Black wildebeest
Where it lives alongside the blue wildebeest, the two species can hybridise, and this is regarded as a potential threat to the maintenance of the species. The black wildebeest was once very numerous and was present in Southern Africa in vast herds, but by the end of the 19th century, it had nearly been hunted to extinction and fewer than 600 animals remained. A small number of individuals was still present in game reserves and at zoos, and from these, the population was rescued.
Black-and-white warbler
The black-and-white warbler breeds in northern and eastern North America. It ranges from the Northwest Territories to the northwest and Newfoundland and Labrador to the northeast, to North Carolina to the southeast and Texas to the southwest. This species is migratory, wintering in Florida, Central America, and northern South America down to Peru. The IUCN estimates the extent of occurrence, or range, to be 11 500 000 km.