Balancing moult data by subsampling non-moulting birds prior to regression analysis

  • Bo T Bonnevie


During the analysis of moult records from the SAFRING database it was found that for some datasets the records were not evenly distributed temporally and the proportion of moulting to non-moulting birds was not what would be expected from random sampling. In an attempt to balance these data, the records of non-moulting birds were subsampled with different sample sizes prior to moult regression analysis, and the  resulting moult estimates were then compared. The results suggest that subsampling non-moulting birds such that they occur in the expected proportion to actively moulting birds, based on the duration of moult, provides the best estimates of moult.

OSTRICH 2010, 81(3): 265–268

Author Biography

Bo T Bonnevie
Information Technology Division, Rhodes University, PO Box 94, Grahamstown 6140, South Africa

Journal Identifiers

eISSN: 1727-947X
print ISSN: 0030-6525