Japanese White-Eye at the Kona Farmer's Market

Bird-watching in Hawai'i can be frustrating. There are a great many colorful and easily seen birds, and there is the quandary of knowing that most all of them are introduced and invasive species. The native birds are rarely seen, as they have drastically decreased numbers, and have been driven into last stands in the high elevation forests. Many of them have gone extinct already.

Bird malaria is one of the worst causes, but there are many others. By the 1920s, so few native birds were found in the coastal towns that well-meaning people brought in tropical species to fill the void. Other birds were introduced to help control insect pests in the pervasive sugar cane fields. One can see the point of choosing non-native birds versus no birds, and one can also realize the lack of research that would have warned against introducing new species without understanding the potential negative effects.

Probably no bird illustrates the quandary so well as the Japanese White-eye or Mejiro (Zosterops japonicus). It arrived on the islands in the 1920s and 1930s for insect control purposes, and for better or worse it was a perfect fit for Hawai'i. It spread beyond the cane fields and into the montane forests, and is now the most populous land bird on the island. It is omnivorous, meaning it competes with numerous other native birds for insects and fruits. It may be a vector for bird diseases.

Who, me??

And yet...it's a beautiful bird, and fun to watch as it hangs upside down to snatch seeds.  It's said to be a beautiful singer, and there is emerging evidence that it might have become a pollinator for some native Lobelioid species whose original pollinators have gone extinct. Endangered native Hawaiian Hawks have started preying on them.

In any case, they are on the islands to stay, for better or worse. And they may be filling the environmental niche left behind by the sadly extinct native birds. And if you think about it, the most populous bird on the island could have been something far more obnoxious (I think of European Starlings on the mainland, for instance).