A Study of Resourse Selection by the Black Kites in the urban landscape of National Capital Region, India
Awarded to: Nishant Kumar, Wildlife Institute of India, Dehradun for his MSc. dissertation to Saurashtra University, Rajkot, Gujarat
Black Kites, Milvus migrans, are the scavenger and predator raptors of the old world. In India they are synanthropic and perform the ecological role of city scavengers. Abundance and distribution of these birds has suffered change due to rapid infrastructural changes in the developing cities which likely limit or change spatial layout of the available habitat and food. Many cities in the old world (London, Cape Verde, Istanbul) have experienced decline in the population of Milvus kites owing to rapid urbanization. Indian sub-continent almost lost its main scavenger, White Backed Vultures, in the last century. After this loss, existence of Black Kites, the most abundant raptor of the old world proves very vital.
From December 2012 till April 2013 Nishant’s study focused on (a) Estimating the abundance of Black Kites on the Ghazipur dump site and the abundance of nesting pairs in National Capital Region (NCR). (b) Evaluating factors influencing nesting habitat selection combined with a broad understanding of its foraging habits. (c) Estimating nest survivorship in the urban landscape.
These parameters were examined at 24 selective sample quadrats, each measuring 1 km2, in NCR. Nests were searched intensively at each site while trying to develop and test a new method to count the kites on the Ghazipur dump using photographic counts and software ImageJ. Data from 116 nests and nest site covariates were used to model nest survivorship under Known Fate scheme in Programme MARK.
Nishant and his team estimated the current abundance of nesting pairs of Black Kites at 7 sample sites. The mean nest density was 15 nests/ km2 (se: 7.94) and it ranged from 0 nests / km2 in Mahipalpur to 67 nests / km2 in North Campus area. Nesting kites were selective while choosing a nest site, as evident by significant partial correlation between nest density, food index and green cover (partial r = 0.64, p = 0.06). The sites at the best trade-off between green cover and food availability (North Campus and Delhi Zoo) had the highest nest densities. While developing a new methodology, they estimated more than 2400 kites on the Ghazipur dump. Through behavioural observations and broad examination of regurgitated pellets, they could confirm scavenging as well as predacious nature of Black Kites. The overall probability of a nest to produce a viable fledgling was 0.45 (95% CI: LCL- 0.21, UCL- 0.61). The nest survivorship was stage specific for pre-laying (0.60, se: 0.014), incubation (0.84, se: 0.014) and nestling stage (0.90, se: 0.009). The lower survival probability of 0.60 at pre-laying stage is likely because of surplus nest formation at sites with good foraging opportunities.
Technical Paper published in BIRD STUDY, Journal of British Trust of Ornithology, titled, “Density, laying date, breeding success and diet of Black Kites Milvus migrans govinda in the city of Delhi (India)” Nishant Kumar, Dhananjai Mohan, Yadvendradev V. Jhala, Qamar Qureshi (Wildlife Institute of India, Post Box # 18, Chandrabani, Uttarakhand 248001, India and & Fabrizio Sergio (Estacion Biologica de Donana-CSIC, C/ Americo Vespucio, s/n, Sevilla 41092, Spain)
Project findings or conclusion
This ideal model system of a top trophic level species living in such close contact with humans is extremely rare and almost non-existent in the wild in terms of sample size availability and ease of manipulative experiments. The tolerance of the species for nest condition manipulations observed during my field work will make the ecological inferences of this study accurate and applicable. There are added benefits of these birds being a city scavenger and a valid model to propagate conservation education amongst the general in India.