1000th hihi hatched at ZEALANDIA
Hihi were first introduced into Zealandia in 2005 with 60 birds translocated from Tiri Tiri Matangi Island. Since then they have bred successfully every year and this week the 1000th hihi hatched at Zealandia was issued with its unique combination of coloured leg bands.
The hihi/stitchbird is a small forest-dwelling passerine endemic to New Zealand. At present the species is classified as “Nationally Vulnerable” under the Department of Conservation’s “Threat of Extinction” system. This makes it just as endangered as the very rare takahē. The hihi has been steadily increasing in numbers with intensive management across New Zealand’s six reintroduction sites, but it is still at serious risk of extinction. Introduced predators, disease, the loss of genetic diversity and environmental disturbances continue to pose a risk to the long-term viability of the species.
The hihi is truly unique. It was previously considered to be a relative of the honeyeaters (a group that includes bellbirds and tui), but it has now been reclassified as the sole member of its own family (Notiomystidae)—there are only just over 30 bird species across the globe that are that this unique. It is in fact more closely related to the wattle birds, tīeke and kōkako, than anything else. It has a mating system unlike any other being highly promiscuous with intense competition for breeding opportunities and notably being the only bird species worldwide known to mate face to face.
In pre-European times the species was distributed throughout the North Island and its offshore islands. However, by the end of the 19th century the only population that remained was that on Te Hauturu-o-Toi (Little Barrier Island). Since the 1980s translocation has been used to establish and maintain populations. There are currently six sites where hihi have been reintroduced but numbers at these still total less than 500, Zealandia is home to the largest mainland population of around 100 adults.
So, what happened to the other 900 birds that we banded? The hihi is not particularly long-lived with three to four years being an average lifespan although one male at Zealandia reached the ripe old age of nine. A typical sex imbalance in favour of males and their promiscuous nature (male hihi testes swell during breeding season, to about 4% of their body mass, at this time the testes are bigger than the male’s brain!) make for a highly competitive breeding environment. Dispersal is possibly also a key factor at Zealandia with bush corridors and suburban gardens adjoining the perimeter fence and predation of birds foraging outside is a real risk. All the more reason to continue creating safe suburbs for our feathered neighbours!
The name hihi means ‘ray of sunshine’ for the bright flash of yellow when they catch the sun while flying through the bush. The birds were well known to Māori and were said to be an indicator of ecosystem health being among the first to disappear as forest clearances encroached and environmental degradation increased. Today they are a key research species in conservation biology and a world-renowned study system in small population recovery, but they continue to be one of our rarest and most vulnerable species.