Oriental, Asiatic, Eastern honey buzzard
The Crested honey buzzard (Pernis ptilorhynchus) is a medium-sized bird of prey that belongs to the family of other diurnal raptors such as kites, eagles, and harriers. The name of this species is derived from its unusual diet which consists mainly of the larvae of bees and wasps extracted from honey combs.
The Crested honey buzzard appears long-necked with a small head resembling that of a pigeon. It has a long tail and a short head crest. It is brown above, but not as dark as the European honey buzzard, and paler below. A dark throat stripe is present. Unusually for a large bird of prey, the sexes can be distinguished. The male has a blue-grey head with a brown iris, while the female's head is brown and the iris is yellow. She is slightly larger and darker than the male. The male has two black bands in the tail and three black underwing bands, while the female has three black tail bands and four narrower black underwing bands. The juvenile has extensive black primary tips with narrower underwing bands. It has a yellow cere at the base of the bill, and a dark iris. The coloration and the tail pattern of the species are highly variable.
Crested honey buzzards spend summer in Siberia and Japan, and winter in tropical Southeast Asia and the Indian subcontinent. Elsewhere, these birds are more or less resident. Crested honey buzzards prefer to live in well-forested lowland and hilly areas that are broken by open glades. In South and Southeast Asia, they are sometimes found in small groves near villages.
Crested honey buzzards are usually seen soaring singly or in pairs, or perched on a tree top. During migration, they may sometimes form small groups. In flight, these birds have deep elastic beats and high upstrokes. They glide and soars on flat or slightly arched wings at right angles to the body. They are quiet even while nesting, and sometimes only may utter a single high-pitched screaming whistle. Crested honey buzzards are diurnal birds and hunt by day. Unlike most of their relatives, they prefer larvae, pupae, and honey combs of social wasps and thus have special adaptations for this diet. When foraging both underground and arboreal nests, the birds have to contend with stinging attacks by wasps. The feathers around the head and neck are well suited to repelling such attacks. The honey buzzard has a dense mat of short feathers under its beak, around its eyes and nostrils, and on its neck with barbules closer together. They are stiffer with more hooks and nodes for barbules to attach to one another, yielding an armor-like appearance. In their summer breeding grounds in Japan, Crested honey buzzards dig up underground social wasp nests with their talons. The short toe depth and long talon on the second digit facilitate this behavior. In addition, the long slender beak with a hooked tip, and the eyes set far back, are adaptations well suited for foraging in underground nests. The tongue of these birds also has a groove adapted for extracting larvae from the honey comb.
Crested honey buzzards are carnivores. They are specialist feeders, living mainly on the larvae of social bees and wasps, and eating bits of comb and honey. They may also consume other small insect prey such as cicadas and occasionally eat small birds, reptiles, and frogs.
The breeding season in the migratory range is June to mid-September in central Siberia and April to August in Japan. In India, it is April-June, though it starts in February in South India. During this time the birds perform a mating display which includes wing clapping. The nest of a Crested honey buzzard is a platform of sticks 40-80 cm (16-31 in) across, lined with dry or green leaves. It is located at a height of 10-28 m (33-92 ft) in conifers in the north, and 6-20 m (20-66 ft) in banyan, mango, casuarina, or coconut in India. The female normally lays 2 eggs that are variable in color and range from pale cream to chestnut brown. Incubation takes 4-5 weeks and the chicks hatch altricial. They fledge in 5-6 weeks and become independent after further 58 weeks. The Male and the female share the responsibilities of rearing the young.
This species is vulnerable to wind conditions. Due to climate changes, the wind support for migration over the 680 km (420 mi) migratory pathway over the East China Sea could be reduced. Japanese researchers have developed a mathematical model to estimate the effect of climate change on the favorable winds over this section. They predict a slight reduction in the migratory areas due to this wind change effect by the middle of the 21st century and a complete loss of the migratory pathway by late in the century. The other serious threat to Crested honey buzzards is the loss of their native habitat.
According to IUCN Red List, the total population size of the Crested honey buzzard is around 100,000-1,000,000 individuals which is roughly equivalent to 66,666-666,666 mature individuals. The national population estimates include around 10,000-100,000 breeding pairs and around 1,000-10,000 individuals on migration in China; less than 100 breeding pairs, 1,000-10,000 individuals on migration and around 50-1,000 wintering individuals in Taiwan; around 10,000-100,000 breeding pairs and 1,000-10,000 individuals on migration in Korea; around 10,000-100,000 breeding pairs and 1,000-10,000 individuals on migration in Japan and around 10,000-100,000 breeding pairs and 1,000-10,000 individuals on migration in Russia. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
