While most of New Zealand’s seabirds and shorebirds are now legally protected species, this has not always been the case. Today’s populations of seabirds and shorebirds are a remnant of the seabird life before New Zealand’s human settlement.
Early Polynesian settlers harvested seabirds – such as petrels, penguins, shags, and albatrosses – for food, to trade, and for feathers and down. They later developed customary practices – which some iwi and hapū continue to use today – to ensure future harvests.
Early European settlers largely viewed seabirds and shorebirds as pests (shags) or game (pied stilts, dotterel) (Hutching & Walrond, 2015). Waves of European settlement brought predators, such as pigs, cats, and dogs, and rural and urban coastal development that destroyed breeding habitats.
The loss or modification of breeding habitats due to coastal development or from browsing mammals is still a pressure on seabirds and shorebirds. Introduced predators – such as pigs, cats, dogs, stoats, rats, and mice – eat eggs and young birds. Nesting sites can be damaged by livestock, people, vehicles, and severe weather events.
Ocean storms can be devastating for seabirds. In July 2011, for example, thousands of dead and stranded prions (a type of sea petrel) were found along New Zealand’s coastline and further inland as a result of an ocean storm. This caused a large dent in New Zealand’s broad-billed prion population (Miskelly, 2011). Ocean storms may become more intense to the south of New Zealand during winter due to climate change (Mullan et al, 2011).
At sea, the main human-related pressures on seabirds are bycatch from commercial and recreational fishing and marine pollution. We report below on bycatch from commercial fishing.
Bycatch of seabirds is decreasing but is still a major cause of death for some species
Bycatch occurs when marine animals are unintentionally caught during fishing operations. Some examples of how bycatch occurs during commercial fishing in New Zealand include:
- longline – seabirds attempt to consume hooked bait and become caught by hooks or in fishing lines
- trawling – seabirds collide with trawling equipment, leading to death, or injury that later results in death
- set nets – seabirds become entangled and drown in nets while diving for food (Ministry for Primary Industries, 2013).
Estimated seabird commercial bycatch numbers decreased, from about 9,000 birds in 2003 to 5,000 in 2014. This is likely due in part to mitigation measures, such as bird-scaring devices deployed on fishing vessels (Ministry for Primary Industries, 2016a). We do not have data on the bycatch from recreational fishing.
The Antipodean albatross is classified as nationally critical and has a high risk of dying as a result of becoming caught in commercial fishing gear. Its conservation status has worsened in recent years. (Photo: Neil Fitzgerald)
Some bird species are more vulnerable to bycatch than others, depending on a range of factors such as their foraging behaviour, and the extent their hunting range coincides with commercial and recreational fisheries (see figure 5).
Between 2007 and 2013, five species of seabirds classified as threatened with extinction had a high or very high risk of dying as a result of becoming caught in commercial fishing gear.
This graph shows the risk of fishing-related seabird deaths for threatened species between 2007 and 2013. Visit the MfE data service for the full breakdown of the data.
For more detail see Environmental indicators Te taiao Aotearoa: Bycatch of protected species: seabirds.
Most of our indigenous seabird species are threatened with or are at risk of extinction
New Zealand has 92 resident indigenous seabird species and subspecies that established naturally and breed in New Zealand. Of these, 35 percent (32 of 92) are threatened with extinction (see Appendix 1: New Zealand Threat Classification System), giving New Zealand the highest number of threatened seabird species in the world.
Of the 32 species and subspecies threatened with extinction:
- 12 are nationally critical, facing an extremely high risk of extinction (see Appendix 2: Conservation status of New Zealand’s resident indigenous seabirds, shorebirds, and marine mammals)
- eight are nationally endangered and 12 are nationally vulnerable, facing a high risk of extinction.
Fifty-five percent of our resident indigenous seabirds (51 of 92) are at risk of extinction (see figure 6). This is a lower risk than that for threatened species and includes 26 of 51 species that are naturally uncommon. Only 10 percent (9 of 92) of seabird species or subspecies are not threatened.
Note: There were no species of marine birds for which data was deficient.
This graphs shows the conservation status of indigenous marine seabirds and shorebirds in 2012. Classes graphed include, threatened, at risk, not threatened and data deficient. Visit the MfE data service for the full breakdown of the data.
The conservation status of eight seabird species and subspecies worsened between the 2008–11 and 2012–14 assessment periods. The conservation status of one seabird species, Bounty Island shag, improved over this period, but is still classified as nationally endangered.
Over half our indigenous shorebird species are threatened with extinction
New Zealand has 14 resident indigenous shorebird species and subspecies. Of these, eight (57 percent) are threatened with extinction, four (29 percent) are at risk, and two (14 percent) are not threatened (see figure 6).
Of the eight species and subspecies threatened with extinction:
- four are nationally critical, facing an extremely high risk of extinction (see Appendix 2: Conservation status of New Zealand’s resident indigenous seabirds, shorebirds, and marine mammals)
- one is nationally endangered, and three are nationally vulnerable, facing a high risk of extinction.
There was no change in conservation status of shorebirds between the 2008–11 and 2012–14 assessment periods.
For more detail see Environmental indicators Te taiao Aotearoa: Conservation status of seabirds and shorebirds and Changes in the conservation status of indigenous marine species.