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Tuesday, 20 May 2014

Bird research this week on PubMed: May 2014 Week 2

PubMed listing for 'bird' OR 'songbird' excluding references to influenza and flu - May 2014 Week 2




1. Ecol Evol. 2014 Apr;4(8):1222-32. doi: 10.1002/ece3.994. Epub 2014 Mar 11.

Color expression in experimentally regrown feathers of an overwintering migratory bird: implications for signaling and seasonal interactions.

Tonra CM1, Marini KL2, Marra PP3, Germain RR4, Holberton RL5, Reudink MW2.Author information:
1Migratory Bird Center, Smithsonian Conservation Biology Institute National Zoological Park, Washington, District of Columbia ; School of Biology and Ecology, University of Maine Orono, Maine.
2Department of Biological Sciences, Thompson Rivers University Kamloops, BC V2C 0C8, Canada.
3Migratory Bird Center, Smithsonian Conservation Biology Institute National Zoological Park, Washington, District of Columbia.
4Centre for Applied Conservation Research, University of British Columbia Vancouver, BC V6T 1Z4, Canada.
5School of Biology and Ecology, University of Maine Orono, Maine.

Abstract

Plumage coloration in birds plays a critical role in communication and can be under selection throughout the annual cycle as a sexual and social signal. However, for migratory birds, little is known about the acquisition and maintenance of colorful plumage during the nonbreeding period. Winter habitat could influence the quality of colorful plumage, ultimately carrying over to influence sexual selection and social interactions during the breeding period. In addition to the annual growth of colorful feathers, feather loss from agonistic interactions or predator avoidance could require birds to replace colorful feathers in winter or experience plumage degradation. We hypothesized that conditions on the wintering grounds of migratory birds influence the quality of colorful plumage. We predicted that the quality of American redstart (Setophaga ruticilla) tail feathers regrown after experimental removal in Jamaica, West Indies, would be positively associated with habitat quality, body condition, and testosterone. Both yearling (SY) and adult (ASY) males regrew feathers with lower red chroma, suggesting reduced carotenoid content. While we did not observe a change in hue in ASY males, SY males shifted from yellow to orange plumage resembling experimentally regrown ASY feathers. We did not observe any effects of habitat, testosterone, or mass change. Our results demonstrate that redstarts are limited in their ability to adequately replace colorful plumage, regardless of habitat, in winter. Thus, feather loss on the nonbreeding grounds can affect social signals, potentially negatively carrying over to the breeding period.
PMID: 24834321 [PubMed]

2. Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Apr;89(4-1):042806. Epub 2014 Apr 15.

Impact fragmentation of model flocks.

Miller PW1, Ouellette NT2.Author information:
1Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
2Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.

Abstract

Predicting the bulk material properties of active matter is challenging since these materials are far from equilibrium and standard statistical-mechanics approaches may fail. We report a computational study of the surface properties of a well known active matter system: aggregations of self-propelled particles that are coupled via an orientational interaction and that resemble bird flocks. By simulating the impact of these models flocks on an impermeable surface, we find that they fragment into subflocks with power-law mass distributions, similar to shattering brittle solids but not to splashing liquid drops. Thus, we find that despite the interparticle interactions, these model flocks do not possess an emergent surface tension.
PMID: 24827292 [PubMed - as supplied by publisher]
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3. Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Apr;89(4-1):042707. Epub 2014 Apr 16.

Dynamical maximum entropy approach to flocking.

Cavagna A1, Giardina I1, Ginelli F2, Mora T3, Piovani D4, Tavarone R4, Walczak AM5.Author information:
1Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, Rome, Italy and Dipartimento di Fisica, Università Sapienza, Rome, Italy and Initiative for the Theoretical Sciences, The Graduate Center, The City University of New York, New York, USA.
2SUPA, Institute for Complex Systems and Mathematical Biology, King's College, University of Aberdeen, Aberdeen, UK.
3Laboratoire de physique statistique, CNRS, UPMC and École normale supérieure, Paris, France.
4Dipartimento di Fisica, Università Sapienza, Rome, Italy.
5Laboratoire de physique théorique, CNRS, UPMC and École normale supérieure, Paris, France.

Abstract

We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.
PMID: 24827278 [PubMed - as supplied by publisher]
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4. Evol Appl. 2014 Apr;7(4):506-18. doi: 10.1111/eva.12154. Epub 2014 Mar 20.

Joint effects of population size and isolation on genetic erosion in fragmented populations: finding fragmentation thresholds for management.

Méndez M1, Vögeli M2, Tella JL1, Godoy JA1.Author information:
1Estación Biológica de Doñana (EBD-CSIC) Sevilla, Spain.
2Estación Biológica de Doñana (EBD-CSIC) Sevilla, Spain ; Department of Biology, University of Saskatchewan Saskatoon, SK, Canada ; Schulstrasse 47, 5423, Freienwil, Switzerland.

Abstract

Size and isolation of local populations are main parameters of interest when assessing the genetic consequences of habitat fragmentation. However, their relative influence on the genetic erosion of local populations remains unclear. In this study, we first analysed how size and isolation of habitat patches influence the genetic variation of local populations of the Dupont's lark (Chersophilus duponti), an endangered songbird. An information-theoretic approach to model selection allowed us to address the importance of interactions between habitat variables, an aspect seldom considered in fragmentation studies, but which explained up to 65% of the variance in genetic parameters. Genetic diversity and inbreeding were influenced by the size of local populations depending on their degree of isolation, and genetic differentiation was positively related to isolation. We then identified a minimum local population of 19 male territories and a maximum distance of 30 km to the nearest population as thresholds from which genetic erosion becomes apparent. Our results alert on possibly misleading conclusions and suboptimal management recommendations when only additive effects are taken into account and encourage the use of most explanatory but easy-to-measure variables for the evaluation of genetic risks in conservation programmes.
PMCID: PMC4001448 Free PMC Article
PMID: 24822084 [PubMed]
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