Download or read book Predicting Breeding-bird Occurrences in Oklahoma: Relationship of Species Distributions to Land-cover and Climatic Variation written by Dennis G. Siegfried and published by . This book was released on 2007 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is of practical interest to know the amount of data required to produce reliable models. I developed nine training sets of from 50 to 450 sites for each species to predict occurrence in a 100-site test set. Model performance was determined by the reduction in error of prediction (tau-p) compared to the null. On average, model performance leveled off after 300 sites.