White-fronted Tern

The white-fronted tern is an average-sized tern; its dimensions are 35–43 cm (14–17 in) in length, with a wingspan between 79 and 82 cm (31 and 32 in); the male weighs on average 130 g (4.6 oz). Females are marginally smaller than males, but this is difficult to determine when observing individuals in the wild. Breaking down their monochromatic colouring, the white-fronted tern's lightest features are its all-white body, tail and underwing, with the upper side of the wings a light silvery-grey hue. Through the breeding season there can be a faint pink coloration on the breast, but this is not always visible. The darkest features are the beak, black cap, eyes, feet and the shadowing on the outermost edge of the wingtips. The long ebony-like bill is slender and comes to a sharp point that dulls in colour at the tip. The crown is jet black, interrupted by a variably narrow white band between forehead and bill. The black cap continues over the crown and finishes at the nape. Inky black round eyes sit within the cap. The legs are stumpy with a deep burgundy black tone. A defining feature of the white-fronted tern is its forked tail, most recognisable when in flight and commonly drawing comparisons with a swallow's tail. In the breeding season, the outermost feathers of the tail lengthen, accentuating the already deep fork. …

White-fronted terns are found in New Zealand and Australia. Juveniles will occasionally migrate across to south-east Australia and northern Tasmania. Breeding populations in Australia are only observed in the Bass Strait, on Flinders and Cape Barren Islands. It is the most abundant tern in New Zealand, and lives along the entire coastline. In the North Island, there are significant populations from Auckland to the Bay of Plenty including the Coromandel Peninsula and they are widespread along the coast from Wellington, up towards Manawatu. In the South Island, they are a familiar sight in the Marlborough Sounds and along the east coast into Canterbury, Otago and Southland, where they can be seen year-round. Stewart Island also has flocks and breeding pairs throughout the year. Apart from the main coastline of New Zealand they also populate many of the smaller islands, with large numbers of breeding pairs observed on both the Chatham and the Auckland Islands. They seldom head inland, but there have been recordings of them in the Canterbury area, where they travel up the large braided rivers to feed and nest.

Habitat preferences. White-fronted terns can be found in a variety of coastal habitats. With large flocks preferring coastal waters, harbours, bays and estuaries where they are content to live on either sand, shell or shingle ground. …

White-fronted terns have a reputation for being difficult to monitor and study due to their unpredictable nature. It becomes very apparent in the breeding season, as white-fronted terns seldom return to the same breeding sites year after year, making it difficult for a clear indication of numbers and breeding results.

Breeding. Courtship begins in early October when the warmth of spring has arrived and can continue into January, with individuals constantly arriving at various breeding grounds. A male will fly in from sea with a fish delicately held in its bill; it will fly above groups of females and attempt to gain their attention by calling to them. The male may land and strut around with head and fish held high to attract more attention from potential mates and there may be a suggestive approach by female/s seeking to have the fish fed to them. But at this point, the male will swiftly take flight, closely followed by one or more of his potential mates. The spectacle continues until there remains only one follower. The pair will land together, the male may offer the fish to the female in acceptance of courtship, or he may disapprove of the female and retain the fish for himself. If accepted, the partnership begins. The pair takes to the air together following one another in a magnificent flight display, signifying successful courtship. …