Todiramphus ruficollaris (Holyoak 1974)

Despite the name 'kingfisher', this bird rarely hunts fish but mainly lives on skinks and insects found on the ground and in vegetation (7). Small lizards are a particularly important part of the diet, especially during courtship feeding. Courtship feeding, when one adult feeds another, is carried out at frequent intervals during the courtship period, often followed by mating (8). The territorial Mangaia kingfisher breeds in pairs or as trios, consisting of either two males or two females. In trios with two males, both males mated several times with the female, suggesting polyandry (8). The nest is excavated in a rotten trunk, branch, or in a tree cavity, consisting of a small entrance hole, a short tunnel and an enlarged nest chamber. Nest excavation, as well as incubation and feeding of the chicks, is undertaken by all the adults in the pair or trio. Eggs are laid from November to January, with pairs generally laying two eggs and trios laying three, and incubation lasts for 21 to 23 days (8).

The Mangaia kingfisher has been the focus of population surveys undertaken in 1992 and 1996 (3), but it has been proposed that further research is required to determine population trends and requirements for long-term survival (5). The Taporoporo'anga Ipukarea Society, an environmental non-governmental organisation in the Cook Islands, has proposed a project to eradicate the common myna from Mangaia. A feasibility report in 2006 concluded that such a measure is justified and possible (9). However the Society decided to undertake a more detailed study of the actual impacts of the myna on kingfisher nesting before committing itself to myna eradication. The initial study in the 2006 to 2007 breeding season showed that there were many more territories in the secondary forest than expected and that seven nests were successful. Of the three that failed, one definitely failed because of myna interference and this was probably the cause of the other two failing also. The study will continue a further two seasons (7).

This small, pretty kingfisher is endemic to a single island, Mangaia, which fossil records show used to have 13 resident landbirds, but now only five survive (3). It has greenish-blue plumage, with a narrow yellowish-orange headband above the eye and a wide, dull, yellowish-orange collar, which extends further across the breast on females. The underparts are white, and the strong, black bill is straight and dagger-shaped, perfect for dealing with animal prey (4). The call of the Mangaia kingfisher is a characteristic "tanga-eeeoo", repeated three to five times in succession, hence its traditional name Tanga'eo. The Mangaia kingfisher is sometimes considered to be a subspecies of the more widespread chattering kingfisher, Todiramphus tutus (2).

The Mangaia kingfisher inhabits forest growing on makatea. They are also common in inland lowlands in mature secondary forest (2) (6) (7).

Occurs only on Mangaia Island, the most southerly island in the Cook Islands (5).

Classified as Vulnerable (VU) on the IUCN Red List 2006 (1).

The decline in numbers of the Mangaia kingfisher in the recent past has been largely attributed to the introduction of the common myna (Acridotheres tristis). Mynas were introduced around 1960 in an effort to control the coconut stick-insect, but there is evidence that mynas are impacting on the Mangaia kingfisher by aggressive behaviour at nest sites (6) (9). However, whether the common myna is the primary cause of kingfisher declines is hard to ascertain. Cats and rodents are also present in forests on Mangaia, and are potential predators of the kingfisher (6), as are long-railed cuckoos (Eudynamis taitensis), although there is only anecdotal evidence of cuckoo harassment of the Mangaia kingfisher (6). The loss and fragmentation of forest habitat on Mangaia, caused by clearance for agriculture and browsing by goats, is likely to be more significantly implicated in the kingfisher's decline (2) (5).