Field Notes: Thai Raptors


“Raptors” is the imprecise word that WC uses for falcons, hawks, eagles and buzzards. East Asia – or at least Thailand – seems to have a much greater variety of raptors than the New World. Here’s a selection of seven or so that WC photographed in Thailand this year and some brief notes on each. Photographing darkish birds against a bright sky is always problematic; these aren’t great photos. But they do show field marks and reveal the variety of raptors the country offers.

Eastern Marsh Harrier, Buen Boraphet, Thailand

The Eastern Marsh Harrier is a cogener to the more familiar New World Northern Harrier. Both are members of the genus Circus and, as you might expect, have much the same hunting style. This species winters in Indochina and other parts of southeast Asia, and breeds further north in Siberia, Mongolia and northern China.

Crested Serpent Eagle, Kaen Krachen, Thailand

This species has a wide range, a diet much broader than its name would suggest, and variable coloration. A study in India found it ate some 173 different prey items, ranging from termites and earthworms to reptiles and small mammals. The species seems quite adaptable to habitat disturbance, including logging. The systematics of this bird are completely unsettled; the numerous subspecies may prove to be full species.

Crested Goshawk, Kaen Krachen, Thailand

(This is a tight crop and the bird is still small in the frame; it was a long ways off.) Another species distributed across southeast Asia and India, this is a forest hunter, like its fellow Accipiter, North America’s Northern Goshawk. The eleven subspecies vary widely in size, ranging length from 30 to 46 centimeters, and wingspan from 224 to 450 centimeters. Preferred prey depends upon size/subspecies, but includes small mammals, lizards, frogs, birds and even large insects.

Black Baza, Kaeng Krachan N.P., Thailand

Mrs. WC spotted this bird along the side of the road. Black Baza are in a different genus than Accipiters like the Crested Goshawk, but still in the family Accipitridae. This is a southeast Asia species, generally found below 3,000 feet but in a variety of habitat types. It’s mostly an insectivore, although has been documented feeding on small mammals and reptiles. As you can see from the comparatively large eye, this is a crepuscular species.

Oriental Honey Buzzard, Doi Inthanon N.P., Thailand

Another member of the family Accipitridae, but in the genus Pernis, this remarkable species feeds primarily on social bees and wasps, their larvae and chunks of honeycomb and honey. It will take small mammals and reptiles, primarily to feed its young, but those are incidental. The species has a number of adaptations to deal with stinging insects, extracting larvae and digging out nests: scale-like feathers around the eyes, a long cere (a waxy, fleshy covering on the base of the upper bill), slit-like nares (nostril openings, more or less), a thin bill with hooked tip and long digits on its feet. Honey Buzzard, indeed.

Collared Falconets, Doi Inthanon N.P., Thailand

(Another case where the birds were very far away and the crop is very high.) This is one of the tiniest Falcons, of the family Falconidae. This species really is truly tiny, smaller than a Northern Shrike, just 30-50 grams, but can capture and kill birds as large as Pipits. It’s primarily an insectivore, but is known to take small birds. It’s found in southeast Asia with an additional isolated population in the Himalayas. We worked pretty hard to find this bird.

Black-eared Kite, Doi Chang Dao, Thailand

Finally, here’s a Black-eared Kite, depending who you talk to a subspecies of Black Kite (Milvus migrant lineatus) or a separate species. It is very widely distributed, in Asia from the Urals to Japan, south to southern India and the Indochinese Peninsula. It has a generalist diet. In flight, at least WC, it looks more like an eagle than an Accipiter.

Altogether, WC saw 17 species of raptors in Thailand and got photos of varying quality of 12 of them. It would be a very good trick to find that many in the U.S. in a comparably sized area.