'Akepa

Maximum longevity: 10 years (wild)

Little is known about predation pressures on akepas. Introduced species, such as domestic cats (Felis silvestris), Polynesian rats (Rattus exulans), black or roof rats (Rattus rattus), brown rats (Rattus norvegicus), Indian mongooses (Herpestes javanicus), and common mynas (Acridotheres tristis), are believed to be potential predators. Natural predators are thought to be bird-eating owls, pueos (Asio flammeus sandwichensis), and Hawaiian hawks, or 'los (Buteo solitarius).

Known Predators:

• pueos (Asio flammeus sandwichensis)
• 'los (Buteo solitarius)
• domestic cats (Felis silvestris)
• Polynesian rats (Rattus exulans)
• brown rats (Rattus norvegicus)
• black or roof rats (Rattus rattus)
• Indian mongooses (Herpestes javanicus)
• common mynas (Acridotheres tristis)

Akepas range in body length from 10 to 13 centimeters, have a wingspan of 59 to 69 millimeters, and weigh anywhere from 10 to 12 grams. The males tend to be bright red-orange with brown wings and tails. Females, on the other hand, tend to be green or grey with yellow on the underside. Their yellow bills are known for their lateral asymmetry, which is an adaptation to help obtain food.

Range mass: 10 to 12 g.

Range length: 10 to 13 cm.

Range wingspan: 59 to 69 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes colored or patterned differently; male more colorful

Tagged females in the wild have lived for at least 10 years. No information on akepas living in captivity could be found. Little is known about the causes of mortality. Juveniles have a lower survivorship than adults, and most hypothesized causes of mortality relate to juveniles. Predation from introduced species is one of these possible causes, as well as diseases transported through mosquitos.

Range lifespan
Status: wild: 10 (high) years.

Akepas inhabit closed canopied forest composed of native trees, including ohia (Metrosideros collina) or koa (Acacia koa) trees. The densest populations of Hawai'ian akepas tend to be found above 1,500 m. Little is known about the specific locations of the Maui akepa populations, but they are believed to live in montane areas as well.

Range elevation: 1,100 to 2,100 m.

Average elevation: 1,600 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: rainforest

Akepas are found mainly on the island of Hawai'i. Hawai'ian populations are currently located mostly on the eastern slopes of Mauna Kea, the eastern and southern slopes of Mauna Loa, and the northern slope of Hualalai. There is one subspecies on the island of O'ahu and another one considered extinct on Maui. Akepas do not migrate.

Biogeographic Regions: oceanic islands (Native ); pacific ocean (Native )

Other Geographic Terms: island endemic

The genus name Loxops comes from the Greek word Loxia, which means "to look like a crossbill", and is given to the akepa because of its asymmetrical bill shape. The species epithet coccineus comes from the Latin word coccinus, which means scarlet, in reference to the adult male plumage color. The common name, akepa, in Hawaiian means "lively" or "nimble" which describes their restless behavior. Also, the word "kepa" means "to cut obliquely" or "turn to one side", which could be a reference to the distinguishing asymmetrical bill shape.

Akepas are songbirds that use vocalizations to communicate in most cases. Little is understood about the functions of akepa vocalizations, although these birds vocalize throughout all months of the year. The male call is a high-pitched, descending trill. Juvenile communication is used mainly as a means of obtaining the attention of the parents and maintaining contact with parents. Akepas are not known to make any nonvocal sounds.

Communication Channels: visual ; acoustic

Perception Channels: visual ; tactile ; acoustic ; chemical

Both extant subspecies of akepas are listed as endangered according to the IUCN Red List, the United States Endangered Species Act list, and the state of Hawai'i. The largest threat for the species is habitat destruction as a result of logging and forest clearing for animal grazing. Other reasons include predation of akepas by introduced species and declining numbers of ohia trees, in which akepas build their nests. Currently much of the lands akepas inhabit have become state or national parks, but more is needed to save their dwindling populations.

US Migratory Bird Act: no special status

US Federal List: endangered

CITES: no special status

IUCN Red List of Threatened Species: endangered

Hawaiian akepas have no negative economic impact on humans.

Akepas are an important part of the native Hawai'ian avifauna and attract ecotourism.

Positive Impacts: ecotourism

Akepas may help to pollinate flowers when they eat nectar. They may also impact the populations of insects on which they prey.

The odd, asymmetrical bills of akepas help them to pry apart scales of buds in search of their prey. They feed on insects and spiders, though their main diet consists of caterpillars. They have been seen feeding on nectar to a lesser extent. They may take nectar incidentally while searching for insect prey but the brushy tip of the tongue and the capability to role it up into a tube suggest adaptations for nectar feeding.

Animal Foods: insects; terrestrial non-insect arthropods

Plant Foods: nectar

Primary Diet: carnivore (Insectivore , Eats non-insect arthropods); herbivore (Nectarivore )

Akepas search for a single partner, during which the male performs a mating ritual in order to attract a female. Akepas form monogamous pairs during July and August (the postbreeding flocking period) and bonds last several years. In a majority of observed pairs, the birds only obtained a new mate after the previous mate had disappeared.

Mating System: monogamous

In the prebreeding period, akepa males display their most aggressive behavior. Competitive groups have been seen in aerial displays that can reach up to 100 m off the ground. These males sometimes get into dogfights, in which two or more individuals will engage in twisting or circular chase fights. In addition, males engage in aggressive “song bouts”, where two or more individuals vigorously sing at the same time in close proximity to one another.

The breeding period of akepas begins in March and ends by September. The male and female search for nesting sites after pairing. Females are responsible for nest construction. Once the clutch is laid the female incubates the eggs. After hatching, little is known about the young. Both parents feed the chicks, which develop their juvenile plumage by day 12. Young akepas are often dependent on parental care well after leaving the nest, and both parents participate in this stage of care.

Some females have been observed to breed successfully in their second year, although it is more common for females to commence breeding in the third year. Males have not been observed to breed successfully in their second year. Akepa juvenile plumage looks much like the female adult plumage: green or gray with a gray underside. Males usually do not obtain their full adult plumage until their fourth year. Nonetheless, some third year males successfully mate before they obtain full adult plumage. The delayed acquisition of adult male plumage in monogamous, non-territorial birds in which males perform parental care is highly unusual and only known in akepas. Researchers have hypothesized that it may be a result of the highly competitive and complicated mating rituals the males perform. These factors could have selected for males with delayed maturation because younger males are not capable of competing with the older males for a mate.

Breeding interval: Akepas usually breed once yearly.

Breeding season: Akepas breed from March until September.

Range eggs per season: 1 to 3.

Range time to hatching: 14 to 16 days.

Range fledging age: 16 to 20 months.

Range time to independence: 10 (high) weeks.

Range age at sexual or reproductive maturity (female): 2 to 3 years.

Range age at sexual or reproductive maturity (male): 3 to 4 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous

Once the clutch is laid, typically with one or two eggs and in rare cases with three, the eggs are incubated for 14 to 16 days by the female. Throughout this period the males sometimes feed the females, although females also forage for themselves. After hatching little is known about the young. Females brood the hatchlings for up to 8 days. Males, in return, feed females until after the brooding period. Both males and females will feed the young after this stage of development. Young akepas leave the nest around 16 to 20 days after hatching. They remain near the parents during this period, following their parents and vocalizing to beg for food. They may remain dependent on their parents for up to ten weeks after hatching.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)

The akepa is principally found high up in the forest canopy, where it forages for invertebrates amongst twigs, crevices and, in particular, the leaf and flower buds of the ohia tree. Using its unusual, crossed bill tips, it pries open the buds, extracting caterpillars and spiders (2) (3) (4) and sweeping out nectar with the brush-like tip of its tongue (3). The reproductive behaviour of the akepa is relatively complex, with the juvenile males engaging in pre-breeding periods of competition, lasting from October to March, for a number of years before finally breeding. Competitive activities include chases, group displays and stunning aerial “dogfights” in which rival males may soar together up to 100 metres into the air before separating. The males compete for the opportunity to form long-term breeding pairs with females possessing the brightest yellow-orange patches. These females are more likely to raise chicks successfully than duller females of the same age, but are much less abundant (3). Nest building occurs from early March to late May, with the female locating a suitable tree cavity in which a clutch of one to three eggs is laid. During incubation, the male provides food for the female, and, once hatched, contributes to the feeding of the chicks as well. Fledging occurs from early April to late June, with the fledglings remaining with their parents until September or October, at which point they join foraging flocks (3).

Listed as Endangered by the U.S. Fish and Wildlife Service in 1970, the akepa was one of the species targeted in the 1982 Hawaii Forest Bird Recovery Plan, leading to the improved protection and management of its habitat (3). A number of protected areas currently support akepa populations, in particular, Hakalau Forest National Wildlife Refuge, which contains large numbers. Within these areas, reforestation efforts are helping to restore this species' habitat in the long-term, while artificial nesting boxes are providing a promising short-term benefit to the akepa's survival (2) (3). Unfortunately, there are no simple solutions to the threat of disease. Wiping out introduced mosquitoes does not appear to be feasible and, therefore, the only solution may be to try and find disease-resistant akepa individuals which can be selectively bred and distributed amongst the wild populations (3). While it is hoped that such efforts will preserve the akepa in the wild, should its population crash, captive breeding programs have been established to ensure that this fascinating species is prevented from disappearing forever (2) (3).

Superficially resembling a finch, the akepa is diminutive species which is remarkable for its unusual bill, the tips of which are misaligned due to the lower part curving slightly to the side (2) (3). The male undergoes a lengthy and significant change in plumage colour over the course of its development. In its first and second year, the juvenile male is mainly greyish-green and resembles the adult female, but by its third year it develops a bright orange head and a dull brownish-orange body. Finally, in its fourth year it obtains the full mature colouration (4) (5), with arresting bright red-orange plumage over its entire head and body, except on the wings and tail which are dark brown or black (2) (6). Although the female mostly remains a dull greyish-green throughout its development, the adult female does obtain yellow-orange patches on the breast, throat and head, which become increasingly bright with age (3). The akepa's vocalisations vary from a slow trilling song to a characteristic call, cheedle-ee (2).

Historically common throughout Hawaii Island, today the akepa is restricted to forests at elevations between 1,300 and 2,100 metres (3). This species is totally reliant on the presence of large mature trees with naturally occurring cavities for nesting, favouring forests composed of ohia (Metrosideros polymorpha) (2), or a mix of ohia and koa (Acacia koa) (3).

While today, the only surviving akepa population is that of the subspecies Loxops coccineus coccineus on Hawaii Island, additional subspecies of akepa were previously found on Oahu and Maui (2) (3). The Oahu subspecies has been extinct for over 50 years (4), but the Maui subspecies disappeared more recently, with the last sighting in 1988 (2).

Classified as Endangered (EN) on the IUCN Red List (1).

With its dependence on large, mature trees, the extensive forest clearance that has occurred on Hawaii has had a catastrophic effect on the akepa. Not only have significant numbers of mature trees been lost to logging, but the remaining exposed trees have become more vulnerable to windfall. Despite reforestation efforts, the planted trees take decades to develop natural cavities, and cannot possibly provide the akepa with nesting habitat fast enough to offset its rapid population decline (2) (3). A further threat to this species is the introduction of non-native predators and disease-carrying mosquitoes to Hawaii. The mosquitoes transmit avian malaria and avian pox, to which the previously unexposed akepa lacks any resistance. As a result, its population has become restricted to elevations above 1,300 metres, where the cooler temperatures prevent the mosquitoes' survival. Nevertheless, as global climate change causes temperatures to rise, the disease is likely to spread to these higher elevations (3).

The Hawaiʻi ʻakepa (Loxops coccineus) is an endangered ʻakepa native to Hawaiʻi in the Hawaiian Islands. All three of the ʻakepa were considered monotypic before being split by the NACC of the AOU in 2015. The Hawaii ʻakepa was first collected by western science during Captain James Cook's third voyage around the world. Several specimens were collected, as well as feather leis (necklaces resembling strings of flowers) constructed by Hawaiian artisans. The specimens were classified when brought back to England several years later. The Latin name of the bird, Loxops coccineus, means "crossed" (Loxops) and "red" (coccineus).