Kereru

The kereru, a pigeon species indigenous to New Zealand, exhibits significant physical attributes - measuring up to 51cm in length from beak to tail, and weighing approximately 650g. The distinctive iridescent green and bronze plumage, accompanied by a bright white chest, distinguishes this species. 

Notably, the kereru plays a crucial ecological role as the only bird with a beak large enough to swallow fruit larger than 12mm in diameter and disperse the seeds again whole. 

Vocalisations from the kereru are generally limited to intermittent "oos". While brief, moderate-volume "oos" are emitted in response to alarming stimuli - such as the proximity of a harrier - more extended, low-volume "oooooooos", characterised by a rising tonality, serve as contact calls, frequently reiterated. 

The kereru maintains a widespread presence throughout New Zealand and congregates seasonally in moderate-sized feeding flocks, typically comprising 20 - 50 individuals, with instances of large gatherings occasionally surpassing 100 birds.