Myadestes palmeri

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	Passeriformes	Turdidae

Scientific Name:

Myadestes palmeri

Species Authority:

(Rothschild, 1893)

Common Name/s:

English

–

Puaiohi, Small Kauai Thrush

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered B1ab(iii) ver 3.1

Year Assessed:

2009

Assessor/s

BirdLife International

Evaluator/s:

Bird, J., Butchart, S., Symes, A.(BirdLife International)

Justification:
This species qualifies as Critically Endangered because it has an extremely small range, wholly confined to one upland area where habitat quality is continuing to decline. It has apparently always been rare, although the reasons for this are unclear and the range and population trends are difficult to judge, because it is extremely elusive, and occurs in some areas that are difficult to access. Recent reintroduction of captive-bred individuals has however led to a significant population increase and if declines in habitat quality are halted the species may be eligible for downlisting in the future.

History:

2008	–	Critically Endangered
2004	–	Critically Endangered
2000	–	Critically Endangered
1994	–	Critically Endangered
1988	–	Threatened

Geographic Range [top]

Range Description:	Myadestes palmeri is endemic to Kaua`i in the Hawaiian Islands (USA), where recent records are all from the Alaka`i Wilderness Preserve. It has recently been lost from the Waiau and possibly the Halekua drainages¹¹, but may be expanding its range in the Mohihi drainage¹⁰. It formerly occurred in lowland habitats, but probably only locally, and was extirpated from these areas by the end of the 19th century^5,10,19. During 1998-2000, the population was estimated at c.200, possibly up to 300, wild individuals^2,6,10,12. Few birds were detected after two recent hurricanes, but the current population size is likely similar to pre-hurricane numbers^1,7,10. A captive-breeding programme began in 1996 and has facilitated the successful reintroduction of individuals into the wild annually since 1999, with almost 180 individuals released as of autumn 2008²⁰, resulting in successful breeding in the wild by captive-bred birds.
Countries:	Native: United States
Range Map:	(click map to view full version)

Population [top]

Population:	Conrow (1999), Lieberman and Kuehler (1998), Snetsinger et al. (1999), T. Snetsinger in litt. (2000), P. Roberts in litt. (2007).
Population Trend:	Increasing

Population:

Conrow (1999), Lieberman and Kuehler (1998), Snetsinger et al. (1999), T. Snetsinger in litt. (2000), P. Roberts in litt. (2007).

Population Trend:

Increasing

Habitat and Ecology [top]

Habitat and Ecology:	It is now restricted to high-elevation `ohi`a forests. It is a ravine specialist, favouring stream banks with a rich understorey^1,4,8. Many recorded nests have been placed in cliffs above streams. It is primarily frugivorous, with arthropods (particularly insects) forming an important dietary component^4,8,10. At least one bird died after malaria infection in the wild, but some birds may be disease resistant^3,10. It has potentially high but variable productivity, with pairs producing 0.4 to 4.9 young per year in three years of observation¹⁰. It is now the sole native frugivore on Kauai, and probably plays a major role in seed dispersal within its range.
Systems:	Terrestrial

Habitat and Ecology:

It is now restricted to high-elevation `ohi`a forests. It is a ravine specialist, favouring stream banks with a rich understorey^1,4,8. Many recorded nests have been placed in cliffs above streams. It is primarily frugivorous, with arthropods (particularly insects) forming an important dietary component^4,8,10. At least one bird died after malaria infection in the wild, but some birds may be disease resistant^3,10. It has potentially high but variable productivity, with pairs producing 0.4 to 4.9 young per year in three years of observation¹⁰. It is now the sole native frugivore on Kauai, and probably plays a major role in seed dispersal within its range.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	The destruction of the understorey by feral pigs has been implicated in this species's rarity⁴. Avian pox-like lesions have been observed on a mist-netted bird³, and avian malaria is suspected to cause some mortality^10,14. Although hurricanes have caused serious damage to its habitat, the species appears to recover relatively well, probably because ravines are better sheltered^1,10. Predation by native Short-eared Owls Asio flammeus and alien mammals (e.g. rats) suppresses productivity and competition for food with introduced insects, birds and mammals may also have negative impacts^10,16. Several plants, including blackberry (Rubus argutus), Australian tree fern (Cyathea cooperi), Kahili ginger (Hedychium gardnerianum) daisy fleabane (Erigeron annuus) and strawberry guava (Psidium cattleianum) have significantly altered areas currently and recently occupied by Puaiohi, and have the potential to convert the forest canopy, understorey and cliffs used for nesting substrate to unsuitable habitat¹⁸.

Major Threat(s):

The destruction of the understorey by feral pigs has been implicated in this species's rarity⁴. Avian pox-like lesions have been observed on a mist-netted bird³, and avian malaria is suspected to cause some mortality^10,14. Although hurricanes have caused serious damage to its habitat, the species appears to recover relatively well, probably because ravines are better sheltered^1,10. Predation by native Short-eared Owls Asio flammeus and alien mammals (e.g. rats) suppresses productivity and competition for food with introduced insects, birds and mammals may also have negative impacts^10,16. Several plants, including blackberry (Rubus argutus), Australian tree fern (Cyathea cooperi), Kahili ginger (Hedychium gardnerianum) daisy fleabane (Erigeron annuus) and strawberry guava (Psidium cattleianum) have significantly altered areas currently and recently occupied by Puaiohi, and have the potential to convert the forest canopy, understorey and cliffs used for nesting substrate to unsuitable habitat¹⁸.

Conservation Actions [top]

Conservation Actions:	Conservation actions underway: It is protected in the Alaka`i Wilderness Preserve. Rat poison bait stations have placed near a few nests with moderate success¹⁰. Bait stations are also placed around the release sites for captive-bred individuals at the time of release. Several types of rodent-resistant nest boxes have been installed in nesting habitat, and one pair was documented to nest successfully in one box. Control of feral ungulates has proved difficult in less accessible areas of the Alaka`i Wilderness Preserve, which is rarely visited by hunters, and alternatives are expensive and of limited effectiveness¹⁵. An ungulate exclusion fence is planned for a portion of the Alaka'i plateau, which will include 5-10% of the species's range. A captive population was established in 1996, and 14 birds were released into the wild in 1999^2,6,12,13. In subsequent years, between 5 and 19 birds have been released annually for a total of nearly 180 released as of autumn 2008²⁰. The captive-bred birds have bred with each other and with wild birds¹³. Results of the releases have been mixed, with birds released in 1999-2001 surviving better than birds released from 2002-2006. The release strategy for 1999-2001 was highly successful, with 31 out of 34 released birds surviving at least one month after release and confirmed breeding occurring in the wild¹⁵. From 2002 through 2007, roughly half of released birds survived for one month or longer. Research on the factors limiting the species and the potential of management actions is ongoing. Conservation actions proposed: Carry out regular surveys to monitor population trends. Conduct research to determine the impacts of predation and habitat degradation by alien species. Protect the Alaka`i Wilderness Preserve from the invasion of introduced plants and feral ungulates⁸. Remove rats and cats from the Alaka`i Wilderness Preserve⁹. Continue captive breeding and release efforts.

Conservation Actions:

Conservation actions underway:

It is protected in the Alaka`i Wilderness Preserve. Rat poison bait stations have placed near a few nests with moderate success¹⁰. Bait stations are also placed around the release sites for captive-bred individuals at the time of release. Several types of rodent-resistant nest boxes have been installed in nesting habitat, and one pair was documented to nest successfully in one box. Control of feral ungulates has proved difficult in less accessible areas of the Alaka`i Wilderness Preserve, which is rarely visited by hunters, and alternatives are expensive and of limited effectiveness¹⁵. An ungulate exclusion fence is planned for a portion of the Alaka'i plateau, which will include 5-10% of the species's range. A captive population was established in 1996, and 14 birds were released into the wild in 1999^2,6,12,13. In subsequent years, between 5 and 19 birds have been released annually for a total of nearly 180 released as of autumn 2008²⁰. The captive-bred birds have bred with each other and with wild birds¹³. Results of the releases have been mixed, with birds released in 1999-2001 surviving better than birds released from 2002-2006. The release strategy for 1999-2001 was highly successful, with 31 out of 34 released birds surviving at least one month after release and confirmed breeding occurring in the wild¹⁵. From 2002 through 2007, roughly half of released birds survived for one month or longer. Research on the factors limiting the species and the potential of management actions is ongoing.

Conservation actions proposed:

Carry out regular surveys to monitor population trends. Conduct research to determine the impacts of predation and habitat degradation by alien species. Protect the Alaka`i Wilderness Preserve from the invasion of introduced plants and feral ungulates⁸. Remove rats and cats from the Alaka`i Wilderness Preserve⁹. Continue captive breeding and release efforts.

Citation:	BirdLife International 2009. Myadestes palmeri. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.1. <www.iucnredlist.org>. Downloaded on 18 March 2010.
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