Justification Although this is one of Hawaii's most adaptable native birds, it has a very small, fragmented range, and there is evidence of declines on O`ahu and Hawai`i. The species is consequently classified as Endangered.

Family/Sub-family Monarchidae

Species name author (Gmelin, 1789)

Taxonomic source(s) AOU checklist (1998 + supplements), Sibley and Monroe (1990, 1993)

Identification 14 cm. Small monarch flycatcher that often cocks its tail. Adults have white tips to tail feathers, white rump, and white wing bars. Immatures have buffy or rufous wingbars (VanderWerf 2001). Kaua`i adult grey above, white below, rusty-tinged breast has indistinct sooty border, white throat. O`ahu adult chocolate-brown above, white below with brownish streaks on breast, and with black chin irregularly blending into white throat. Hawai`i adult variable and sexually dimorphic, male has black chin, female white (VanderWerf 2001). Similar spp. Introduced Japanese Bush-warbler Cettia diphone duller with prominent eyebrow and no white markings. Introduced juvenile White-rumped Shama Copsychus malabaricus larger, darker above, with dark spots on breast. Voice Song a lively whistled eh-leh-PYE-o, calls include sharp chup, two-note squeak-it like dog's toy, and raspy chatter.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

240,000

decreasing

6,500 km²

Yes

Range & population Chasiempis sandwichensis is endemic to the Hawaiian Islands (USA)^5,7. On Hawai`i, C. s. bryani had an estimated population of c.2,500 birds in 1983, and may be declining. The other two subspecies on Hawai`i had populations estimated at c.63,000 for C. s. sandwichensis and c.150,000 for C. s. ridgwayi in 1976-1979⁶. Surveys in the Central Windward region of Hawai`i from 1977 to 2003 indicate that the species is stable at high elevations and declining at low elevations<sup>13</sup>, and there is also evidence of a decline in the Ka`u region between 1976 and 2005¹⁷. On O`ahu, C. s. ibidis had an estimated population of 1,973 in 1992-2000, restricted to c.47 km<sup>2</sup> in the Ko`olau and Wai`anae mountains, and including six isolated populations of 50-500 birds and several others of 10 or fewer<sup>7,8,9</sup>. The breeding population on O`ahu is c.1,770 birds, which is lower than the total population, owing to a male-biased sex-ratio¹⁴, and the species continues to decline over much of its range, particularly in the Wai`anae mountains<sup>18</sup>. On Kaua`i, C. s. sclateri had an estimated population of nearly 40,000 in 1968-1973, apparently reduced by c 50%, at least temporarily, in the 1990s².

Ecology: On Hawai`i, bryani occupies arid, mostly high-altitude mamane and mamane-naio woodland, sandwichensis occurs in mesic habitats on western and south-western slopes, and ridgwayi is restricted to wet, eastern slopes<sup>3,6,7</sup>. On O`ahu, ibidis is most abundant in mesic forest in valleys⁹. On Kaua`i, sclateri is most abundant in wet to mesic montane forest, also occurring in woodland, scrub, savanna and drier habitats, at lower densities. It feeds on insects and other invertebrates⁶.

Threats The habitat of bryani has been heavily browsed by feral ungulates and introduced grasses suppress regeneration and potentially increase the risk of fire⁶. On O`ahu habitat loss to development has been extensive, with 56% of the former range of ibidis zoned for agricultural or urban development<sup>9</sup>. Diseases, such as avain pox and malaria, spread by mosquitos, are a problem at low and middle elevations on all islands, increasing mortality of adults by c.25% on O`ahu, and possibly preventing birds from nesting^10,11,15. Malaria prevalence in the species on O`ahu has been recorded at 87%, with 36% of birds showing signs of avian pox<sup>15</sup>. High prevalences in mosquito-borne diseases and local declines in the species's population are associated with high rainfall<sup>14,15</sup>. Nest-predation by black rats Rattus rattus is the most serious current problem on O`ahu^7,8,9,14. Fires are known to destroy key habitat and promote the spread of alien plants on O`ahu¹⁴. Hurricane Iniki, in 1992, drastically reduced all populations of sclateri⁴.

Conservation measures underway For bryani, the removal of goats and sheep from Mauna Kea has allowed regeneration, and cats and rats were controlled¹⁰, although this has now ceased due to an end in funding¹⁶. For ibidis, captive breeding has been suggested¹⁰, and rat control in 1997-1999 resulted in a 127% increase in reproductive success stabilising studied populations^9,12. Rat control is currently taking place at some populations on Oahu¹⁶. Critical habitat has been designated for this species on O`ahu<sup>11</sup>. Habitat restoration and reforestation at mid and high elevations on Hawai`i is expected to benefit sandwichensis and ridgwayi¹⁶.

Conservation measures proposed For bryani, improve fire management, continue control of mammalian predators and herbivores, and reforest areas adjacent to the Mauna Kea Forest Reserve. For ibidis, conduct research into disease resistance¹⁰, implement further measures to control introduced predators⁸, and protect forest from fires and development¹⁴. For sclateri, monitor the population.

References 1. Conant et al. (1998). 2. Jacobi and Atkinson (1995). 3. Pratt (1980). 4. Pratt (1994). 5. Pratt et al. (1987). 6. Scott et al. (1986). 7. VanderWerf (1998b). 8. VanderWerf et al. (1997). 9. VanderWerf et al. (2001). 10. E. VanderWerf in litt. (1999). 11. USFWS (2001). 12. VanderWerf and Smith (2002). 13. Gorresen et al. (2005). 14. USFWS (2006). 15. VanderWerf et al. (2006). 16. T. Pratt in litt. (2007). 17. Tweed et al. (2007). 18. E. VanderWerf in litt. (2007).

Further web sources of information

Audubon WatchList

U.S. Fish and Wildlife Service - Revised Recovery Plan for Hawaiian Forest Birds 2006 Chasiempis sandwichensis ibidis

Text account compilers Phil Benstead (BirdLife International), Alison Stattersfield (BirdLife International), Tom Stuart (BirdLife International), Joe Taylor (BirdLife International)

Contributors Rick Camp (US Geological Survey), Scott Fretz (Hawaii Division of Forestry and Wildlife), Marcos Gorresen (US Geological Survey), Thane Pratt (US Geological Survey), Eric VanderWerf (US Fish & Wildlife Service), Bethany Woodworth (US Geological Survey)

IUCN Red List evaluators Stuart Butchart (BirdLife International), Joe Taylor (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Chasiempis sandwichensis. Downloaded from http://www.birdlife.org on 9/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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