Japanese White-eye (Zosterops japonicus). (Credit: Image courtesy of Wikimedia Commons)ScienceDaily (Sep. 18, 2009) — In the late 1920s, people intentionally introduced birds known as Japanese white-eyes into Hawaiian agricultural lands and gardens for purposes of bug control. Now, that decision has come back to bite us. A recent increase in the numbers of white-eyes that live in old-growth forests is leaving native bird species with too little to eat, according to a report published online on September 17th in Current Biology, a Cell Press publication.

The findings show that introduced species can alter whole communities in significant ways and cause visible harm to the birds that manage to survive. “Native Hawaiian songbirds cannot rear normal-size offspring in the presence of large numbers of introduced Japanese white-eyes,” said Leonard Freed of the University of Hawaii at Manoa. “Their growth is stunted.” “Just as there are permanent effects of stunted growth in human children, there are permanent effects in adult birds,” added Rebecca Cann, also of the University of Hawaii at Manoa. “Birds cannot use their shorter bills to feed efficiently for themselves or when feeding their young. Stunted birds have higher death rates than normal size birds. The Japanese white-eye is causing this problem for native Hawaiian birds by depleting the food available for growth, survival, and breeding.” Undernourished birds are left more susceptible to other threats, including infectious diseases. “Birds can only tolerate malaria if they have adequate nutrition to mount an immune response,” Freed said. “They can only tolerate chewing lice if they have adequate nutrition to replace heat lost through plumage degraded by the lice.” …

Introduced Japanese White-eyes Pose Major Threat To Hawaii’s Native And Endangered Birds