AVIS-IBIS

Birds of Indian Subcontinent

Nesting Ecology of the Grey-Headed Fish-Eagle At Prek Toal, Tonle Sap Lake, Cambodia

Publication Type:Journal Article
Year of Publication:2010
Authors:Tingay, RE, Nicoll, MAC, D. Whitfield, P, Visal, S, McLeod, DRA
Journal:Journal of Raptor Research
Volume:44
Issue:3
Date Published:2010
ISBN Number:0892-1016
Keywords:Accipitridae, Cambodia, Corvidae, Corvus, Corvus corone, Haliaeetus, Haliaeetus ichthyaetus, Ichthyaetus, Ichthyophaga, Ichthyophaga ichthyaetus
Abstract:Abstract Little is known about the ecology of the Grey-headed Fish-Eagle (GHFE; Ichthyophaga ichthyaetus) despite it being a globally near-threatened species in apparent decline. We here present the first quantitative information on nesting ecology of this species, in a regionally significant population at Prek Toal, part of the seasonally flooded swamp forest surrounding the Tonle Sap Lake, Cambodia. We found that GHFE selected trees as nest sites that had an open crown structure and were relatively tall. Grey-headed Fish-Eagles preferred nesting closer to permanent water than expected, but the timing of breeding did not differ according to distance to permanent water: we suggest that their preference for nests near water may reflect an advantage based on prey availability. Water snakes, known prey of GHFE, were significantly more abundant at a site in permanent water than at a temporarily flooded site, in December. We also found that human habitation was negatively correlated to GHFE nest-site occupancy rates. This may reflect indirect effects of human exploitation of GHFE food supplies, which may be exacerbated in the future by changes to the Tonle Sap ecosystem resulting from upstream dam construction.Abstract Little is known about the ecology of the Grey-headed Fish-Eagle (GHFE; Ichthyophaga ichthyaetus) despite it being a globally near-threatened species in apparent decline. We here present the first quantitative information on nesting ecology of this species, in a regionally significant population at Prek Toal, part of the seasonally flooded swamp forest surrounding the Tonle Sap Lake, Cambodia. We found that GHFE selected trees as nest sites that had an open crown structure and were relatively tall. Grey-headed Fish-Eagles preferred nesting closer to permanent water than expected, but the timing of breeding did not differ according to distance to permanent water: we suggest that their preference for nests near water may reflect an advantage based on prey availability. Water snakes, known prey of GHFE, were significantly more abundant at a site in permanent water than at a temporarily flooded site, in December. We also found that human habitation was negatively correlated to GHFE nest-site occupancy rates. This may reflect indirect effects of human exploitation of GHFE food supplies, which may be exacerbated in the future by changes to the Tonle Sap ecosystem resulting from upstream dam construction.
URL:http://dx.doi.org/10.3356/JRR-09-04.1
Short Title:Journal of Raptor Research
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith