Kauai Oo Moho braccatus Scientific name definitions

Paul W. Sykes Jr., Angela K. Kepler, Cameron B. Kepler, and J. Michael Scott
Version: 1.0 — Published March 4, 2020
Text last updated January 1, 2000



Walking, Hopping, Climbing, Etc

Kaua‘i ‘Ö‘ö. Active; moved quickly and decisively, frequently holding tail cocked in 30–80° angle (Munro 1944a, Conant et al. 1998, J. L. Sincock unpubl., PWS). Some movements reminiscent of ‘Elepaio, but ‘ö'ö was more active. Hopped along horizontal branches; not reported on ground, but observed as low as 1 m (J. L. Sincock unpubl.). Sometimes foraged while clinging woodpecker-like on trunks of trees and branches (Perkins 1903, Munro 1944a). When moving short distances between perches or blossoms, combined saltatory leap with short flight.

Bishop's ‘Ö‘ö. Described as active (Munro 1944a).

Hawai‘i ‘Ö‘ö. Active and agile in hopping about canopy foraging in flower patches and within forest strata with great celerity, but did not exhibit the degree of agility of Kaua‘i ‘Ö‘ö in movements in foliage and dense undergrowth (Perkins 1903, Munro 1944a).

Kioea. Reported to be “very active and graceful in motions” (Peale 1848).


Kaua‘i ‘Ö‘ö. Strong, direct, and quick when flying through treetops, but seldom flew above forest canopy (Munro 1944a). When crossing large openings outside canopy, had pattern of rapid wing beats followed by brief glide (Hart 1976).

Hawai‘i ‘Ö‘ö. Flight reported to be similar to that of Boat-tailed Grackle (Quiscalus major; Wilson and Evans 1890). Wing movements quick, but flight relatively slow and somewhat undulating. Often glides when traveling short distances between branches. Tends to fly above canopy rather than through forest strata (Wilson 1890a, Wilson and Evans 1890, Munro 1944a).

Kioea. Probably strong flier, given its wing structure.


Preening, Head-Scratching, Stretching, Bathing, Anting, Etc

Kaua‘i ‘Ö‘ö. Frequently scratches and preens; observed doing so for up to 20 min at a time (Hart 1976, J. L. Sincock unpubl., PWS). Scratches head with foot underwing (PWS).

Sleeping, Roosting, Sunbathing

Kaua‘i ‘Ö‘ö. One pair that was observed daily 2–5 Oct 1974 roosted on branches in crown of same live ‘öhi‘a and commenced calling in early morning before departing to forage (J. L. Sincock unpubl.).

Daily Time Budget

Kaua‘i ‘Ö‘ö. Limited information. Conant et al. (Conant et al. 1998) studied behaviors for brief periods in early Jul 1975 (see Table 1 and Table 2).

Hawai‘i ‘Ö‘ö. More active in morning until about 09:00 and in early evening, but on foggy or rainy days remains active throughout day (Henshaw 1902a, Perkins 1903, Munro 1944a).

Agonistic Behavior

Kaua‘i ‘Ö‘ö. See Spacing, below.

Hawai‘i ‘Ö‘ö. Very aggressive in defense of favored foraging patches. Drives off intruders at such sites by rushing toward them as if to attack, erecting tail feathers, raising wings, and exposing yellow axillary tufts and undertail coverts (Perkins 1903); vocalizes throughout this threat display.


Kaua‘i ‘Ö‘ö. Highly territorial during breeding, chasing away conspecifics and other species. Both members of pair vigorously defend territory around nest for radius of 30–40 m (J. L. Sincock unpubl.). Also sometimes defends food patches of blossoms, exhibiting a size-based hierarchy (Conant et al. 1998). See Food habits: feeding, above.

Hawai‘i ‘Ö‘ö. No information during breeding. Dominant at favored food patches, exhibiting a size-based hierarchy (Perkins 1903, Berger 1981).

Sexual Behavior

Little known. Lepson (Lepson 1998) suggested that in-creased sexual dimorphism of modified tails among the 4 ‘ö‘ö species relative to body size indicates sexual selection on tails from intrasexual aggression or intersexual mate choice. He further stated that patterns of yellow feather-tufts among the 4 congeners (but not between the sexes) may indicate that males and females experienced similar evolutionary pressures for this feature. Tail possibly evolved under influence of sexual selection in males, and conspicuous yellow feather-tufts by social selection in both sexes (Lepson 1998).

Kaua‘i ‘Ö‘ö. JMS and Fred Zeillemaker observed attempted copulation at 11:30 on 6 Jun 1975 (J. L. Sincock unpubl.). While perched near nest cavity on Halepa‘akai Stream, lone male on 24 May 1983 several times raised feathers at base of hindneck, giving appearance of a ruff similar to that of displaying cowbirds (Molothrus spp.) and drooped its wings slightly. This may have been courtship display, although no female was present (PWS). Male collected by George Munro on 15 Sep 1898 (UWBM 19426) in postbreeding condition had testes measuring as follows: left, 1.8 × 0.8 mm; right 1.0 × 0.5 mm. Another nonbreeding male, taken by Frank Richardson on 21 Jul 1960 (BPBM 6701; Richardson and Bowles 1964), had testes measuring 2 mm each in length.

Hawai‘i ‘Ö‘ö. In courtship display, used its long plumelike tail; extended wings, yellow axillary tufts, and undertail coverts; and vocalized.

Social and Interspecific Behavior

Kaua‘i ‘Ö‘ö. Social nonbreeding period; foraged in groups of 4–8 individuals and infrequently joined foraging guilds of drepanids (Perkins 1903). Relatively tame and curious—more so than other ‘ö‘ö—but adept at using thick foliage for concealment (Wilson and Evans 1890, Perkins 1903, J. L. Sincock unpubl.).

O‘ahu ‘Ö‘ö. The yellow orbital rings found on 2 specimens may have existed in younger adults, functioning to signal age and lower status relative to older birds with black orbital rings (Lepson 1998).

Bishop's ‘Ö‘ö. Somewhat gregarious, probably during nonbreeding season. Perkins (Perkins 1903: 442) described seeing “about a score of the Oo that I watched while they were feeding, at a time when the ‘öhi‘as and lobelias were both in flower,” and Munro (Munro 1944a: 85–86) “saw a group of about half a dozen in 1904.” Said to be somewhat curious, but restless and shy when closely approached and readily attracted by imitation of its calls (Rothschild 1893a, Perkins 1903, Munro 1944a).

Hawai‘i ‘Ö‘ö. In pairs during breeding; social nonbreeding period, foraging in groups of up to 12; foraging groups may have included hatch-year birds (Henshaw 1902a, Perkins 1903).

Kioea. Given its large size compared to most other forest birds on Hawai‘i I., Kioea probably was dominant at feeding sites in and around flowering concentrations.


Kinds Of Predators

Kaua‘i ‘Ö‘ö. Prehistorically, probably preyed on by the now extinct owl Grallistrix auceps (Olson and James 1991); historically, by Short-eared Owls (Asio flammeus sandwichensis); after Polynesian settlement (about 400 ; Kirch 1974), by Polynesian rats (Rattus exulans); and after European contact (1778), by black rats (R. rattus) and feral house cats (Felis catus; Ralph and Van Riper III 1985, Scott et al. 1986). Black rats common (at least after 1968) throughout forested mountains of Kaua‘i, including Alaka‘i area (J. L. Sincock unpubl.).

Hawai‘i ‘Ö‘ö. Historically, probably preyed on by Short-eared Owls and Hawaiian Hawks (Buteo solitarius); after European contact, by black rats (Ralph and Van Riper III 1985). Tens of thousands taken by Hawaiians for their feathers (Wilson 1890a, Rothschild 1893a, Brigham 1899, Perkins 1903), especially after European contact, when demand increased for feather artifacts as trade items.

Kioea. Hawks and owls (now extinct) preyed on honeycreepers (Olson and James 1991), and possibly also honeyeaters; historically (since 1778), Kioea probably preyed on by Hawaiian Hawk and Short-eared Owl. Unknown if taken by early Hawaiians.

Manner Of Predation

Kaua‘i ‘Ö‘ö. No information. Black rats are avid tree climbers, making eggs and nestlings vulnerable.

Hawai‘i ‘Ö‘ö. No information except for considerable human exploitation. Birds captured using various types of birdlime on branches, including use of live Hawai‘i ‘Ö‘ö and ‘I‘iwi as decoys. After European contact, shot with guns (Henshaw 1902a, Ralph and Van Riper III 1985).

Response To Predators

Kaua‘i ‘Ö‘ö. In late afternoon of 26 May 1983, a Short-eared Owl flew to within 6 m of a Kaua‘i ‘Ö‘ö perched in crown of live ‘öhi‘a. At approach of owl, ‘ö‘ö dropped quickly and silently vertically out of sight in denser cover in forest strata below (PWS). For alarm calls, see Sounds: vocalizations, above.

Hawai‘i ‘Ö‘ö. Said to be very wary of humans, possibly because of long history of persistent hunting (Wilson 1890a, Rothschild 1893a, Perkins 1903).

Recommended Citation

Sykes Jr., P. W., A. K. Kepler, C. B. Kepler, and J. M. Scott (2020). Kauai Oo (Moho braccatus), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.kauoo.01