Most of those who paraglide here will at some point get to see soaring birds in the sky, and even share a thermal with one of them. Taiwan is home to some indigenous raptors and also a migration route for sun-followers. Most of the paraglider pilots here are known to us by name, or from post-flight conversation over a beer in the landing area. Since the pilots with feathers only pass us in the air and usually don’t talk, this page attempts to put names to the faces.
I personally have a bit of a love-hate relationship with these animals. On the one hand I marvel at the hollow-bones which act as their built-in varios, their fantastic eyesight with which they can spot debris and insects rising in thermals literally from kilometers away. Then of course there is the speed and glide which make the paraglider pilot weep.
On the other hand it seems unfair that they can use motor power (flap) when they make a bad decision, and land in tree without damaging themselves or suffering any embarrassment at all.
There are a pair of birds that live in the hills around my house and every sunny day they cruise around, themaling and gliding their way around their territory, and calling out their piercing song along the valley. To me it sounds like a call from a friend to come flying. To a mouse it probably sounds like the end of the world. Maybe we are both right.
Black Kite (Milvans Migrans) The Latin name means migrating raptor, though the ones you see in Taiwan are resident, not migratory. The Black Kite is a medium-sized bird of prey in the family Accipitridae which also includes many other diurnal raptors such as eagles, buzzards, and harriers.
This kite is probably the most common of all the raptors and especially widespread throughout the temperate and tropical parts of Eurasia and parts of Australasia. European and central Asian birds are migratory, moving to the tropics in winter, but species from warmer regions such as the Indian Pariah Kite or the Australasian Fork-tailed Kite, are resident.
Black Kites will take small live prey as well as fish, household garbage and carrion. They are well adapted to living in cities and can be seen even over densely populated areas. They are attracted to fires and smoke where they hunt insects dragged aloft by thermal lift. Large numbers may be seen soaring in thermals over cities, hoping to feast on some hapless bugs. In some places they will readily swoop to take to food offered by humans, their habit of swooping to pick up dead rodents from roads often leads to them being hit by vehicles. They are also a major nuisance at some airports where they are considered important birdstrike hazards.
The Black Kite can be distinguished from the Red Kite by its slightly smaller size, less forked tail and generally dark plumage without any rufous. They nest in forest trees, often close to other kites. A smart paraglider pilot knows birds may be leading him not to the next thermal, but to his home.
Though these birds are resident to Taiwan they are not usually aggressively territorial. I’ve only once been chased out of ‘restricted airspace’ by Kites, presumably near a nest. Usually they calmly fly around and past you, barely seeming to notice your clumsy presence.
In terms of flight performance it’s noted that this bird has a minimum sink rate in glide of about 0.5m/s, vmax of about 16m/s and a best glide of about 15:1 at about 9m/s, falling off rapidly after that. He has quite poor performance compared to vultures or condors, though he does quite well compared to a hang glider, and beats a paraglider hands down.
Grey-Faced Buzzard (Butastur Indicus) A medium sized raptor with a grayish head and face, a white throat with a dark mesial streak and a white supercilium. The back and upper breast are brown, the lower underparts are whitish barred with brown. The tail bears three wide black bands. The iris, cere, legs and feet are yellow. Juveniles are generally paler and are streaked brown on the breast. In other words, they are quite a bit more colorful than the Black Kite, as well as a bit smaller.This species feeds mainly on frogs, reptiles and rodents, the preferred habitat being low mountains, hills and foothills. They breed in eastern China, eastern Russia and Japan, and winter mainly in Indochina, Malaysia and the Philippines. In Taiwan they are a common spring and summer migrant, and a few remain for the winter on Lanyu Island. As with most buzzards, these birds thermal and fly great distances by soaring during migration. Taiwan lies on a major migration route for this species, and large numbers may be seen moving southward in October along the Hengchun Peninsula, and northward in late March and early April along the terraced mountains of Taichung and Changhua.
The species breeds in Japan, Korea, Manchuria and Eastern Siberia. Their winter range includes Southern China, SE Asia, the Philippines, Celebes and New Guinea. There appear to be two populations. The first population group being found on Japan and the second on mainland Asia. The Japanese population migrates through the Ryukyu Islands and Taiwan to winter in the Philippines. The second population moves south into Southern China and SE Asia to winter. There is some indication that small numbers of Russian and Manchurian birds also use the island route to winter in the Philippines. Current estimates are that the Japanese population totals about 32,000 pairs with their young of the year.
As the Japanese population moves south in the fall, they enter Taiwan in large flocks in the NE part of the island and follow the eastern side of the central mountain range. They fly south following the ridges and roosting in river valleys. At the southern tip of Taiwan they pass through the Hengchun Peninsula in large numbers in the second week of October and often roost close to Manzhou Village. In the spring they tend to follow the western foothills of the central mountain range northwards in small groups and gather in fairly large numbers from mid to late March in the Baguashan area in Changhua County.
Some of the above text was borrowed from various places.