Protected, Endangered or Threatened:
Understanding the Classification of Illinois’ Wildlife

State-endangered species, including the Blanding’s turtle (Emydoidea balndingii), state-threatened species, such as the eastern small-footed bat (Myotis leibii) or Illinois protected species, including Illinois’ state animal the white-tailed deer (Odocoileus virginianus)—three classifications of wildlife commonly mentioned in OutdoorIllinois Journal articles. What do they mean? Endangered, threatened and protected classifications are tricky and often have complex and intertwined regulations.

Endangered and Threatened Species

Under the Illinois Endangered Species Protection Act, plants and animals can be placed in two categories, endangered or threatened, determined by their level of treats to their long-term survival. It is important to note that the definitions within this article apply on a state level and not federal. Under the Federal Endangered Species Act of 1973, definitions for these categories slightly vary from Illinois’.

In Illinois, the term endangered applies to species of plants or animals that are in serious danger of extinction in all or mostly all of the territory it lives in. The term threatened applies to animals or plants that are likely to become endangered in the near future. According to the 2020 Checklist of Illinois Endangered and Threated Animals and Plants, Illinois lists 19 fish, 3 amphibian, 9 reptile, 23 bird, 5 mammal, 47 invertebrate, and 246 plant species as endangered. Additionally, 17 fish, 6 amphibian, 9 reptile, 6 bird, 3 mammal, 6 invertebrate, and 66 plant species as threatened.

Protected Species

By authority of 520 ILCS 5/, known as the “Wildlife Code,” most wild birds and wild mammals, including all of their parts and nests, are protected. Protection does not account for a species’ current population size or distribution in habitat range. Additionally, protection is used to prevent overhunting or removal of certain species in the state.

Evaluating Species for E/T Listing

Illinois Department of Natural Resources’ Endangered Species Program Manager Joe Kath identified the six criteria used in evaluating if a species warrants listing as endangered or threatened in Illinois.

1. Species or subspecies designated as federally endangered or threatened
2. Species proposed for federal endangered or threatened status that occur in Illinois
3. Species that formerly were widespread in Illinois but have been nearly extirpated from the state due to habitat destruction, collecting, or other pressures resulting from the development of Illinois
4. Species that exhibit very restricted geographic ranges of which Illinois is a part
5. Species that exhibit restricted habitats or low populations in Illinois, or
6. Species that are significant disjuncts in Illinois i.e., the Illinois population is far removed from the rest of the species’ range

Overlapping Classifications

With these definitions laid out, it’s important to understand how they apply to wildlife in Illinois. Given the varying parameters of each definition, it is possible to have some overlap (see graphic below). For example, the gray wolf (Canis lupus) is listed as both endangered, meaning at risk for extinction in Illinois, and protected, meaning listed under the protection of the Wildlife Code. However, the lake sturgeon (Acipenser fulvescens), which is an endangered species of fish in Illinois, cannot be listed as protected as the Wildlife Code pertains only to wild birds and mammals.

For more information on the history of the Illinois Endangered Species Protection Act, read OutdoorIllinois Journal’s November 2023 article Illinois Endangered Species Protection Act Celebrates 50th Anniversary in 2023. For additional information about Illinois’ Wildlife Code and its protection of animals, check out OutdoorIllinois Journal’s November 2023 article Coexisting with Urban Wildlife.

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Kaleigh Gabriel is a Wildlife Outreach Specialist with Lewis and Clark Community College, working out of the Illinois Department of Natural Resources building to assist the Division of Wildlife Resources. Growing up just between Sangamon and Christian counties, she spent a lot of her time hunting and fishing in Illinois. She received her bachelor’s degree in writing/journalism from Manchester University, Indiana.