Seasonality and plasticity in the use of native and introduced plant resources by a large forest parrot

Human‐induced environmental change is reshaping plant communities, requiring native animals to adapt their foraging behaviour to track and exploit novel food resources. Trees such as pines ( Pinus spp.) introduced for plantation forestry outside of their native ranges often become naturalized. Here, we studied the dietary plasticity of Kākā Nestor meridionalis , a large forest parrot endemic to Aotearoa New Zealand, in a mixed native broadleaf and introduced pine forest. We observed the natural foraging behaviour of Kākā over the course of a year to document the seasonal use of all food resources and assess the variation in overall monthly foraging frequency and dietary niche breadth. We examined the seasonal use of Pinus radiata , a non‐native conifer with year‐round canopy seed storage, to determine whether Kākā foraged on pine seeds seasonally during periods of peak native seed consumption, or opportunistically throughout the year. In 288 h of sampling carried out over 12 months, we documented 485 foraging bouts on six main food items. Observed foraging frequency was significantly higher in autumn and winter. Monthly niche breadth was widest in early spring (September, B = 0.58) and narrowest in early summer (December, B = 0.21). Kākā switched sequentially between native plant resources throughout the year. Fruit consumption peaked in autumn, ground‐foraged seeds in early winter, sap and flowers from late winter to early spring, while wood‐boring invertebrates were eaten year‐round. Pine seeds accounted for 10.5% of foraging observations, and their seasonal use differed from that of ground‐foraged seeds, indicating greater temporal independence in their consumption. Our findings contribute to the knowledge of how the dietary plasticity of parrots can help inform conservation and habitat management in human‐modified habitats to build resilience in recovering populations.