Biochemical and environmental insights of declining vulture population in some Asian countries

Traces of diclofenac and its derivative compounds have been found in the carcasses of vultures across India and its neighboring countries, and it is known that the biomagnification of diclofenac from the consumption of infected domestic animal carcasses contributes to vulture mortality. However, reports also indicate that problems associated with their habits and habitats, food and feeding behavior, nesting and breeding, reproduction, epidemic and endemic diseases, and environmental factors, such as high temperatures and cyclones, might also be contributing factors. Adequate information is not available to confirm whether only diclofenac is the primary cause of vulture mortality versus their susceptibility to microbial pathogens, diseases or physiological conditions, such as oxidative stress due to diclofenac biomagnification. Death due to other contaminants or pollutants has also been not adequately studied. So future research may be able to determine whether the biomagnification of diclofenac and other organic/inorganic pollutants or some other factors are responsible for vulture mortalities. Further investigations into the health issues related to life cycles and pathology need to be performed to restore the sharply declining vulture populations in India and across the globe. In this context, India is ahead of other countries in adopting recovery plans for vultures, for which the rate of decline of long-billed vultures is now 16% per year compared to that of oriental whitebacked vultures which is 44% per year.