Breeding behaviour and breeding success of feral pigeons in the Bloemfontein urban area

Abstract

Breeding activities of feral pigeons (Columba livia) in the Bloemfontein urban area occur throughout the year with a decrease during the late summer months when seasonal rainfall in the region reaches a peak. Nest construction is relatively primitive and is characterised by a loose composition of nesting material on accumulated dry bird droppings. Two eggs represent the most common clutch size and eggs are usually laid within two days of each other. Both parents are involved in the incubation process lasting more than two weeks, during which the eggs undergo a progressive decrease in mass. Recently hatched nestlings are covered in yellow down and are largely helpless. True feathers only start to emerge after the first week, and from the third week individuals can move about unsteadily. Apart from the first number of days after hatching, nestlings of rare single egg clutches constantly maintain a body mass lower than those from an average clutch. The overall success of 247 breeding pairs for this study was 34%. Egg loss is higher than the mortality rate of nestlings, and is mainly affected by climatic factors such as rainfall. Predation appears to be the most important factor influencing nestling mortality. Aggressive interactions between speckled pigeons and rock doves, however, as well as possible intraspecific aggression also play a significant role.