Impacts of Introduced Avian Diseases on the
Decline and Extinction of Native Hawaiian Honeycreepers
It is becoming increasingly clear that the introduction of Culex mosquitoes and avian pox and malaria to the Hawaiian Islands has had landscape level impacts on the geographic distribution of highly susceptible native Hawaiian honeycreepers. The Pacific Island Ecosystems Research Center (PIERC) has taken a leadership position in identifying the role these diseases continue to play on the decline and extinction of native forest bird communities. Past accomplishments include development of new diagnostic tools for detection of disease, surveys of critical forest bird habitats in the islands to determine the status of disease and vector distribution, and tests of the effectiveness of habitat management as a method for controlling mosquito populations. Ongoing research efforts at PIERC are developing a better understanding of disease and vector ecology, investigating the natural evolution of resistance to these diseases in some species of native honeycreepers, and testing potential management strategies that can be adopted by Federal, State, and private agencies in Hawaii.

Fig. 1. Anianiau (Hemignathus parvus) from the Alakai Wilderness Preserve, Kauai. This species is currently restricted to high elevation montane rain forests on Kauai. Like other native honeycreepers, Anianiau are highly susceptible to avian pox and malaria and have disappeared from former low elevation habitats because of mosquito transmitted avian diseases.

Fig. 2. Foot lesions caused by avian pox virus. The large swellings caused by the virus make it difficult for birds to perch and forage. Vision may be impaired when lesions occur around the eyes and beak.

ancestor: one colonizing species of finch, possibly a Eurasian rosefinch (Carpodacus sp.) or, less likely, the North American house finch (Carpodacus mexicanus)

Nectar-feeding honeycreepers evolved dramatically curved bills designed for probing and extracting the nectar from the flowers of Hawaii's endemic lobelias and other plants. Insectivorous honeycreepers developed thin, warbler-like bills for picking insects from the foliage. Seed-eaters developed stouter, stronger bills for cracking tough husks. Some species probed or cracked bark with strong hooked bills seeking wood-boring insects, thereby filling a niche woodpeckers do elsewhere.

The 'I'iwi is one of the many species of honeycreepers that
are believed to have evolved from a single ancestral species
which colonized the islands millions of years ago. Its bright
red feathers were highly prized by the Hawaiians who used
them to make feathered capes, helmets, and other ornaments
for the alii or chiefs. The birds were caught by professional
bird catchers who smeared tree sap onto a branch next to a
flower blossom.When the bird lighted on the branch to sip
the flower nectar it was caught.

Their movements are also unique as they spend much of
their time hanging upside down poking their long, curved
bills into flowers. The lehua blossom is one of their favorite
foods. Like many native species, the 'i'iwi are becoming
scarce. Disease, habitat loss, and predation by introduced
animals has taken its toll on the birds.

Abstract: The Hawaiian honeycreepers are a dramatic example of adaptive radiation but contrast with the four other songbird lineages that successfully colonized the Hawaiian archipelago and failed to undergo similar diversification. To explore the processes that produced the diversity dichotomy in this insular fauna, we compared clade age and morphologic diversity between the speciose honeycreepers and the comparatively depauperate Hawaiian thrushes. Mitochondrial-DNA-based genetic distances between these Hawaiian clades and their continental sister taxa indicate that the ancestral thrush colonized the Hawaiian Islands as early as the common ancestor of the honeycreepers. This similar timing of colonization indicates that the marked difference in diversity between the Hawaiian honeycreeper and thrush clades is unlikely to result from differences in these clades' tenures within the archipelago. If time cannot explain the contrasting diversities of these taxa, then an intrinsic, clade-specific trait may have fostered the honeycreeper radiation. Because the honeycreepers have diversified most dramatically in morphological characters related to resource utilization, we used principal components analyses of bill characters to compare the magnitudes of morphological variation in the ancestral clades from which the Hawaiian honeycreeper and thrush lineages are derived, the Carduelini and Turdinae respectively. Although the Carduelini share a more recent common ancestor and have a lower species diversity than the Turdinae, these finch-like relatives of the honeycreepers exhibit significantly greater variation in bill morphology than do the continental relatives of the Hawaiian thrushes. The higher magnitude of morphological variation in the non-Hawaiian Carduelini suggests that the honeycreepers fall within a clade exhibiting a generally high evolutionary flexibility in bill morphology. Accordingly, although the magnitude of bill variation among the honeycreepers is similar to that of the entire passerine radiation, this dramatic morphological radiation represents but an extreme manifestation of a general clade-specific ability to evolve novel morphologies. (http://www.eeb.cornell.edu/lovette/pdf/Myadestes.pdf)

Fig. 3. Blood smear from a native honeycreeper with avian malaria. The malarial parasites (Plasmodium relictum) attack red blood cells and cause severe anemia. Birds with acute infections are unable to forage and are easy prey for introduced predators.

Fig. 4 Culex quinquefasciatus, the southern house mosquito, was accidently introduced to the Hawaiian Islands in 1826. This spread of this vector of avian malaria and pox throughout the Hawaiian Islands was hastened by the creation of aquatic larval habitats by human and feral pig activity.

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      ( 8:13 PM ) hillary  
"Allopatric speciation"

"The Hawaiian honeycreepers form an endemic family."

I love the idea of an endemic family, one that is rooted in place and just peters out if it is transplanted (peters, ha ha).

Telespiza cantans Laysan Finch
Telespiza ultima Nihoa Finch
Psittirostra psittacea Ou
Loxioides bailleui Palila
Pseudonestor xanthophrys Maui Parrotbill
Hemignathus virens Hawaii Amakihi
Hemignathus flavus Oahu Amakihi
Hemignathus kauaiensis Kauai Amakihi
Hemignathus parvus Anianiau
Hemignathus ellisianus Greater Akialoa
Hemignathus lucidus Nukupuu
Hemignathus munroi Akiapolaau
Oreomystis bairdi Akikiki
Oreomystis mana Hawaii Creeper
Paroreomyza maculata Oahu Alauahio
Paroreomyza flammea Kakawahie
Paroreomyza montana Maui Alauahio
Loxops caeruleirostris Akekee
Loxops coccineus Akepa
Vestiaria coccinea Iiwi
Palmeria dolei Akohekohe
Himatione sanguinea Apapane
Melamprosops phaeosoma Poo-uli

Hawaiian Honeycreepers (Drepanidae)


The Hawaiian honeycreepers provide another example of an adaptive radiation on an archipellago. In Hawaii, at least until historical times, there were about 28 living species and 17 fossil species of birds in the family Drepanidae that pretty clearly have all evolved from a single ancestral species that colonized the Hawaiian islands some time in the past. These species show a great variety of morphologies and habits (see figure): Several of the species occur on more than one island; however, 27 of the 45 living and fossil species inhabit(ed) just one island. Moreover, 7 of the species inhabiting more than one island have different subspecies on different islands, indicating population divergence that is in process. This pattern is exactly what is expected from allopatric speciation on archipellagos, with the added realization that once a new species evolves it may occasionally colonize additional islands.

The Hawaiian honeycreepers exhibit extensive diversification in bill shape and in the type of food that is eaten. The family includes thin-billed species that feed on insects (e.g. Himatione sanguinea), long-billed species that feed on nectar (e.g. Drepanis funerea), thick-billed seed eaters (e.g. Psittirostra bailleui), and woodpecker-like species (e.g. Hemignathus wilsoni). The arrows indicate inferred evolutionary transitions. Not all species are portrayed. (From D. J. Futuyma. 1998. Evolutionary Biology. Sinauer, Sunderland, MA.)
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      ( 8:04 PM ) hillary  
I'll be damned if Honeycreepers aren't finches!! How's that for coincidence? Honeycreeper isn't a bad name for a novel, you know. I already have a title, but I just may change it.

Hawaiian Honeycreepers - Family Drepanididae
This family is endemic to the Hawaiian islands. Some authorities categorize this group as the Subfamily Drepanidinae of the Finch family Fringillidae. Some honeycreepers have finch-like bills adapted to feeding on seed pods. Many honeycreepers with pointed or curved bills feed on nectar and insects. The flowers of the native 'ohi'a lehua (Metrosideros polymorpha) are utilized for food by a number of honeycreepers and the curved bills of some species appear to be specifically modified for nectar feeding in lobelioid flowers. Hawaiian honeycreepers are found in high elevation native forests.

'I'IWI - Vestiaria coccinea
Found in 'ohi'a lehua forests. Feeds on the nectar of 'ohi'a lehua flowers high in the forest canopy and from tubular blossoms in the understory. 'AMAKIHI - Hemignathus virens
Common in native forests above 2,000 feet. Feeds more on insects and is less dependant on nectar. Female is a darker, olive green color.

'AKOHEKOHE - Palmeria dolei
Crested honeycreeper - Endangered
Found only in the rain forests of east Maui at elevations of 4,500 to 6,500 feet. PALILA - Loxioides bailleui
Endangered
Found only in the dry forests on the slopes of Mauna Kea, Big Island, 6,000 to 9,000 feet.

'APAPANE - Himatione sanguinea
Commonly found in 'ohi'a lehua rain forests. Nectar forms the main part of this species' diet. Feeds also on insects. 'AKIAPOLA'AU - Hemignathus munroi
Endangered - Found only on the island of Hawaii. Fewer than 500 individuals remain. Feeds by chipping away bark to find insect larvae.

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The DNA samples come from a drop of bird blood or from bone of extinct species, some of them dead for a thousand years. By comparing the DNA of related species, biologists can construct a family tree. Most of the research on DNA comparisons for Hawaiian birds has been done by Dr. Rob Fleischer and his collaborators at the Smithsonian Institution. They have learned that the Hawaiian honeycreepers evolved from sparrow-like birds that made their landfall in Hawai`i about 4-5 million years ago, when Kaua`i was an active volcano and most of the rest of our state didn't yet exist.

The DNA shows that the original honeycreeper rapidly evolved into a large number of species, the descendants of which are still with us today. In some cases, the DNA also documents when a species colonized new Hawaiian islands as they emerged from the sea. Getting back to the `auku`u and the `io, DNA and the molecular clock would say that the heron reached Hawaii in the last few thousand years, and that the hawk arrived about a million years ago.

some pictures
http://www.camacdonald.com/birding/Sampler7b-HawaiianHoneycreepers.htm #

      ( 8:00 PM ) hillary  
No finches in Malaysia says Judy. Not true, but we will take it as truth, that there are no notable finches in Malaysia. How about Hawaiian Honeycreepers as the object of Pete's affection?

The Hawaiian Honeycreepers
Bird Families of the World
H. D. PRATT, Lousiana State University Museum, USA

The Hawaiian Honeycreepers are typified by nectar feeding, their bright colouration and canary-like songs. They are considered one of the finest examples of adaptive radiation, even more diverse than Darwin's Galapagos finches, as a wide array of different species has evolved in all the different niches provided by the Hawaiian archipelago. The book will therefore be of interest to evolutionary biologists and ecologists as well as professional ornithologists and amateur bird watchers. As with the other books in the Bird Family of the World series, the work is divided into two main sections. Part one is an overview of the Hawaiian Honeycreeper evolution and natural history and Part two comprises accounts of each species. The author has produced his own outstanding illustrations of these birds to accompany his text.
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      ( 11:03 AM ) hillary  
The squirrel story re: Jack #