The rose-ringed parakeet (RRP), Psittacula krameri, has become established in at least four Pacific Island countries (Hong Kong China, Japan, New Zealand, U.S.A.), including the Hawaiian islands of Kaua'i, O'ahu, and Hawai'i. Most Pacific islands are at risk of RRP colonization. This species was first introduced to Hong Kong in 1903 and Hawai'i in the 1930s-1960s, established since 1969 in Japan, and in New Zealand since 2005 where it has repeatedly established after organized removals. The founding birds were imported cage-birds from the pet trade. In native India, RRP are generally found associated with human habitation and are considered a severe agricultural pest. In the Hawaiian Islands, RRP are increasing and expanding their geographic ranges below 500 m elevation. Population estimates in 2018 on Kaua'i were ∼6,800 birds, which was a threefold increase and a 22.5% annual growth rate in the prior 6 years, whereas O'ahu had ∼4,560 birds with a 21% annual growth rate the prior 9 years; these rates suggest a population doubling time of ∼3.5 years. Wild RRP can live 14+ years, can reproduce after 1.5 years, and have few effective predators. Breeding pairs produce 1-3 fledglings annually. RRP are seed predators and rarely seed dispersers; their flock-foraging behavior can result in severe damage to orchard and field agricultural crops including tropical fruit and corn (Zea mays), and such economic damages are especially pronounced on Kaua'i. Island societies should prevent new introductions and consider RRP deterrents and population control methods to protect resources.
Lava flows at Pu'uhonua o Honaunau National Historical Park on the island of Hawai'i contain tree molds identified as native loulu (Pritchardia sp.) palms on the basis of gross morphology and surface features and patternings. The vegetation is reconstructed as loulu forest with an admixture of dicot species, represented by branched molds. Occurrence of loulu forest at @1000 b.p. (calibrated radiocarbon dates on charcoal from beneath the flow) suggests that these palms persisted into the early period of Polynesian settlement on the Kona coast and that Pritchardia was an important component of precontact vegetation in this area.
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