Survival estimates for two Hawaiian honeycreepers

摘要

Most Hawaiian forest birds are endangered by habitat loss and degradation, predation by introduced mammals, and introduced diseases, but species recovery planning has been hampered by lack of demographic information, such as annual survival rates. To address this knowledge gap, we analyzed markrecapture data using the program MARK to estimate apparent survival in the endangered Maui parrotbill (Pseudonestor xanthophrys) and Maui 'alauahio (Paroreomyza montana). Annual survival estimates were high in adult Maui parrotbills (0.84 ± 0.04) and Maui 'alauahio (0.78 ± 0.15). Survival was lower in hatch-year parrotbills (0.76 ± 0.09) and hatch-year 'alauahio (0.64 ± 0.13), and survival of 'alauahio also varied among years (0.51 ± 0.18 to 0.95 ± 0.06 in adults). These results provide important baseline data for two little-known species of honeycreepers and, together with ongoing nest success and productivity studies, will enable assessment of population trends and inform management decisions. Mark-recapture methods are a useful tool for monitoring populations of rare and cryptic species that are difficult to monitor using traditional survey methods.