HAWAIIAN FINCHES

Thus far suspected to have blown over 3500 km from the New World, the Hawaiian Finches or Honeycreepers, earlier grouped in Drepanidinae within Emberizidae, later in its own family Drepanididae, are since 2003 (H&M) in the subfamily Carduelinae within Fringillidae: FINCHES, EUPHONIAS AND HAWAIIAN HONEYCREEPERS.

The feathers of these birds were used by the natives to decorate their clothes, that’s why the Germans call them Kleidervögel (Clothes birds).

Charles Darwin (1837, 1842) was the first to suggest that coral atolls might grow on subsiding platforms. Hess (1946) recognized that flat-topped submarine peaks, which he named guyots, were drowned islands. He thought that they were volcanic, bare of sediments and coral, and had been planed off by erosion at sea level. He attributed their depth to rising sea level caused by sediment deposition in the oceans. Menard and Dietz (1951) agreed with Hess that submergence was primarily due to a rise in sea level, but they thought that local subsidence might also play a role.

At the other hand, the Hawaiian (Myadestes sp.) Solitaire Thrushes, are related to the Mesoamerican Myadestes spp.. (The Hawaiian Monarch Flycatchers [Chasiempis sp.] originate from the Old World, and are found in many more Pacific islands).

Evolutionary biologists and ornithologists consider the Hawaiian Honeycreepers (that actually are Finches, and most of which are insectivores) to be one of the finest examples of adaptive radiation -- even more diverse than Darwin's famous Galápagos Finches (that actually are Tanagers).

In a 1988 Birding article, it is said that the Hawaiian honeycreepers are believed to be related either to the cardueline finches (siskins, redpolls, crossbills, etc.) or the Emberizidae (buntings, tanagers, etc.), both of which are well represented in North America. The ancestor of the honeycreepers probably colonized the islands via a chain of islands, now represented by the Emperor Seamounts, that stretched northward to the Aleutians, at a time when the present larger Hawaiian islands had not yet emerged from the sea. Thus, they may well have their closest relatives in North America.

But a 2011 study revealed that the ancestor of the rosefinches, a group of Eurasian species, is the closest relative to all the extant Hawaiian honeycreepers, that all have a musky smell. They transformed their bills to act like insectivore nuthatches, warblers or parrotbills, nectarivore hummingbirds, or even woodpeckers, next to seed-eating finches, and appear to relate to the Eurasian Carpodacus split of the ancestor of the rosefinches (with an earlier radiation into North America, Haemorhous, that was up to ca. 2010 thought to be a Carpodacus as well), possibly established by hopping from Kamchatka through now drunken islands (Guyots) of the Hawaiian-Emperor Seamount Chain, rather than blown over 3500 km from Japan to the Midway Islands and so on.

Having evolved just 5 mya, Hawaiian honeycreepers are much too young a lineage to be consider a "Family" among the many ancient lineages that are currently supportable at that status. Almost all of today's bird Families diverged 20 mya or more. The traditional "family" Drepanididae was down-graded to a subfamily [Drepanidinae] by the early 21st century. Currently the AOU simply lists the genera among this radiation as members of a much broader Carduelinae subfamily, along with rosefinches, Purple & House finches, crossbills, siskins, and goldfinches.

The various types of Hawaiian honeycreepers evolved in a "single line" evolution — as is usual in isolated radiations — with one exception. The emergence of the "creepers" is an example of convergent evolution. The "creepers" are the Hawaii Creeper (right) on the Big Island, Akikiki (or 'Kauai Creeper') Oreomystis bairdi, and Maui Alauahio (or "Maui Creeper") Paroreomyza montana. These arose through two separate divergences from the main evolutionary line near the base of the lineage, and then they evolved to resemble each other in their barking-hunting habits through convergent evolution.

While there were 15 extant species in 1980, and 20 in 1989 by upgrading of subspecies, there are now 17, and 18 incl. one subspecies. Over 20 species disappeared since the 19^th century, after another 10 since Polynesians arrived 1,500 years ago.

The House finch (Carduelinae within Fringillidae) from North America, and the Saffron finch (Thraupidae) from South America were introduced to Hawaii.

A single last pair of the Hawaiian Honeyeaters only survived up to the 1980s, the female of which disappeared after the Hurricane Iwa in 1982 (Meliphagidae, from 2008 Mohoidae).

BAND-RUMPED STORM-PETREL (Oceanodroma castro). One (103-1973) 12 Sep 1970, about 25 miles west of San Diego, San Diego Co. (GMcC; JA, SS, RW). This is the first to be recorded from California. The nearest known nesting localities are in the Hawaiian and Galapagos islands, but this species clearly wanders widely over the warmer ocean waters.

Diet

Eight of the extant Hawaiian Honeycreepers mainly eat insects, two seeds, one a combination of nuts and fruits, three nectar, six a combination of nectar and insects. These species are unable to interbreed. Many Hawaiian plants have developed tubular flowers that may differ strikingly from flowers of their relatives. Such flowers fit the bills of nectar-feeding birds like a glove on a hand and have the pistil placed so it can pick up pollen from the bird’s forehead. This so-called coevolution is a protection against being ‘robbed’.

Sources: The Howard and Moore complete checklist of the birds of the world, Wikipedia

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