Chroicocephalus bulleri
The Black-billed Gull, Chroicocephalus bulleri, is a graceful and distinctive medium-sized gull endemic to New Zealand, primarily found on the South Island. Adults display a striking white head and body, pale grey upperparts, and conspicuous black legs and a slender, deep black bill, which gives the species its common name. In flight, it exhibits a white leading edge to the wing and a distinct black primary wedge, contrasting with its white tail. Measuring approximately 35-38 cm in length wit...
This species primarily inhabits the dynamic braided river systems of the South Island, particularly during the breeding season. During the non-breeding season, they disperse to coastal estuaries, harbours, and agricultural areas, generally found from sea level up to low to mid-elevations.
Their diet is highly generalized and opportunistic, primarily consisting of invertebrates such as earthworms, insect larvae (especially agricultural pests like grass grubs), and flying insects (caught on the wing). They also consume small fish, crustaceans, carrion, and food scraps, foraging by g...
Black-billed Gulls are highly social and diurnal birds, spending their days foraging and interacting in large flocks, often numbering in the thousands during non-breeding periods. They are famed for their colonial breeding, forming some of the largest gull colonies in New Zealand, often numbering...
The Black-billed Gull is entirely endemic to New Zealand, with its core breeding range concentrated on the braided river systems of the South Island, particularly in Canterbury, Otago, and Southland regions. Non-breeding individuals and juvenile birds disperse more widely across both the South an...
Endangered
- The Black-billed Gull is the only gull species in the world that breeds exclusively on braided riverbeds, making its survival intrinsically linked to these dynamic and threatened ecosystems. - Known in Māori as Tarāpuka, it holds cultural significance as an indigenous species. - Despite being a...