In summer they prefer cabbage tree and nikau fruit.  By early autumn, they are usually feeding on late ripening native fruits, such as karaka, taraire and tawa berries.  Once they ripen in autumn, the kahikatea are also a favourite food source, but many Kereru become intoxicated from feasting on the berries.  This is when they are most likely to fly into windows, often dying from the impact. 

Kereru are our only remaining endemic bird capable of swallowing the large native fruits such as karaka and taraire, and dispersing them intact.  This means that Kereru are vital to the health of mixed podocarps and broadleaf forests in New Zealand, ensuring a diverse composition of trees through the forest. 

If Kereru have a year-round supply of food in their home range, their territory may only be 20-30 ha, but if, as is more usual, they need to search widely for their food, they may have a series of seasonal home ranges in a 20-30km area.

The display flights of Kereru are one of the most eye-catching sightings of these birds.  The male bird flys rapidly upward, then stalls with wings open, and dives steeply, usually back to a preferred perch high in a tree. In the breeding season (which is long in the Auckland region – from early spring to late summer), male Kereru perform these flights one to two weeks before egg laying begins by the female.  

A breeding pair will usually produce one egg each season in a roughly constructed nest platform of twigs, and share the raising of the chick.  It takes about a month for the egg to hatch, and then four to six weeks for the chick to fledge.  The adults continue to feed it for another two weeks - a commitment of more than three months by the pair to raise one chick. 

Populations of this beautiful endemic New Zealand pigeon, Hemiphaga novaeseelandiae, are believed to be in gradual decline throughout the country.
Introduced pest predators such as possums and rats are the greatest threat to their survival, as well as cats and stoats.  Habitat loss is another cause of decline and hunting of Kereru occurs, although it has been forbidden by law since 1921.