Glassy eyes stare down
from vibrant yellow crowns,
solemn statues lined up
for shady shopping trips
to markets masked with colour.
Wild or caught
traded or trapped,
to capture this scene.
Sifting carbon through feathers
we sort fruits from nuts
and plants from seeds,
grounding traffic through tests
to give flight to future fancies
of silent, empty cages.
This poem is inspired by recent research, which has shown that stable isotope analysis can be used to help combat the illegal trade of cockatoos.
The yellow-crested cockatoo is a critically endangered species from Indonesia and East Timor with a global population of fewer than 2,500. There is a global ban on the trapping and international trade of yellow-crested cockatoos that have been caught in the wild. Despite this, in Hong Kong it is legal in some cases to sell captive-bred birds; however, it is difficult to differentiate a wild-caught from a captive-bred cockatoo just by eye. This means that illegally caught yellow-crested cockatoos can be laundered in the legal market by claiming they have been bred in captivity.
This new study has identified a novel forensic tool for differentiating between wild and bred cockatoos, by making use of stable isotope analysis. Stable isotopes are alternative forms of elements with different molecular weights that are found naturally and do not decay radioactively. Stable isotope analysis of elements such as carbon, nitrogen, and sulphur is used in ecology to trace the flow of nutrients through food webs. By using this technique on the feathers from Hong Kong’s wild, yellow-crested cockatoo population and on feathers from pet cockatoos owned by private individuals, the researchers in this study have shown that both stable carbon and nitrogen isotope values differed significantly between wild and captive cockatoos, indicating consumption of different plant and protein types in their diets. Enforcement officials could apply this test in the future to determine whether a cockatoo has been raised in the wild or in captivity. This research therefore presents a powerful tool for government authorities in their efforts to regulate wildlife trade, both for yellow-crested cockatoos and other endangered species as well.