The white-fronted tern (Sterna striata), also known as tara, sea swallow, black-billed tern, kahawai bird, southern tern, or swallow tail, was first described by Johann Friedrich Gmelin in 1789. A medium-sized tern with an all-white body including underwing and forked tail, with grey hues on the over the upper side of the wing. In breeding adults a striking black cap covers the head from forehead to nape, leaving a small white strip above the black bill.
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.
The black cap of non-breeding adults retreats towards the top of the forehead and above the eyes, while at the same time losing some of its intensity. Immature white-fronted terns are similar but have speckles of white through the cap. Along with a slight coloration on the wings and tail, which appear as a brownish cream. The juvenile plumage is very pronounced with flecks of light to dark grey and warm milky browns on the upper side of the wing, back, and mantle. The cap is incomplete and mottled, having dark black markings in front of and behind the eyes.