The fairy pitta (Pitta nympha) is a small and brightly colored species of passerine bird in the family Pittidae. Its diet mainly consists of earthworms, spiders, insects, slugs, and snails. The fairy pitta breeds in East Asia and migrates south to winter in Southeast Asia. Due to various habitat and anthropogenic disruptions, such as deforestation, wildfire, hunting, trapping, and cage-bird trade, the fairy pitta is rare and the population is declining in most places. Listed on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II, this bird is classified as vulnerable on the IUCN Red List of Threatened Species.
Taxonomy The fairy pitta is one of around 14 species in the genus Pitta. Within the genus, it is most closely related to the hooded pitta, with these two species forming a clade that is sister to the blue-winged pitta.
The fairy pitta was first described in 1847. It was formerly considered to be conspecific with the Indian pitta, but it has since been split due to differences in plumage, morphology, and vocalization. The generic name Pitta is from the Telugu word pitta, meaning a pretty bauble or pet, while the specific epithet nympha is from the Latin word nympha, meaning nymph. Alternative names for the species include lesser blue-winged pitta, Chinese pitta, little forest angel, and eight-coloured bird.
The species is monotypic. In contemporary taxonomy, the fairy pitta forms a superspecies with the Indian pitta, mangrove pitta (P. megarhyncha) and blue-winged pitta (P. moluccensis). The fairy pitta is the most northerly species of pitta and is the only species breeding in northeast Asia.
Description The fairy pitta has a body length of and is easily discernible for its plumage of seven different colors reminiscent of a rainbow. Its back and wing bows are green, scapulars and upper tail coverts are green and cobalt. There is a blue rump on upper tail coverts. The tail is dark green with a cobalt tip, and the tarsi are yellowish brown.
The fairy pitta has different colors of wing coverts as well. Its primary coverts are dark blue, secondary coverts are greenish blue, greater and middle coverts are dark green, and lesser coverts are cobalt or bright blue. The bird's white patch on each of their brownish-black primaries are noticeable when it flies. Its lower body, including nape, chest, and side, is cream-colored, except for the lower belly and undertail coverts, which are red. The bird has a chestnut crown. From its forehead to the back of its head is mantled with brown plumage, whereas its median is striped with black from lores to nape. The off-white supercilia extend across the nape. The fairy pitta has a white throat and a black beak.
A species with a similar appearance is the blue-winged pitta, which is larger than the fairy pitta. The blue-winged pitta has buff crown sides and supercilia, rather than the chestnut of the fairy pitta, brighter upper tail coverts, darker yellowish brown belly, and vivid blue on upper wing coverts.
The song of the fairy pitta is clear and whistled kwah-he kwa-wu, which is similar to that of the blue-winged pitta, but longer and slower.
Distribution and habitat
The fairy pitta is a migratory species and travels from Northeast Asia, where it breeds in summer (April–September) to South and Southeast Asia to spend the winter (October–March). Sightings have been reported from India and Indochina, including both the Bruneian and Kalimantan sides of the island of Borneo, and New Guinea, as well as in China, North Korea, South Korea, and Taiwan. Recorded stopovers are in North Korea, Vietnam, Hong Kong, the Philippines, and Thailand. Following the same migratory routes in both spring and autumn every year, the majority of passages occur in April and September to October. Even though the bird is fairly widespread throughout the eastern part of Asia, the fact that it is highly localized in subtropical forests suggests that the fairy pitta is faithful to wintering sites and requires specific habitat conditions.
The fairy pitta leaving from Borneo in spring arrives in the Korean Peninsula in early or mid-May and departs back to south in October. However, migrations occur throughout the country in spring and winter. The fairy pitta breeds on the coasts, islands, or in dense and moist deciduous forests, such as camellia forest, in Hwanghae Province, Gyeonggi Province, South Gyeongsang Province, and South Jeolla Province. Among those habitats, the fairy pitta mostly prefers islands off the southern part of Korea. Especially in Geoje in South Gyeongsang Province and Jeju Island, regular visits of the fairy pitta to the same locations have been reported. In Jeju Island alone, more than 60 pairs are thought to be breeding regularly in the altitude of 100 m to 600 m in Halla Mountain, making the island the most important breeding ground in South Korea. Subspecies in the Korean Peninsula is distributed to East China, as far as to the Shandong Peninsula, and limited regions in Taiwan.
In Japan, the fairy pitta arrives at both the Sea of Japan and the Pacific sides of southern Japan, including the islands of Kyushu, Honshu, Shikoku, Tsushima, with notable populations in Miyazaki Prefecture, Kōchi Prefecture, Hiroshima Prefecture, and as far north as Hokkaido, in mid-May. Similar to the groups breeding in Korea, the fairy pitta in Japan favors places with dense undergrowth of bushes, ferns, scrub, and grass, but with good visibility to be aware of predators or disturbances. The bird here exclusively nests in coastal deciduous evergreen forests. In 1991, 93.5% of the breeding sites were found in broadleaf evergreen or deciduous forest, whereas only 6.5% were in mixed coniferous-broadleaf forest. In recent years, however, a trend of the fairy pitta nesting in plantations has been noticed. In Kōchi Prefecture, for instance, the fairy pitta prefers Japanese red pine (Pinus densiflora) forest during the early days of its breeding season. The fairy pitta in Japan mostly dwells on hill slopes below the altitude of 500 m, but occasional recordings indicate that some pairs live at altitudes as high as 1,200 m.
In Taiwan, the species was similarly found to favor areas covered with thick crown layer, variety of trees, no shrub or vine near the nest, and steep slopes that prevent intrusion of other animals. Arriving in mid to late April, the bird is usually spotted in the central and western regions, where much of the land is hilly or mountainous, at altitudes no higher than 1,300 m.
In China, the fairy pitta seems to be widely distributed in the mountains in the southeast, in mixed forests at altitudes between 500 m and 1,500 m. The same preference extends to Hong Kong, where the bird stops along its course of migrations.
Behavior The fairy pitta is a territorial bird, and the male defends its territory through calls. Its general habit is however secretive. From mid-May to early June, sometimes to late July, it likes to perch on a high tree branch in a posture resembling that of a kingfisher. However, the fairy pitta tends to repeatedly shake its tail up and down while singing on a branch.
Diet and feeding The fairy pitta mostly feeds on the ground, wandering solitarily. Its diet largely consists of earthworms of several species, beetles, and other hard-shelled insects. A variety of other small animals such as lepidoptera larvae and adults, spiders, snails, lizards, frogs, small snakes, and shrews, occasionally form part of its diet. Earthworms make up 73%–82% of the diet fed to the nestlings, followed by homoptera larvae (4%–8.6%). Although not entirely identifiable, lepidopteran adults and pupae likely make up 11% of the nestling diet. The fairy pitta's preference for earthworms with their high energy content makes the abundance of this food item critical for nesting success.
Reproduction The fairy pitta makes a relatively large nest in the dark place, such as in the crevice between rocks in thick broadleaf forest or foliage on a slope, 1–5 m above the ground. The entrance is lined with cattle dung and the nest itself is lined with lichen. If necessary, the male aggressively defends the nest, chases after and attacking intruders. Such defensive behavior is only displayed until the eggs are laid.
The female lays from 4 to 6 eggs per bredding attempt, from May to mid-July. The egg has a light gray background with small light brownish purple and grey dots, and is 25–27.5 mm in the major axis and 19–22.5 mm in the minor axis. Both male and female incubate the eggs; the female usually feeds the hatchlings, while the male keeps watch. In the first 4 days after hatching, the fairy pitta rarely leaves the nest. This is probably because temperatures are low during the rainy season and the nestling hatches without any down feathers. The nestling has its first plumage within 14 days after hatching. Throughout the breeding season, the adult bird rarely goes farther than 100–400 m from the nest. In June or July, the chick fledges, but the rearing continues until the nestling is ready to migrate south. The average reproductive success of the fairy pitta is 41.9%.
Mortality The predators most affecting the reproductive success of the fairy pitta are snakes, followed by mammals such as macaques, cats and weasels. The raiding of nests by jungle crows (Corvus macrorhynchos) and cat snakes during breeding season has also been reported frequently. During migrations, the bird is exposed to danger from falcons. The rate at which adult fairy pittas return from the wintering grounds appears to be 16–26%; most casualties happening on the bird's northward migrating and during breeding seasons from May to July. Fewer birds are lost during the autumn migration in October. Another cause of mortality is window strikes. As for many other species of bird, casualties from human-bird interaction are identified as a leading cause of decline in the fairy pitta.
Status and conservation
Population trend and threats There is no very accurate estimate of total population size of the species. Estimated numbers include ranges of 100 to 10,000 breeding pairs and 50 to 1,000 migrating individuals respectively in China, Korea, Japan, and Taiwan; total population size is thought to be somewhere between a few thousand and a few tens of thousands of individuals. Although researchers estimate that the largest number of birds survive in China, no concrete study has been done. However, a worldwide trend of decline in the fairy pitta is clear enough to lead to a classification of the species as vulnerable on the IUCN Red List of Threatened Species and as endangered in CITES Appendix II. The main causes for the decline are habitat loss, trapping, hunting, and human disturbances.