Communal roosting of Black-winged Kites Elanus caeruleus and possible influence of rainfall and wheat cultivation

The Black-winged Kite Elanus caeruleus is widespread across the Indian Subcontinent, South-East Asia, Sub-Saharan Africa, parts of northern Africa, and Iberia. It is relatively common across large parts of its distribution range. Its population is increasing in the Iberian peninsula and northern Africa, and its distribution is expanding to other parts of Europe (Ławicki & Perlman 2017; Llorente-Llurba et al. 2019). In India, however, the recent State of India’s Birds Report 2020 estimated a 34.6% (CI ±10.1) decline in its population over the past 25 years, and a 5.7% (CI ±2.3) decline over the past five years (SoIB 2020). Local population sizes of this species are known to fluctuate as it moves large distances in search of sporadically abundant prey. Such movements are expected to be linked to rainfall, and booms in rodent populations (Naoroji 2006; Llorente-Llurba et al. 2019; Kemp et al. 2020). Despite the charisma of this species, as a raptor, and it widespread occurrence, it remains poorly studied outside Europe (Naoroji 2006). The Black-winged Kite prefers open habitats, such as savannah grassland and agricultural fields, which have widespread grassy or herbaceous vegetation with scattered trees (Kemp et al. 2020). It is commonly found in agricultural areas of seasonal crops interspersed with trees. It predominantly feeds on rodents, but also eats insects and small birds (Naoroji 2006). It is a solitary forager, but known to roost communally (Parejo & Aviles 2001). Communal roosting behaviour of raptors is of much interest to ornithologists and conservationists, but there are few first-hand reports of communal roosting in Black-winged Kites (Table 1).

In this note we describe one of the largest communal roosts of the Black-winged Kite. We present data on rainfall and agricultural cultivation for the landscape surrounding the roost. We present perceptions of local farmers about the correlation between rainfall, wheat cultivation, and rodent abundance, and put forth a hypothesis about the conditions that may have led to such a large aggregation of the Black-winged Kite.