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Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray, golden crownbeard, is a sunflower-like herbaceous annual plant ranging in height from 0.3 to 1.7 m with showy yellow flowers. It is native to the southwestern United States, the Mexican Plateau, and other parts of tropical America. Its invasive characteristics include high seed production (as many as 300-350 seeds per flower and multiple flowers per plant), seed dormancy, ability to tolerate dry conditions, and possible allelopathic effects. Disturbed areas with a relatively sandy substrate within warm, arid climate zones are vulnerable to invasion by V. encelioides. Veresina encelioides is found on all of the main Hawaiian islands except Ni'ihau but is particularly problematic on Midway and Kure Atoll, where it may threaten the habitat of nesting birds such as Laysan and black-footed albatrosses and Christmas and wedge-tailed shearwaters. Many other Pacific islands with similar habitats could be invaded by the V. encelioides. The plant has become naturalised in many other U.S. states, parts of South America, the Bahamas, Cuba, the Dominican Republic Puerto Rico, parts of Europe, Saudi Arabia, India, Ethiopia, Morocco, Botswana, Namibia, Israel, and Australia. It is a pest of various crops in the southern United States and India and is poisonous to sheep and cattle. Verbesina encelioides can be controlled via herbicides or mechanical means, but measures must be repeated due to the presence of persistent seed banks. Further research on V. encelioides is needed to understand its population dynamics, allelopathic properties, and impacts on natural ecosystems.

Between 1892 and 1930, 58 percent (30 taxa) of Hawaiian endemic forest birds either were greatly reduced or became extinct. The order in which the islands experienced major declines ofseveral forest birds is Oahu (ca. 1873-1887), Hawaii (1892-1900), Mo10kai (1893-1907), Maui (18941901), Kauai (after 1900), and Lanai (1926-1932). Loss of habitat, reduced food supply, introduced avian diseases, as well as predation by man, feral cats, mongooses, and Norway rats (Rattus norvegicus) all appear to have reduced some species ofbirds, but none ofthese factors adequately explains the accelerated rates ofdecline offorest birds that occurred after 1892. Although it has been assumed that roofrats (Rattus rattus) reached Hawaii with the first European ships at the end of the 18th century, there is circumstantial evidence, independent of the bird decline data, that indicates that this rat did not arrive until after 1840, probably between 1870 and 1880. The hypothesis is advanced that after its establishment on Oahu in the 1870s, R. rattus spread to the remaining large islands in the group, resulting in a stepwise accelerated decline offorest birds on each island in turn. Hawaii thus parallels some other Pacific islands where major reductions of birds have followed the establishment of R. rattus. The need for precautions to prevent rats from reaching rat-free islands in the Hawaiian group is emphasized.