Australia is like a pet shop
with its doors thrown open.
Strange marsupials, frilled
lizards, and gaudy birds dot
the countryside. And many of Australia’s
birds, from cockatoos to budgies, are pet
shop staples. Until the mid-1980s, trappers
collected 11 species of finches from
the grasslands of northern Australia, earning
up to $11 per bird in the pet trade.
The most valuable of these was the
Gouldian Finch, a tiny, outrageously
colorful bird that is now one of the most
popular cage birds in the world. “I’m
always amazed wherever I go; I walk into
a pet shop and Gouldians are there,” said
Sarah Pryke, a biologist at Macquarie
University in Sydney, Australia, who has
worked on the finches since 2005.
She studies them because, despite their
ubiquity behind bars, Gouldian Finches
are nearing extinction in the wild—a sad
paradox that afflicts other beloved cage
birds, including the Java Sparrow and
South America’s Red Siskin. Learning
how to bring back wild populations, and
discovering the ways in which their caged
counterparts can and cannot help, is an
ongoing puzzle. Fortunately for Gouldians,
recent focus on the birds’ unusual
nesting sites may help turn the tide.
Hundreds of thousands of Gouldian
Finches used to live in Australia’s tropical
savannas, but by the 1980s their numbers
had crashed to 2,500 or fewer. The pet
trade was not so much to blame as the
bird’s fussiness and naïveté, Pryke said.
Gouldian Finches eat the seeds of only
about a dozen species of grasses; they
nest only in deep, hollow branches of two
species of eucalyptus trees; and if they are
bred in captivity, they emerge into the
wild clueless about predators.
Brad Congdon, of James Cook University,
was part of an early project to
release captive-bred birds from an aviary
at the Jabiru Safari Lodge in northern
Queensland. When they first opened
the doors, the birds didn’t even wake up.
When they did leave, “they were like lollipops
for raptors,” Congdon said. “They
just did not know what to do when any
predators came around.”
Captive-bred birds can have problems
in the wild, said Eduardo Iñigo-Elias,
who leads the Cornell Lab’s Neotropical
Conservation Initiative. For example,
endangered Puerto Rican Parrots were
raised using Hispaniolan Parrots as surrogate
parents. The chicks developed just
fine, but they only learned the dialects of
their foster parents and failed to recognize
their own species once released.
So even though Gouldian Finches
breed well in captivity, issues with genetics,
behavior, and disease mean they can’t
be used to restock the wild population.
Instead, Pryke studies captive birds to
learn about wild ones. A breakthrough
came when her team focused on nest
sites, which for years hadn’t been studied
because tree holes seemed plentiful on the
Australian savanna. But it turns out they
weren’t the right kind of tree holes.
“Gouldians are really fussy about what
they’ll use,” Pryke said. “They like a very
small entrance, and they like a very deep,
long entrance, and they pretty much won’t
breed in anything else.” So Pryke and her
colleagues invented a nest box that looks
like a cross between a bluebird box and
a didgeridoo. “They love it really, really
dark, and they love to run down this sort
of tunnel into their box,” Pryke said.
The first few years of results have been
promising. In places where just 40 percent
of adults nested each year, the addition of
nest boxes pushed the nesting rate to 90
percent, and also reduced predation and
increased brood sizes, Pryke said.
Using teams of graduate students and
volunteers, Pryke has now built more
than 3,000 of these boxes, and Gouldian
Finch populations in her study areas have
tripled. “It suggests that if we can get the
environment right, [nest boxes] could
probably help to increase these birds back
to good numbers,” she said.