In a world with global travel, animals and plants are finding it
easier than ever to move to new places.
And when they move to new places, sometimes they can take over, becoming an invasive species.
A group of scientists determined
which three bird species are most likely to become an invasive problem.
Let's look at which species, and why they made the list.
Common Starling
This species is native to Eurasia and northern Africa. These birds have been
intentionally introduced to other parts of the world because they eat some agricultural pests.
The Soviet Union installed 25 MILLION nest boxes to attract European Starlings.
And as omnivores they are adaptable to whatever food is available.
The birds easily live alongside humans, so their range has expanded with our range.
Common Starlings are excellent at competing for food, but they have
another way to out-compete native species. Starlings nest in cavities like tree hollows.
The supply of tree hollows is limited and doesn't change quickly. Starlings
can be quite aggressive in defending a cavity, and they are also aggressive
enough to steal a tree hollow from another species. There are an estimated 140 million
Common Starlings in the United States, leaving many fewer nesting sites for other birds.
Red-vented Bulbul
Naturally found in Asia, the Red-vented Bulbul has been introduced to many islands in the Pacific
Ocean. They are aggressive and chase other bird species away from resources. They make bowl nests,
so there is no competition for cavities. But their ability to spread on islands,
where many species already are declining makes them especially harmful. Like on the islands of
New Caledonia, where they are spreading out from urban centers to compete with native species.
The species they are outcompeting don't have anywhere else to go. The Red-vented Bulbul
doesn't have the range or population of the Common Starling, but it has the same ability
to spread alongside humans, so this may be an invasive species in your area in the future.
Common Myna
Another adaptable omnivore that lives alongside humans and nests in cavities, the Common Myna
causes many of the same problems as the Common Starling. But the rate of its expansion makes it
even more of a problem. Both intentional and unintentional introductions have occurred since
the 1700's. Common Mynas have spread to Australia, the United States, the Middle East, and southern
Africa. Australia named this species the most important pest/problem to their native species
in 2008. And this spread was mostly because they are so well-adapted to live in cities.
The scale of intentional introductions was tiny compared to the Common Starling.
Even so, Common Mynas have spread across the world.
Common Mynas are territorial and will chase away other birds from nest sites.
They also sometimes feed on eggs and chicks from other species.
So What Can We Do?
The traits that these birds share are that they are adaptable, aggressive,
and compete for limited resources. It's not clear what can be done about these invasive birds.
The reason they are a problem in the first place is because they are so
GOOD at surviving. The United States poisons over a million Common Starlings each year, but all
that death is only 1 percent of the population, and the population is able to quickly recover.
The National Wildlife Federation has information about combatting invasive species,
but they only talk about NEW invasions, not how to deal with existing problems. Maybe the best
we can do in the future is just preventing new invasive species. It seems likely that
we and our ecosystems will have to adapt to these invasive species, rather than them adapting to us.
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