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Although stable hydrogen (δ2H) and carbon (δ13C) isotopic compositions of bird feathers have been increasingly used to understand the migration of birds through assignment of individuals to established isoscapes, far less is known about the structure of feather isoscapes based on stable sulphur isotope (δ34S) assays. While δ2H isoscapes have been used to investigate the migratory origins of the Globe Skimmer (Pantala flavescens) dragonfly in India, no isotope studies have been applied to avian migration patterns in that region. Here, based on museum collections, we report the feather δ34S values of 13 avian species that included marine birds with expected 34S enriched feathers, resident birds throughout India and a single migratory species, Bar-headed Goose (Anser indicus). Feathers from the marine birds were the most enriched (20.6 ± 1.2 ‰, n = 10; range = 4.4 ‰) in 34S but terrestrial resident species also showed unexpectedly high δ34S values (11.7 ± 4.8 ‰, n = 74; range = 19.9 ‰) throughout most of India but the Himalayan region and Gangetic plain typically showed δ34S values less than 6.4 ‰. Our results show the utility of feather δ34S studies to decipher avian and other animal migration between these two regions.

Enriching the isotopic composition of diet is a tool that is used very readily to determine different patterns of nutrient sourcing and availability. This isotopic enrichment can be done on some sugars. In the wild, many lepidoptera feed on nectar primarily comprised of sucrose, yet isotopically enriched glucose is more widely available due to ease of enrichment and associated price. This experiment tests if true armyworm (Mythimna unipuncta) gain mass similarly when raised on diets with varying sucrose and glucose concentrations.

The authors regret that the printed version of the above article contained an omission of an individual deserving of co-authorship. The correct and final version follows. The authors would like to apologise for any inconvenience caused. < Reyd A. Smith1⁎, David J. Yurkowski2, Kyle J.L. Parkinson1, Jérôme Fort3, Holly L. Hennin4, H. Grant Gilchrist4, Keith A. Hobson5, Mark L. Mallory6, Paco Bustamante3, Jóhannis Danielsen7, Svend E. Garbus8, Sveinn A. Hanssen9, Jón Einar Jónsson10, Christopher J. Latty11, Ellen Magnúsdóttir10, Børge Moe9, Glen J. Parsons12, Christian Sonne8, Grigori Tertitski13, and Oliver P. Love1>

Temporal variation in the connectivity of populations of migratory animals has not been widely documented, despite having important repercussions for population ecology and conservation. Because the long-distance movements of migratory animals link ecologically distinct and geographically distant areas of the world, changes in the abundance and migratory patterns of species may reflect differential drivers of demographic trends acting over various spatial scales. Using stable hydrogen isotope analyses (δ2H) of feathers from historical museum specimens and contemporary samples obtained in the field, we provide evidence for an approximately 600 km northward shift over 45 years in the breeding origin of a species of songbird of major conservation concern (Blackpoll Warbler, Setophaga striata) wintering in the foothills of the Eastern Andes of Colombia. Our finding mirrors predictions of range shifts for boreal-breeding species under warming climate scenarios and habitat loss in the temperate zone, and underscores likely drivers of widespread declines in populations of migratory birds. Our work also highlights the value of natural history collections to document the effects of global change on biodiversity.

Using stable isotope measurements of insect tissues to determine origin and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, the primary fuel of migration, has not been as thoroughly researched. We explored isotopic links between diet and stored lipids in laboratory raised True armyworm moths (Mythimna unipuncta) using δ13C and δ2H measurements. Pupae were randomly separated into four groups (n=20) and fed isotopically distinct nectar, each consisting of a combination of high δ13C (C4 sugar), or low δ13C (C3 sugar) carbohydrate, with high δ2H (deuterium spiked), or low δ2H (tap) water. After 6 days of feeding, lipids were extracted for isotopic analysis using CF-IRMS. The carbohydrate contributed to approximately 80% of the δ13C and water contributed to approximately 13% of the δ2H in lipids. Lipids from C4 fed moths had higher δ13C values compared to C3 fed moths (-29.1 vs -16.6 ‰, P2H values compared to moths given tap water (-187.3 vs -254.6 ‰, P13C which can be used to provide continental isoscapes for tracking sources of stored lipids.

Graphs show the same deuterium data as Fig. 3 in the main text, but with the two years plotted separately. The fat scores are shown as different colours. The fat scores are shown as different colours. (PDF 257 kb)

Full detail of acknowledgments

1) Condor tagging and movement estimations. 2) Stable isotopes estimations

Information on wing-wear categories, stable isotope analysis, and natal origin assignments to potential migrants are given as well as the acknowledgements

Supplementary material from "Long-distance autumn migration across the Sahara by painted lady butterflies: exploiting resource pulses in the tropical savannah"

Previous studies have shown that natural abundance of deuterium (D), and to a lesser extent 13C, in feathers of migrant songbirds in North America can be used to infer geographic origins of molt. We used that approach to investigate whether Bicknell's Thrush (Catharus bicknelli) populations could be segregated on the breeding grounds at six sites in eastern North America to evaluate contributions from the breeding areas to wintering populations. Further, we tested our isotopic model using feathers from hatching-year migrant Swainson's Thrush (Catharus ustulatus) and Gray-cheeked Thrush (Catharus minimus) moving through southern Manitoba and Ontario and found that δD values were consistent with northerly boreal forest natal sites in northwestern and central Canada. Despite a strong latitudinal gradient in δD of average growing season precipitation over the breeding range, we found considerable overlap in δD values of Bicknell's Thrush among all breeding sites. No strong pattern in δ13C values of feathers with latitude was apparent. Nevertheless, the more negative δD values of feathers from wintering birds in the Dominican Republic compared to breeding area samples suggested that birds from more northerly locations in North America contributed to this population of wintering birds. High variance in feather δD values within breeding populations also suggested high natal dispersal, considerable movement of birds among island habitats on the breeding grounds, or both. Even higher variances in feather δD values from small study areas on the wintering grounds, compared to similar-sized areas in the breeding range, suggest that many different breeding populations mix in winter habitat.

We studied foraging segregation between two different sized colonies of little penguins Eudyptula minor with overlapping foraging areas in pre-laying and incubation. We used stomach contents and stable isotope measurements of nitrogen (δ 15N) and carbon (δ 13C) in blood to examine differences in trophic position, prey-size and nutritional values between the two colonies. Diet of little penguins at St Kilda (small colony) relied heavily on anchovy while at Phillip Island (large colony), the diet was more diverse and anchovies were larger than those consumed by St Kilda penguins. Higher δ 15N values at St Kilda, differences in δ 13C values and the prey composition provided further evidence of diet segregation between colonies. Penguins from each colony took anchovies from different cohorts and probably different stocks, although these sites are only 70km apart. Differences in diet were not reflected in protein levels in the blood of penguins, suggesting that variation in prey between colonies was not related to differences in nutritional value of the diet. Anchovy is currently the only available prey to penguins throughout the year and its absence could have a negative impact on penguin food supply, particularly at St Kilda where the diet is dominated by this species. While it is difficult to establish whether diet segregation is caused by inter- or intra-colony competition or spatial differences in foraging areas, we have shown that colonies with broadly overlapping foraging ranges could have significant differences in trophic position, diet composition and prey size while maintaining a diet of similar nutritional value. © 2011 The Authors. Austral Ecology © 2011 Ecological Society of Australia.

Comunicación presentada en Second Conference on "Bird Migration and Global Change: movement ecology and conservation strategies, BMGC 2010", que se celebró en Algeciras (España) del 17 al 20 de Marzo de 2010

Analysis of the stable-hydrogen isotope content (δD) of feathers taken from a first-winter Marbled Duck Marmaronetta angustirostris shot in Essex on 1st September 2007 showed little difference between juvenile feathers grown at the natal site and those grown during the post-juvenile moult. The δD values of both groups of feather were similar to those expected if the bird had grown feathers in coastal areas of northern Europe, but differed significantly from those in feathers from known wild individuals taken from the species’ nearest breeding areas, in Spain. These results suggest that the bird originated from outside of the normal breeding range of the species and was most likely to have been of captive origin

We used stable-isotope analysis (SIA) to evaluate sources of variation in the diet of and prey selection by Magellanic penguins Spheniscus magellanicus breeding on the Argentinean Patagonia coast. Our aim was to determine potential sources of variation in diet, focusing mainly on sex and age, although geographic and temporal effects were also taken into account. In addition, we evaluated how prey selection affects offspring quality. We measured stable nitrogen ( δ15N) and carbon (δ13C) isotope values in whole blood of chicks (n = 98), yearlings (n = 15) and adults (n = 143) in 9 different breeding colonies during 2 consecutive breeding seasons (1999 and 2000). We also measured stable isotope values in representative prey consumed by this species. Stable nitrogen and carbon isotope values in blood for penguins varied from 17.8 to 20.0” and from -18.1 to -14.8”, respectively. Both colony and season had a significant effect on the 2 isotope signatures. Adult males had higher blood δ15N and δ13C values than females. Age significantly affected both δ15N and δ13C values, with chicks showing the highest and yearlings the lowest δ15N values. Chicks showed lower δ13C values than yearlings and adults. Mean prey δ15N values ranged from 13.6 ” in squid to 18.0 ” in octopus. As anchovy, the main prey consumed by the species in the study area, did not differ from other fish species (hake) in its δ15N value, we used it to represent a fish dietary alternative. Using a 2 source (anchovy and squid) isotopic mixing model, we determined that the mean proportion of anchovy in the diet was 49% for yearlings, 76% for chicks, and 69% and 67% for adult males and females, respectively. Sex and age differences in diet, as revealed by stable isotopes, may be the consequence of individual morphology (sexual size dimorphism) and reproductive constraints imposed by chick development since growing young require more nutritive prey than adults and yearlings. This reasoning would also explain the significant and positive correlation found between proportion of anchovy in the diet and body condition of chicks.

Ratios of the stable carbon (δ13C) and hydrogen (δD) isotopes in newly grown remiges of Ruddy Ducks (Oxyura jamaicensis) are influenced by the isotopic character of food types and ambient water. Systematic isotopic foodweb and water differences between coastal wintering grounds and prairie breeding grounds of Ruddy Ducks provide the basis for using isotopic analyses of feathers to trace the location and timing of molt. Anecdotal evidence, based largely on captive birds, suggests that Ruddy Ducks replace their remiges twice each year (once each on the breeding and wintering grounds), but a recent literature analysis indicates that this phenomenon is rare. Thus, we investigated the extent to which a biannual molt of the remiges occurs in the wild and at the population level. We analyzed the stable isotopes of carbon (n = 57 birds) and hydrogen (n = 50 birds) in flight feathers to estimate the prevalence of the so-called “double molt” of remiges in free-living Ruddy Ducks. Our data showed that natural populations of Ruddy Ducks express an overwhelming unimodal distribution of isotope ratios in their remiges, suggesting that they undergo a single molt at or near the breeding grounds. Only 3 to 6 of 50 birds from Manitoba showed isotopic evidence consistent with growing remiges on the wintering grounds. Feathers from Ruddy Ducks harvested during the fall in the Mississippi Flyway had isotopic profiles consistent with growth on northern freshwater breeding sites. Thus, our results confirm that the replacement of remiges twice each year by Ruddy Ducks is rare, and they suggest that this dual stable-isotope technique can be used to infer general molting origins of North American waterfowl.