Diurnal, seasonal and annual abundance patterns of California quail (Callipepla californica) in the Marlborough Sounds, New Zealand, 2010–2019

The California quail was introduced to New Zealand in 1862 as a game bird, and today is held in high regard by recreational hunters. The species is widespread through the North and South Islands, except for the regions of Westland, Fiordland, and Southland. However, it is suspected that populations have been declining in recent decades. Our study focused on the California quail population in the Marlborough Sounds along six road sections between Manaroa, Picton, and Havelock during 2010–2019. Analysis of quail counts using a Generalised Linear Model revealed that year (decline from 2010 to 2019), season (highest in spring, lowest in winter) and vehicle traffic (highest at low traffic, lowest at high traffic) all showed significant relationships with the mean number of quail counted per survey. Quail numbers also showed significant relationships with time of day (highest in evening, lowest in afternoon) and road section (highest from Portage to Te Mahia). The decline in quail counted over the 10-year period was possibly due to loss of suitable habitat through forest regeneration, and perhaps also increased predation by certain introduced mammals. We recommend future research to further investigate the causes of the decline, given that confirmed declines in exotic quail populations may have similar implications for native species that also prefer open habitats within the Marlborough Sounds region.