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Not all bird species present in North America are native to North America. Other species have found their way over here either on purpose or by accident as humans moved from place to place. These non-native species can be the root cause of a lot of problems in ecosystems. Not all non-native species are a threat, but many are and affect the survival rate of our native birds.
In the United States, we have about a hundred species of bird that are not native.1 Let’s take a look at a few:
Starlings
These birds were purposefully released in New York City by a fan of Shakespeare. When released, they were 120 birds. Today, they number 46 million. They wreak havoc on our environment. They are believed to cause $800 million worth of damage to crops every year. They also compete with native birds for nests.1 They also carry diseases that affect birds, humans, and other animals.2
Mute Swan
These birds were introduced in the 1800s and have proven to be responsible for ruining ecosystems. They have big appetites and would eat so much of the aquatic vegetation that it didn’t have time to recover in order to provide food for other species in that environment.3
Rock Pigeon
These were brought over in the 1600s. These birds are often found in cities. They don’t wreak the same havoc on the environment as the Mute Swan or the Starling, but they do carry diseases and parasites that can pose a risk to native species.1&3
House Sparrow
These were also introduced in New York City – as a solution to handle another problem. They were released to handle the caterpillar population that was affecting basswood trees. They used to be found in Europe and Asia, but now can be found worldwide. They affect native species through competition for nest boxes.1
Do you know of any other invasive species in the United States? Reply to this email or share with us on social media!
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