Unraveling the effects of non-native wildlife

I think we all have heard about the issue of non-native species and how they can interrupt a habitat.

There are many examples of this in both plants and animals. One of the big problems in the plant world is European buckthorn (Rhamnus cathartica). It is a small tree native to Europe, Northwest Africa, and Western Asia. It was brought here by people to be planted as an ornamental tree and has spread rapidly across the country, growing in all sorts of habitats and crowding out native trees and shrubs.

There are also some non-native mammals that were introduced to North America that are considered a major problem. The Norway rat or brown rat (Rattus norvegicus) is a good example. Contrary to its common name, it most likely originates from the plains of northern China and Mongolia. When it was named back in the 1500s, it was incorrectly thought to come from Norway. This animal has spread around the world and has been the cause of disease and contamination of food. If you have ever seen a large rat, especially on farms, undoubtedly you are seeing this non-native rat species.

We have countless non-native insects as well. One that jumps to mind is the Asian lady beetle. Similar to our native ladybugs, the Asian lady beetle was introduced on purpose to North America to control aphids in agricultural crops. It quickly spread across the entire country in just a decade or two. Many believe our native beetle is now extinct or nearly so.

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In the bird world, there are several prime examples of non-native birds being introduced to the United States.

The European starling (Sturnus vulgaris) and the house sparrow (Passer domesticus) are well-known, widespread, and generally disliked by most bird watchers. I often ask people who express their dislike of starlings and sparrows why they feel that way. The response I often receive is simply because they are “not native.” However, when I inquire further, they usually cannot provide any other reason beyond the birds’ non-native status. Interestingly, when I point out that the ring-necked pheasant is also not native, I don’t encounter the same level of animosity, presumably because people appreciate the appearance of the pheasant.

Last week, while leading a photography tour of southern Florida, we spent some time photographing an absolutely stunning bird. A large green parrot-like bird, about 12 inches long, with a dark hood and bright red ring of feathers around each leg. They are amazing-looking birds, and everyone was thrilled to capture some stunning images. While we were photographing, I explained to the group that these birds were not native. They asked casually how they got to Florida since they are native to the south-central part of South America, many thousands of miles away.

These birds were trapped and sold in the pet trade, and people purchased them from pet stores. When they realized that the birds needed a lot of care and tended to be very loud and demanding, many people released them. Naturally, the newly released birds found each other and began to reproduce. Now, large flocks of these birds fly around places like Florida, Arizona, and Texas.

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What I found most interesting is that no one seemed upset that these beautiful birds were not native. There was no outcry of disdain and dislike for these magnificent-looking birds. And that is precisely the problem. People often rely on their emotions and are quick to judge something without any background information or education.

Because of its beauty, elegance, and pleasing appearance, we often think it’s OK and irrelevant whether it is non-native or not. We simply like it. We often fail to consider the scientific or biological ramifications of a non-native bird on a given ecosystem. Nanday parakeets often outcompete other birds for local food sources. Their diet consists of seeds, fruits, nuts, and berries, which are the same food sources for other birds.

While looking through my long lens, I noticed the parakeets spent a lot of time feeding on the seed heads from low-growing flowers. Native ground birds, such as ground doves, now need to compete with the parakeets for the seeds produced by these flowers.

I guess my point is, native vs. non-native species is a tricky subject. It is important we don’t let our emotions get in the way of sound, reasonable, and scientific decisions. Nothing in nature is simple and has clear black-and-white answers. Until next time …

Editor’s note: Stan Tekiela’s NatureSmart column appears twice a month in the Eden Prairie Local News. Tekiela is an author, naturalist, and wildlife photographer who travels extensively across the United States to study and capture wildlife images.

You can follow his work on Instagram and Facebook. He can be contacted via his website at www.naturesmart.com.