[2] Most authorities refer to two major clades: Gypaetinae (Gypaetus, Gypohierax and Neophron) and Aegypiinae (Aegypius, Gyps, Sarcogyps, Torgos, Trigonoceps and possibly Necrosyrtes).

[4][5] Despite the name of the group, "Old World" vultures were widespread in North America until relatively recently, until the end of the Late Pleistocene epoch around 11,000 years ago.

Historically, it was thought that this was due to feeding habits, as feathers would be glued with decaying flesh and blood.

However, more recent studies have shown that it is actually a thermoregulatory adaptation to avoid facial overheating; the presence or absence of complex feathers seems to matter little in feeding habits, as some vultures are quite raptorial.

[9] Within Africa, a combination of poisonings and vulture trade (including use as bushmeat and traditional medicine) account for roughly 90% of the population declines.

[9][10] Vulture populations are particularly vulnerable because they typically feed in large groups and easily fall victim to mass poisoning events.

[12] Bans on diclofenac in veterinary practices have been implemented in Pakistan and Nepal and selling or using the drug in India can result in jail time.

[13] But while the Government of India banned diclofenac, over a year later, in 2007, it continued to be sold and remains a problem in other parts of the world.

[16] In Kruger National Park, white-backed vultures will be eradicated in the next 60 years if poisoned carcasses are not detected and neutralized.

Park officials often lack the training to identify toxic chemicals before it is too late and calling on average community members to turn in perpetrators reports is challenging if financial incentives to do so are insufficient.

As vultures play an important role in ecosystems, their population decline can have cultural, public health, and economic implications for communities.

[19] For communities such as the Parsi, who practice sky burials in which human corpses are put on the top of a Tower of Silence, vulture population declines can have serious cultural implications.

[10] Poison response training would be an important implementation in conservation efforts because this is one of the most prevalent threats to vulture populations.