The Micronesian myzomela (Myzomela rubratra) is a small honeyeater. It is found on the Caroline and Mariana archipelagos, both part of Micronesia. It occurs in and around the edges of forests, as well as coconut plantations, coastal strand, savanna brush, villages, towns, and gardens.
Both sexes have a predominantly dark body with scarlet patchesthe location and coloration, however, varies widely by subspecies. When mature, the female, unlike the male, usually has olive fringing on her tail and wing feathers and brown on her body. The male does not have any brown on his body. Juveniles are much more brown than adults and have little or no red coloring. The Micronesian myzomela has a unique song at dawna continuous stream of trilled whistles and phrases, lasting for about 25 minutes on Kosrae, Yap, or Pohnpei, or a wheezy whistle on the Mariana Islands. Later in the day, the Kosrae bird produces a short, variable song and a wide array of scolding or buzzy calls. On the Mariana Islands, the daytime song is a simple and tuneful "per-mit-you". The Palau bird's call is unique to the species, resembling that of the great crested flycatcher or Micronesian starling. It is omnivorous, feeding on nectar and small invertebrates, mainly insects.
The Micronesian myzomela likely breeds year-round. Courtship behaviors are variedgrounded displays where pairs walk together along branches on Aguiguan; erratic aerial chases where the male chases the female, often touching wingtips on Guam. The nest is built low to the ground, in shrubs or small trees with thick foliage, often along woodland edges, open areas, or near residential buildings. It is cup-shaped, and may be composed of grasses and other plant fibers, often with a distinct inner lining. The nest measures between in width and in depth. The bird usually lays 1 to 2 eggs per , which are glossy and white to off-white with brown speckles, with dimensions of about . Incubation is probably done solely by the female and takes 15 to 16 days. Hatchlings are altricial, fledging after two weeks.
It is considered a least-concern species by BirdLife International with an estimated total population of 850,000–900,000 individuals spread across an estimated range of ; however, land development and invasive species have led to a decline on some islands, among them Guam, where the introduced brown tree snake drove the Micronesian myzomela to local extinction in 1986.
Taxonomy The Micronesian myzomela was first formally described as Cinnyris rubrater by René Lesson in 1827 on Kosrae. In 1835 it was designated Certhia cardinalis by Heinrich von Kittlitz. In 1850, Charles Lucien Bonaparte became the first to place it in its current genus, Myzomela, assigning it the specific epithet sanguinolenta (from Latin sanguis, meaning "blood".) It was then renamed by Gustav Hartlaub, first in 1852 as M. rubrater, then in 1854 as M. rubratra, which it has kept since. In 1932, Ernst Mayr deemed it conspecific with the cardinal myzomela, however it was later split back out in 1987 due to differences in appearance and voice. Its specific epithet, rubratra, is a compound of Latin rubra and atra, meaning "red" and "black" respectively, and its genus, Myzomela, comes from Greek muzaō (meaning "to suck") and meli (meaning "honey").
Within the genus Myzomela, the Micronesian myzomela is most closely related to the Rotuma myzomela (M. chermesina); together, they form part of a small clade that also includes the sulphur-breasted myzomela, the Samoan myzomela, and the cardinal myzomela. Subspecies
Seven subspecies of the Micronesian myzomela are recognized.
Description The Micronesian myzomela is a small honeyeater measuring 13 cm in length. The sexes differ in size and appearance: the adult male weighs 15 g (range 12.7–18 g) and has a 72 mm wing chord, a 13 mm bill, a 55 mm tail, and a 21 mm . The adult female is smaller, weighing 12.7 g (range 10.4–15 g) and with a wing chord measuring 66 mm, a 11 mm bill, a 55 mm tail, and a 20 mm tarsus. The bill is distinctly curved downwards. It is colored brown with a yellow base in juveniles, darkening with age, becoming completely black in adults. Similarly, the also darkens with age, starting bright yellow and becoming black in adults. The tongue is also bright yellow. Its iris is dark brown, and its toes and tarsi are scaly and dark brown, with the undersides of the feet being dull yellow.
The female has dusky brown tail and wing feathers fringed with olive, and a predominantly black or brown body with scarlet patches. The male is similar, though his patches are more vermilion and he lacks any brown coloring. The extent and placement of the patches vary between subspecies in both sexes. Juveniles of both sexes are browner compared to adults and have little to no red coloring. Juveniles molt three months after fledging, taking on a new formative plumage that greatly resembles adults; however, they may have slightly duller body feathering. One to three months after breeding, the Micronesian myzomela will molt into its adult plumage, completely replacing all of its feathers; however, this is sometimes paused, likely for additional breeding.
Geographic variation On Kosrae, the adult male's body is almost entirely scarlet, excluding the thighs and the lores (the area between the eye and nostrils), which are black. The adult female's plumage is similar, although she is smaller in size, and her coloring is duller. The juvenile of both sexes is reminiscent of the adult, although it is of a lighter tone in comparison, and its coloring is not as vivid.
The adult male of Pohnpei strongly resembles that of the Kosrae bird, except that the black markings on his lores and below the eye are more substantial, and the tips of his colored feathers are brighter. The adult female is also similar to that of Kosrae, though the extent of her red plumage is greatly reduced. Her chin, throat, and the underside of her tail are reddish. The rest of her body is colored various shades of brownish-gray, occasionally with reddish patches. The juvenile male resembles the adult, except that his scarlet coloring is less vivid and is thinner on his , forehead, , and the base of his tail. The red coloring is usually absent from his neck and the top of his head. The juvenile female is also like the adult, but her scarlet coloring is thinner and only visible on her back, rump, underparts, and the base of her tail.
On Chuuk Lagoon, both sexes look similar to the Kosrae bird. The adult male's feathers are lighter on the tips. The adult female's underparts are colored a brighter scarlet. The juvenile male looks similar to the adult female, except the feathers on his head and neck have less scarlet coloring on the tips. The juvenile female resembles the juvenile female of Kosrae, except that her upperparts are grayer and her underparts are darker.
On Yap, the adult male resembles the adult male of the Mariana Islands, although his legs are shorter, and his plumage is less orange-hued. The adult female's upperparts are a dark green-brown. Her underparts are paler but otherwise similar, though her breast and abdomen may be yellow-gray. Her head, rump, and lower back, along with her entire frontside, are all tinged scarlet. The immature male resembles the adult female, but his lower back, rump, the underside of his tail, and the top of his head are a much deeper scarlet. His lower parts are tinged with scarlet, though paler than the adult male's. The front of his neck is only faintly tinged, showing a dark band. Some specimens have faintly fringed with scarlet and a very narrow olivaceous on the quills' fringes. Immature females and young birds of both sexes resemble the adult female but have a weaker scarlet tinge.
In Palau, the adult male resembles the Kosrae bird; however he is smaller and the scarlet coloring on his body is darker, more so than that of any other subspecies. The adult female resembles the female of Pohnpei, although her abdomen, the underside of her tail feathers, and her "armpits" (axillary feathers) are rust-gray. Unlike all other subspecies, the top of her head is only partly colored red. The juvenile male resembles the adult except for his lighter and scantier scarlet coloring. His wings and tail are green-brown, and the underside of his tail is off-gray. The juvenile female is like the adult, just that her scarlet coloring is paler and her underparts are tinted red.
On Rota, Aguiguan, Tinian, and Saipan, both sexes resemble the Kosrae bird, with minor differences. The adult male is slightly smaller and his scarlet coloring is more orange. Unlike the other subspecies, the wings and tail of the southern Mariana male are tinted olive. The adult female is also smaller and paler in color. Her upperparts are dark green-gray occasionally mottled with scarlet, and the underside of her tail and her abdomen are red-gray. She can be differentiated from other subspecies by her scarlet-tipped feathers on the top of her head, and the dark olive coloring on the edges of her tail feathers. Birds from Anatahan north to Asuncion are visually identical to these at all ages and in both sexes.
Vocalizations
The Micronesian myzomela has a complex dawn song that differs from its vocalizations later in the day. On Kosrae, the song begins before there is enough light to see the bird and lasts until it is visible (about 25 minutes); it has been described as sounding like multiple birds singing in unison. The song consists of a continuous stream of trilled whistles and phrases, which may be transcribed as "cheeky cheeky can't beat the heat," "too sweet to eat," or "she eats a pizza". The dawn song on Yap and Pohnpei is similar but slower and less slurred. Later in the day, the Kosrae bird's song is short and highly variable, usually consisting of two slurred notes ("seee-oo SEET" or "schweer cheap-beer") and one emphatic note. The calls have been described as "rather uninteresting" but are more variable still, and include sharp "tseep!" notes that may be repeated, short buzzy calls, and rough scolds.
The dawn song on the Mariana Islands is a "wheezy whistle"; on the Northern Mariana Islands it can be transcribed as "ee-zoo-zee-zoo-zee" or "zeeoo-ZEE-zoo-zee". The daytime song, most commonly heard in the early morning, is a simple and tuneful "per-mit-you". In Palau, the calls are unlike those of the Mariana Islands populations and instead resemble those of the great crested flycatcher of North America; the Palau call may also be confused with that of the Micronesian starling.
Distribution and habitat The Micronesian myzomela is a permanent resident of the Caroline and Mariana islands. It has not been observed moving between islands, but the short distances between some in a chain means it is probably capable of interinsular travel: the closely related Rotuma myzomela, which is found on Rotuma of open ocean away from Pohnpei, is likely the result of a rare dispersion between the two islands. The Micronesian myzomela can be found in and on the edges of forests, including secondary, Clinostigma, mangrove, and agroforest types. It also inhabits coconut plantations, coastal strand, savanna brush, villages, towns, and gardens.