Storks frequently rest on their heels in this ungainly position. The forward bending leg joint, frequently called the "knee" is homologous with the "ankle" between the tibia and tarsus. This is why it bends forward. The true knee in birds is located at the very top of the tibia. This species takes up to four years to reach full maturity. Males and females are similar although males are marginally larger. This is an adult showing pink tertials which give this species its name. A nearby nesting colony was situated in Mesquite (Prosopis juliflora). This species is listed as "Near Threatened" by IUCN. Declines have been attributed to hunting, wetland drainage and pollution; but populations in India appear to be relatively secure. Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA | hand-held (no adapter).
Reference:
Hancock, J.A., Kushlan, J.A. and Kahl, M.P. (2010) Storks, Ibises and Spoonbills of the World. Christopher Helm Publishers, London.