Breeding Habits of Water Birds

976 Words2 Pages

Chapter 1. INTRODUCTION Many species aggregate for feeding, roosting and nesting activities, which are prevalent among water birds (Weins, 1992). Why animals form breeding colonies is a major unresolved question in evolutionary biology. The topic continues to stir lively debate (Danchin & Wagner 1997, Tella et al., 1998) and has been the focus of long term studies (Hoogland 1995; Brown & Brown 1996; Danchin et al. 1998). One of the principal issues has been whether colonies form due to limited breeding habitat; with animals forced into nesting aggregations at a nest cost, or result from social benefits of clustering (Food finding, reduced predation; Lack 1968; Alexander 1974; Hoogland & Sherman 1976; Wittenberger 1981). The nesting patterns in birds ranges from widely spaced solitary nesters to densely packed colonies of hundreds of individuals. Colonial nesting occurs in 29 of the 129 avian families (Lack, 1968). Colonial nesting is an important feature among a majority of the members of the Pelicaniformes and Ciconiformes (Ali & Ripley, 1987, Burger, 1981). The nesting colonies of these birds that represent spatial and temporal clumping of nests are popularly referred to as Heronries. Colonial waterbirds face significant threats to the long-term stability of their populations and habitats due to such impacts as the destruction of freshwater wetlands, destruction and degradation of coastal ecosystems, depletion of the forage base in freshwater, coastal, and marine ecosystems, contaminants, sea level rise, and various conflicts with human land and resource use. For some species, these threats have resulted in declines in numbers. In other cases, these disturbances have resulted in colonial waterbird species becoming nuisance... ... middle of paper ... ...The endangered Lesser Adjutant Storks (Leptoptilous javanicus) also breed in Bhitarkanika Wildlife Sanctuary which has recently been identified as an Important Bird Area (IBA) of the country. The heronry is located in an island covered with mangrove vegetation. Enhanced foraging due to the presence of abundant foraging areas in and around the heronry in terms of wetlands and agricultural fields, decreased predation due to the remoteness of the nesting site, are supposed to be the major factors in governing the largest congregation of waterbirds in the heronry. So far, there exists no empirical ecological data on the heronry. Hence it is felt imperative to study the breeding biology of the nesting birds, resource exploitation in terms of nest material and food, nutrient requirements of the breeding birds, change in the land use pattern in foraging areas if any,

More about Breeding Habits of Water Birds

Open Document