Skua studies (population numbers, territorial behaviour, the breeding cycle, mortality and the effect of the penguin colonies on normal activity of skuas) at Cape Royds and Cape Hallett colonies

The penguin and skua colonies at Cape Royds were used to study skua-penguin association. A population count of skuas (Catharaeta maccormicki) at Cape Royds was conducted from late October to late February. A general survey of the skua colonies in mid-November was conducted and from this three groups (Green Lake colony, Cape Royds colony and the Cape Barne colony) of about 20 pairs/group were selected for comparison of the daily activities, territorial behaviour and chick development and mortality of the skua pairs associated with the penguin colonies and with those in other areas. The effect of the penguin colony on the normal activity of the skuas (being the behaviour of the birds if the colony was considered as being removed from the environment) was investigated by;
a) determining the influence of the penguin colony on the pattern of skua flight along the coast and
b) determining the number of skuas that received some advantage from being in the same general area as a penguin colony.
The daily rhythms of activity at different periods during the breeding season (the period before egg laying, incubation of the eggs, chick rearing and when the chicks fledge and become independent and both adults and chicks lose their territorial behaviour) was also observed and described. During the chick rearing stage primary feather growth was used for chick growth and the weights of each chick was used for the degree they were being fed. Territories were mapped and assigned a number to identify individual birds. Some birds were banded and the schedule of banding and the layout of the territories was recorded. A similar study was conducted in the following season on skuas at Cape Hallett.