Kent A. Hatch

Using stable isotopes to unravel and predict the origins of great cormorants (Phalacrocorax carbo sinensis) overwintering at Kinmen

The Food and Agricultural Organization of the United Nations and the World Organization for Animal Health have called for a better understanding of the role that migrating birds may play in spreading H5N1 highly pathogenic avian influenza (HPAI). Bird banding, traditionally used in studies of migration, is limited by low recapture rates. Telemetry can only be applied to larger species and a limited number of birds. We show that analyses of multiple stable isotopes (delta(13)C, delta(15)N, delta(18)O and deltaD) can provide an understanding of the number of breeding populations represented at large congregations of wintering birds, probable locations of these breeding populations, and which breeding populations do not contribute migrants to a wintering site. As Asia is thought to be the origin of many HPAI strains and the center of their evolution, and as bird migration is poorly understood in this part of the world, we recommend that, in addition to banding, satellite, and VHF telemetry, the stable isotope analysis of migration patterns should become a part of long-term surveillance studies.

Carbon stable-isotope tracking in breath for comparative studies of fuel use

Almost half a century ago, researchers demonstrated that the ratio of stable carbon isotopes in exhaled breath of rats and humans could reveal the oxidation of labeled substrates in vivo, opening a new chapter in the study of fuel use, the fate of ingested substrates, and aerobic metabolism. Until recently, the combined use of respirometry and stable‐isotope tracer techniques had not been broadly employed to study fuel use in other animal groups. In this review, we summarize the history of this approach in human and animal research and define best practices that maximize its utility. We also summarize several case studies that use stable‐isotope measurements of breath to explore the limits of aerobic metabolism and substrate turnover among several species and various physiological states. We highlight the importance of a comparative approach in revealing the profound effects that phylogeny, ecology, and behavior can have in shaping aerobic metabolism and energetics as well as the fundamental biological principles that underlie fuel use and metabolic function across taxa. New analytical equipment and refinement of methodology make the combined use of respirometry and stable‐isotope tracer techniques simpler to perform, less costly, and more field ready than ever before.

STABLE NITROGEN AND CARBON ISOTOPES MAY NOT BE GOOD INDICATORS OF ALTITUDINAL DISTRIBUTIONS OF MONTANE PASSERINES

Abstract We examined δ15N and δ13C values of feathers from nine species, belonging to three feeding guilds (herbivores, omnivores, and insectivores), of wild passerines at eight sites along an altitudinal gradient (339–2,876 m asl) within Taroko National Park, Taiwan. We examined: (1) if altitudinal patterns in feather δ15N and δ13C are consistent with previously published values for plants and soils, (2) if feather δ15N and δ13C differ among sites, and (3) if there are year-to-year and/or month-to-month fluctuations in feather δ15N and δ13C of the same birds. We found no simple relationship between feather isotope values and altitude. Feather δ15N values decreased significantly with increasing altitude for insectivores, but not for herbivores and omnivores. Feather δ13C values increased significantly with increasing altitude for herbivores and omnivores, but not for insectivores. Altitudinal trends in feather δ15N and δ13C values exhibit even more inconsistent patterns when data were analyzed by species; feather δ15N and δ13C values for some species increased significantly with increasing altitude, others decreased significantly with increasing altitude, and still others exhibited no significant relationship between isotopic values and altitude. The R2 for the relationship between feather δ15N, δ13C values and altitude was generally low regardless of whether the analysis was by feeding guilds or species. This indicates much of the variation cannot be explained by altitude. There were either no significant differences between sites, or significant differences between some but not all sites when investigating δ15N or δ13C, whether by feeding guilds or by species. Our study suggests that carbon and nitrogen isotopes may be not useful markers to track altitudinal migration of montane passerines.

Brush-tipped Tongue Structure of the Taiwan Yuhina (Yuhina brunneiceps) and White-eared Sibia (Heterophasia auricularis)

Abstract The Taiwan Yuhina (Yuhina brunneiceps) and White-eared Sibia (Heterophasia auricularis) are nectar-feeding babblers endemic to Taiwan. We describe the morphological features of the brush-tipped tongues of these species. The tongue divides into two parts and then into four parts towards the distal end for both species. The tongues of the Taiwan Yuhina and White-eared Sibia are specialized organs adapted for collection of nectar.

Toe Clipping Does Not Affect the Survival of Leopard Frogs (Rana pipiens)

Toe clipping is commonly used to identify individual frogs in mark–recapture studies. However, Institutional Animal Care and Use Committees (IACUCs) often have reservations about approving studies that include toe clipping as a way to mark animals. Previous studies indicate that recapture rates of terrestrial frogs and toads decrease with increasing numbers of toes clipped. It is not known whether these decreases are due to decreased survival rates, increased avoidance of recapture, or some other reason. The goal of this paper is to provide IACUCs with a quantitative analysis of the effects of toe clipping on survival so that they can make informed, data-based decisions when approving studies using this method, rather than basing decisions on anthropomorphic biases. We conducted a large (n  =  100) laboratory experiment to determine the effects of toe clipping on the frog Rana pipiens. We found no evidence that the number of toes clipped affected either the survival rate of Leopard Frogs or the number of days that frogs survived over a 13-week period.

Regional Scale High Resolution δ18O Prediction in Precipitation Using MODIS EVI

The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, paleoclimatology, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict δ18O in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated δ18O are highly correlated and thus the EVI is a good predictor of precipitated δ18O. We then test the predictability of our EVI-δ18O model and demonstrate that our approach can provide high accuracy with fine spatial (250×250 m) and temporal (16 days) scale δ18O predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and δ18O in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape.

Towards a physiologically based diagnosis of anorexia nervosa and bulimia nervosa

Diagnosis of anorexia nervosa (AN) and bulimia nervosa (BN), while including such physiological data as weight and the reproductive status of the individual, are primarily based on questionnaires and interviews that rely on self-report of both body-related concerns and eating-related behaviors. While some key components of eating disorders are psychological and thus introspective in nature, reliance on self-report for the assessment of eating-related behaviors and nutritional status lacks the objectivity that a physiologically based measure could provide. The development of a more physiologically informed diagnosis for AN and BN would provide a more objective means of diagnosing these disorders, provide a sound physiological basis for diagnosing subclinical disorders and could also aid in monitoring the effectiveness of treatments for these disorders. Empirically supported, physiologically based methods for diagnosing AN and BN are reviewed herein as well as promising physiological measures that may potentially be used in the diagnosis of AN and BN.