Last of the dinosaurs

From ANIMAL PEOPLE, March 1996:

NEW YORK––The world learned
last year what leading-edge paleontologists
began to whisper a decade ago––that the
dinosaurs were not reptiles but close kin to
birds, or more precisely, that birds are not
merely descendents but survivors of
Dinosauria, a living branch of the therapod
dinosaur family. Among the therapods were
Ornithomimus, actually named for resembling
a bird; Gallimimus, essentially a giant
ostrich; the hawk-like Oviraptors and
Velociraptors; and the Tyrannosaurids,
including Tyrannosaurus Rex.
“Yo, T-Rex!” chortled Newsweek.
“Your mama’s a turkey!”

As maverick scientist Bob Bakker
postulated in his 1986 book The Dinosaur
Heresies, most if not all dinosaurs seem to
have been warmblooded, to have hatched and
reared their young in nests, had keenly developed
auditory and communicative senses,
may have had feathers, and might have had
intelligence at contemporary avian levels. A
fast-growing body of evidence was seemingly
capped on December 20, when Mark Norell
of the American Museum of Natural History
in New York City unveiled the fossilized
skeleton of an Oviraptor, apparently killed by
a sandstorm 80 million years ago, protecting
her 15 eggs to the last in precisely the brooding
position of a mother hen.
As 1996 opened, Chinese paleontologist
Lian-hai Hou announced his discovery
of a pair of 142-million-year-old fossils
appearing to represent the earliest known
birds capable of flight.
Ironically, birds have been recognized
as living links to dinosauria just as
unprecedented numbers of avian species are
plunging toward extinction. The S i l e n t
Spring scenario the late Rachel Carson postulated
in 1964 won’t happen––not soon, anyway––because
the chemicals most implicated
in the threats to species she documented have been banned or
restricted, and are gradually vanishing from the avian food
chain. Raptors and waterfowl, the bird classes most at risk in
Carson’s time, are demonstrating resiliency, with some
human help, including laws safeguarding critical habitat and
providing at least seasonal protection from hunters. Other
avian classes, including crows, starlings, sparrows, pigeons,
and seagulls, have demonstrated themselves to be quite at
home in human-created habitat––enough so to move into
niches vacated by more sensitive species. Gulls, indeed,
could be considered coyotes of the air, spreading into the
interior of North America when hawks and owls were fewest,
much as coyotes took advantage of heavy fox-trapping to take
over habitat in the midwest and east a few decades earlier.
And the sobriquet “rats with wings” often applied to pigeons
is apt in the sense that like Norway rats, pigeons are extremely
intelligent, quick to breed, and almost impossible to extirpate
from attractive territory.
But the hardiness of some birds contrasts with the
tenuousness of the continued existence of others, among
them many of the most unique and charismatic.
Kakapos & kiwis
If birds are living dinosaurs, the big flightless birds
are among the dinosaurs’ closest living relatives––not species
who lost the ability to fly, as theorists long held, but rather
species who most probably never evolved flight. Among
them, the dodo, the great auk, and the moa, among others,
have perished within the past few centuries. Thanks perhaps
to speculative commercial breeding, the ostrich, emu, and
cassuary are at no risk of extinction, despite the threats of
grazing, cultivation, and drought to their diminished wild
habitat. Kiwis, however, native to New Zealand and without
predators for 70 million years until humans arrived, are in
serious trouble, their numbers dropping by an estimated 4.3%
per year. The North Island brown kiwi is disappearing at the
rate of 5.8% per year. New Zealand Department of
Conservation kiwi recovery program coordinator Hugh
Robertson considers predictions that kiwis will vanish from
the mainland within 20 years pessimistic, but only those
populations on predator-free offshore islands have managed
any population increase in recent years.
The kakapo, a fat, flightless green parrot also
native to New Zealand, is in such imminent peril that the
British-based World Conservation Monitoring Center recently
placed it on a list of the 20 species most likely to become
extinct in 1996. Among the oldest known bird species, speculatively
linked in descent to a parrot-like therapod called
P s i t t a c o s a u r u s, kakapos are believed to have an individual
lifespan of 60 to 80 years, but the estimated 50 kakapos left
in the wild have raised only one offspring to adulthood since
1990, with just three others close to fledging. About 30 years
ago kakapos seemed doomed because no females were among
the known population, but then 200 kakapos including
females were discovered on Stewart Island––and almost as
quickly, were devastated by feral cats. Eventually they were
removed to the relative safety of Codfish, Little Barrier, and
Maud islands, where their main enemies are rats and stoats.
Like the kiwi and the moa, who shared the same habitat, the
kakapo evolved in the absence of predation, never developing
either the ability to fly or other defenses. Nor do they
reproduce quickly or easily: even when partners are available,
they mate only once in four or five years.
Penguins
Penguins, the most plentiful flightless birds, are
also in trouble. The penguin population at the Punto Tombo
reserve in southern Argentina, numbering 500,000 in 1986,
fell 16% from then to 1994––and then fell 21%, to circa
325,000, between November 1994 to November 1995,
according to studies by the private Fundacion Patagonia
Natural. Explain FPN director Guillermo Harris, “The penguins
at Punta Tombo are not getting enough to eat.” The
Argentine government admits that Argentine fishers caught
45,000 more metric tons of hake in 1994 than their 390,000-
metric ton quota, but blames depletion of anchovies, squid,
and cod, the penguin dietary staples, on foreign fleets.
Penguin starvation due to the combination of overfishing
with adverse climatic factors was also reported in
Antarctica during 1995. Whole generations of chicks perished.
The better publicized harm done to penguins by oil
spills is of relatively small magnitude. A spill off Punto
Tombo killed 17,000 penguins in just one 1991 incident, and
lesser spills cumulatively kill 20,000 penguins a year, the
FPN estimates, but the biggest known spills afflicting pengins
during 1995 were the July grounding of the ore carrier
Iron Baron off Tasmania in July; a slick of unknown origin
that hit Dyer Island, South Africa; and the wreck of the
trawler Magellanes II off Patagonia in September. Known
penguin casualties from all three spills combined came to
fewer than 1,000.
Because penguins are monogamous and incubate
just one egg per year per couple, they recover slowly from
population drops.
Neotropical songbirds
Migratory neotropical songbirds too are in
decline––and also have an ancient pedigree, as in March
1995 Walter Boles of the Australian Museum in Sydney
announced positive identification of two bones from a 55-million-year-old
songbird, 25 million years older than the oldest
previously known songbird remains. The find, expected by
evolutionary theorists, dates songbirds to within 10 million
years of the abrupt Cretaceous/Tertiary extinction 65 million
years ago of every known terrestrial species larger than a
housecat and the majority of then-extant birds as well. A
working hypothesis pursued by researchers is that a relatively
rapid evolution of smaller birds followed, perhaps involving
the mico-miniaturization of special abilities originating with
larger dinosaurs. Whatever happened, songbirds were successful.
The 4,000 neotropical migratory bird species living
today represent about half of all the world’s known avians.
But the 1995 Audubon Christmas Bird Count confirmed
a 50% drop in migratory neotropical songbird numbers
over the past two decades in the eastern U.S., part of a 30%
drop noted by the 1989 North American Breeding Bird
Survey, confirmed by delegates to last summer’s Fifth
Congress of Neotropical Ornithology.
The major cause of their decline is believed to be
the loss of about 42 million acres of tropical forest per year in
Latin America, the Caribbean, and southern Mexico.
But different species are affected in different ways.
Blackpoll warbler numbers are down 60%; Kirtland’s warbler,
which ranges from the Bahamas to Michigan’s Lower
Peninsula, has increased from just 200 “singing males” in
1971 to 764 “singing males” in mid-1995, with 101 added to
the population just last year. The increase is believed to be
due to jackpine restoration in Michigan, as Kirtland’s warblers
nest only in jackpine.
Three other endangered neotropical migratory birds,
the golden-cheeked warbler, the black-capped vireo, and the
red-cockaded woodpecker, are identified by Republican
members of Congress as species whose recovery is precluded
by the present Endangered Species Act, which they hold
gives landowners an incentive to destroy the birds’ potential
habitat before any––whereafter, development might be virtually
forbidden.
Dutch and British studies recently identified still
another possible threat to neotropical songbirds: traffic noice
so confuses some birds that many wrens, blue tits, woodcocks,
and pheasants can no longer able to keep their songs
in key––and can’t make themselves heard above the din.
Thus the reproductivity of songbirds dwelling within two to
three miles of busy roads is much lower than among songbirds
living farther away.
45,000 volunteers worldwide joined the 1995
Audubon Christmas bird count––the largest and longest-running
index to bird populations, begun in 1900 as a protest
against Christmas bird-killing contests. Since 1966 the
Audubon counts have been augmented by the North American
Breeding Bird Survey, which counts the “singing males” of
180 species heard along roadsides. Because the flight calls of
about 50 of those species are almost inaudible from the
ground, and because they migrate mostly at night, Bill Evans
of the Laboratory of Ornithology at Cornell University in
Ithaca, New York, has maintained electronic listening posts
at seven upstate New York locations, the prototypes for a
proposed network of 40 stations that would monitor the major
flyways from Cape May, New Jersey, to central Nebraska.
Less noticed, tropical birds are declining in other
parts of the world as well––and the longterm effect could be
catastrophic. Red-knobbed hornbills, for instance, carrying
up to 265 figs at a time back to their nests, along with the fruits
of more than 50 other tree species, are the chief means of
reseeding the rainforest of Sulawest (Celebes), Indonesia,
Wildlife Conservation Society researcher Margaret Minnaird
reported recently in Natural History. But agricultural clearing
has claimed about 90% of Sulawest, threatening both the hornbills
and the rainforest itself with extinction.
Bird conservation
Among the efforts underway to save bird species,
none are of higher profile or cost per specimen than the effort
to save the California condor––another relic perhaps dating to
dinosaur days. The Peregrine Fund hopes to release nine captive-bred
California condors in the Vermillion Cliffs region of
Arizona, north of the Grand Canyon, this April. Of 27 captive-bred
California condors released into California habitat
since 1992, 13 remain in the wild. Once soaring over the
whole southwest, the California condor was extirpated from
everywhere but a small part of southern California by 1987,
when the last wild survivors were brought into a Species
Survival Plan managed for the U.S. Fish and Wildlife Service
by Michael Wallace of the Los Angeles Zoo. The program is
also breeding Andean condors, still common in Argentina
and Chile but extirpated from the northern Andes, for reintroduction
to Venezuela and Colombia.
Early releases of captive-bred condors had mixed
success, as the birds electrocuted themselves on power lines
or broke wings flying to the cables; sought out human company,
unnerving pet owners and parents of small children
who couldn’t shake the feeling the huge birds wanted lunch;
poisoned themselves by drinking antifreeze; and in at least
one instance, drew gunfire. But bald eagle reintroduction ran
into comparable problems at first. Now the eagles are among
the few once endangered species to come off the federal
endangered species list due to population recovery.
In New York, where 198 Alaskan bald eagles have
been released since 1978, 103 were recently counted in the
Upper Delaware watershed area and 25 more were found near
West Point, along the Hudson River. As many as five at a
time have soared over the ANIMAL PEOPLE o f f i c e ,
inspecting but not molesting the resident menagerie.
Reintroductions of eagles continue. A federal effort
to restore bald eagles to central Louisiana enjoyed a hint of
success last fall, as one pair nested in the Lake Ophelia
National Wildlife Refuge, while the state had, altogether,
101 active nests in 22 parishes. The eagle reintroduction
involved capturing fledglings in southern Louisiana, where
the species is already fairly well established; raising them in
a tower, a tactic called “hacking” that was perfected during
the New York releases; and letting them go when they develop
flight feathers. Thirty-two of 33 “hacked” Louisiana birds
survived to release, while a raccoon killed one.
Meanwhile, in a rare international effort to save a
bird species, the U.S. Fish and Wildlife Service, the San
Diego Zoological Society, and the Environmental Ministry of
Mexico have teamed up to establish a 750-acre breeding
reserve in northeastern Mexico for the endangered maroonfronted
parrot, one of the few parrots with a preference for
high elevations––nesting at up to 9,000 feet. About 3,500 of
the parrots survive at 24 sites in the limestone cliffs within a
150-mile radius of El Taray, Mexico.
But a USFWS plan to protect endangered Mexican
spotted owls in New Mexico, Arizona, Colorado, and Utah,
published in January, seems no more popular than the many
plans issued over the years in connection with the northern
spotted owl native to old growth forests in the Pacific
Northwest. Logging within 600 acres of active Mexican spotted
owl nesting or roosting sites would be restricted to certain
species; otherwise, logging could resume, after a two-year
hiatus while the plan was drafted, within about 80% of the
owls’ known U.S. range. The Forest Service is also working
on a spotted owl protection plan, and the two plans must be
reconciled before any plan takes effect. The Mexican spotted
owl was designated a threatened species in 1993.
Other counts
The annual winter eagle gathering at
Brackendale, British Columbia, reportedly drew just half
the 1984 record count of 3,766, the most ever seen at one
site. Environmentalists blame the decline on septic discharges
from the allegedly overburdened sewage treatment
plant serving the nearby Whistler ski resor. A move is underway
to have Brackendale declared a provincial eagle reserve.
A phalarope “wreck,” a set of weather conditions
driving phalaropes to shore, delighted northern
California birdwatchers this winter. Usually feeding on water
insects and plankton, far out to sea, creating small
whirlpools with their feet to bring food to the surface, red
phalaropes previously came to the California coast in 1934,
1959, 1969, and 1982. Unlike most birds, phalarope
females are the brightly colored members of the species, who
perform the courtship rituals and have multiple mates; drab
phalarope males incubate the eggs and feed the young.
The whooping crane count at the Aransas National
Wildlife Refuge along the Texas Gulf coast hit 149 this winter,
up from 132 in 1994-1995 and breaking the 1990-1991
record of 146. The U.S. Fish and Wildlife Service has counted
the endangered cranes annually for more than 60 years.
The clapper rail population in and around the
San Francisco Bay National Wildlife Refuge is up to 600,
says refuge biologist Jean Takekawa. The refuge is the sole
habitat of the endangered rails, whose numbers fell from
circa 1,000 in 1981 to just 240 by 1991. Their recovery began
after the USFWS and California Department of Fish and
Game trapped out egg-eating feral red foxes, whose ancestors
escaped from defunct local fur farms, and feral cats, who
prey upon adult rails. Humanitarians objected that the foxes
and cats should have been removed by less cruel means.
EarthWatch offers bird-counting study trips t o
Alaska, Tanzania, Mexico, Hungary, Italy, and Wisconsin
this summer, at about $1,300 apiece. Details: 617-926-8200.
BIRD BRAINS
Biologist Gavin Hunt of Massey University in
Palmerston, New Zealand, reported in the January 18 edition
of Nature that the Corvus moneduloides crow of the New
Caledonia islands 900 miles east of Australia have developed
tool-making and use methods with “three features new to tool
use in free-living nonhumans, that only appeared in early
human tool-using cultures after the Lower Paolithic: a high
degree of standardization, distinctly discreet tool types with
definite imposition of form in tool shaping, and the use of
hooks.” Hunt presented evidence amassed from 1992 into
1995 that the crows make both hooks and saw-like tools from
plant matter with their beaks, for use in catching insects.
Letters published in recent editions of N e w
S c i e n t i s t, a leading British scholarly journal, document
pigeons using the London subway system to travel, apparently
purposefully, around the city. Writers noted that the
pigeons often ignore handouts from human passengers as they
go about their business, and hop rather than fly from the cars,
as if unafraid and certain of their destination. Said an unappreciative
London Undergound spokesperson: “Pigeons are
classified as vermin and if they are caught they should be
destroyed.”
An international team of four leading behavioral
e c o l o g i s t s in November 1995 published evidence that great
spotted cuckoos use extortion, not deception, to coerce magpies
into hatching their young. Rather than laying their eggs
in a magpie’s nest and departing, the researchers found,
cuckoos keep the nests under observation. If the magpies
push the cuckoo eggs out, the cuckoos destroy the magpie
eggs or hatchlings. “It’s an offer that the birds cannot refuse,”
said lead author Andres Moller, of Copenhagen University.
“It’s just the same as in the human mafia: if you resist, it
turns out very badly.”
BIRD BODIES
Ruby-throated hummingbirds have a top power
output of 133 watts per kilo of muscle, report University of
Texas researchers Robert Dudley and Peng Chai. Human output
peaks at 15 watts per kilo.
The hoatzin, an ancient vegetarian bird native
to Venezuela, converts into nutrients and energy up to 70%
of the plant fiber it ingests, reports Alejandro Grajal of the
Wildlife Conservation Society, who in 1990 discovered that
the hoatzin digestive tract more resembles that of cattle than
that of other birds. The hoatzin level of digestive efficiency is
comparable to that of cattle, Colobine monkeys, kangaroos,
and tree sloths. The hoatzin is among the estimated 3% of
bird species whose primary diet is green leaves and buds.
More bird news
Air Force Colonel Tom Gresch on January 11 formally cited the ingestion
of Canada geese into the engines as the cause of the first-ever crash of an AWACS
radar plane last September at Elmendorf Air Force Base near Anchorage,
Alaska––and blamed base officials for failing to respond to warnings that unusually
dense waterfowl migrations last fall could become a flight hazard. Thirty-four dead
geese and four wounded geese were found in the plane’s wreckage. The crash killed all
24 crew members.
About 275 of the 800-odd North American bird species have been sighted
in Central Park, New York, says Environmental Defense Fund official Roger
Pasquier, who rates the 136-year-old park one of the top 14 birdwatching sites in the
U.S., in a bracket with the Everglades and Yosemite. The variety of species present at
any one time, currently about 100, is reportedly increasing.
Ethiopia recently honored the exterminators who used pesticides to kill an
estimated 20 million birds in the Gode and Jijiga regions during 1995. The birds were
accused of eating food grain.