Multiple Reversals of Bill Length over 1.7 Million Years in a Hawaiian Bird Lineage.

Evolutionary change has been documented over geological time, but reversals in morphology, from an ancestral state to a derived state and back again, tend to be rare. Multiple reversals along the same lineage are even rarer. We use the chronology of the Hawaiian Islands and an avian example, the Hawaiian honeycreeper 'amakihi (Hemignathus spp.

Vector movement underlies avian malaria at upper elevation in Hawaii: implications for transmission of human malaria.

With climate warming, malaria in humans and birds at upper elevations is an emerging infectious disease because development of the parasite in the mosquito vector and vector life history are both temperature dependent. An enhanced-mosquito-movement model from climate warming predicts increased transmission of malaria at upper elevation sites that are too cool for parasite development in the mosquito vector. We evaluate this model with avian malaria (Plasmodium relictum) at 1,900-m elevation on the Island of Hawaii, with air temperatures too low for sporogony in the vector (Culex quinquefasciatus).

Females lead population collapse of the endangered Hawaii creeper.

Population collapses result from drastic environmental changes, but the sexes may differ in vulnerability. Collapse of the endangered Hawaii creeper (Oreomystis mana) at Hakalau Forest National Wildlife Refuge resulted from food limitation associated with increased numbers of an introduced bird (Japanese white-eye, Zosterops japonicus), which competes with the creeper for food. Both creeper sexes had stunted bill growth and the greatest change in molt of native species in the community.

Changes in timing, duration, and symmetry of molt of Hawaiian forest birds.

Food limitation greatly affects bird breeding performance, but the effect of nutritive stress on molt has barely been investigated outside of laboratory settings. Here we show changes in molting patterns for an entire native Hawaiian bird community at 1650-1900 m elevation on the Island of Hawaii between 1989-1999 and 2000-2006, associated with severe food limitation throughout the year beginning in 2000. Young birds and adults of all species took longer to complete their molt, including months never or rarely used during the 1989-1999 decade.

Negative effects of an introduced bird species on growth and survival in a native bird community.

Exploitative competition is a major determinant of community structure in natural assemblages [1, 2], but, introduced species are rarely competitors that lead to extinction of native species [3, 4]. Here we document strong community-wide competition from the Japanese white-eye (Zosterops japonicus) on native Hawaiian passerine birds. Introduced in 1929 [5], white-eye successfully invaded old-growth forest and coexisted with eight native species [6], overlapping multiple foraging substrates with each but evidencing no agonistic interactions [7].

Explosive increase in ectoparasites in Hawaiian forest birds.

Ectoparasites, particularly chewing lice in the Phthiraptera (Insecta), affect the ecology of numerous host species. Most lice are highly host-specific, and there are no documented cases of major increases of chewing lice, within populations, over years. During continuous study from 1987-2005 at upper elevation forests on the island of Hawaii, chewing lice were exceedingly rare and, until 2003, were found in just 2 of 12 species of native and introduced birds.