M Sc Dissertation(WII)

Sunbirds are excellent model organisms to study resource dependent territoriality or feeding territoriality due to their dependence on nectar which is both renewable as well as quantifiable. It is well established in many of its ecological counterparts such as American hummingbirds of family Trochilidae, Australian honeyeaters of family Meliphagidae, and Hawaiian honeycreepers of the family Fringillidae. This study is exploratory research aimed to find the presence of feeding territoriality in an Indian sunbird community as well as to test the threshold model of feeding territoriality. The study was done in an heterogenous resource landscape which is not quite comparable to previous studies done on acres of land dominated by single plant species. Though the sunbird community agreed to some basic principles, the results reflect a much complex response to changes in flower abundance and intruder pressure.

There has been a number of studies on bird communities and their relationships with habitat features of floristics and physiognomy. In particular, the spatial distribution of bird communities along the axis of structural variables of a habitat has received a wider attention in the light of recent findings on landscape behaviour. Most of these works relate to either temperate or neotropical forests and our knowledge of community dynamics of tropical deciduous forests is very limited, for there has been hardly any comprehensive study in the tropics. The present study was done in the deciduous forests of the Pench National Park, Central India (M.P) between "November, 1996 and April, 1997 covering winter (November,1996-1anuary,1997) and summer (March, 1997-April, 1997). Seven distinct habitat types were identified for the study based on floristic and structural diversity. Seasonal data on 27 habitat structural variables were collected from bird-centered sampling plots. Point count census technique was employed to study the bird population. Principal Components Analysis (PCA) was used to determine the patterns of inter-relationships among the habitat structural variables. Canonical Correspondence Analysis (CCA) was done to understand the relationships of habitat components to the distribution of bird communities. For guild analysis, two different sets criteria were used to identify the guilds among the bird populations viz., food type and foraging behaviour. Twelve guilds were recognized based on the food type and, six among the insectivores with respect to foraging behaviour. The results of the PCA showed that habitat structural variables of tropical deciduous forests have a marked pattern of inter-relationships on two axes of landscape behaviour, viz., heterogeneity and complexity. But they failed to reveal any such segregation vis-a-vis bird community structure, as the scale of measurement did not address all the members of the community. The spatial distribution pattern of bird communities in relation to habitat architecture was shown by CCA to be not very tenacious; the interactions of other extraneous factors like floristics, habitat dynamics, phenophases of vegetation, disturbance, or interactions within the community may influence the habitat selection process. There was no linear correlation observed between Foliage Height Diversity and Bird Species Diversity; possible explanations and alternative views have been discussed briefly. The response of bird communities to floristics was found to be inconsistent across habitat types as positive linear relationship was detected only for Teak-dominant forests in winter, and for Anogeiss Boswellia forests and Cleistanthus collinus woodland in summer. Guild compositions of various habitat types were not found to be significanty different from each other though the seasonal change was consistent across all the habitats.

M Sc Dissertation(WII)

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