Reconstructing ecological niche and feeding ecology of pre-contact New Zealand avifauna from Harwood, Otago Peninsula

Over 25% of endemic bird species have become extinct since the time of the first human settlement of Aotearoa | New Zealand in the mid-13th century CE. This has been attributed to multiple factors, including human impact from over-hunting, habitat loss, and the introduction of successive waves of novel mammalian predators. In this study, we analyse carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope values from bulk bone collagen of 19 positively identified living and extinct bird species from the coastal pre-contact (i.e. before 1769 CE) subfossil site at Harwood (831–1534 CE, n = 39) on Otago Peninsula in the southeastern South Island. We compare the δ¹³C and δ¹⁵N values to the broadly contemporaneous coastal early Māori archaeological site at Wairau Bar (1288–1320 CE, n = 48) in the northeastern South Island, and the modern-day known feeding ecology of living species. A number of the extant birds analysed displayed δ¹³C and δ¹⁵N values that supported a diet similar to their known modern-day feeding ecology. However, a few species, such as the pārera | grey duck (Anas superciliosa), pūtangitangi | paradise shelduck (Tadorna variegata), tarāpuka | black-billed gull (Chroicocephalus bulleri), and tarāpunga | red-billed gull (Chroicocephalus novaehollandiae), may have had different regional feeding ecologies prior to human arrival. Our research is significant because it is one of the first comprehensive investigations of the pre-contact diet of birds in Aotearoa