Males defend their brood and nest most often, while females also engage in defense sometimes. Threat displays such as the bent neck and forward threat are used to scare off predators. When defending themselves from aerial attack, nenes produce alarm calls, huddle in groups and spread wings, or they simply fly away. Chicks usually hide behind parents, leaving defense to them.
Known Predators:
Anti-predator Adaptations: aposematic
Adult nenes are either sepia or dark brown, with no difference in plumage between males and females. The face and crown are black, while the cheeks are cream-colored and the neck is buff with black streaks. The body is brown to grey, the wings are brown to gray, with white tips and the bottom side of the tail is black. The eyes, beak, and feet are black as well. Nenes have longer legs and less toe webbing than other geese, adaptations which aid walking on lava flows.
Range mass: 1.8 to 2.3 kg.
Range length: 53 to 66 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Annual mortality varies greatly from study to study, depending on whether the animal is wild or in captivity, locality, elevation, etc. The range is from 0 to 87% annual mortality, with slightly lower mortality rates for males than females. In the wild the main causes of mortality include exposure (from low temperatures in high nesting locations), predation (from several indigenous and introduced raptor species, as well as rats, pigs, dogs and mongoose), competition with other species (due to an overlap in diet with game birds and grazing mammals), and starvation or dehydration due to drought. In captivity, 84% of deaths resulted from parasites and diseases while the remaining 16% resulted from trauma. Males die evenly throughout the year. Female mortality occurs mainly in the breeding season when they are most vulnerable to exposure, trauma, and stress from egg laying and predation.
Range lifespan
Status: wild: 28 (high) years.
Range lifespan
Status: captivity: 42 (high) years.
Average lifespan
Status: wild: 213 months.
Nenes inhabit a variety of habitats, including grasslands, scrub forests, and sparsely vegetated volcanic slopes.
Range elevation: 0 to 2400 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; scrub forest ; mountains
The Hawaiian Goose, or nene, is endemic to the Hawaiian Islands.
Biogeographic Regions: pacific ocean (Native )
Other Geographic Terms: island endemic
Other than threat and mating displays and sounds described previously, vocalizations are used to communicate with family members, solidify territory, send alarm calls, and threaten predators. Nenes also murmur when foraging as a way of maintaining foraging distance between family members. Chicks can send pleasure calls, distress calls, sleepy calls and greeting calls. Calls are louder during and close to breeding season.
In addition to auditory cues, vision is key in foraging and recognizing family members, predators, and opponents.
Communication Channels: visual ; tactile ; acoustic
Other Communication Modes: duets
Perception Channels: visual ; ultraviolet; tactile ; acoustic ; chemical
Early Hawaiian settlers used nenes as a food source and hunted the birds to near extinction. In 1907, a hunting ban was placed on these birds, but still approached extinction by 1940 due to predation by introduced species as well as degradation of habitat and other human related destruction. In 1957, nenes were named the state bird in Hawaii and efforts to rescue the almost extinct population, including breeding in captivity and protecting nesting areas began. Though early programs for reintroducing birds into the wild failed, later ones have been very successful and the wild nene population is recovering at around 800 individuals. Currently the greatest threat to nenes is predation of eggs by introduced Indian mongooses (Herpestes javanicus).
US Migratory Bird Act: protected
US Federal List: endangered
CITES: appendix i
State of Michigan List: no special status
IUCN Red List of Threatened Species: vulnerable
Since they fly low, nenes often collide with fences and automobiles. Otherwise, there are no known adverse effects of nens on humans.
Nenes are the state bird of Hawaii and are thus a state symbol.
Positive Impacts: ecotourism
Nenes are important at spreading seeds for many of the plants on which they feed. They are also important food sources for many of the predators mentioned in the previous predation section.
Ecosystem Impact: disperses seeds
Nenes are herbivores and forage solely on land. They eat leaves, grasses, flowers, berries, flowers, and seeds. Nenes usually eat the more nutrient rich bottom part of grasses, and grab and pull food with their beaks. Several important grasses on the Hawaiian islands that are eaten by nenes include Digitaria violascens, Andropogon virginicus, Sporobolus africanus, Carex wahuensis and some others.
Plant Foods: leaves; seeds, grains, and nuts; fruit; flowers
Primary Diet: herbivore (Folivore )
Nenes form life-long pair bonds. The male attempts to court the female by stiffly walking in front of her and showing her the white area under his tail. After the female has accepted the male, the two engage in a triumph ceremony in which the male aggressively pushes away rivals and then calls loudly. This is followed by calling into each other's ears. The display before copulation is comparable to other geese, except done on land instead of water. The head and neck are mutually dipped onto the ground, more and more synchronously. Finally the female becomes ready and the male mounts the female. Afterwards, the male raises his wings, pulls his mate's head back and touches her nape with his beak. This is followed by simultaneous calling by both birds, followed by the female flapping its wings and the male strutting.
Mating System: monogamous
Nenes have an extended breeding season ranging from August through April. However, the majority of nesting occurs between the months of October and March, and eggs are usually laid during the winter months between October and January. Nesting occurs on the ground in areas of dense vegetation. Nests are lined with plants and soft down. The female incubates and the male guards the female on the nest. Clutches consist of between 1 and 5 eggs, with an average of 3. Chicks are precocial, stop following parents within one year, and are sexually mature within 2 to 3 years.
Breeding interval: Breeding occurs once a year, though not all pairs lay eggs every year.
Breeding season: Breeding occurs from August through April, with most activity from October to March.
Range eggs per season: 1 to 5.
Range time to hatching: 29 to 31 days.
Average fledging age: 3 months.
Average time to independence: 1 years.
Range age at sexual or reproductive maturity (female): 2 to 3 years.
Range age at sexual or reproductive maturity (male): 2 to 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
The female selects the nesting site, usually near her own natal site. Females dig a shallow scrape, usually under a bush or tree, and line the scrape with vegetation. Males rarely contribute to nest building. Females incubate the eggs, while the male guards her, though not constantly. The female spends roughly four hours of each day away from the nest, when she eats and rests. During hatching, the female spends more time on the nest, and stays on top of the young until their down dries. The young do not need to be fed by parents. Young readily forage within the first day. However, they remain close to their parents until roughly one year old.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Protecting: Male, Female); pre-independence (Protecting: Male, Female)
The nene (Branta sandvicensis), also known as the nēnē or the Hawaiian goose, is a species of bird endemic to the Hawaiian Islands. The nene is exclusively found in the wild on the islands of Oahu,[3] Maui, Kauaʻi, Molokai, and Hawaiʻi. In 1957, it was designated as the official state bird of the state of Hawaiʻi.[4]
The Hawaiian name nēnē comes from its soft call.[5] The specific name sandvicensis refers to the Sandwich Islands, a former name for the Hawaiian Islands.[6]
The holotype specimen of Anser sandvicensis Vigors (List Anim. Garden Zool. Soc., ed.3, June 1833, p.4.) is held in the vertebrate zoology collection at World Museum, National Museums Liverpool, with accession number NML-VZ T12706.[7] The specimen was collected from the Sandwich Islands (Hawaiian Islands) and came to the Liverpool national collection via the Museum of the Zoological Society of London collection, Thomas Campbell Eyton’s collection, and Henry Baker Tristram’s collection.
It is thought that the nene evolved from the Canada goose (Branta canadensis), which most likely arrived on the Hawaiian islands about 500,000 years ago, shortly after the island of Hawaiʻi was formed. This ancestor is the progenitor of the nene as well as the prehistoric giant Hawaiʻi goose (Branta rhuax)[8] and nēnē-nui (Branta hylobadistes). The nēnē-nui was larger than the nene, varied from flightless to flighted depending on the individual, and inhabited the island of Maui. Similar fossil geese found on Oʻahu and Kauaʻi may be of the same species. The giant Hawaiʻi goose was restricted to the island of Hawaiʻi and measured 1.2 m (3.9 ft) in length with a mass of 8.6 kg (19 lb), making it more than four times larger than the nene. It is believed that the herbivorous giant Hawaiʻi goose occupied the same ecological niche as the goose-like ducks known as moa-nalo, which were not present on the Big Island.[9] Based on mitochondrial DNA found in fossils, all Hawaiian geese, living and extinct, are closely related to the giant Canada goose (B. c. maxima) and dusky Canada goose (B. c. occidentalis).[8]
The nene is a medium-sized goose at 41 cm (16 in) tall. Although they spend most of their time on the ground, they are capable of flight, with some individuals flying daily between nesting and feeding areas. Females have a mass of 1.525–2.56 kg (3.36–5.64 lb), while males average 1.695–3.05 kg (3.74–6.72 lb), 11% larger than females.[10] Adult males have a black head and hindneck, buff cheeks and heavily furrowed neck.[11] The neck has black and white diagonal stripes.[11] Aside from being smaller, the female Nene is similar to the male in colouration. The adult's bill, legs and feet are black. It has soft feathers under its chin. Goslings resemble adults, but are a duller brown and with less demarcation between the colors of the head and neck, and striping and barring effects are much reduced.
Nene gosling on Kauai
Unison calling Kīlauea Point
The nene is an inhabitant of shrubland, grassland, coastal dunes, and lava plains, and related anthropogenic habitats such as pasture and golf courses from sea level to as much as 2,400 m (7,900 ft).[12] Some populations migrated between lowland breeding grounds and montane foraging areas.[13]
The nene could at one time be found on the islands of Hawaiʻi, Maui, Kahoʻolawe, Lānaʻi, Molokaʻi, Oʻahu and Kauaʻi. Today, its range is restricted to Hawaiʻi, Maui, Molokaʻi, and Kauaʻi. A pair arrived at the James Campbell National Wildlife Refuge on Oʻahu in January 2014; two of their offspring survived and are seen regularly on the nearby golf courses at Turtle Bay Resort.
The breeding season of the nene, from August to April, is longer than that of any other goose;[14] most eggs are laid between November and January.[10] Unlike most other waterfowl, the nene mates on land.[11] Nests are built by females on a site of her choosing, in which one to five eggs are laid (average is three on Maui and Hawaiʻi, four on Kauaʻi). Females incubate the eggs for 29 to 32 days, while the male acts as a sentry. Goslings are precocial, able to feed on their own; they remain with their parents until the following breeding season.[10]
The nene is a herbivore that will either graze or browse, depending on the availability of vegetation. Food items include the leaves, seeds, fruit, and flowers of grasses and shrubs.[12]
The nene population stands at 3,862 birds, making it the world's rarest goose.[15] It is believed that it was once common, with approximately 25,000 Hawaiian geese living in Hawaiʻi when Captain James Cook arrived in 1778.[11] Hunting and introduced predators, such as small Indian mongooses, pigs, and feral cats, reduced the population to 30 birds by 1952.[11] The species breeds well in captivity, and has been successfully re-introduced. In 2004, it was estimated that there were 800 birds in the wild, as well as 1,000 in wildfowl collections and zoos.[11] There is concern about inbreeding due to the small initial population of birds. The nature reserve WWT Slimbridge, in England, was instrumental in the successful breeding of Hawaiian geese in captivity. Under the direction of conservationist Peter Scott, it was bred back from the brink of extinction during the 1950s for later re-introduction into the wild in Hawaiʻi. There are still Hawaiian geese at Slimbridge today. They can now be found in captivity in multiple WWT centres. Successful introductions include Haleakala and Piʻiholo ranches on Maui.[16][17] NatureServe considers the species Imperiled.[18]
{{cite web}}: CS1 maint: url-status (link) The nene (Branta sandvicensis), also known as the nēnē or the Hawaiian goose, is a species of bird endemic to the Hawaiian Islands. The nene is exclusively found in the wild on the islands of Oahu, Maui, Kauaʻi, Molokai, and Hawaiʻi. In 1957, it was designated as the official state bird of the state of Hawaiʻi.
The Hawaiian name nēnē comes from its soft call. The specific name sandvicensis refers to the Sandwich Islands, a former name for the Hawaiian Islands.
