Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise.

Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds.

Absorption and biotransformation of polybrominated diphenyl ethers DE-71 and DE-79 in chicken (Gallus gallus), mallard (Anas platyrhynchos), American kestrel (Falco sparverius) and black-crowned night-heron (Nycticorax nycticorax) eggs.

We recently reported that air cell administration of penta-brominated diphenyl ether (penta-BDE; DE-71) evokes biochemical and immunologic effects in chicken (Gallus gallus) embryos at very low doses, and impairs pipping (i.e., stage immediately prior to hatching) and hatching success at 1.8mugg(-1) egg (actual dose absorbed) in American kestrels (Falco sparverius). In the present study, absorption of polybrominated diphenyl ether (PBDE) congeners was measured following air cell administration of a penta-BDE mixture (11.1mug DE-71g(-1) egg) or an octa-brominated diphenyl ether mixture (octa-BDE; DE-79; 15.4mug DE-79g(-1) egg). Uptake of PBDE congeners was measured at 24h post-injection, midway through incubation, and at pipping in chicken, mallard (Anas platyrhynchos), and American kestrel egg contents, and at the end of incubation in black-crowned night-heron (Nycticorax nycticorax) egg contents. Absorption of penta-BDE and octa-BDE from the air cell into egg contents occurred throughout incubation; at pipping, up to 29.6% of penta-BDE was absorbed, but only 1.40-6.48% of octa-BDE was absorbed. Higher brominated congeners appeared to be absorbed more slowly than lower brominated congeners, and uptake rate was inversely proportional to the log K(ow) of predominant BDE congeners. Six congeners or co-eluting pairs of congeners were detected in penta-BDE-treated eggs that were not found in the dosing solution suggesting debromination in the developing embryo, extraembryonic membranes, and possibly even in the air cell membrane. This study demonstrates the importance of determining the fraction of xenobiotic absorbed into the egg following air cell administration for estimation of the lowest-observed-effect level.

The genetic basis of hair whorl, handedness, and other phenotypes.

Evidence is presented that RHD, RHCE, and other RH genes, may be interesting candidates to consider when searching for the genetic basis of hair whorl rotation (i.e., clockwise or counterclockwise), handedness (i.e., right handed, left handed or ambidextrous), speech laterality (i.e., right brained or left brained), speech dyslexia (e.g., stuttering), sexual orientation (i.e., heterosexual, homosexual, bisexual, or transsexual), schizophrenia, bipolar disorder, and autism spectrum disorder. Such evidence involves the need for a genetic model that includes maternal immunization to explain some of the empirical results reported in the literature. The complex polymorphisms present among the maternally immunizing RH genes can then be used to explain other empirical results. Easily tested hypotheses are suggested, based upon genotypic (but not phenotypic) frequencies of the RH genes. In particular, homozygous dominant individuals are expected to be less common or lacking entirely among the alternative phenotypes. If it is proven that RH genes are involved in brain architecture, it will have a profound effect upon our understanding of the development and organization of the asymmetrical vertebrate brain and may eventually lead to a better understanding of the developmental processes which occur to produce the various alternative phenotypes discussed here. In addition, if RH genes are shown to be involved in the production of these phenotypes, then the evolutionary studies can be performed to demonstrate the beneficial effect of the recessive alleles of RHD and RHCE, and why human evolution appears to be selecting for the recessive alleles even though an increase in the frequency of such alleles may imply lower average fecundity among some individuals possessing them.

Efficacy of selected coccidiostats in sandhill cranes (Grus canadensis) following challenge.

The anticoccidial efficacy of amprolium, clazuril, and monensin were studied in sandhill cranes (Grus canadensis) infected with a mixture of Eimeria spp. oocysts. Five groups of four 1-day-old sandhill crane chicks were maintained on a crumbled ration containing no coccidiostat, amprolium at 2.2 ppm, clazuril at 1.1 ppm, clazuril at 5.5 ppm, or monensin at 99 ppm. After 2 wk on their respective feeding regimens, birds in each of the five groups were administered 25 x 10(3) pooled sporulated Eimeria spp. oocysts per os and observed for another 3 wk. A sixth group of four chicks served as nonmedicated, nonchallenged control during the study. Clinical signs and lesions consistent with disseminated visceral coccidiosis were observed in all challenged controls and birds fed amprolium and clazuril. Birds in these groups died 9-10 days after challenge. In contrast, only one monensin-medicated bird had clinical signs of disseminated visceral coccidiosis, and it died 13 days after challenge (DAC). This and an asymptomatic bird that were necropsied at study termination had less-severe gross and microscopic lesions of disseminated visceral coccidiosis. Two of three monensin-treated birds that survived challenge passed from 50 to 500 coccidial oocysts 11 to 18 DAC but were negative at study termination. Of the coccidiostats tested, monensin, at the dietary level of 99 ppm, was the only anticoccidial drug that provided protection against experimentally induced disseminated visceral coccidiosis in sandhill cranes.

Demographic analysis from summaries of an age-structured population.

Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assigned to one of a set of age classes. For example, it is often possible to distinguish first-year from older birds. In such cases, the population age structure can be regarded as a latent variable governed by a process prior, and the data as summaries of this latent structure. In this article, we consider the problem of uncovering the latent structure and estimating process parameters from summaries of age class information. We present a demographic analysis for the critically endangered migratory population of whooping cranes (Grus americana), based only on counts of first-year birds and of older birds. We estimate age and year-specific survival rates. We address the controversial issue of whether management action on the breeding grounds has influenced recruitment, relating recruitment rates to the number of seventh-year and older birds, and examining the pattern of variation through time in this rate.