The spur-winged plover (Lobibyx novaehollandiae) is an Australian species, self-introduced to New Zealand in 1932 and now established as a breeding species in Southland and parts of Otago. Its establishment and present distribution are outlined. The method of spread in five different localities is demonstrated. Local movement is described.
Counts of grey (Anas superciliosa), mallard (A. platyrhynchos) and hybrid ducks were made on 500 yards of the Avon River and Lakes Victoria and Albert between 16 April and 18 July 1967. During the pre-shooting season (16 April to 5 May) duck numbers rose steadily from about 1150 to 1800. Numbers continued to rise about the same rate during the first five days of the shooting season (6 May to 11 May). During the remainder of the season (12 May to 5 June) the numbers remained about 2200. During the post-shooting season (6 June to 5 July) the numbers declined during the first 14 days to about 1300 and then remained about this level. The increase in numbers during the shooting season was significantly different from both the pre-shooting and post-shooting numbers. The latter were not significantly different from each other. Flight patterns, feeding habits and behaviour during the shooting season are discussed.
During 1967, rooks at West Melton and Banks Peninsula rookeries selected mainly Pinus radiata for nesting and chose the highest safe sites. Nest construction periods varied from 5 to 20 days, the last nests being completed most rapidly. Eggs were laid between 30 August and 6 November. Rookeries showed significant differences in laying date, apparently resulting from differences in food availability. The size of eggs varied with laying sequence. The mean clutch size was different at each rookery, ranging between 2.9 and 3.8 eggs, a similar value to that obtained by past workers in Canterbury but smaller than that of rooks in Britain. Nestling periods were directly related to brood size. Growth rates of nestlings varied with brood size, hatching sequence, partial brood loss and season. Parental feeding visits were largely independent of brood size and ranged from 1.4 to 3.3 visits per hour. Failure of the embryo to develop accounted for most egg losses. Most nestling mortality resulted from parents killing the smallest nestling before it died of starvation. Breeding success varied seasonally and ranged from 38 to 12.7%. Three and four egg clutches occurred most frequently, but larger clutches produced more fledglings.