PIERSMA T (1984) Short contributions: Growth bars in the wings of a Great Crested Grebe Podiceps cristatus?. LIMOSA 57 (3): 112-112.

Great Crested Grebe Podiceps cristatus On 21 December 1979 an adult male Great Crested Grebe of small size and relatively normal weight was collected from commercial fishing nets, standing 4 m deep on the bottom of the IJsselmeer, Netherlands. The body feathers of this bird were normally coloured but its wings were pale (light brown) and barred (fig. 1). It is suggested that the more or less regularly spaced bars in the wing coverts, the alula feathers and the remiges are corresponding and simultaneously grown. One double (dark + light) bar of a primary is about 20 mm wide. According to the data summarized by Prevost (1983), we would predict a daily growth rate of 4-6 mm in a bird of this size and therefore it is highly unlikely, that one double bar represents a daily feathergrowth increment (growth bar) as was put forward by Michener & Michener (1938) and Wood (1950). However single dark and light bars may indicate daily growth bars.

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