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Bermuda's Rare Birds Get Concrete Token of Love

By Rick Weiss
Washington Post Staff Writer
Monday, November 10, 2003; Page A07

The first of them arrived two weeks ago, right on schedule, flying low
over the horizon and landing on a couple of rocky islets off the eastern
tip of Bermuda. White and gray aerobatic birds with long, narrow wings
and romantic dark eyes, the Bermuda petrels, more commonly known as
cahows, started looking for the old burrows they had abandoned last
summer. Soon it would be time for their annual mating extravaganza.

For aficionados of Bermuda's national bird, it is always a thrill when
the cahows make their autumnal return from the still-unidentified
expanses of ocean where they summer. After all, Pterodroma cahow is a
critically endangered species, with only about 70 mating pairs alive today.

But this year's arrival has been especially gratifying, because it came
so close to being a bust.

The craggy islets -- the only spots in the region free of voracious
predators -- are too rocky for the birds to dig natural burrows, so the
cahows are completely dependent on concrete condos built for them by the
Bermuda government. Unfortunately, virtually all of this government
housing was washed away when Hurricane Fabian blew through in September.
With no place for this year's returning pairs to settle and raise the
one precious chick each hatches every year, it looked as though it might
be curtains for the much-beloved birds.

"It's very possible we would have lost the species," said Jeremy
Madeiros, a field naturalist with the Bermuda Conservation Department.
"Their backs were to the ocean, so to speak."

That's when the people of Bermuda got involved, with dozens volunteering
to help Madeiros in a crash reconstruction program.

Divers rescued 40-pound pieces of swept-away cahow housing from depths
of as much as 50 feet. Others braved eight-foot swells in small boats to
deliver 4,000 pounds of wet cement to the islets, a bucket at a time, so
the condos could be rebuilt.

Last week, with the birds arriving in growing numbers, a crew assembled
the last of the new burrows and got out of the way. The cahow, it now
seems, has escaped the grip of extinction for another year.

It is not the first time these tenacious birds have defied the odds.

Hundreds of years ago there were probably a million cahows living on
Bermuda, according to scientists who have studied semi-fossilized
remains. They made their nests in burrows that they dug in the sand or
in deep rock crevices. The birds will raise a chick only if their burrow
is completely dark, even at midday.

Thanks to their spooky mating calls, the birds went unharmed by the
Spanish sailors who began probing the region in the early 1500s. The
calls, made at night, sound like low, guttural moans followed by
high-pitched wailings, and they led sailors to believe that Bermuda was
inhabited by demons. Tradition has it that this is why the otherwise
attractive island remained uncolonized until a boatload of British
sailors shipwrecked there on their way to Virginia in 1609.

As it turns out, the cahows were already in trouble by then because the
Spanish -- though never settling there themselves -- had released pigs
on Bermuda as food for shipwrecked sailors. Those animals all but wiped
out the petrels, except for some that relocated to Bermuda's
inhospitable outer islets. Under growing pressure from English settlers
and the animals they brought, even those isolated birds disappeared by
1620 -- and the species, as far as anyone knew, went extinct.

That is the way it was for more than 300 years.

Then came the cahow's first and perhaps most miraculous comeback: In
1951, scientists discovered that a few of the birds had survived. A
species recovery program was initiated, and the population grew from 18
pairs in 1962 to 63 pairs four decades later.

It was a harrowing climb from the brink. Hardly had protective measures
kicked in during the 1960s when the insecticide DDT took its toll, as it
did on so many birds of that era. The population dipped again, as the
chemical thinned eggshells to the breaking point and births declined.

When DDT was outlawed, the cahow began its next recovery under a
state-run program headed by conservationist David Wingate -- who, at age
15 in 1951, had been part of the effort that led to the cahow's
rediscovery that year.

The birds -- virtually all of which today are labeled with leg bands --
mate for life, though no one knows whether the monogamous pairs spend
their time together or apart when they are away from Bermuda. Very few
cahow sightings have been made during the months the birds are out to
sea. They include some sightings off the coast of the Carolinas and at
least one in the Azores, suggesting the birds may fan out across much of
the North Atlantic.

Come fall, after cleaning out their old burrows -- or, as is the case
this year, moving into new ones -- the birds go out on their night
flights and perform their haunting mating calls.

"They make such fearsome noises," said Ned Brinkley, editor in chief of
the journal North American Birds and a leader of bird tours out of Cape
Charles, Va. "But they are incredible aerialists, supreme in the air.
Even during stormy weather, they engage in these high-speed chases with
antiphonal calling back and forth."

With three-foot wingspans and bodies that weigh little more than a
pound, the birds can soar albatross-like for hours without flapping.
They will dive toward the waves, achieving speeds of 40 mph or more,
then pull up just in time to clear the crests of waves -- sometimes
nicking the frothy caps -- where they take advantage of wave-top winds
to regain altitude and then dive again.

After recementing their marriage on the wing and then mating, pairs fly
off to sea for a month to stuff themselves on shrimp and squid in
preparation for the caloric demands of parenthood. These fully pelagic
birds can drink seawater, excreting excess salt through specialized
tubes attached to their bills.

Dad takes the first month on the nest after mom lays the egg, then they
take turns. After hatching, chicks stay in their dark burrows for weeks
until finally, one night, they come out and stare at the stars for hours
on end as though hypnotized -- a behavior some scientists suspect helps
the fledglings map their location on Earth. In the spring, like their
parents, they fly off to sea, though these youngsters do not return to
Bermuda until they are ready to mate, three to five years later.

When they do, it is amazing, Madeiros said. After spending years soaring
over the Atlantic and bobbing about on the open sea, they invariably
land within a few yards of where they were born.

How they find their way back with such precision is just one of many
questions scientists hope to answer someday -- if Madeiros and his
colleagues can keep the population growing and, as planned, extend the
bird's range to other nearby islands.

The odds seem good right now for this bird that seems to have more lives
than a cat.

=A9 2003 The Washington Post Company