The Caspian Tern is the largest tern in New Zealand.  The heavy silver grey body has white underparts with dark tips to the under wing and the short white tail is forked.  The massive red bill is tipped black and yellow.  The adult has a black cap when breeding heavily flecked white in non breeding plumage.  A slight head crest is sometimes visible.  The call is a loud harsh ‘kaaa’. 

Food is mainly small surface swimming fish such as yellow–eyed mullet, smelt, piper, small flounder and inland species such as whitebait, bullies, trout and small eels.  All are caught by plunging into the water (often fully submerging) at a steep angle 8 – 10 metres above the surface. 

Breeding is between late September and early December usually in large loose colonies in harbours or among sand dunes.  Some pairs nest in isolation on small island beaches, shingle riverbeds or on lake shores.  One to three light stone coloured eggs with dark brown spots are laid in the nest which is a shallow unlined scrape in the sand.  Both adults incubate for 26 – 28 days and brood the chicks for the first 5 – 10 days.  The chicks fledge at 33 – 38 days and continue to be fed for several months. 

There is at least one pair who regularly breeds in the vicinity of Tiri. 

Photography by:  Max McRae ©

References: Heather, B.D.; Robertson, H.A. 2000 The Field Guide to the Birds of New Zealand. Auckland, Viking.
Moon, G The Reed Field Guide to New Zealand Birds.