Breeding of South Island pied oystercatchers (Haematopus ostralegus finschi) on farmland in mid-Canterbury was studied from 1987 to 1997. Each year birds returned to breeding territories from early June; females arrived about six days earlier than males. Laying dates extended from early August to mid-November and were similar in all years. Most first clutches were laid from late August to mid-September. Up to two replacement clutches were laid. Clutch size averaged 2.29 (range 1-3 eggs) and declined through the breeding season, but was consistent from year to year. Mean first clutch sizes were larger than replacement clutches. On average, 47% of eggs hatched and 59% of these chicks survived to fledge. Both hatching and fledging rates declined through the season. On average, 52% of pairs which laid in any year failed to rear a fledgling. Hatching success was greater in cultivated sites than pasture sites, but fledging success was similar at both sites. Trampling by stock, farming activities, and unknown causes were the main causes of egg loss. Sagar, P.M.; Geddes, D.; Banks, J.; Howden, P. 2000. Breeding of South Island pied oystercatchers (Haematopus ostralegus finschi) on farmland in mid-Canterbury, New Zealand. Notornis 47 (2): 71-81. Keywords breeding success; Haematopodidae; agricultural land; land use; population change
The chick-rearing strategy of yellow-eyed penguins (Megadyptes antipodes) breeding on Otago Peninsula was examined in 12 pairs of adults, between 17 November 1996 and 3 1 March 1997, from time of hatching of chicks to parental moult. Differences in behaviour of both male and female parents towards one- or two-chick broods were not statistically significant, but behaviour towards all offspring changed significantly over time with respect to breeding phases. Differences observed resulted from a change in feeding procedure. “Food-walks” started significantly earlier in the course of a feeding session as time progressed, while major components (duration and number of individual feeds) decreased significantly. The changes observed are interpreted as resulting from the chicks’ growing independence in concert with the parents’ decreasing urge to spend time with their offspring outside the still necessary feeding encounters. An evolutionarily stable environment and reliable food source are suggested as the reason for the lack of development of different chick-rearing strategies for different numbers of offspring or for male and female breeders.
Patterns of white feathers on the heads of 10 female and 18 male wild and captive adult black stilts (Himantopus novaezelandiae) were quantified to determine whether the presence and location of white flecking was age- or sex-related. Eleven of the males, but none of the females had white flecking on their heads. Flecking occurred on 2-7 of 9 head regions described and an increased amount of flecking was positively correlated with increasing age. Males without white flecks were 2-7 years old, whereas males with flecks were aged 5-19 years. Most flecking was around the eyes, in the superciliary region and on the crown. We conclude that the presence of white flecking around the eyes or generally scattered on the head is a reliable indicator of a black stilt being old and male.