The Condor 

About: The Condor is an academic journal published by Cooper Ornithological Society. The journal publishes majorly in the area(s): Population & Nest. It has an ISSN identifier of 0010-5422. Over the lifetime, 7532 publications have been published receiving 210413 citations.

Culture and the evolutionary process

Abstract: How do biological, psychological, sociological, and cultural factors combine to change societies over the long run? Boyd and Richerson explore how genetic and cultural factors interact, under the influence of evolutionary forces, to produce the diversity we see in human cultures. Using methods developed by population biologists, they propose a theory of cultural evolution that is an original and fair-minded alternative to the sociobiology debate.

Reproductive success : studies of individual variation in contrasting breeding systems

Abstract: "This book is well worth buying for its detailed summaries of the 25 studies, many of which are classic long-term projects, and for its insights into the factors determining reproductive success."--William J. Sutherland, "TREE" "A must read for anyone interested in evolution, mating/social systems, and population ecology."--John L. Koprowski, "IJournal of Insect Behavior"

Assessing Avian Diets Using Stable Isotopes I: Turnover of 13C in Tissues

Abstract: Studies of birds that use stable isotopes as dietary tracers require estimates of how quickly stable isotopes in tissues are replaced by isotopes derived from the diet. However, isotopic turnover rates in animals in general, and birds in particular, are poorly understood. We established the turnover rates of '3C in tissues of grown Japanese Quail (Coturnixjaponica) by switching the diet of an experimental group from a wheat-based (C3) diet to a corn-based (C4) diet and sampled tissues periodically for 212 days. An exponential model described patterns of isotopic turnover in all tissues. Turnover rates for quail tissues were ranked liver > blood > muscle > bone collagen with the half life of carbon ranging from 2.6 days in liver to 173.3 days in bone collagen. A similar diet-switch experiment was conducted on captive American Crows (Corvus brachyrhynchos) and feather samples were assayed isotopically. Stable isotope values of crow feathers reflected diet during periods of growth. We suggest that stable isotope analysis could be used to determine relative contributions of endogenous and exogenous nutrient sources for feather growth and egg production in captive and wild birds.

Assessing Avian Diets Using Stable Isotopes II: Factors Influencing Diet-Tissue Fractionation

Abstract: Studies using stable-isotope analysis to infer diet require a knowledge of how stable-isotope ratios in consumer tissues are related to dietary values. We determined 61'3C and 6'5N diet-tissue fractionation factors for blood, liver, muscle, bone collagen and feathers of domestic chickens (Gallus gallus), Japanese Quail (Coturnix japonica) and Ring-billed Gulls (Larus delawarensis) and for blood and feather samples of adult Peregrine Falcons (Falco peregrinus) raised on known isotopic diets. In most cases tissues were enriched in 613C and 615N compared to diet. However, fractionation values differed among species, diets, and tissue types and this variation must be considered in isotope dietary studies. We found little evidence that isotopic fractionation factors are influenced by age in adult birds and provide fractionation factors appropriate for granivores feeding in a C-3 biome and for higher trophic-level piscivores and carnivores. American Crows (Corvus brachyrhynchos) raised on a perch diet grew faster and showed lower nitrogen diet-tissue fractionation values than crows raised on a plant-based diet. We suggest that nutritional stress caused substantial increases in diet-tissue fractionation values due either to: (1) mobilization and redeposition of proteins elsewhere in the body; or (2) amino acid composition changes in tissues.

Stable-Nitrogen Isotope Enrichment in Avian Tissues Due to Fasting and Nutritional Stress: Implications for Isotopic Analyses of Diet

Abstract: Studies using measurements of61'5N to delineate diet or trophic level in natural ecosystems are based on the premise that 6'5N values in consumer tissues can be reliably correlated with those in the diet. However, juvenile Japanese Quail (Coturnixjaponica) fed a rationed diet designed to maintain, but not increase, body mass showed significantly enriched tissue 6'5N values over a control group fed the same diet ad libitum. We tested the hypothesis that fasting or nutritional stress can also cause elevated 6'5N values in tissues of wild birds by examining tissues of Arctic-nesting female Ross' Geese (Chen rossii) before and after their period of fasting during egg laying and incubation. Significant declines in body, pectoral muscle, liver and abdominal fat mass occurred from arrival through incubation. Post-incubating geese showed significantly higher pectoral muscle and liver 6'5N values compared to geese taken before clutch initiation but 6a3C values in these tissues were unchanged. We hypothesize a mechanism of tissue 6'5N enrichment due to reduced nutrient intake and discuss the implications of these results to ecosystem studies using stable-nitrogen isotope analysis.