![Three images of parrots, cockatoos and parakeets.]()
Parrot species, including the Yellow-crested Cockatoo
(left), Sulphur-crested Cockatoo (center) and Rose-ringed Parakeet
(right), are flourishing in urban settings around the world.
Credit: Lynn M. Stone/Minden Pictures (left); Martin Willis/Minden
Pictures (center); imageBROKER/Ronald Wittek/Getty Images (right)
North America once had its own parrot. The Carolina Parakeet, a
gregarious green parrot with a yellow head, inhabited much of the
eastern U.S. Its range is thought to have extended from Florida and the
Atlantic Coast west to Texas and north to Illinois and even New York
State—it probably lived in many of the same places the Monk Parakeet is
found in today. Like the Monk Parakeets, Carolina Parakeets regularly
shared spaces with humans and were occasionally seen as crop pests. But
unlike today's urban Monk Parakeets, Carolina Parakeets inhabited wet,
old-growth forest. They were declared extinct in 1939, probably done in
by a combination of deforestation, competition with invasive species,
introduced diseases and hunting. Perhaps the Monk Parakeet is taking up
some of the niche vacated by the Carolina Parakeet—but it's also a
different bird living in a transformed world, one brimming with
opportunities for adaptable species.
Although people may have introduced Monk Parakeets to new locations,
the birds themselves have made the most of these novel circumstances.
Juan Carlos Senar, who is head of research at the Natural Science Museum
of Barcelona, started studying the city's Monk Parakeets out of
curiosity. The museum hosted Monk Parakeet research in the 1970s as
well, before the birds became worrisome. After all, it's objectively
interesting to see displaced parrots adapting to different environments.
Senar observed changes in the birds' behavior, such as how at first
they bred during the Northern Hemisphere winter, when it was summer in
the Southern Hemisphere, then they changed their breeding timing as they
got used to their new environments.
Soon the little green parrots were adding new color to the city's
tile work. In 2000 the Catalan government asked whether Senar and his
team could undertake a formal census. The researchers found that the
birds' population had exploded. They now number in the thousands.
The species' impacts have become clear as its numbers have swelled.
In the U.S., Monk Parakeets stick to human habitats, where they aren't
directly competing with native wildlife for cavities to nest in like
other parrots have to do. But this choice means they sometimes end up in
conflict with humans. Often they'll build their nests on utility
poles—risking power outages and fires.
In Barcelona, the birds cause more types of damage. One of Senar's
studies found that in an agricultural area outside the city, parrots
caused a loss of 28 percent of the corn crop, 36 percent of the plum
crop and 37 percent of the pear crop, among other fruits and vegetables
grown there. They also clip many branches from live trees for their
nests and eat food that other, native species rely on.
Senar emphasizes that he loves the species—he enjoys watching them
and makes a living studying them. But there's a difference between
enjoying a few parakeets and dealing with thousands of them roaming the
city. He fears they'll soon harm ecosystems beyond the city limits if
their population isn't managed: “They're very clever. If we wait too
long, it will be nearly impossible to control them.”
Another, equally adorable parrot species, the Rose-ringed Parakeet
(also known as the Ring-necked Parakeet), illustrates how difficult it
can be to control these charismatic birds when they set up shop outside
their normal range. Like the Monk Parakeet, this species is successful
in its native home ranges in South Asia and sub-Saharan Africa, where it
can thrive in human-altered habitats. A popular caged bird since at
least Victorian times, the green, pink-beaked, long-tailed parrot
started escaping increasingly often in the past few decades; before long
the Rose-ringed Parakeet established itself in cities across Eurasia
and beyond. But unlike Monk Parakeets, Rose-ringed Parakeets don't build
their own nests. They rely on nest cavities, a limited resource for
native wildlife—and they aren't afraid to fight for those spaces.
As the species began colonizing cities, scientists organized to
understand the birds and their impact. In 2013 the European Cooperation
in Science and Technology funded ParrotNet, a five-year project,
headquartered at the University of Kent in England, involving a network
of scientists across Europe tasked with monitoring parrots and
communicating their findings to local governments.
Emiliano Mori, a researcher at the Italian National Research Council
and former ParrotNet member, first noticed the birds on a Mediterranean
summer holiday and wondered how they were affecting the native
biodiversity. He began observing the parrots and the outcomes of their
invasion. Soon he found that Rose-rings were taking nest sites from a
small owl called the Eurasian Scops Owl in Italy. The species wasn't
directly reducing the owls' population, but it was pushing them out of
their preferred spots.
Evidence of the negative consequences of Rose-ringed Parakeets' entry
into new locales continues to mount. Research has shown that they
outcompete birds at feeding stations in the U.K., and they regularly
kill competitors such as Blue Tits and black rats. All the while their
populations have been ballooning in cities around the world.
“Their presence is not good,” Mori says. “We can't tell the complete
scope of their impacts, but every time we look, there's something new to
be discovered.” The researchers continue to find new species affected
by the birds, he says.
ParrotNet produced policy briefs that were translated into various
European languages. Spain has begun removing parakeets. But culling
programs are running up against humans' enduring fascination with these
birds.
![Parakeets flying in a park.]()
Green-Wood Cemetery's Monk Parakeets and other urban parrots
are by-products of the pet trade and wildlife trafficking. Credit: Ali
Cherkis
The parrots' cute factor continues to be a challenge in efforts to
control them, says biologist C. Jane Anderson, who specialized in
charismatic invasive species while she was an assistant professor at
Texas A&M University Kingsville. Anderson studied Rose-ringed
Parakeets on the Hawaiian island of Kauai, where the birds threaten
local agriculture and native species. She used culled samples to
determine when the birds bred and how to tell the difference between
juvenile and adult females—they look similar, but removing (and
euthanizing) the latter is more important for population control.
Anderson can recall multiple anecdotes of public protest hindering
invasive-parrot management. Humans are drawn to animals with babylike
features, called “baby schema ” in psychology: big eyes, big heads and
soft bodies. Culling snakes might not lead to much outcry, but people
like parrots.
It's important to remember how the birds arrived in the first place,
Anderson says. She doesn't want to demonize the parrots; rather she
views controlling them as undoing the damage humans caused. “The truth
is humans moved these animals around,” she says. “I understand why
people would be excited to see a parrot in Barcelona. But they shouldn't
be there.”
It's also important to understand that our cities are not sterile
places devoid of wildlife that needs protection. Cities can be as
ecologically valuable as the surrounding countryside—New York City is a
major migratory bird hotspot, for example. Perhaps the most worrisome
consequence of the Rose-ringed Parakeets is that they outcompete and
kill a type of threatened bat called the greater noctule at the site of
their largest known colony in Europe—an urban park in the Spanish city
of Seville.
The paradoxical truth of the matter is that cities can also serve as
vital habitat for some parrot species. Australian cities host several
native parrots, including the Sulphur-crested Cockatoo. This big, white
parrot, named for its sleek yellow mohawk, is a regular sight around
gardens in Melbourne, Brisbane, Sydney, and beyond. Although their
population is in decline overall, they're not listed as threatened, and
they have found a way to survive successfully in cities. They've
inhabited urban spaces as long as there have been urban spaces, says
Lucy Aplin of the Max Planck Institute of Animal Behavior in Radolfzell,
Germany, and the Australian National University. “Parrots have the
potential, if given the opportunity, to exhibit rapid adaptation to
anthropogenic change.”
In contrast to Monk and Rose-ringed Parakeets, which start breeding
between the ages of one and three years and lay at least three eggs at a
time, Sulphur-crested Cockatoos don't generally breed until they're at
least three or four years old, and they lay just two to three eggs per
nesting season. They're particular about where they nest, seeking out
large cavities in old trees. Yet they've been able to thrive in
Australia's major metropolitan areas.
Certain traits of Sulphur-crested Cockatoos make them quite well
suited to city life. For one thing, they are generalists, feeding on
whatever food they can find—fruits, invertebrates or a discarded chicken
bone. And they're highly intelligent, social creatures capable of
solving problems and teaching their solutions to others. These birds can
build a culture around urban living, passing knowledge through social
networks like humans do. Aplin studies a behavior that has emerged in
Sydney's Sulphur-crested Cockatoos: they've figured out how to open
garbage bins. A group of the birds in southern Sydney first learned to
open the bins, and they transferred the knowledge to nearby cockatoo
roosts. Birds outside the network don't necessarily know how to do it.
Aplin's work has shown that birds on opposite sides of the network have
diverged into subcultures, opening the bins in different ways.
For some imperiled parrot species, cities may be more than just
another comfortable place to call home—they can be a lifeline. Parrots
whose native populations are threatened with extinction are holding on
in some of the world's largest cities. Consider Hong Kong's
Yellow-crested Cockatoos.
During the 1980s and into the 1990s, pet traders exported tens of
thousands of Yellow-crested Cockatoos from their native Indonesia to
Hong Kong, says Astrid Alex Andersson, a postdoctoral researcher at the
University of Hong Kong. Enough birds escaped captivity or were
intentionally released by their owners that they founded a colony in the
city. Although much of Hong Kong is forested, these birds prefer to
nest and feed in the ornamental trees found in the island's urban areas
and don't seem to be outcompeting any native species.
About 200 Yellow-crested Cockatoos live in Hong Kong—approximately 10
percent of the bird's remaining population, says Caroline Dingle of the
University of Hong Kong. Population decline from poaching pressure in
its native habitat led the International Union for Conservation of
Nature to designate the species as critically endangered. Andersson is
studying whether the species has found a useful refuge in the city,
where it's not subject to poaching pressure. “It's possible that these
populations, if you do small things to support them in cities, can
function as species arks—backup populations for the wild ones,” she
says.
![A parakeet sitting in a tree.]()
Credit: Ali Cherkis
Nevertheless, city living isn't all great for parrots. There's
predation: Mori says feral Rose-ringed Parakeets regularly become prey
for raptors, for example. Even for the endangered Yellow-crested
Cockatoo, it'll take further work to determine whether the Hong Kong
populations can actually function as a genetic reservoir or whether city
life has altered them too much to sustain the species. As part of her
research, Andersson is investigating how the city cockatoos differ
genetically from the native population.
A similar question preoccupies Smith-Vidaurre. In the U.S., she is
looking at the complex vocalizations of Monk Parakeets and how they
differ between native and introduced individuals. Each parrot has its
own distinctive voice with changes in the frequency of its squawks. She
found that the introduced parrots have less complex calls than birds in
the native ranges. “Something about their environment might be
constraining their ability to produce or perceive these vocal
signatures,” she says. How permanent are the changes, she wonders? Would
an introduced parrot be able to return to its native range and thrive?
For better, for worse, and sometimes both, parrots have taken over
our cities. Their ability to thrive in our altered habitats is a
testament to what makes these species special and why we should work to
conserve them in the wild while minding the potential impacts of
introduced parrots. They're innovators, problem solvers, socializers and
survivors. That's how they earned our adoration in the first place.
Sometimes it's a joy to stop and marvel at the parrots.