Breeding Behaviour of Black-Winged Stilt, Himantopus himantopus (Linnaeus, 1758) in Agricultural Landscape of Punjab, India

Abstract

During the breeding seasons (2017-2019), the hitherto little known aspects of breeding behavior of Black-winged Stilt, Himantopus himantopus were studied in the ploughed agricultural fields, village ponds and adjacent shallow pools located in rural outskirts in district Ludhiana, Punjab, India. Observations on nest structure, egg laying, incubation, hatching and other behavioural aspects of the parents/chicks were inferred from videorecords, photographs and direct field observations made on 19 clutches containing 59 eggs. In the study area the breeding season extended from April to July. The mean clutch size was 3.29±0.77 (range 1-4, n=19) that differed between the dry ploughed field clutches (3.4±0.70, range: 2-4, n=10) and wet pool/pond sites (2.78±1.09, range: 1-4, n=9). In the dry ploughed fields, the nest scrapes were lined mainly with the wheat rootlets/ straw pieces only. However, the nest material used in/around ponds and pools included predominantly dry twigs, decaying leaves and some thermocol chips. The egg length, breadth, weight, egg shape index and volume (n=54) measured 42.22±2.50 mm, 30.71±1.13 mm, 19.77±2.34 gm, 72.88±3.19 and 20.39±2.36 cm3, respectively. The eggs hatched mostly synchronously after biparental incubation period of 25 or 26 days (n=4). As per traditional method, only 20.34% (12 out of 59 eggs) of the eggs hatched successfully and the hatching success calculated as per the Mayfield Method showed that it was only 2.07% in post-harvest field sites and 36.26% in non-agricultural sites (shallow water pools and edge waters of village ponds). The use of polluted sites as nesting grounds has been opined as a habitat shift and an adaptation in process