The density of shrubs is increasing in many dry grassland ecosystems worldwide. In the dry interior of the South Island, New Zealand, secondary succession generates novel woody communities, as shrubs colonise anthropogenic grasslands where fire frequency has decreased. The avifauna of this dry region is also novel, with many indigenous birds extinct, extirpated or uncommon, and exotic species predominant.
The naturalised European blackbird (Turdus merula) is the most widely distributed avian seed disperser in New Zealand. Together with the native silvereye (Zosterops lateralis) they are the major seed dispersers over large areas of New Zealand. I review the international literature on aspects of the ecology and behaviour of blackbirds relevant to their potential for dispersing weeds in New Zealand. Blackbirds eat a wide range of native and exotic fruit including many naturalised species.