One of New Zealand's iconic braided river birds, the black-fronted tern, is in decline. To turn things around the Department of Conservation and the University of Otago are co-operating in a large-scale South Island wide project to learn more about this small tern.

From September to January the terns breed in loose colonies in the braided riverbeds of the Eastern South Island. Its breeding plumage is very distinctive: A black cap contrasted by a narrow white cheek stripe and slate-grey body plumage, its bill and short legs are bright orange.  To many fishermen, the elegant tern is a familiar sight as they like to feed on hatching mayflies and are often seen near good trout fishing spots. After the breeding season, the terns move to the coast of all three main islands and have been observed feeding many kilometres off-shore.
It is estimated that about 10% of the total population breeds in the Waitaki River, making it a significant stronghold for the species. Unfortunately the tern's populations have been in decline and are currently classed as Endangered. The biggest threat are introduced predators - like cats, hedgehogs, rats, ferrets and stoats - as well as weeds, such as lupins, broom and gorse invading their breeding habitat.

Not much is known about black-fronted terns and their movements: Do the same birds return to the same river each year? Do the breeding colonies mix during the winter? Do birds move from one river to another? This information is though necessary to properly plan protection measures like weed and predator control. The Department of Conservation (Dr Richard Maloney) and the University of Otago (Dr Bruce Robertson and MSc student Ann-Kathrin Schlesselmann) are working together on a South Island wide project to learn about these relationships using genetics. As the birds have very short legs, using coloured bands and simply observing birds is not practicable - nor would it be possible to undertake this on a South Island wide-scale. For the genetic analysis only a small blood sample from a bird is required, which can be later analysed in a laboratory.
This research helps in developing predator and weed control at the right level to protect all the birds within a population. It will allow us to understand better how for example the birds breeding in the Waitaki River are connected to the colonies in the Mackenzie Basin.