The endangered southwestern willow flycatcher (Empidonax traillii extimus) is a small migrant bird that breeds in southwestern United States. According to a 2000 study published in "The Auk," the journal of the American Ornithologists' Union, one-third of tagged southwestern willow flycatchers moved between breeding sites, while two-thirds return to the same breeding sites. The study
suggests that when breeding, southwestern willow flycatchers act as a metapopulation, which is a bigger group of connected populations of a species. This behavior favors genetic diversity within the subspecies Empidonax traillii extimus.
White nose syndrome (WNS) is a fungal disease that has negatively affected many bats species in northeastern USA. Since 2006, populations of little brown myotis (Myotis lucifugus) declined more than 90 percent. This bat species is not globally endangered, but it is critically endangered and can become extinct in the northeastern U.S. As of May, 2011, researchers at the American Museum of Natural History are studying the relation between the disease and the genetic variation found among members of this species.
Endangered tree frogs Leptopelis ragazzii, L. vannutelli and L. susanae are endemic to Ethiopia. A 2011 study published in Endangered Species Research analyzed the distribution of Leptopelis species in Ethiopia, as well as the effect of deforestation and habitat degradation on the populations size. Although theoretically protected in reserves, Leptopelis tree frogs are vulnerable to habitat loss in Ethiopia.
Right whales are members of the genus Eubalaena, one of the most-endangered whales. A 2001 study published in "Molecular Ecology" analyzed mitochondrial DNA from the North Atlantic right whale(Eubalena glacialis) and the southern right whale (Eubalena australis) found in different locations. Researchers concluded that E. glacialis from the North Pacific are more closely related to E. australis than to North Atlantic E. glacialis.