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On February 15, 2012, we were at Partala (22° 49′ 4.56′′ N; 80° 18′ 33.83′′ E), initiating People’s Biodiversity Register. Partala is situated in Narayanganj tehsil of Mandla district in Madhya Pradesh. The village is surrounded by forested hills on three sides, and a small river flows amidst them. The river banks are surrounded by agricultural fields with scattered trees. The main crops are paddy, wheat, maize, and various pulses. The dominant vegetation in this region is Tectona grandis, Terminalia arjuna, Aegle marmelos, Soymida febrifuga, Madhuca indica, Ficus religiosa, and Butea monosperma. At 18:15 hrs we reached a huge Peepal tree Ficus religiosa, which is one of the roosting sites of the Yellowfooted Green-pigeon Treron phoenicoptera. On reaching, we heard a cacophony of nightjar calls from an adjacent field. It was getting dark and we could only see silhouettes of the nightjars flying erratically, crisscrossing each other above the wheat field. There were around 30–35 birds, continuously calling and sallying on swarms of insects (moths). We identified them as Savanna Nightjar Caprimulgus affinis based on their distinct cweetzz, cweetzz, cweetzz calls. Along with nightjars, small insectivorous bats were also observed feasting on the moths. Two more species of nightjars, namely Indian Jungle Nightjar Caprimulgus indicus and Indian Little Nightjar Caprimulgus asiaticus, are found in this region. However, we could not hear the calls of these species to ascertain their presence in the congregation. The nightjars were scattered across the wheat field, and since visibility was extremely poor, we could not take photographs. We observed this congregation for almost half an hour, after which we could not follow their movements due to nightfall. Ali and Ripley (1983) indicate that the Savanna Nightjar forms loose flocks of 7 or 8 while undertaking local movements. Similarly, Rasmussen and Anderton (2005) also state that Savanna Nightjars ‘often fly in groups’. These anecdotes suggest the gregarious tendency of Savanna Nightjars. However, large congregations of Savanna Nightjars, as recorded by us, have not been published. A similar observation was made by P. Jeganathan (pers. comm.) in Sri Lankamalleshwara Sanctuary, Andhra Pradesh, on June 16, 2001. He observed 15 individuals, probably of Indian Little Nightjar Caprimulgus asiaticus, near an agricultural field foraging on insects. The European Nightjar Caprimulgus europaeus is known to form loose parties or flocks of 6 to 20 individuals on their passage to autumn migration (Ali and Ripley 1983). The only known gregarious species of nightjar is the Sand-colored Nighthawk Chordeiles rupestris of South America, with flocks of up to 50 individuals observed (del Hoyo et al. 1999). Del Hoyo et al. (1999) also mention that during migration and in the non-breeding season, more than one species of nightjar join to form groups of more than 20 birds, gathering at good food resources, such as grazing animals, animal corrals, lights or fires, or at insect swarms or termite emergence. Some species of nighthawk, such as Common Nighthawk Chordeiles minor and Lesser Nighthawk Chordeiles acutipennis, often forage in large flocks of several hundred birds. On February 16, 2012, we collected some moths which were identified as Helicoverpa sp., a common pest on wheat. King (1994) mentions that “Adult moths emerge from just after dark to midnight and crawl onto a plant or vertical substrate where their wings dry”. Williams et al. (2011) mentions that “Night birds such as the Tawny Frogmouth and nightjars feed on Helicoverpa moths as they are also active at night.” These probably explain the reason for the large congregation of Savanna Nightjars sighted by us at Partala. It is very likely that such assemblages are common in this region. However, this needs further investigation. |
