Ragupathy Kannan

Nesting Habitat of the Great Hornbill (Buceros bicornis) in the Anaimalai Hills of Southern India

Abstract Anecdotal evidence suggests the endangered Great Hornbill (Buceros bicornis) needs mature, large old-growth trees for nesting. We tested this hypothesis by measuring vegetation characteristics at 24 nest sites in southern India and compared these data with that obtained from equal numbers of unused forest sites. Characteristics significantly different from surrounding forest at hornbill nesting sites were several properties related to size of trees. The nesting habitat characteristics of the species stress the importance of mature forests with emergent trees for nests of the Great Hornbill. Trees used by Great Hornbills for nests, compared to unused trees, averaged 18.5 m taller, 0.85 m greater in diameter, and emerged more above the forest canopy by 12.7 m. Canopy height, canopy cover, and number of large trees >75 cm DBH were greater at nest sites than at unused sites by 5.79 m, 3.15%, and 1.63 trees, respectively.

Wild Great Hornbills (Buceros bicornis) Do Not Use Mud to Seal Nest Cavities

Abstract The literature pertaining to nesting of the Great Hornbill (Buceros bicornis) is ambiguous regarding whether the birds use mud as plaster material to seal their nest cavity entrances. We studied the breeding biology of the species in southern India and detected no evidence of mud delivery or usage in 183 hrs of nest observations. Chemical analysis of plaster material showed that it was composed exclusively of fecal material and not mud.

House Sparrows Associated with Reduced Cliff Swallow Nesting Success

Abstract We quantified the impact of nesting and roosting House Sparrows (Passer domesticus) on nesting success of Cliff Swallows (Petrochelidon pyrrhonota) in colonies in western Arkansas in 2007 and 2008. Two sections of a large swallow colony under a bridge with House Sparrows were compared in 2007 to two sections with little House Sparrow usage. Nesting success of Cliff Swallows (percent of nests yielding at least 1 chick) was 61% in sections with low House Sparrow activity, significantly higher than the 30% in sections with high House Sparrow activity. House Sparrows defended a broad zone surrounding their nests from Cliff Swallow nesting attempts. We compared the proportion of nests used, clutch sizes, and brood sizes of Cliff Swallows in two colonies in 2008, one with and one without House Sparrow activity. In the colony without House Sparrow activity, 48% of old and new nests were used by swallows versus only 8% in the colony with House Sparrows. Swallow clutch sizes were similar in the two colonies, but swallow brood sizes in the colony with no House Sparrows were significantly higher, mean  =  2.3 nestlings per nest (mode  =  2; 75th percentile  =  3) compared to 0.8 nestlings (mode  =  0; 75th percentile  =  1) in the colony with House Sparrows. This suggests Cliff Swallows are less successful when House Sparrows are present in colonies.