The absolute best place in the entire world to see a golden-winged warbler is north central Minnesota.

There are nearly 140,000 golden-wings in the world, scattered from here east through the Great Lakes states to the Appalachians. During nesting season we host about 50% of them.

The species is listed as near-threatened. That means the warblers basically are close to being endangered in the near future. They are dependent on our conservation efforts to prevent them from becoming vulnerable.

And a vulnerable species, categorized by the International Union for Conservation of Nature (IUCN), is threatened with extinction unless the circumstances threatening its survival and reproduction improve.

Vulnerability is caused mainly by loss of preferred habitat.

Defining the conservation of animal life as well as achieving it is complicated.

The IUCN, established in 1964 with headquarters in Switzerland, "is the global authority on the status of the natural world and the measures needed to safeguard it," according to its website. It has 1,400 member organizations from 170 countries. Its Red List is seen as the most authoritative guide to the conservation status of thousands of plant and animal species.

Fourteen bird species either resident or breeding in Minnesota, or occasional visitors here, join the warbler in the Red List's near-threatened category.

They include king rail, greater prairie-chicken, Northern bobwhite, black scoter, common eider, piping plover, ivory gull, Bell's vireo and cerulean warbler. The warbler, vireo and plover nest in the state.

Most Minnesota birds are listed as species of least concern. Their populations are stable, threats distant.

Categories go from least concern to near-threatened, to vulnerable, then endangered, critically endangered, extinct in the wild (live captives), and extinct period.

Minnesota sees three vulnerable species — long-tailed duck, snowy owl and rusty blackbird. Vulnerable means at high risk of unnatural (human-caused) extinction without human intervention.

Whooping cranes, occasional visitors here during migration, are an endangered species, at high risk of extinction.

We have or see no species listed as critically endangered. The single extinct species once seen here is the passenger pigeon.

There are 10,999 bird species in the world according to the IUCN. Of those, 10,947 have been assessed. Five species are extinct in the wild, 233 critically endangered, 460 endangered, 798 vulnerable, 1,001 near-threatened, and 8,460 are of least concern. For 52 species there is insufficient data.

To sum up, about 9,500 species are not threatened at the moment, while about 1,400 species are considered to be under threat of eventual extinction. Habitat loss is the greatest threat to any species.

The golden-winged warbler nests in early successional woodland, the regrowth of timber-harvest or burned land. It is unlikely to be found in coniferous or mature woodland. Interbreeding with the blue-winged warbler is a problem.

The bird is a "species of management concern," according to the U.S. Fish and Wildlife Service (USFWS). That agency allocates money to states for creation and restoration of succession habitat.

A request to move the golden-winged warbler to the next level of concern — vulnerable — was made in 2011. A status assessment is due to be complete in 2024, according to Georgia Parham of the USFWS Great Lakes region offices in Indiana.

"The assessment is a rigorous evaluation of the status of the species, including an examination of threats and conservation actions," she wrote in an e-mail. (It should be rigorous if it takes 13 years.)

"The assessment will help inform our determination whether listing is warranted for the golden-winged warbler."

The species has an annual decline throughout its range of 9%, according to data from breeding bird surveys, a yearly state census conducted by volunteers.

Lifelong birder Jim Williams can be reached at woodduck38@gmail.com.

Whooping crane review

The whooping crane, by the way, is scheduled for a population status review this year. That is required by law for all species listed in the Endangered Species Act. Total population of the crane was 657 in 2021.

The proposed review has raised concern among some bird conservation organizations. They fear reduction of the protection level offered if the present endangered status is changed to threatened, one notch lower. They believe the crane population status should be left alone.

IUCN members from U.S.

Here are examples of the 138 U.S. members of the International Union for Conservation of Nature (IUCN/Red List): International Crane Foundation. National Wildlife Federation, the Nature Conservancy, Wild Sheep Foundation, Lincoln Park Zoo, Cornell Botanical Gardens and the Pew Charitable Trusts.