THE BREEDING PHENOLOGY OF THE ROYAL ALBATROSS ( Diomedea epomophora sanfordi ) 1937-1974

NOTE This paper w as read at the 16th International Ornithological Congress, Canberra Australia in 1974. The results were interim analyses within a long term study and only the abstract was published at the time. Further analyses undertaken by the remaining author in 1993, which will be published elsewhere, have indicated some significant changes during the further development of the colony at Taiaroa Head Accordingly this paper is published to provide a reference point for other publications. The royal albatross (Diomedea epomophora) breeds only in the New Zealand region as two subspecies, the northern sanfordi and the southern epomophora. Though the populations and the basic elements of breeding appear to be similar, the northern royal differs in commencing its breeding cycle some three weeks earlier, and is both smaller and darker than the southern royal. The main breeding population of sanfordi (Figure 1) is in the Chatham Islands where a population of some 7,500 breeding pairs is estimated. However, a small overflow population has established itself at Taiaroa Head, Dunedin, on the mainland of southern New Zealand. This colony has since 1937 been subject to extensive protective measures designed to prevent the depredations of curious humans and their associated introduced predators. The early protective efforts which resulted in the now well known studies of Dr Lancelot Richdale have been continued since 1951 by the New Zealand Wildlife Service through the efforts of two dedicated field officers, Messrs. Stan Sharpe and Alan Wright, without whom the present continuation of Dr Richdale's studies would have been impossible. From 1937-1973 some 94 chicks were fledged at Taiaroa Head, and 62% have survived to the age of 5 years. This high survival rate is combined with a mean expectation of further life of 46 years at the commencement of breeding. With assistance from sporadic bursts of immigration the breeding population has increased from 2 birds in 1937, to some 30 birds in 1974, twenty-three of which are known age progeny of the colony. Accordingly the following data are based almost entirely on the detailed studies of the past six years (1968-74) using a fully identifiable population containing a high proportion of known age birds. For the purposes of this discussion the following broad definitions will apply: 1. Breeding adults. Those birds which have been associated in the production of an egg in any season used for analysis. 2. Bereaved breeders. Birds which had bred …