Drepanididae (Hawaiian honeycreepers)
Lesser Akialoa Hemignathus obscurus (Gmelin, 1788)
- RMNH 110.013: Hawaii. Cabinet Temminck, 1820 (bought at auction Bullock Museum, 1819).
- RMNH 110.014: juvenile, male. Kau, Hawaii Island, Hawaii, June 1895. Collector: Perkins; Donator: A. Newton, Cambridge, 1901.
The fact that the various species of Drepanididae or Hawaiian honeycreepers are not discussed separately but as a group, illustrates the heavy losses this family has suffered. Fifteen species are extinct and of the remaining species four subspecies have disappeared. Many of the surviving (sub)species are on the verge of extinction.
Like the Darwin-finches of the Galápagos Islands, the Hawaiian honeycreepers show a wide range of feeding adaptations, as is illustrated in the highly specialized, very diverse beaks of the various species. Birds which extract honey from flowers or insects from holes and crevices in trees have long, thin and curved beaks, wheras the beaks of Drepanididae that live on various kinds of fruits or seeds are finch- or parrot-like. Several species played an important role in pollinating some of the endemic plants. Now that many Drepanididae have disappeared, some of these plants are also faced with extinction. The role of the birds has partly been taken over by volunteers, who, armed with brushes, scout the volcano slopes and carefully transport pollen from one plant to another.
Most skins of Drepanididae in Naturalis were collected by Robert Perkins, a British ornithologist who lived on Hawai'i. They were donated to the museum on 13 February 1901 by Alfred Newton, chairman of “the joint commitee appointed by the Royal Society and British Association for Zoology of the Hawaiian Islands”. The donation existed of 19 skins and one nest. According to Newton it was a very valuable collection. In fact worth at least £ 30 !
The accompanying letter testifies the importance of the donation. Newton writes to Otto Finsch, curator of birds at the museum: "I hope the Birds will be appreciated, as I am sure they will be by you, as you are aware of the fact that the whole indigenous Fauna of the Islands is doomed to extinction, even the insects are rapidly disappearing ("Yes! and even the Landshells!!"). I do not say this to enhance the value of one little collection, but in the interest of science, that all possible care may be taken to keep the specimens for posteriority. Of some of these species I am confident it will never be in anybody's power to obtain more specimens. On the Island of Oahu Mr. Perkins estimates that one half of the species of birds originally inhabiting it, are already extinct, and some which were fairly common, are now hardly to be found, so rapid has been the change."
Newton's pessimism proved to be justified. Around 1900 the Hawaii Mamo Drepanis pacifica, the Kona Grosbeak Chloridops kona, the nominate race of the Oahu Nukupuu Hemignathus lucidus lucidus and all forms of the Akialoa with the exception of the Greater (Kauai) Akialoa, Hemignatus ellisianus stejnegeri, were extinct. The Kauai Akialoa was last seen in the 1960s and is now also considered extinct.