Great Indian Bustard Ardeotis nigriceps is currently listed as Endangered under criterion C2a(ii) because it was thought to have a population of 250-999 individuals, which is suspected to be declining (at an estimated rate of 20-29% over 10 years) on the basis of past observed declines and ongoing threats, primarily hunting pressure in some areas and the conversion of grassland habitats to cultivation and pasture, accompanied by other factors such as increased pesticide usage and disturbance.
This species’s population has declined from an estimated 1,260 individuals in 1969 (Dharmakumarsinhji 1971 in Dutta et al. 2010) to c.300 individuals in 2008 (Dutta et al. 2010). A calculation of the rate of decline over three generations (47 years) using these data, and assuming an exponential trend, suggests that the species has declined at a rate equivalent to c.82% over 47 years. This indicates that the species may be eligible for Critically Endangered under the A criterion.
Given the latest estimate for the number of individuals of this species, it is possible that the population includes fewer than 250 mature individuals. If this were found to be the case, the species could qualify for Critically Endangered under criterion C1, on the basis that it is also undergoing a continued decline of at least 25% over 16 years (one generation).
Population viability analysis carried out by Dutta et al. (2010) suggests that the remaining sub-populations are very susceptible to the harvesting of adult birds, and that present levels of off-take are unsustainable. Dutta et al. (2010) also point out that threats posed by infrastructure development, such as collisions with road vehicles and powerlines, exacerbate the situation.
It is proposed that the species be uplisted to Critically Endangered under criteria A2a, A3c,d, A4a,c,d on the basis that a decline of at least 80% has occurred over the last three generations and is projected to continue owing to continued hunting pressure and ongoing habitat loss and degradation. Comments on this proposed uplisting would be welcomed, and further information is sought, particularly on the number of mature individuals in the population.
Dutta, S., Rahmani, A. R. and Jhala, Y. V. (2010) Running out of time? The great Indian bustard Ardeotis nigriceps – status, viability, and conservation strategies. Eur. J. Wildl. Res. Published online: 24 November 2010.