PROP D (2008) Great White Egret Casmerodius albus hunting Common Voles among geese. LIMOSA 81 (1): 24-26.

Thousands of geese, mainly White-fronted Goose Anser albifrons, forage in winter in the meadows of the Eempolder, Noord-Holland. About 40 GreatWhite Egrets, a recent immigrant, feed in the same area, mainly on Common Voles Microtus arvalis. The egrets are strongly attracted to groups of grazing geese. At timesmore than 20 egrets are hunting among a large group (>1000) of geese, mostly in the periphery. Observations showed that egrets nearly double the numer of voles caught per unit time in the vicinity of the geese. Most likely the increased hunting efficiency of the egrets is related to the various sounds of the geese. The voles may be triggered to peek out of their burrows in the zone of noise around the geese. An alternative explanation is that the voles detect the egrets less easily because of the overall sound disturbance. Further investigation is required to prove this theory and to get insight in the foraging dynamics of geese, egrets and voles.

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