Roosting ecology of Black-Headed Ibis (Threskiornis melanocephalus) in urban and rural areas of southern Rajasthan, India

The roostingecology of most waterbird species is poorly known and even less is known from southernAsia, where many species inhabit human-modified areas. Roosting ecology of theBlack-headed Ibis (Threskiornismelanocephalus) was studied in urban and rural settings in southernRajasthan, India. Analyses focused on assessing whether site characteristicsvaried between nest sites, urban and rural roost sites, and paired sites (i.e.,a waterbird roost site near Black-headed Ibis roosts but without Black-headedIbis). Additionally, the hypothesis that factors affecting Black-headed Ibisnumbers at roosts would be similar at urban and rural sites was tested. Treecharacteristics (canopy cover, girth at breast height) were different (P < 0.05) between nest and roostsites. Urban roost sites experienced 2.3 times greater disturbance than ruralroost sites. Paired site characteristics were similar to urban roost sites(multi response permutation procedure, significanceof δ = 0.3), but were dissimilar to rural roost sites. Co-occurringroosting bird assemblages were significantly different between roosts andpaired sites (significance of δ < 0.01)in urban and rural settings. Black-headed Ibis numbers at urban roosts wereinfluenced by multiple variables, but models showed considerable ambiguity atrural sites. Results strongly suggest that including roost sites in a speciesstatus assessment is important.