Behaviour It is a colonial burrow-nesting, annually-breeding species (ACAP 2009). Most eggs are laid in mid-November/late December, hatch in late January/February and chicks fledge in May/June at about three months old. Chick provisioning can continue until June (Bell et al. 2009). The youngest recorded bird returning to a colony was two years of age, and the age of first breeding has been recorded at four years of age (Bell et al. 2016a). Feeding behaviour is characterised by surface feeding and shallow diving in groups of up to 300 individuals that are frequently seen to associate with fishing vessels and cetaceans. Black Petrels have been recorded diving up to 34 m, but over 85% of all dives were less than 5 m and over 90% were during the day (Bell 2016). Preliminary geolocator data suggest that it preferentially forages on the continental shelf or at seamounts (ACAP 2009), with most foraging trips taking at least 15 days (Bell et al. 2009). Further data suggest foraging areas are highly variable, although birds travel mainly west and east of northern New Zealand (Bell et al. 2009). Habitat Breeding It nests in virgin podocarp and mixed broadleaf forest above 500 m. On the mainland, it reportedly bred up to 1,200 m, mostly in tall forest, but also in alpine tussock grasslands (Marchant and Higgins 1990). Diet Its diet is dominated by squid and supplemented by tunicates, crustaceans and cyclostomes (Bell et al. 2009). 

Procellaria parkinsoni breeds on Great and Little Barrier Islands, New Zealand, where the populations number c.880 pairs (in the 35-ha study site) and 620 pairs respectively (Bell et al. 2016a, b). It once bred in the mountains of the North and South Islands, but had disappeared from the mainland by the 1960s. It migrates to the eastern Pacific Ocean between the Galápagos Islands, southern Mexico and northern Peru (Heather and Robertson 1997). On Little Barrier, it was abundant in the late 1800s but the population was decimated, mainly by feral cats, until predators were eradicated in 1980. The trend obtained from census grid data for Great Barrier Island estimated a population growth rate between -2.3% and 2.5% per year, depending on juvenile annual survival. Assuming a juvenile annual survival rate of 88%, the population growth rate was estimated to be -1.1% per year (Bell et al. 2014). Nevertheless, there is considerable uncertainty in the model and further research is needed to clarify the population trend.

Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Cats were eradicated on Little Barrier Island by 1980. Between 1986 and 1990, 249 fledglings were transferred from Great Barrier to Little Barrier in an attempt to boost population size. Follow-up monitoring indicates mixed results (Imber et al. 2003). The population on Little Barrier has been studied since 2014/15 (Bell et al. 2016b). A long-term population study was initiated on Great Barrier in 1996 to study populations annually to determine trends and assess breeding success (Taylor 2000, Bell et al. 2007). Tracking research has been completed on both Little Barrier and Great Barrier (E. Bell in litt. 2012). Feral cat trapping was undertaken on Great Barrier Island in 2011/2012 and is scheduled to continue in future breeding seasons, along with a rodent control programme (per E. Bell in litt. 2012). Rattus exulans was eradicated from Little Barrier in 2004 (E. Bell in litt. 2012).

Conservation Actions Proposed
Complete an accurate census of Little Barrier Island. Monitor Great Barrier study populations annually to determine trends, and assess breeding success. Monitor the effectiveness of increased mitigation application in the main fisheries threat in New Zealand from bottom longlining through an electronic monitoring project (Black Petrel Working Group 2016). Continue and expand predator control at Great Barrier if monitoring indicates that any predators are causing a population decline (Taylor 2000).