Do fragmented forests host sufficient birds for forest restoration on Banks Peninsula, New Zealand?

Agricultural areas set aside for native forest restoration are often in highly fragmented landscapes. This fragmentation can reduce local abundance of native avifauna that carry out bird-plant mutualisms for forest regeneration. Te Whenua Ora | High Bare Peak (HBP) is a fragmented forest landscape on Banks Peninsula transitioning back into continuous forest. Five-minute bird counts (5MBCs) in forest were used to compare the diversity and abundance of bird species at HBP with that of Hinewai Reserve, a nearby ecological restoration project that has naturally regenerated back into forest over more than 35 years. High Bare Peak had more introduced bird species than Hinewai, likely due to the forest patches being smaller and in close proximity to pasture, but the two sites had similar counts of pollinating and seed-dispersing native bird species. The mean number of korimako | bellbirds (Anthornis melanura) was the same at HBP and Hinewai (0.8 per 5MBC), and there were more tauhou | silvereyes (Zosterops lateralis) at HBP than at Hinewai (0.99 vs. 0.56, respectively). Kererū (Hemiphaga novaeseelandiae) counts were low at both Hinewai and HPB (0.2 and 0.06, respectively), but kererū are often under-represented in 5MBCs. These results indicate that bird diversity and abundance should be sufficient for bird-plant mutualisms to develop in forest patches at HBP at least to a level similar to that in Hinewai. This study suggests that small forest patches can play an important role in the restoration of native forests through maintaining populations of key pollinating and seed-dispersing bird species.