Table 1. Study species, collected feathers and sampling locations from samples analyzed in this study including species abbreviations. Black feathers or black areas of feathers were in all cases We measured the stable isotope ratios of carbon and significantly depleted in d13C compared to white areas nitrogen using continuous-flow isotope-ratio mass spec- Table 2, Fig.
The difference ranged between 0. Delta Plus XP mass spectrometer. Three occurred. The black feathers of shags were, however, lab standards gelatine and two isotopically distinct alanines enriched in 15N, a result which also did not differ between were used to correct for instrumental drift over a 12 h run. The carbon-to-nitrogen ratio gives an indication of the Table 2. Rapid Commun. For abbreviations, see Table 1. Future studies should While many studies have found much larger differences in look at other components with varying proportions in d13C,25 the differences between black and white feathers seen feathers e.
It may be somewhat premature to agree with Norris observed in some stable isotope studies. For Imperial Shags in both age groups we cannot exclude a Although stable isotope analyses remain a powerful tool, different timing in the moult of black and white feathers and these results show once again that great caution should be consequently differences between black and white feathers exercised when comparing isotope values derived from bulk may be due to behavioural changes or nutritional stress.
Not only do different tissues show different Nevertheless, the differences were consistent among years, isotope fractionation factors, but the isotope value of the which is a first indication that changes in diet, foraging same tissue may depend on its chemical composition4 and, locations or such intrinsic factors as nutritional stress are not more specifically, on the pigmentation of that tissue.
Thus, responsible unless they occur stereotypically each year. Acknowledgements Polar Biol. Nina Dehnhard provided Field- Global Change Biol. Funding for the stable isotope work was provided by Environ. Health Stud. Condor ; Deep-Sea Res. Part I ; Acta ; Pigment Cell Res. Armada - E Timpul. Carbon - Boom bap Original Radio Edit. Aerial Carbon Ft. Maidan - Depinde Original Radio Edit. Deliric1 - Cox Feat. Sisu feat. Raku - Oxigenarea creierelor Original Radio Edit. Pacha man - Pe cine combati Original Radio Edit.
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Bogdan Gavris - Mi-e tare dor de prietenii mei Originala Canada Goose. More: 2. Tundra Swan. Wood Duck. Blue-winged Teal. Cinnamon Teal. Northern Shoveler. Eurasian Wigeon.
American Wigeon. Northern Pintail. Green-winged Teal. Ring-necked Duck. Greater Scaup. Lesser Scaup. Surf Scoter. More: White-winged Scoter. Black Scoter. Long-tailed Duck. More: 3. Common Goldeneye. More: 4. Barrow's Goldeneye.
Hooded Merganser. Common Merganser. Red-breasted Merganser. Ruddy Duck. Wild Turkey. Sharp-tailed Grouse. Gray Partridge. Ring-necked Pheasant. Pied-billed Grebe. Horned Grebe. Red-necked Grebe. Eared Grebe. Western Grebe. Clark's Grebe.
Rock Pigeon. Eurasian Collared-Dove. Mourning Dove. Common Nighthawk. Broad-tailed Hummingbird. American Coot. Sandhill Crane.
Black-necked Stilt. American Avocet. Black-bellied Plover. Semipalmated Plover. More: 5. Upland Sandpiper. Long-billed Curlew.
Marbled Godwit. Stilt Sandpiper. Baird's Sandpiper. Least Sandpiper. Buff-breasted Sandpiper. More: 6. Pectoral Sandpiper. Semipalmated Sandpiper. Western Sandpiper. Long-billed Dowitcher. Wilson's Snipe. Wilson's Phalarope.
Red-necked Phalarope. Spotted Sandpiper. Solitary Sandpiper. Greater Yellowlegs. Lesser Yellowlegs. Sabine's Gull. Bonaparte's Gull. Franklin's Gull. Ring-billed Gull. California Gull. Herring Gull. Caspian Tern. Black Tern. Common Tern. Forster's Tern. Red-throated Loon. Pacific Loon. Common Loon.
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