Ardea
Official journal of the Netherlands Ornithologists' Union

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Konter A. (2008) Seasonal evolution of colonial breeding in the Great Crested Grebe Podiceps cristatus: a four years’ study at Lake IJssel. ARDEA 96 (1): 13-24
A field study at the Dutch IJsselmeer on colonial nesting of Great Crested Grebe Podiceps cristatus over four breeding seasons focused on the phenomenon of breeding aggregation. Grebes settled in two types of habitat: ‘Bulrush’ and ‘Reed’. Pairs in Bulrush nested later in the season, and therefore produced smaller clutches, compared to pairs breeding in Reed. Breeding pairs showed high variability in the timing of arrival, nest building and egg laying (‘laying date’). Pairs that started nest building early in the season, took more time to produce a clutch. They also produced larger clutches, but experienced more egg loss, compared to pairs breeding later in the season. Corrected for laying date, year and habitat, there was no effect of coloniality, as measured by nearest neighbour distance, on clutch size and egg loss. I conclude that colonial breeding in the Great Crested Grebe results from suitable habitat progressively filling-up with breeding pairs, without accruing any reproductive advantages.


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