Extinct & Endangered – pt.2

The International Union for Conservation of Nature (IUCN) gathers data through research and field projects on all known species of plants and animals.  They work to educate people on conserving nature and sustainably using natural resources.  The IUCN publishes a document known as The Red List providing the conservation status of all species.  There are nine possible levels including Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, Extinct, Data Deficient, and Not Evaluated.

An endangered species is one that is likely to become extinct in the near future, either world-wide or locally in a known range.  Critically endangered species are at extreme risk of extinction in the immediate future.  A species is vulnerable when its population and breeding numbers are at risk, but have a chance to improve.  Several factors considered are the current population size, how fast the population has increased or decreased over a short period of time, whether breeding rates are high or low, and what threats exist from habitat loss, poaching, and invasive species.

The Eskimo curlew, Numenius borealis, spends northern hemisphere summers breeding on the Alaskan and western Canadian tundra.  As the weather turns colder, they migrate to Argentina by flying east to the Atlantic Ocean, and then south.  Although nests are built on open ground, they are difficult to find and study.  Food includes berries, insects, and snails, but incubation and rearing habits have never been clearly identified.  During migration in the mid-1800s, populations would darken the skies as tens of millions of birds followed the warmer weather.  Eskimo curlews were hunted on both continents year-round.  If a bird was wounded, the other flock members would circle back, becoming additional targets for hunters.  Development cuts up large breeding areas to smaller sections reducing food sources and enabling predators to severely impact populations.  The species is listed as critically endangered, although there has not been a confirmed sighting since 1963.

The proboscis monkey, Nasalis larvatus, another endangered species, is found mostly in the mangrove forests in Borneo; it is one of the largest monkeys native to Asia.  Living in swamps and lowland areas along rivers, they are excellent tree climbers and swimmers, having the ability to swim underwater for short distances.  Their large noses, smaller in females and upturned in juveniles, are thought to make their calls louder and more attractive to the opposite sex.  They communicate through a variety of calls to signal alarm and threat warnings, and to keep infants and group members close.  Rapid loss of habitat to logging and oil palm plantations, plus hunting for their meat, considered a delicacy in some areas, have reduced populations by more than half in the last fifty years.

^{Whooping Crane, Grus americana, by Trish Gussler, May 2018; Whooping Crane, Grus americana, by Diana Robinson, Mar 2018; Whooping Crane, Grus americana, by Evangelio Gonzalez, Dec 2018}

The whooping crane, Grus americana, is one of only two crane species native to North America, and it remains on the list of endangered species although it may be starting a comeback.  Birds build a nest on a slight rise in a marsh where one or two eggs are laid.  Normally only one egg survives, and the juvenile stays with the parents for six to eight months.   Populations were never large, but prior to European settlement, there were an estimated 10,000 birds.  Hunting for meat and feathers, in addition to predation and habitat loss, drastically reduced population size from the mid 1800s to the early 1900s.  Through several programs of captive breeding, wetland management, and extensive efforts to assist the juveniles in learning migration routes by following ultralight aircraft, populations have rebounded to about 600 today. 

^{JSNM Extinct Endangered display; JSNM Eskimo curlew, Numenius borealis; JSNM Proboscis monkey face, Nasalis larvatus; JSNM Proboscis monkey, Nasalis larvatus; all pictures by DonArnold, Feb 2024}

In the final blog on this topic, we will take a look at a few success stories – species that have recovered with populations that continue to get stronger.  Many nature museums have information and extinct species on display to learn from.  All of the above species, and more, can be found at the Jurica-Suchy Nature Museum, so please stop by, or visit a local nature museum where you live.