Browsing by Subject "moult count"

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    Update to the African Penguin population model taking account of new moult count information
    (2009) Robinson, William M L; Butterworth, Doug S
    Refitting the penguin model to adjusted data taking into consideration possible undercounting of moulters in recent years, we have been able to obtain a better model fit. Also, analysis indicates that the depletion of penguins (expressed as abundance in 2008 relative to 2002) is about 5% less than previously estimated at the colony assumed to be the origin of the extra moulters at Stony Point. The calculated model likelihoods suggest that these birds are more likely to come from Dassen Island.
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    Update to the Robben Island moult count series for 2011
    (2011) Robinson, William
    The 2010/2011 penguin moult season conventionally runs from 1 July 2010 to 30 June 2011. During this period, counts of moulting birds were made on 20 occasions (Table 1). These counts have now been converted to aggregates for the year using the technique of fitting the sum of two Gaussian curves and calculating the area under the function (Robinson and Butterworth 2010).