Towards a problem of spatial structure investigation of bird colonies – a new method of computer analysis. - A.V. Drouziaka, D.A. Vayner. - Berkut. 13 (2). 2004. - P. 283-294.
Spatial structure of the bird’s colonies is being formed under the influence of a number of internal and external, in relation to colony, factors. However, in the studies of colonial birds’ breeding biology the analysis of participation of territorial behaviour in colony structure formation is required. A method enabling to estimate the nest territory dimensions, on the basis of comparatively simple data – nest allocation scheme, is presented in this paper. Territory dimension of each nest is estimated using position of its nearest neighbors, which presumably are contiguous by their territories. To select these “contiguous neighbors” we use their regular position, to compare with to those neighboring nests, whose position is determined by inhabitant heterogeneity and does not carry information on nest territory dimensions. The method is recorded as a computer program “Nest” and is tested on different objects. These are Black-headed Gull and White-winged Tern colonies and also 5 computer models, imitating colonies, formed on habitats of different heterogeneity. At these imitations, mean nest territory dimension is pre-postulated by the user. Models are processed by “Nest” program and several traditional methods, followed by comparative analysis of precision of their estimates (Table 1). We have no any data on nest territory dimensions for the real colonies, but we compared the precision of estimations of mean nest territory dimension and its dispersion for each colony calculated by “Nest” and by traditional methods, using standardized coefficient of variation (Table 2). It is shown, that “Nest” program estimates nest territory dimensions more precisely than other considered methods, in the most homogeneous habitats. Comparative analysis of the spatial structure of the real colonies disposed that “Nest” program gives the most consistent and unbiased estimate. The last versions of the “Nest” program and programs-imitators, modeling colony structures, are accessible at http://ecoclub.nsu.ru/nest. [Russian].
Key words: colony, spatial structure, nest, habitat, method.
Address: A.V. Drouziaka, Institute of Animal Systematics and Ecology, SB RAS, Frunze strt, 11,
Novosibirsk, 91, 630091, Russia; email: druz@ecoclub.nsu.ru.