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The European crow (Corvus corone) occurs in two subspecies (or species) with distinct plumage coloration: the black carrion crow (C. c. corone) and the grey and black hooded crow (C. c. cornix). We tested 42 passerine microsatellite loci for amplification in the European crow and identified 20 loci that were both polymorphic and easy to score. In 50 individuals sampled in the Danish part of the species’ pan‐European hybrid zone, the number of alleles ranged between two and 21. One locus deviated from Hardy–Weinberg equilibrium and had a high estimated null allele frequency. These 20 loci were highly successful in amplifying polymorphic products also in other crow populations and in another Corvidae species, the rook (Corvus frugilegus). 相似文献
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Pedro P. Olea 《Population Ecology》2009,51(1):161-174
The spatial and temporal variation in population sizes of animal colonies are rarely studied simultaneously. I examined factors
determining colony size (number of nests) for 23 colonies from the only breeding population of rook Corvus frugilegus in Spain over 7 years. Population sizes within colonies were highly predictable over time, with autocorrelations up to a
distance (lag) of 6 years. Autoregressive mixed models were used to explain colony size as a function of environmental factors,
while controlling for temporal autocorrelation. These factors included refuse tips, widely used as food resource, and a derived
variable that incorporated the two factors most often related to avian colony size (inter-colony competition and foraging
habitat around colonies). Autoregressive models provided a better fit to the data than models which did not consider temporal
autocorrelation. The information-theoretic (AICc-based) approach revealed uncertainty in the selection of the best model explaining colony-size, but relatively strong support
for certain variables. The highest weights of evidence were for year (ω
i
= 0.90) and the number of competitors per unit of foraging habitat (i.e., derived variable; ω
i
= 0.63), showing that the size of rook colonies in Spain was negatively affected by inter-colony competition relative to
the foraging habitat surrounding the colonies. This variable measured within a 6-km radius from the colonies had ~30 times
higher weight of evidence (more plausible) than the same variable measured within 3 km, indicating that food limitation may
occur outside the breeding period. Sizes of colonies tended to decrease when distance between the colony and the nearest refuse
tip increased. There was some evidence supporting the idea that the effect of the number of competitors per unit of foraging
habitat on colony size varied from year to year, but statistical power was weak. These findings suggest that variation in
number of rook nests within colonies reflects spatial and temporal heterogeneity of net food via both inter-colony competition
and foraging habitat around the colony.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Natsumi Arai 《Biochemical and biophysical research communications》2010,397(3):553-558
Molecular cloning, molecular phylogeny, gene structure and expression analyses of growth hormone (GH) were performed in a passerine bird, the jungle crow (Corvus macrorhynchos). Unexpectedly, duplicated GH cDNA and genes were identified and designated as GH1A and GH1B. In silico analyses identified the zebra finch orthologs. Both GH genes encode 217 amino acid residues and consist of five exons and four introns, spanning 5.2 kbp in GH1A and 4.2 kbp in GH1B. Predicted GH proteins of the jungle crow and zebra finch contain four conserved cysteine residues, suggesting duplicated GH genes are functional. Molecular phylogenetic analysis revealed that duplication of GH genes occur after divergence of the passerine lineage from the other avian orders as has been suggested from partial genomic DNA sequences of passerine GH genes. RT-PCR analyses confirmed expression of GH1A and GH1B in the pituitary gland. In addition, GH1A gene is expressed in all the tissues examined. However, expression of GH1B is confined to several brain areas and blood cells. These results indicate that the regulatory mechanisms of duplicated GH genes are different and that duplicated GH genes exert both endocrine and autocrine/paracrine functions. 相似文献
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Selva N Cortés-Avizanda A Lemus JA Blanco G Mueller T Heinrich B Donázar JA 《Biology letters》2011,7(4):608-610
Many long-lived avian species adopt life strategies that involve a gregarious way of life at juvenile and sub-adult stages and territoriality during adulthood. However, the potential associated costs of these life styles, such as stress, are poorly understood. We examined the effects of group living, sex and parasite load on the baseline concentration of faecal stress hormone (corticosterone) metabolites in a wild population of common ravens (Corvus corax). Corticosterone concentrations were significantly higher in non-breeding gregarious ravens than in territorial adults. Among territorial birds, males showed higher stress levels than their mates. Parasite burdens did not affect hormone levels. Our results suggest a key role of the social context in the stress profiles of the two population fractions, and that group living may be more energetically demanding than maintaining a territory. These findings have implications for understanding hormonal mechanisms under different life styles and may inspire further research on the link between hormone levels and selective pressures modulating gregarious and territorial strategies in long-lived birds. 相似文献