commission knows of only one documented case where a Florida panther
attacked a human being, and that was in the 1880s.
But a few people are completely opposed to their protected status, and many
others are uneasy about their presence or proximity. For example, in 2004, an
Indian tribe requested the removal of a male panther, which was moved 60 miles
away (and killed by another panther). More recently, the same group is worried
that a female and two cubs are too close to residences and campgrounds. And
one real instance of provocation occurred in February of this year when, over
the course of several forays, a radio-tracked panther named Don Juan (the
father of 30 kittens) entered residential properties to dispatch “chickens,
ducks, a turkey, a pig, and a house cat.” So this animal was caught and
removed to another area.
Officials
of the U.S. Fish and Wildlife Services and of groups seeking protection for
the panther have made various proposals to mitigate or to solve the perceived
problem (danger to humans and their possessions) and the proven problem (lack
of adequate territory for the growth of stable Florida panther populations).
Such proposals include fencing out deer, which attract panthers; removal of
truly aggressive individuals from proximity to humans; “aversive
conditioning” of less aggressive ones (chasing them with dogs, hitting them
with slingshots); transport of some of them to Central Florida (but there is
insufficient contiguous habitat there) and/or to other States they formerly
inhabited, i.e. Georgia and Arkansas (but reintroduction of predators meets
fierce resistance from humans, and the Florida panther population is too small
to permit this anyway). Ultimately, this large predator, like others, can be
saved only if humans accept their presence and cease destruction of their
habitats, an unlikely prospect.
Eidtor's Note: In addition to being the home of the
Florida panther, the 729,000-acre Big Cypress National Preserve is the site of
some 158,000 acres of never loggged "hat rack" (unusually short) Pond
Cypress and some 23,000 acres of never logged Florida Slash Pine. (See the
online edition of Old Growth in the East on this web site.)
--Posted March 17, 2006
__________________________________________________________
Suit on Behalf of
Cerulean Warbler
March 3, 2006
, five conservation groups filed suit against Interior Secretary Gale Norton
and the US Fish and Wildlife Service (FWS) for ignoring their five-year-old
petition to list the Cerulean Warbler as an endangered species.
The population of these warblers has decreased by almost 82% throughout
its
US
range during the last forty years. The
bird breeds in the forests of the eastern
United States
in the summer and migrates to
South America
for the winter. It needs “large
areas of mature, undisturbed forest to reproduce successfully,” National
Audubon reports. The warbler thus
appreciates and uses old growth.
The logging and
fragmentation of mature forests in the
United States
and in the
Andes
and northern
South America
are major causes of the bird’s decline.
Listing the bird would require FWS to develop a recovery plan and
ensure that actions of the federal government do not hinder its recovery.
The suing organizations are Defenders of Wildlife, Heartwood, National
Audubon, Southern Appalachian Biodiversity Project, and Western North Carolina
Alliance. For more information, go
to www.audubon.org/news/press_releases/Cerulean_Warbler_03_03_06.html
--Posted March 15, 2006
__________________________________________________________
Fire
in the East, Fire in the West
(Summary by Robert M. Davis of Tim
Wright’s “A Tale of Two Fires,” American
Forester, Winter 2004, pp. 28-31)
This article describes the
divergent causes and effects of forest fires in the East and in the West,
based on the examples of conflagrations in Los Alamos, New Mexico and the
Shenandoah National Park in Virginia in 2000.
Shenandoah National Park supports some one hundred acres of old growth,
but most of it is in hollows, which would have offered protection from fire.
In the West, much of the
moisture from ocean storms falls on the coastal mountains with the result that
areas east of them are relatively dry. Lightning frequently strikes,
unaccompanied by rain, setting off fires. The forests are mostly coniferous,
with a high content of flammable resin. There are numerous ladder fuels”,
i.e. tall grasses, low branches, and bushes. These conditions enable the fires
to reach the canopy and to burn with extreme heat, destroying not only surface
vegetation but also sub-surface seeds and other organisms. Hence, the fire in
Los Alamos ruined a community and left a charred landscape still blackened
with burnt trees and bare, lifeless ground.
The
conditions in the East are quite different. Rain usually accompanies the
thunderstorms and inhibits fires. Unlike those in the West, fires in the East
are usually caused by humans. The greater diversity
of trees and bushes, including thick patches of mountain laurel in the
Shenandoah and similar areas, is less conducive to canopy fires and to extreme
burning temperatures. This area was covered largely with oaks and chestnuts at
the time of the arrival of the Europeans, who cut much of the timber. The
chestnuts died out by the 1930s. While building the Skyline Drive in those
years, the Civilian Conservation Corps planted mountain laurel to control
erosion, and these bushes have formed nearly impenetrable thickets below the
forest canopy.
The
Shenandoah National Park includes 196,000 acres stretched out along a 106 mile
length, with a maximum width of 15 miles. This narrow width and the relatively
dense adjacent human populations necessitate a strict policy of fire
suppression, resulting inevitably in the build-up of combustibles. The fire of
2000 charred 24,000 acres, affecting especially the laurels and the smaller
trees. But four years later, new growth on and close to the ground was
evident, and quaking aspens, which thrive after fires, have grown back. In
most places, the ground had been cleaned of fuels without damage to the root
systems. In the few places where the canopy burned, sunlight has promoted the
growth of flowers and berries in the cleared areas. So this burn exemplifies
the beneficial results of fire. If fuels accumulate too much, the next one may
be less benign.
--Posted February 17, 2006
__________________________________________________________
On Murrelets
The marbled murrelet, a small bird that
lives along the U.S. Pacific Coast, modestly produces a single egg during its
breeding season, if she feels up to it. This bird was listed as a threatened
species in 1992 by the federal government. Its decline, as well as that of the
northern spotted owl, was attributed to logging of the old-growth forests.
However, a study by researchers of the University of California at Berkeley,
points to an additional cause.
An examination of the chemical composition of murrelet feathers from
1895 to 1911, saved in museums, shows that birds of those earlier years
consumed a nutritious diet of oil-rich sardines, anchovies, and squid. The
fishing industry has seriously depleted the numbers of these fishes, and the
nitrogen isotopes coming from them are less abundant in modern-day murrelets,
who have had to resort to less nutritious krill and crustaceans. Since more
energy is required to dive and catch krill, less is available for reproduction
and the nurture of young. Off the coast of Oregon, sardines have resurged, but
this study was focused on the Monterrey Bay area of California. If valid, as
seems to be the case, it suggests that the population stability of murrelets,
and probably many other species, are functions of
multiple factors.
Summarized by Robert Davis, from Michael.Milstein,
“Study Finds ‘Double Whammy’ Harmed Murrelet’s
Population”, The Oregonian [Portland, Oregon], Jan. 3, 2006
--Posted February 5, 2006 __________________________________________________________
Snowmobiles and Lynx-Coyote Interactions
One, little discussed, impact of snowmobiles is that, by compacting
snow, they enable coyotes to enter high-elevation, deep-snow areas, which
provide habitat for lynx. Here,
through predation and competition for food, they threaten the survival of
lynx. A study in northern
Utah
’s High Uintah Wilderness found concentrations
of coyote tracks around snowmobile destinations.
In another study in the same area, 30% of coyote scat found above 8000
feet contained the remains of snowshoe hare, a staple food for lynx.
Source: George
Wuerthner. Personal
communication, citing Barry Gilbert. 2006. --Posted
January 22, 2006
__________________________________________________________
Briefs on Wildlife
Populations
As coastal species of fish have declined or crashed in numbers (or have
been eliminated), trawling for species in deeper waters has increased. The
latter fishes grow, mature, and reproduce more slowly because of the colder
water. Thus they are at risk of quicker depletion. Researchers from Memorial
University of Newfoundland report that in a 17 year period beginning in 1978,
the populations of five species (roundnose
grenadier, onion-eye grenadier, blue hake, and spinytail
skate) have declined by 89%. (New York Times, January 5, 2006)
Biologists appear to be succeeding in restoring the populations of native
fish species in the Colorado River (such as speckled dace, blueheads,
flannelmouth suckers, and chubs) by removing
non-native trout. This year, more than 17,000 non-natives have been caught and
killed. The numbers of trout are down and natives are again dominant in
certain parts of the river, according to the Arizona Fish and Game Department.
Other reports, however, warn that natives are still in danger, especially
chubs, at least in part because of the consequences of the Glen Canyon Dam.
(Associated Press, November 29,
2005)
The
wiliwili is the only native dryland tree still
widespread in Hawaii. But it is under attack by the tiny erythrina
gall wasp, which has spread from Oahu to all the major islands. Large
collections of the wiliwili are kept in the
National Tropical Botanical Garden and the Waimea
Valley Audubon Center, where they are being “drenched”
with an insecticide. Stores of seeds are being collected and
saved, just in case... Also, biologists are seeking insect predators of
African gall wasps, hoping to use them against the erythrina,
with tests planned to ensure that other Hawaiian insects are not harmed.
(Associated Press December 15,
2005)
--Robert M. Davis--posted January 16, 2006
__________________________________________________________
Changing Habitat in China
The population of China, about 1.3 billion persons or approximately 21%
of the world’s total, resides on roughly 10% of the earth’s surface.
According to Mr. E. Jingping, China’s
vice-minister for water resources, in the year 2004 alone, more than 1.6
billion tons of top soil were lost. The affected areas consist of 3.6 million
hectares or 37% of the territory, especially in the region between the Yellow
and Yangtse Rivers and the north of China, where
the Gobi Desert is spreading, although most areas suffered some loss. From
1997 to 2004, there was a loss of 5.7% of topsoils on arable lands.
We can only hope that China’s planting of thousands of square miles
of forest each year will eventually slow the rate of loss.
The average of water resources available per inhabitant in China is only
one-quarter of the world-wide average. More than 300,000 Chinese lack access
to potable water. Furthermore, groundwater supplies, providing around 70% of
drinking water, are polluted, in 90% of the cities, with organic and chemical
materials. 40% of the water for irrigation also comes from groundwater.
Although the article does
not deal with the ramifications of these statistics, it is obvious that
China
’s soil and water problems have enormous
consequences, not only for agriculture and human health, but for entire
ecosystems and for
Asia
’s geopolitical situation.
(Summary of an article by Christiane
Gauss, “En 2004, la Chine a connu une
érosion importante de
ses sols”, Le Monde,
Dec. 29, 2006.)
--Robert M. Davis, posted January 10, 2006
_______________________________________________________________
Good Neighbors
(Based on Carl Zimmer’s “A Pair of Wings Took Evolving Insects on a
Nonstop Flight to Domination”, New
York Times, November 29, 2005)
It
is always disconcerting and embarrassing to learn how little we know about our
closest neighbors. A case in point is the flea, and its life and times. From
the article cited above (itself based on the book Evolution
of the Insects, by David Grimaldi of the
American Museum of Natural History and Michael Engle of the University of
Kansas), we learn that fleas exemplify the transformation of insects since
they came on land over 400 million years ago. Fleas are descended from scorpionflies,
which have long wings and strong eyes. The closes relatives of fleas are the
24 species of snowfleas, which have weak eyes and
tiny wings and cannot fly. The 5000 other species of fleas split off from snowfleas
160 million years ago and evolved further in the same directions, i.e. they
have no wings and their eyes are covered, adaptations to their new habitats,
such as the hair of animals...
Fleas
are a small part of the insect kingdom, which numbers perhaps 5 million
species, many more than all other animals and plants combined. Their total
biomass also exceeds that of all other animals.
Furthermore, they are essential to the health of forests and bodies of water.
The disappearance of large numbers of the insects seems, and may be,
inconceivable. Many species of insects--roaches, houseflies, and
pesticide-resistant crop-eating insects, for example--have adapted to and
thrive on the conditions imposed by human activities. Yet many other insect
species dependent on single plant species for food or on certain habitats
could be extirpated when humans destroy that habitat or that plant, and we
could lose beneficent (to humans) insect species and be left with more that
are inimical to us. So we owe some consideration to our six-legged neighbors.
--Robert M. Davis, posted December 30, 2005
________________________________________________________________
Evolution
on the Islands
Charles Darwin’s observations of the birds on the Galapagos Islands
were an important factor in his theory of evolution by natural selection.
For a long time, however, it was generally believed that species had
migrated from continents to islands and ceased to evolve there, eventually
dying out and being replaced by others from the mainland.
Some
80 years ago, Ernst Mayr challenged this view.
Studying the resemblances and differences among avian species in the Pacific
islands by their anatomies and colors, he laid the basis for the opposing
theory: new species evolve when populations are isolated, as on islands.
Christopher E. Filardi and Robert Moyle
of the American Museum of Natural History have recently (see Nature,
November 10, 2005) added substantial support to this theory by their study of
monarch flycatchers, a group of birds species on
the Pacific islands. Using
DNA from live birds on the islands and from others preserved in
the museum (some from as far back as the 1880’s), they have shown that a
common ancestor existing in Australia and New Guinea between 2 and 5.6 million
years ago gave rise to 13 species spread out as far as Fiji and Hawaii. Some
of these flycatchers re-colonized Australia and New Guinea from the Solomon
Islands. Other studies suggest that islands have been the sites of similar
evolutionary patterns for other animals (e.g. lizards) and even plants.
Monarch
flycatchers, like many species, are now threatened by human activities. Filardi
argues that it is very important to preserve island biodiversity as a source
of new biodiversity.
Summarized
by Robert M. Davis, from Carl Zimmer, “In Give and Take of Evolution, a Surprising Contribution
from Islands,"New York Times, November 22, 2005
--Posted December 16, 2005
______________
Running
Buffalo
Clover
The Winter 2005 issue of The Nature
Conservancy’s magazine Nature
Conservancy announces that conservancy botanists have found two new
populations of Running Buffalo Clover (Trifolium
stoloniferum) in
West Virginia
. The clover is a federally
endangered species. The
populations are on land belonging to the paper company MeadWestvaco,
which has agreed to work with the conservancy to preserve the clover.
Running Buffalo Clover was once common from
West Virginia
to
Kansas
, particularly along buffalo trails. However,
it depended on the buffalo to stir up the grand and distribute the seed.
With the disappearance of the buffalo from the East, the clover
declined. It was presumed to be
extinct by 1985 when a botanist discovered a population in
West Virginia
. Now patches are known to exist in
Missouri
,
Kentucky
, and
Ohio
in addition to
West Virginia
.
We accidentally came across an identified patch on the lawn of
Ashland
, the Henry Clay Estate, in a residential area of
Lexington
,
Kentucky
. The clover was circled by a band
of red ribbon and marked by a small sign to prevent mowing in the spring. Running
Buffalo Clover bears white flowers and creeps along the ground like white
clover, but differs from that species in that the flower heads are on stems
with leaves rather than on bare steams, and the leaflets are rounded and not
marked by a “v.” A brief
account of the species is available online at http://www.ca.uky.edu/agc/pubs/agr/agr142/agr142.htm
.
--Mary Byrd Davis, posted November 30, 2005
______________
Impact of the Reintroduction of Wolves in
Yellowstone
The reintroduction of wolves may be significantly altering, or
correcting, the ecology of
Yellowstone
National Park
. Wolves disappeared from the park
in the 1920s. For the next several
decades, apparently, elk happily munched on willow, cottonwood, and aspen
shoots, drastically reducing the numbers and size of the
these trees. In 1995,
fourteen wolves from
Canada
were brought to the park; seventeen more were added in 1996.
Within the next decade, this population grew to around 170 in 13 packs
dispersed throughout the park, and the trees along the streams made a strong
comeback as the elk moved to the uplands.
This phenomenon has enabled scientists to greatly increase the
knowledge of wolf biology, much of which has been published in a book by
Douglas Smith and Gary Ferguson, Decade of the Wolf: Returning the Wild to Yellowstone (The Lyons
Press, 2005).
Smith, a wolf biologist, says that “Wolves have caused a trophic
[nutritional] cascade.” William
Ripple, a botanist at
Oregon
State
University
, attributes changes in vegetation and animal populations to an
“ecology of fear.” However,
a canid biologist, Robert Crabtree, citing
climatic factors and flooding as causes of the outbursts of tree growth along
the stream banks, asserts that the wolf is not the sole source of the changes.
The ripples through the ecology include the following:
--where willows, cottonwoods, and aspens return, they stabilize the
stream banks and shade the water, cooling it, encouraging more and larger
trout;
--these trees also attract certain avian species, such as yellow
warblers and eastern sparrows;
--beavers have also increased in number:
in 1996, there was 1 beaver dam on the northern range of the park;
there are now 10;
--the number of coyotes has decreased by half; this has increased the
rodent populations and, in turn, those of red foxes and raptors;
--the elk herd has dropped to 11,000 from 19,000 in 1994; a study
indicates that 53% of the loss is caused by grizzlies who eat elk calves, only
13% by wolves, and another 11% by coyotes [who presumably take only sick or
weak calves]; the herd has moved to higher, more open ground, fear making it
more circumspect.
Although not hunted, wolves face two principal dangers: 1) traffic
fatalities, 24 having been killed by vehicles in 10 years; 2) the parvovirus
carried into the park by domestic dogs. The
wolf population has dropped from 170 to 130 in the last year.
More time and testing are needed to determine the role of the virus and
other possible factors in this decrease.
(Summary of Jim Robbins, “Hunting Habits of Wolves Change the
Ecological Balance in Yellowstone,” New
York Times, October 18, 2005)
--Robert M. Davis, posted November 8, 2005
The
Przewalski Horse
According to University of
Kentucky biologists, cited in the excellent article by John Noble Wilford,
there are two extant species of horse: 1. all of the domestic
breeds, “from Shetland pony to Clydesdale”; 2. the wild horse Equus
ferus przewalskii,
the Przewalski horse, or P-horse, for short, named
after a Russian explorer of Polish descent who identified it in the 19th
century. In Mongolia, it is called the takhi.
The two species diverged from a common ancestor 500,000 years ago. Beginning
about 6,000 years ago, the first was domesticated and the various breeds were
developed. The takhi, however, was never tamed.
It is an animal about the size of a large pony, short-legged, tan to
tawny, with a dark mane, living in families called harems, consisting of
females, foals, “bachelor” males, and a dominant stallion. This wild horse
roamed Central Asia until the 1960’s, when it disappeared from the wild, due
to hunting and loss of habitat to livestock.
Fortunately,
there were 300 of these horses in captivity in Europe, where
breeding and reintroduction
programs were organized by the Foundation for Preservation and Protection of
the Przewalski Horse, in the Netherlands. In 1992,
sixteen horses were taken to Hustai National Park
in Mongolia and to Tikhin Tal,
a site at the western edge of the Gobi Desert. Guided by biologists and
veterinarians of the International Takhi Group,
several European countries
participate now in the program, and many more have been
reintroduced.
For
the first year, takhi are kept within large
electrified enclosures while they adapt to the cold winters and develop
immunity to tick-borne diseases. There are now 300 P-horses, or takhi,
in Mongolia, including 170 in Hustai National Park
, the rest on remote sites at the edge of the Gobi. It is hoped that
15-20 foals will have been born this year.
Since
takhi, with 66 chromosomes, can breed with
domestic horses, with 64 chromosomes, producing fertile offspring with 65
chromosomes, there is concern
about maintaining the purity of the species, if indeed it is
still pure. Successive generations would regain the 66th chromosome, and some
biologists believe that the added gene flow from interbreeding could be
beneficial. In any event, this is another paradoxical instance of human
intervention both extirpating and then, hopefully, saving a wild species.
(Summary of John
Noble Wilford, “Foal by Foal, the Wildest of
Horses Is Coming Back”, New York Times,
October 11, 2005.)
--Robert M. Davis, posted October 28, 2005
______________
Another Species Saved?
There were no sightings of the black-footed ferret, a rare, nocturnal
mammal that hunts prairie dogs, from 1943 to 1981, when a small colony was
found in northwestern Wyoming. Since then 3000 have been bred in captivity and
released in western states, including 173 in Colorado.
There is evidence that they are thriving and reproducing there, and it
is estimated that there are at least 400 in South Dakota, Wyoming,
Montana, Arizona, and Colorado. Jacob Smith of the Center for
Native Ecosystems, in Denver, credits the Endangered Species Act for saving
this species, and points out that its continued survival depends on the
protection and promotion of prairie dog populations.
(Based on Associated Press and New York Times, September 17, 2005)
--Robert M. Davis, posted October 26, 2005
______________
Return of the Andean Condor
From an aesthetic, anthropocentric point of view, the world’s
largest flying bird, Vultur
gryphus, or the Andean condor,
aground, is rather unappealing , especially, no doubt, when it quarrels with
its comrades as they tear away chunks of carrion, their dietary staple.
From the same point of view, the condor aloft is a magnificent
glider, soaring on thermal currents with its 10-foot wingspan, up to
altitudes of 15,000 feet, over a range of 4,500 miles from Colombia to
Tierra del Fuego in Argentina. Ancient
civilizations revered this giant as a deity, and four modern nations claim
it as their national bird.
Like most large creatures in the wild, the Andean condor is threatened
by hunting, pollution, development, and even, indirectly, by civil strife,
as armed groups impede efforts to save the bird. Nonetheless, such efforts
are being made with some success by biologists, conservationists, and some
local farmers who must persuade their neighbors that condors will not carry
away their children, sheep, or (live) cows. Since 1989, American zoos have
raised and sent to Colombia 60 young condors. The youngsters are taught to
fly and are familiarized with the terrain and predators before being
released into the wild and steep Andes. They are then tracked by tiny radio
transmitters attached to their wings, and are even fed (primarily dead cows)
until they are able to find enough food through their own efforts. From a
total population reduced to about 60 a generation ago, the number of condors
has risen to about 180. Only if there is continued success in raising and
reintroducing individuals for many years will this species have a stable
population. The obstacles, all man-made, are formidable.
(Based on Juan Forero,
"In a Corner of the
Andes, Help and Hope for Giant
Birds", New York Times, September 13, 2005)
--Robert M. Davis, posted
October 21, 2005
______________
Ant Forestry
In
the Peruvian Amazon, there are areas of up to one-third of an acre dominated
by a single species of tree, D. hirsuta. Various
legends and scientific theories have been put forward to explain this
phenomenon. A doctoral student at Stanford University, Megan E. Frederickson,
in experiments reported in the journal Nature, has shown that these
monocultural tracts, called “devil’s gardens” by local inhabitants, are
the work of a species of ant called M. schumanni. From its abdomen, this ant
injects formic acid into saplings of species other than D. hirsuta, thus
killing them off within weeks. This process of eradication benefits both D.
hirsuta by giving its members more light, nutrients, and water, and M.
schumanni by providing more space for its colonies. These colonies can be of
enormous size and longevity. Analysis
of one colony showed that its initial construction was contemporaneous with
that of some of the early gothic cathedrals (on a different continent, of
course).
(Summary
of Henry Fountain, “A Devil’s
Garden, Tended by Ants”, New York Times, September 27, 2005)
__________
Giant Squid
Until September 30, 2004, no giant squid had been photographed in its natural
habitat. On that date, two Japanese scientists finally accomplished this, near
the Bonin Islands 600 miles south of Tokyo, according to their report in the Proceedings
of the Royal Society B (B for Biological Sciences).
The technology employed to view (but not personally approach) this
elusive and legendary creature consisted of floating lines from which were
suspended a robotic camera and hooked baits.
The giant squid, itself prey of sperm whales, is an active predator with eight
short arms and two long tentacles. The invasion of its domain ended badly for
this individual. One of its eighteen foot long tentacles became caught on a
hook and was torn off when the
squid finally escaped after a struggle of over four hours.
(Summarized from the New York Times, September 28, 2005)
__________
Bird Songs, Music,& Language: Is
"Bow wow" Displaced by "Tweet tweet?"
Biologists have generally regarded bird songs as means of protecting territory
and attracting mates. This explanation did not satisfy Charles Darwin, who
believed that birds possess a natural aesthetic sense. Because many bird songs
seem to be unduly long and complicated, and not proportionately effective,
Stephen Jay Gould wondered if evolution might have produced traits or
activities, such as the songs and beautiful feathers of birds, that correspond
to :”spandrels” in architecture, features that serve no purpose other than
one of fashion or aesthetics. Dr. David Rothenberg,
a professor of philosophy, amateur ornithologist, clarinetist, and composer,
influenced by Paul Winters’ “Common Ground” album of the 1970s (in which
calls of eagles, wolves, and whales are integrated with human music), has
further pursued this question. Traveling the world for five years, he has
interacted musically with various species of birds using his clarinet, an
experience that has convinced him that some birds do in fact react to music,
changing their songs. Thus, he believes that bird songs are not necessarily or
essentially invariable or utilitarian, that they sing “because they can”
and “they must”. He further wonders if “song and melody may very well
have evolved before words and language”.
Dr. Rothenberg has published an account of his
experience and thought in a book, Why Birds Sing: a Journey into the
Mystery of Bird Song and an accompanying CD of human and bird music.
(Summary
of Claudia Dreyfus, “A Conversation with David Rothenberg”,
New York Times, September 20, 2005)
---Robert M. Davis, posted October 14, 2005