Sheila Conant

Founder events and variation at microsatellite loci in an insular passerine bird, the Laysan finch (Telespiza cantans)

Historically documented founder events provide opportunities to assess the effects of population size reductions on genetic variation, but the actual magnitude of genetic change can be measured only when direct comparisons can be made to the source or ancestral population. We assayed variation at nine microsatellite loci in the translocated population of the Laysan finch (Telespiza cantans) at Pearl and Hermes reef (PHR), and compared the level of variation to that in the source population on Laysan Island. Heterogeneity in allele frequencies was highly significant at eight of the nine loci, primarily as a result of fluctuations in allele frequencies in the three PHR populations. Intra‐ and interpopulational measures of genetic diversity generally matched predictions based on the well‐documented history of three islet populations at PHR: significantly lower numbers of alleles and polymorphic loci, as well as higher pairwise FST values and genetic distance, were observed for the two populations that underwent severe size reductions. Changes in heterozygosity at single loci were unpredictable, as both significant increases and decreases were observed in founder populations. A significant excess of heterozygotes was found in two populations and was highly significant over all four finch populations (P < 0.003). Estimates of effective population size from temporal changes in heterozygosity and allele frequencies were very small (Ne≤ 30) as a result of the founding events and the constraints of islet area on population numbers. We concluded that the PHR population is not adequate as a secondary genetic reserve for T. cantans, and an alternative refuge needs to be established.

Evolutionary ecology and radiation of Hawaiian passerine birds.

The Hawaiian islands contain the most spectacular variety of landbirds ever discovered on remote oceanic islands. The Hawaiian honeycreepers, having evolved from a presumably single founding species of cardueline finch, comprise most of this avifauna. Birds from at least three other families of passerines and five families of non-passerines also radiated in Hawaii. Recent discoveries of a fossil avifauna indicate that most radiations were more extensive than previously thought. Classical analysis of the radiation of Hawaiian birds, especially the honeycreepers, focused on characters related to acquisition of food. Recent studies of bill size and shape in relation to food resources, and of foraging mode in relation to interspecific competitors, provide models of how divergence in diet and/or bill morphology might have evolved. Studies of geographic variation among subspecies on different islands and among populations within islands have revealed extensive divergence in characters such as sexual chromatism, nest sites and nest morphology.

GENETIC VARIABILITY AND TAXONOMIC STATUS OF THE NIHOA AND LAYSAN MILLERBIRDS

Abstract The Millerbird (Acrocephalus familiaris) is an endemic Northwestern Hawaiian Islands reed warbler that existed until about 1923 on Laysan Island (A. f. familiaris) and currently occurs in a small population on Nihoa Island (A. f. kingi). The two populations are described as separate subspecies or species on the basis of size and plumage differences. We assessed genetic variation in blood samples from 15 individuals in the modern Nihoa population using approximately 3000 base pairs (bp) of mitochondrial DNA (mtDNA) sequence and 14 microsatellite loci. We also obtained up to 1028 bp of mtDNA sequence from the fragmented DNA of museum specimens of three birds collected on Nihoa in 1923 and five birds collected on Laysan in 1902 and 1911 (ancient samples). Genetic variation in both marker types was extremely low in the modern Nihoa population (nucleotide diversity [π]  =  0.00005 for mtDNA sequences; observed heterozygosity was 7.2% for the microsatellite loci). In contrast, we found three mtDNA haplotypes among the five Laysan individuals (π  =  0.0023), indicating substantially greater genetic variation. The Nihoa and Laysan taxa differed by 1.7% uncorrected mtDNA sequence divergence, a magnitude that would support designation at the subspecies, and perhaps species, level relative to other closely related Acrocephalus species pairs. However, in light of strong ecological similarity between the two taxa, and a need to have additional populations to prevent extinction from stochastic effects and catastrophes, we believe these genetic differences should not deter a potential translocation of individuals from Nihoa to Laysan.

Seeking the Sacred Raven: Politics and Extinction on a Hawaiian Island

Seeking the Sacred Raven: Politics and Extinction on a Hawaiian Island.—Jerome Mark Walters. 2006. Island Press, Washington, DC. 286 pp. ISBN 1-55963-090-6.

Detrimental effects of two widespread invasive ant species on weight and survival of colonial nesting seabirds in the Hawaiian Islands

24.95 (cloth). Seeking the Sacred Raven: Politics and Extinction on a Hawaiian Island, by Jerome Mark Walters, DVM, is the author’s very personal version of the decline of the ‘Alalā or endemic Hawaiian Crow (Corvus hawaiiensis). Walters’s writing belies his training as a scientist; his book is infused with what some readers will find contrived spirituality that can be distracting or downright annoying and is laden with hubris. In our opinion, the book lacks objectivity; Walters chooses sides—a private landowner is the heroine, and biologists are portrayed as antagonists. The veracity of much of what is written, especially the direct quotations, cannot be verified, although the bias of the author (e.g., the title of chapter 14, “Scientist to the Rescue”) comes through loud and clear. The book also has numerous errors of fact and, more importantly, errors of omission. For starters, the ‘Alalā is not extinct. At present, there are many more individuals in captivity (57) than there were in initial captive populations of other critically endangered species, like the California Condor (Gymnogyps californianus) and Whooping Crane (Grus Americana), and, like the ‘Alalā, these species are now increasing. A number of what seem like minor errors (see Tummons [2006] for examples) will be aggravating to those readers who, through personal experience, know the story better than Walters. On the positive side, this book communicates many of the frustrations of doing conservation work in Hawai‘i. Walters’s description of the captive propagation program’s history is perhaps the most incomplete part of the account. According to Dr. Fern Duvall, who directed the ‘Alalā captive propagation program from 1984 to 1996, the author spoke to him only once for about an hour about ten years before the book was published; hardly enough to get a very complete picture of that period of the program. In 1984, when Duvall took over as a temporary hire, the captive crows were housed adjacent to a U.S. Army training area where the sound of artillery, exploding bombs and helicopters flying a few hundred feet over the aviaries were daily occurrences. After years of pressure from Duvall, other biologists, and environmental organizations, the U.S. Army and the State of Hawai‘i found funding to construct aviaries at a run-down former state prison facility on the Island of Maui. We read virtually nothing of this in the book. Instead, Walters merely recounts the captive propagation program’s inadequate infrastructure and funding under Duvall, as well as the lack of genetic variation in the captive flock, neither of which Duvall had any control over. Having informed readers of the captive flock’s low genetic variation and the possible role of this in the program’s lack of success, Walters denigrates virtually all efforts made by state and federal biologists to bring new genetic material into the captive flock. Those efforts