Long-term population changes of native and introduced birds in the Alaka'i Swamp, Kaua'i

Jeffrey T Foster, Erik J. Tweed, Richard J. Camp, Bethany L. Woodworth, Corey D. Adler, Tom Telfer

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Within the last 30 years, five endemic bird species of the Alaka'i Swamp, Kaua'i, Hawai'i, have likely gone extinct. We documented population trends of the remaining avifauna in this time period to identify a common pattern in the Hawaiian Islands: decline of native species and expansion of introduced species. We conducted bird surveys over 100 km2 of the Alaka'i and Kōke'e regions of Kaua'i in March-April 2000 to estimate population size, distribution, and range limits of seven native and six introduced forest birds. We compared the results with four previous surveys conducted over the last 30 years. Five of the seven native species we studied have fared well, maintaining sizeable populations (> 20,000 individuals) and unchanged or increasing numbers. The endemic 'Akikiki (Oreomystis bairdi), however, declined from 6296 (SE ± 1374) to 1472 (SE ± 680) individuals and exhibited range contraction from 88 to 36 km2. The 'I'iwi (Vestiaria coccinea) also experienced a decline and contraction, though not as severe. Populations of several introduced forest birds are increasing, but all species, excluding the Japanese White-eye (Zosterops japonicus), were at low numbers (<5,500 individuals in survey area). One introduced species, the Japanese Bush-Warbler (Cettia diphone) recently invaded, whereas another, the Red-billed Leiothrix (Leiothrix lutea), has been extirpated. Two hurricanes in the past 20 years appear to have most strongly affected nectarivores and may have contributed to the decline or extinction of several other species. Overall, native bird populations on Kaua'i have exhibited species-specific responses to limiting factors. Although most native populations appear stable, the extant native avifauna is vulnerable as a result of limited distributions and the potential for widespread habitat degradation.

Original languageEnglish (US)
Pages (from-to)716-725
Number of pages10
JournalConservation Biology
Volume18
Issue number3
DOIs
StatePublished - Jun 2004
Externally publishedYes

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Birds
swamps
swamp
bird
avifauna
birds
introduced species
native species
contraction
indigenous species
nectar feeding
limiting factor
hurricane
Hurricanes
hurricanes
population size
Hawaii
extinction
eyes
habitat

Keywords

  • Alaka'i Swamp
  • Endangered birds
  • Exotic species
  • Island populations
  • Range contraction

ASJC Scopus subject areas

  • Ecology
  • Environmental Science(all)
  • Environmental Chemistry
  • Nature and Landscape Conservation

Cite this

Long-term population changes of native and introduced birds in the Alaka'i Swamp, Kaua'i. / Foster, Jeffrey T; Tweed, Erik J.; Camp, Richard J.; Woodworth, Bethany L.; Adler, Corey D.; Telfer, Tom.

In: Conservation Biology, Vol. 18, No. 3, 06.2004, p. 716-725.

Research output: Contribution to journalArticle

Foster, Jeffrey T ; Tweed, Erik J. ; Camp, Richard J. ; Woodworth, Bethany L. ; Adler, Corey D. ; Telfer, Tom. / Long-term population changes of native and introduced birds in the Alaka'i Swamp, Kaua'i. In: Conservation Biology. 2004 ; Vol. 18, No. 3. pp. 716-725.
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