—Columbids often exhibit irregular movement patterns in response to fruit abundance. We tested whether the abundance of nonbreeding Plain (Columba inornata) and White-crowned (C. leucocephala) pigeons was correlated with Thrinax parviflora fruit production in a dry forest in southeastern Jamaica. Monthly, from November to March, we counted the number of pigeons leaving the forest to roost in an...

Ahstract: In this paper we discuss the thresholding methods [1] due to Kittler and Illingworth. Two methods arc suggested in [1]. namely, 1) minimizing a criterion function and 2) iterative search of the minimum error threshold. We have tested the two methods. The first one is found to be robust even in the case of weak bimodality in the histogram. The second one is faster than the first, but a...