Threatened in their homeland, feral Mexican parrots thrive on LA’s
exotic landscaping Native Mexican range for Lilac-crowned Parrot
(purple) and Red-crowned Parrot (red) and introduced range for both
species (green) in southern California. Credit: Diversity and
Distributions (2024). DOI: 10.1111/ddi.13817
During a walk through the Huntington Botanical Gardens with her mother
one morning, Brenda Ramirez was alarmed by the sudden squawks, warbles,
and screeches of troops of parrots flying overhead at great speed in
tight, precise formations.
"I asked my mom what they were," Ramirez recalled of that day 14 years
ago. "She said, 'Mija, they are just like the parrots from Mexico we've
seen in zoos, except for one thing: They are free flying and breed in
the trees along our city streets.'"
Ramirez was entranced by this fleeting glimpse of adaptation by
[1]tropical species in one of the world's greatest asphalt jungles.
Now, at 27, she leads a team of investigators at the Free Flying Los
Angeles Parrot Project based in Occidental College's Moore Laboratory
of Zoology, which aims to resolve a biological puzzle: How did
red-crowned and lilac-crowned parrots establish local urban breeding
populations via the pet trade from Mexico, where both species are on
the brink of extinction?
A potential answer is that Southern California cities have only in the
last 100 years provided these sister species with a resource untapped
by [2]native birds: the fruits and flowers of exotic trees used for
landscaping, according to the team's new [3]report in the journal
Diversity and Distributions.
Their findings add to a growing body of evidence that some
[4]introduced species including these feral parrots can experience
rapid niche shifts beyond what appears to be possible in the forested
regions of northern Mexico they evolved in.
For example, the driest month in Southern California is significantly
drier than any portion of their native habitats in the western and
eastern coastal regions of Mexico, the study says. The timing of the
precipitation here is also different, with a winter rainfall regime
rather than summer rains.
"Artificial irrigation may close the gap between native and introduced
climates," the study suggests, "allowing more year-round vegetation in
Southern California cities than expected given its natural
precipitation levels."
That "urban oasis effect" created by sprinkler watering systems "could
partly explain why introduced parrots do not seem to be spreading
beyond urban centers," it says. "Their intelligence and behavioral
plasticity might further allow them to adapt to urban life."
The look of Southern California's green canopies has changed
significantly since the 1950s and '60s, when developers turned up their
noses at native oaks and sycamores. They chose instead to landscape
their subdivisions, apartment complexes, business parks, shopping
centers and roadways with nonnative trees, including sweet gums,
camphor, carrotwood, fig, and ficus trees—all favored by parrots.
For reasons that are not fully understood, several hundred parrots seek
evening accommodations each night in the limbs of fig and London plane
trees lining a bustling stretch of Rosemead Boulevard in Temple City.
The odd locale is believed to be one of the most populous roosting
sites for parrots in the Los Angeles area.
"It's just cultural memory: They spend all day feeding on the seeds,
berries, and flowers of the surrounding tropical treescape," said John
McCormack, director and curator of the Moore Lab of Zoology, during a
recent visit to the boulevard. "At sundown, they come together here to
rest and sleep."
The parrots are beloved overnighters here, and residents are on
constant alert for poachers. A video of nets in the trees and an
unidentified man slamming captured parrots against a concrete wall
between Rosemead Boulevard and East Las Tunas Drive on Oct. 26 fueled
angry calls and letters to the local Los Angeles County sheriff's
station, City Hall and other government agencies.
It remains unclear whether the man shown in the video was killing some
of the parrots he trapped and taking others with him to sell on the
illegal wildlife market.
Those birds and other introduced species of parrots and parakeets that
have found niches in the clatter and commotion of Southern California
city life are believed to be descendants of released pets, especially
during the 1970s and '80s, when the illegal importation of such wild
birds reached its peak, according to the study.
Red-crowned parrots, whose home range is restricted to the lowlands of
northeast Mexico, were first recorded in the Los Angeles area in 1963.
Since then, the population has swelled to more than 3,000 birds, the
study says.
The number of lilac-crowned parrots, which are endemic to tropical
lowlands in west Mexico and became established locally in the 1980s, is
about 800 birds.
Given that both species are considered endangered in their home ranges
in Mexico due to habitat loss and trapping for the pet trade, local
established flocks have become prized for their conservation potential.
The two species are so similar in size and color that even experts have
a tough time telling them apart. Both are crow-sized, chunky birds that
establish lifelong pair bonds that usually produce one brood per
breeding season.
However, both species have been seen together in the same flocks,
underlining the importance of monitoring the birds for signs of
hybridization that could undermine proposals to reintroduce urban
[5]parrots from Southern California to their native habitats in Mexico.
In the meantime, the Moore Lab Project aspires to become a hub for
urban parrot ecology.
More information: Brenda R. Ramirez et al, Convergent niche shifts of
endangered parrots (genus Amazona) during successful establishment in
urban southern California, Diversity and Distributions (2024). [6]DOI:
10.1111/ddi.13817
2024 Los Angeles Times. Distributed by Tribune Content Agency, LLC.
Citation: Threatened in their homeland, feral Mexican parrots thrive on
LA's exotic landscaping (2024, March 8) retrieved 9 March 2024 from
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References
1.
https://phys.org/tags/tropical+species/
2.
https://phys.org/tags/native+birds/
3.
https://onlinelibrary.wiley.com/doi/10.1111/ddi.13817
4.
https://phys.org/tags/introduced+species/
5.
https://phys.org/tags/parrots/
6.
https://dx.doi.org/10.1111/ddi.13817
