Aotearoa's Seabird Superhighway: Why the Hauraki Gulf is a Global Treasure
Did you know the Hauraki Gulf is a globally significant seabird superhighway? While only about 365 of the world's 11,000 bird species are considered seabirds, a staggering one-third of all seabirds are found in Aotearoa, New Zealand.
Critically, the Gulf itself hosts 27 breeding species, including five that breed nowhere else on Earth. This includes two avian treasures: the endangered tara iti (NZ fairy tern), our rarest bird, and the Takahikare raro (NZ storm petrel), which was famously rediscovered in 2003 after being thought extinct. (Information and inspiration courtesy of the Seabird Trust)
Countless other seabirds also visit this vital region, but they are not as well known as forest birds – so let’s put a few in the spotlight…
Kawau tikitiki (Spotted shag) are one of the Gulf’s most elegant commuters — sleek, streamlined, and unmistakable in flight. With their long, narrow wings and rapid wingbeats, they skim low over the water like they know exactly where they’re going (and usually do). During breeding season, they’re instantly recognisable by their blue-green facial skin, blue eye rings, dark crest, and the fine black spots that give them their name. Classed as ‘Nationally Vulnerable’, these striking birds are mainly found in the South Island but have a declining population in the Hauraki Gulf.
Kawau tikitiki historically bred widely in the Auckland region, yet this species experienced a massive population decline in the early 20th century because of unrestricted hunting. Shooting was banned in the 1930s, and by 1960, populations had rebounded to at least 2000 breeding pairs in the Firth of Thames area. However, despite decades of legal protection and successful eradication of introduced predators from breeding colonies, numbers have continued to decline.] – reference below
Over the last 10 years, monitoring in one area around the Firth of Thames and Waiheke has shown a significant decline of nest sites, a shocking 6% per year, down to 300. (annual colony survey results, Lovegrove, Rayner, Landers).
When fish numbers drop or coastal waters become disturbed, shags can struggle to find the food they need to breed successfully, making them early indicators of change in the marine ecosystem, the veritable canary in a coalmine.
Zhang, J., Rayner, M.J. 2025. INT2024-06 Interaction of spotted shags with northern North Island set net fisheries. Report prepared for the Department of Conservation, Conservation Services Programme.
