Changes in egg size of exotic passerines introduced to New Zealand
|Title||Changes in egg size of exotic passerines introduced to New Zealand|
|Publication Type||Journal Article|
|Year of Publication||2005|
|Authors||Cassey, P, Blackburn, TM, Evans, KL|
|Type of Article||paper|
|Keywords||Ashmole's hypothesis, clutch volume, egg size, introduced birds, reproductive effort|
Bird species introduced to New Zealand from high northern latitudes are expected to change their breeding behaviour to conform to well-known geographic gradients in avian reproductive parameters. Here, we demonstrate reductions in average egg size and clutch volume for eight species of exotic passerine originating in the UK, and show that the magnitudes of these reductions appear to trade-off against reductions in annual variation in clutch size. Possible reasons for the trade-off are discussed.