mating system

Extra-pair copulation (EPC) occurs frequently in hihi (stitchbird), Notiomystis cincta, resulting in a high rate of extra-pair paternity. It occurs despite resistance by females, and is often witnessed by the paired male. We studied male behaviour to assess whether extra-pair males were timing copulation attempts to coincide with peaks in female fertility, and whether paired males were behaving in ways to reduce cuckoldry. Extra-pair males concentrated copulation attempts at peaks in female fertility.

Three pairs of kiwis were fitted with radio transmitters and followed for two years in a forest remnant in Hawke's Bay. Laying began in late June or July, when both sexes reached peak weight, and usually finished in November. Twelve of 14 nests were in burrows, 470-900 mm long. Females laid 2-5 eggs each season, 21-60 days apart; clutches which failed in the first few weeks of incubation were replaced. Completed clutches comprised two eggs. A second clutch laid after the first had successfully hatched was recorded only once.

In a polygynous mating system, males frequently compete by locating and defending sites with resources essential to female survival and reproduction. We investigated seasonal changes in site occupancy in a sexually dimorphic, harem-forming insect, the Auckland tree weta (Hemideina thoracica). First we established artificial cavities as diurnal refuge cavities and potential harem guarding sites.