Our Invasive Wildlife Species

Oct 22, 2018

You may have heard of some invasive wildlife species here in the Northwoods, but do you know our native species have invaded some other countries as well?

In this week's episode of Wildlife Matters, the Masked Biologist looks at one of our more insidious invasive species here in Wisconsin, as well as species of our that have invaded Europe.

If you haven’t heard, we occasionally have problems with pigs and boars here in the Northwoods. Feral pigs were sighted on state land near Rhinelander in 2007, and on a Vilas County trail camera in 2011. From time to time, I have people tell me that they have seen a pig either in person or on a trail camera. It was not widely advertised, but about a year ago a Russian boar that escaped from captivity was shot southwest of Rhinelander. While escapes of European or Russian boars occasionally occur, the more common animals you are likely to see are feral pigs. They either move into the area along river courses, escape from captivity, or they originated on a farm and escaped, eventually becoming feral. If you happen to see wild pigs, they are legal to shoot with a small game license but you should definitely contact the local warden or state wildlife biologist so they can take a blood sample and test for diseases.

Feral pigs are one example of invasive wildlife species that can cause a large amount of damage. Since this country was settled, wildlife has been imported by citizens, government officials, crop producers, the pet trade, shipping containers, and other means. Some of these animals, like European starlings, may not have a great impact on our daily lives. Others, like the cane toad or python in Florida, are killing wildlife, pets, and even injuring people. As a wildlife biologist, I closely watch the concerns our country has about invasive wildlife species. According to the National Wildlife Federation, over 40% of our country’s threatened and endangered species are at risk because of an invasive species. Invasive wildlife species are successful because they are usually very good at surviving and reproducing. They are willing to eat almost anything, live almost anywhere, and they have no natural predators. They have an unfair advantage and a good head start, and once numbers get away from wildlife managers, they are almost impossible to control.

Before we drown in a pool of our own tears, though, we should consider the possibility that we have inflicted similar monstrous critters on other continents. For example, there is a furry marauder that is overtaking the British Isles, and there seems to be no stopping it—our own Eastern or gray squirrel. The raccoon is also marching across the globe, terrorizing Japan and Germany so much so that there is an industry devoted to trying to exclude them from homes and capture and destroy them whenever possible. I did a bit of research, and found an information clearinghouse website for European invasive species. DAISIE, which stands for Delivering Alien Invasive Species Inventories for Europe hosts a website called www.europe-aliens.org. It is an excellent website, and if you know your binomial nomenclature, you will have no trouble using it.

I checked out the website’s list of the top 100 worst invaders, and recognized some creatures we appreciate here in the United States. The Canada goose, American mink and Ruddy duck joined raccoons and squirrels.  Further down the list were the wood duck, blue-winged teal, and American robin. These are serious threats to wildlife across Europe, and are the subjects of extensive control programs. The ruddy duck, for example, has been the target of extensive control efforts since the early 1990s, and their numbers continue to spread. They apparently displace a native duck that can interbreed with Ruddies, which puts it at risk for extinction. So factors like increased travel and trade around the globe, climate change, and lack of habitat management will likely only result in increasing numbers of invasive species everywhere.

Striving to make new things familiar and familiar things new, this is the masked biologist coming to you from the heart of Wisconsin’s great Northwoods.