Saving two birds with one stone

Across the planet, poachers have reached into the last remote habitats to harvest wildlife populations used for clothing, eaten, or kept as pets in faraway cities. In some cases, the traded organisms have escaped and are now thriving in their introduced habitats.

The exhaustive international trade of wildlife has pushed many species to the brink of extinction. Coincidentally, many of the same species have been introduced to urban centres or wilderness areas outside their natural ranges. Ironically, a recent study shows that these introduced populations may provide hope for these threatened species. 

A research team from Hong Kong and Australia identified 49 globally threatened species (listed by the International Union for the Conservation of Nature as Vulnerable, Endangered, or Critically Endangered) which have established introduced populations outside their native distribution. These include amphibians, reptiles, mammals, and birds, as well as insects and plants, with introduced populations found on all continents except Antarctica.

One example is the Yellow-crested Cockatoo (Cacatua sulphurea), a species in peril due to extensive pet trade. Many of these pet birds were accidentally or deliberately released in their new environments and as a result about 200 of them, an estimated 10% of the bird's global population, are now found on Hong Kong Island although the native range of them lies in Indonesia and East Timor.

Reintroduction of this species to its native range in Indonesia and East Timor could help to buffer populations there, which are rapidly declining due to poaching.

In addition to the reintroduction of birds to their native range harvesting of introduced cockatoos in Hong Kong could offset pressure on their native counterparts. Both approaches could also eliminate threats the introduced population might pose to native species in its introduced environment, such as monopolising nesting sites and triggering population declines of local birds.

Combined, augmenting declining populations in their native ranges and eliminating the threats to native ecosystems could save two birds with one stone. This creative tactic could be essential to save species imperiled by wildlife trade as well as eliminate threats the same species pose in their adopted territories.