Gull populations are falling at such an alarming rate they now feature alongside kiwi and kakapo on the threatened species list.
While numbers are still high compared to many threatened species, their populations have declined dramatically, and are predicted to continue to do so - by up to 70% over the next 30 years. This is due to a range of factors including predation, land-use change, weed encroachment on breeding sites, and water extraction form braided rivers.
Black-billed gulls are currently classified 'Nationally Critical' – the highest threat category, usually reserved for our rarest birds, because of expected decline. The Rotorua black-billed colony is the most northern breeding colony known, and also one of the smallest, with less than 100 pairs present.
"Rotorua's population is particularly unique as gulls are usually found alongside braided rivers rather than geothermal lakes," explains Ranger Caraline Abbott. "It's unusual to see either of these species breeding so far inland. The Rotorua population is quite unique in that context'.
Sulphur Bay is also an important area for many other native birds including dabchicks, scaup and black swans. DOC has recognised the need to step-up predator control in the area to protect native birdlife and has initiated a community led pest control network around Sulphur Bay with support from Rotorua Lakes Council. Phase one of the programme focuses on rodents and mustelids which easily predate on ground nesting birds such as gulls. With fewer predators, eggs are more likely to hatch and chicks will survive to go on to reproduce.
A Rotorua man was recently prosecuted for being in charge of uncontrolled dogs that disturbed and killed red-billed gulls in Sulphur Bay. Disturbing protected birds and destroying nests is an offence under the Wildlife Act 1953 which can result in imprisonment or a fine of $100,000.