Nēnē

Nēnē eat plants.

They nibble leaves, seeds, flowers and fruits.

Nēnē eat only plants. They nibble the leaves, seeds, flowers and fruits of at least 50 kinds of grasses, sedges, small plants and shrubs, both native Hawaiian plants and ones brought from elsewhere. What they eat depends on where they live.

By eating fruits and seeds, nēnē help spread seeds to new places. People should never feed them: geese that are fed learn to come close to cars and roads.

The DLNR lists leaves, seeds, flowers and fruits of at least 50 native and non-native grasses, sedges, herbaceous plants and shrubs, with diet varying by place and habitat; the IUCN says it feeds on a wide range of plants (Banko et al. 1999), and the NPS calls it a herbivore. Nēnē help disperse seeds and influence which plants grow in early successional plant communities (DLNR).

In upland habitats food is usually not nutritious enough for goslings to grow well (NPS), and a lack of suitable lowland habitat, especially for rearing young, may limit population growth (IUCN). Feeding by people teaches nēnē to beg and to approach moving cars (NPS; DLNR).

Nēnē often walk near people and roads.

Drivers need to slow down when they see them.

Long ago, flocks of nēnē moved between high mountain slopes, where they fed, and lowlands, where they nested. Some nēnē do this again today.

Nēnē often live near people, on golf courses, pastures and roadsides. That makes cars a danger to them, so in Hawaiʻi there are signs asking drivers to slow down near nesting places.

Historically, flocks moved between high-elevation feeding areas and lowland nesting areas (DLNR); seasonal movements are being seen again in some recovered populations, and the IUCN codes the species as an altitudinal migrant.

Nēnē readily use human landscapes such as golf courses and pastures, which brings conflict: collisions with cars are an important threat, birds can be put at risk near airports (on Kauaʻi, 640 birds were moved to Hawaiʻi Island and Maui from 2011 to 2016 to reduce the risk of bird strikes), and fed birds learn to approach people and cars (IUCN; NPS). Press releases, posters, signs and postcards ask drivers to take care near nesting sites (IUCN).

Once there were only about 30 nēnē left in the wild.

People raised and released many more, and now there are a few thousand.

There may have been about 25,000 nēnē in Hawaiʻi in 1778. Hunting, the loss of lowland homes, and animals that people brought to the islands, such as mongooses, cats, dogs and rats, made their numbers fall. In the 1950s only about 30 were left in the wild.

People began breeding nēnē in captivity in 1949 and released more than 2,800 of them. Today there are a few thousand, but they still need help: workers control predators, mow grassland, fence nesting areas and teach people not to feed nēnē. The nēnē is listed as near threatened.

BirdLife International assessed Branta sandvicensis as Near Threatened for the IUCN Red List (B2ab(ii,iii,iv,v); C2a(i); assessed 14 January 2021, published 2021). The population is increasing (3,252 birds estimated in 2018; 2,600 to 3,300 individuals in established subpopulations, about 1,700 to 2,200 mature), but without continued predator control and habitat management its range, habitat and numbers would likely decline. Generation length is 11.54 years.

It declined through hunting, habitat loss and introduced predators, to about 30 wild birds by 1951 (IUCN; DLNR). Captive breeding began in 1949 and more than 2,800 captive-bred birds were released from the 1960s until the late 2000s. Current threats include introduced mammal predators (the small Indian mongoose, the main egg predator, is absent from Kauaʻi), loss and degradation of lowland habitat, road collisions, toxoplasmosis spread by cats (thought unlikely to affect the population as a whole), droughts and low genetic diversity. It was downlisted from Endangered to Threatened under the US Endangered Species Act (2019 per the DLNR; 2020 per the IUCN) and remains endangered under Hawaiʻi state law (DLNR).