Philippine creepers

(Rhabdornithidae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Rhabdornithidae

Thumbnail description
Medium-sized birds with long, slender bills and brush-tipped tongues; shaded and marked with brown, black, gray, and white

Size
6–7 in (15–17 cm), 3–4 oz (80–95 g)

Number of genera, species
1 genus, 3 species

Habitat
Forest

Conservation status
Not threatened

Distribution
Endemic to several major and minor Philippine Islands

Evolution and systematics

The rhabdornises are an obscure family, still only partially known. They have been difficult to classify, and no significant DNA-DNA hybrid, mitichondrial DNA, or other molecular comparison studies have been made.

Some ornithologists once placed the rhabdornises as a sub-family within the treecreepers (family Certhiidae), but the idea has been discarded since the birds show no real resemblance to the true treecreepers and behave quite differently. When foraging, treecreepers run along the tops of tree branches and crawl about over tree bark on the trunks and main limbs, but rhabdornises hop and jump between branches, and show no significant "creeping" behavior. Rhabdornises also have brush-tipped tongues, a feature unknown among the Certhiidae. As of 2002, ornithologists generally concur in placing rhabdornises in a discrete family, Rhabdornithidae. Their closest relations are probably the babblers (family Timaliidae).

As of 2002, the life sciences recognize three species of rhabdornises within a single genus: The greater rhabdornis (Rhabdornis grandis) which is not recognized by Peters, the stripe-breasted rhabdornis (Rhabdornis inornatus), and the stripe-headed rhabdornis (Rhabdornis mysticalis).

Physical characteristics

Rhabdornises are medium-sized birds, very similar in size, coloring, and behavior, so much so that they may be indistinguishable to untrained eyes. The coloring and patterns are somewhat cryptic, favoring browns, red-browns, blacks, and whites, with much dark streaking on the upperparts and lighter streaking elsewhere.

Distribution

The major Philippine Islands of Luzon, Samar, Leyte, Mindanao, Negros, and Panay, and several smaller islands: Catanduanes, Masbate, Calicoan, Dinagat, Basilan, and Bohol.

Habitat

Dense, tropical, primary and secondary lowland and montane forest, in the upper levels and crowns of trees.

Behavior

Rhabdornises are diurnal and social, spending their days foraging in flocks. These flocks may be mixed species, either of rhabdornis or non-rhabdornis species. At dusk, rhabdornis flocks settle down in groups among the upper branches of forest trees for the night.

Feeding ecology and diet

The main rhabdornis fare is insects, which the birds search for on the bark of tree trunks and branches and among flowers, but all add nectar, fruit, and seeds to the diet.

Reproductive biology

Little is known about rhabdornis reproductive biology. They nest in tree holes, but there is no information on what they use for nest materials or on the appearance of the eggs. Breeding probably begins in March.

Conservation status

The stripe-breasted rhabdornis and stripe-headed rhabdornis are common throughout their ranges, while the greater rhabdornis is relatively rare and confined to mountainous regions in Luzon. None are listed on the IUCN 2000 Red List of Threatened Species. In the longer run, all may be endangered, since the native forests of the Philippines are being destroyed at an accelerating rate.

Significance to humans

None known.

Species accounts

List of Species

Greater rhabdornis

Rhabdornis grandis

taxonomy

Rhabdornis grandis Salomonsen, 1953.

other common names

English: Long-billed rhabdornis; French: Rhabdornis á long bec; German: Langschnabel-Rhabdornis; Spanish: Trepador Filipino Grande.

physical characteristics

This species has an average length of 6.7 in (17 cm) and weighs about 3.3 oz (93 g). The male is larger than the female, but the sexes are similar in coloring, with black or dark brown bills and brown eyes, and olive-gray legs. Upperparts are patterned with gray, brown, black, and white, in characteristic streak patterns. The face has a black mask with white lines above and below. The lower breast and belly are white.

distribution

The Cordillera and Sierra Madre on Luzon Island.

habitat

Middle-elevation (330–3,300 ft; 100–1,000 m), tropical forest.

behavior

The greater rhabdornis forages in groups or mixed-species flocks in the upper levels of forests. Greater rhabdornises will often flock with stripe-headed rhabdornises in flowering or fruiting trees.

feeding ecology and diet

Forages like other rhabdornis species, hopping and jumping along branches, searching for and eating insects among leaves, bark, and flowers. It will vary its diet with nectar, seeds, and fruit.

reproductive biology

Nests in tree holes. Enlarged gonads in May.

conservation status

Uncommon, but not threatened.

significance to humans

None known.

Stripe-breasted rhabdornis

Rhabdornis inornatus

taxonomy

Rhabdornis inornatus Ogilvie-Grant, 1896.

other common names

English: Plain-headed rhabdornis, plain-headed creeper; French: Rhabdornis á tête brune; German: Braunkopf-Rhabdornis; Spanish: Trepador Filipino de Cabeza Lisa.

physical characteristics

These birds are 6.3 in (16 cm) long, and weigh about 3 oz (86 g). As with its bigger relative, the sexes show little in the way of

color differences. Both sexes have a black bill, dark brown eyes, and legs ranging from grayish yellow to horn. The upperparts are medium-brown, while the crown, tail, and primaries are darker brown. The mask is dark brown, bordered above and below by white. The throat is grayish white and the center of the belly is white, while the breast, flanks, and undertail feathers are streaked white and brown. The female has lighter brown upperparts and mask.

distribution

Endemic to the islands of Samar, Basilan, Leyte, Mindanao, Negros, and Panay.

habitat

Prefers tropical forest over 2,600 ft (800 m) above sea level, but will sometimes range into lower levels.

behavior

Behavior is similar to that of the stripe-headed rhabdornis, but stripe-breasteds prefer smaller foraging flocks of 4–5 individuals. The birds will sometimes roost in large numbers in the isolated canopy of a group of trees in a clearing. The call is a high-pitched note of "tzit" repeated often, sometimes in a rapid staccato.

feeding ecology and diet

Forages in middle to higher altitude forests, but may range lower. Its diet covers a wide selection of insects and fruits. On Mindanao, field researchers saw one individual snag and eat a tree frog. In eastern Mindanao, residents witnessed over 100 Rhabdornis inornatus individuals gathering in a great flock to flycatch among seasonal swarms of flying insects.

reproductive biology

Nests in April; enlarged gonads in March and April. Eggs not described.

conservation status

Not threatened.

significance to humans

None known.

Stripe-headed rhabdornis

Rhabdornis mysticalis

taxonomy

Rhabdornis mysticalis Temminck, 1825. Two subspecies.

other common names

English: Striped-headed creeper; French: Rhabdornis á tête striée; German: Streifenkopf-Rhabdornis; Spanish: Trepador Filipino de Cabeza Rayada.

physical characteristics

The two subspecies of the stripe-headed rhabdornis vary somewhat in size. Rhabdornis mysticalis mysticalis is 6.2 in (15.8 cm) long and weighs about 3 oz (85 g). Rhabdornis mysticalis minor is 5.7 in (14.5 cm) long, at 2.75 oz (78 g).

The sexes are similarly colored, and males are larger than females. Both subspecies have black bills, dark brown eyes, and dark horn legs. Males have a blackish brown crown and nape with numerous white streaks, a broad stripe through the

eye, while the face and the rest of the neck are blackish brown. The female differs in having a lighter brown crown and face.

distribution

Philippine islands of Luzon, Negros, Panay, Masbate, Contanduenes, Leyte, Mindanao, Samar, Basilan, Bohol, Calicoan, and Dinagat.

habitat

Tropical forest from sea level up to 3,900 ft (1,200 m) above sea level.

behavior

Diurnal and quite active, in canopy and middle story of forests, forest edges, and secondary growth in groups or in mixed flocks of up to 25 individuals. At dusk, they may form large roosting groups of several hundred individuals. The call is an unmelodious, high-pitched "tsee tsee WICK tsee," the "tsee" notes very soft and the "WICK" sharp and loud.

feeding ecology and diet

Foraging and diet are like that of the other rhabdornis species, with insects as main fare varied with nectar, fruit, and seeds.

reproductive biology

Breeding biology is poorly known. The species is thought to nest in tree cavities as does the stripe-breasted rhabdornis. Enlarged gonads in March.

conservation status

Not threatened.

significance to humans

None known.

Resources

Books

Fisher, Tim, and Nigel Hicks. A Photographic Guide to the Birds of the Philippines. Sanibel Island, FL: Ralph Curtis Publishing Inc., 2000.

Kennedy, Robert S., Pedro C. Gonzales, Edward C. Dickinson, Hector C. Miranda Jr., and Timothy H. Fisher. A Guide to the Birds of the Philippines. Oxford: Oxford University Press, 2000.

Organizations

BirdLife International. Wellbrook Court, Girton Road, Cambridge, Cambridgeshire CB3 0NA United Kingdom. Phone: +44 1 223 277 318. Fax: +44-1-223-277-200. E-mail: [email protected] Web site: <http://www.birdlife.net>

Haribon Foundation for the Conservation of Natural Resources. 9A Malingap Cot, Malumanay Streets, Teachers' Village, 1101 Diliman, Quezon City, Philippines. Phone: +63 2 9253332. E-mail: [email protected] Web site: <http://www.haribon.org.ph>

IUCN–World Conservation Union, USA Multilateral Office. 1630 Connecticut Avenue, Washington, DC 20009 USA. Phone: (202) 387-4826. E-mail: [email protected] Web site: <http://www.iucn.org/places/usa/inter.html>

Oriental Bird Club, American Office. 4 Vestal Street, Nantucket, MA 02554 USA. Phone: (508) 228-1782. E-mail: [email protected] Web site: <http://www.orientalbirdclub.org>

Kevin F. Fitzgerald