Patterns of success in game bird (Aves : Galliformes) introductions to theHawaiian islands and New Zealand

Most species of birds introduced to oceanic islands belong to one of two or ders, Passeriformes or Galliformes. Among passeriforms on several islands, interspecific competition has been identified as a factor limiting introduc tion success. One pattern associated with interspecific competition among i ntroduced passeriform birds is morphological over-dispersion. We tested for morphological over-dispersion among surviving sets of introduced galliform s on the six main Hawaiian Islands and New Zealand. At least 45 galliform s pecies have been introduced to these islands. Overall, we found that game b irds were consistently over-dispersed morphologically. The effect was most pronounced on New Zealand and least evident on Moloka'i and Kaua'i. On four islands (Hawai'i, Maul, Lana'i, O'ahu), the surviving species showed inter mediate levels of morphological over-dispersion. We also re-evaluated the r ole of introduction effort in limiting introduction success and found the e vidence supporting this hypothesis to be weak. Our results suggest that com munity-level factors, including environmental factors and interspecific com petition, play an important role in determining the outcome of galliform in troductions.