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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.


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.


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.


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.


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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Tuesday, 13 May 2014

Egg colour variation and egg rejection in response to Cuckoo parasitism. Yang et al Evolution and Ecology 7 May 2014

Egg color variation, but not egg rejection behavior, changes in a cuckoo host breeding in the absence of brood parasitism

Canchao Yang 1, Yang Liu 2, Lijin Zeng 3 and Wei Liang 1*

Author Information
1- Ministry of Education Key Laboratory for Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou, China
2- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
3- Department of Biology, University of California, Riverside, California, USA
* Correspondence 

Wei Liang, Ministry of Education Key Laboratory for Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China. Tel: +86 898 65883521; Fax: +86 898 65818360; E-mail:

Article first published online: 7 MAY 2014


DOI: 10.1002/ece3.1096

Original Research - Online Open Access article

© 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.


Interactions between parasitic cuckoos and their songbird hosts form a classical reciprocal “arms race,” and are an excellent model for understanding the process of coevolution. Changes in host egg coloration via the evolution of interclutch variation in egg color or intraclutch consistency in egg color are hypothesized counter adaptations that facilitate egg recognition and thus limit brood parasitism. Whether these antiparasitism strategies are maintained when the selective pressure of parasitism is relaxed remains debated. However, introduced species provide unique opportunities for testing the direction and extent of natural selection on phenotypic trait maintenance and variation. Here, we investigated egg rejection behavior and egg color polymorphism in the red-billed leiothrix (Leiothrix lutea), a common cuckoo (Cuculus canorus) host, in a population introduced to Hawaii 100 years ago (breeding without cuckoos) and a native population in China (breeding with cuckoos). We found that egg rejection ability was equally strong in both the native and the introduced populations, but levels of interclutch variation and intraclutch consistency in egg color in the native population were higher than in the introduced population. This suggests that egg rejection behavior in hosts can be maintained in the absence of brood parasitism and that egg appearance is maintained by natural selection as a counter adaptation to brood parasitism. This study provides rare evidence that host antiparasitism strategies can change under parasite-relaxed conditions and reduced selection pressure.

Study species and study areas

The red-billed leiothrix (Leiothrichidae) is a medium-sized, green-and-yellow babbler with a conspicuous bright red bill. It is a common resident species native to the Himalayas, Myanmar, southern China, and Vietnam where it is found in a wide variety of habitats, including broadleaf evergreen, pine and mixed forests, forest edges, secondary growth, and varied scrub, from sea level to 4000 m a.s.l. It was recorded as one of the normal hosts of the common cuckoo in India (Baker 1942) and builds open-cup nests in branches in dense vegetation and lays polymorphic eggs that vary in color from white to bluish-green with blood-red marking patterns (Fig. 1). 

Figure 1
Eggs and nests of the red-billed leiothrix (Leiothrix lutea). Photograph by C. Yang.

Egg rejection ability and egg color variation in songbirds species are considered to be defensive strategies that evolved to limit cuckoo parasitism and, hence, are traits believed to be under strong selection. Here, we have shown that internest variation in the chroma and brilliance of egg background color and intranest variation in the UV component of hue and the brilliance of ground-color and markings are lower in populations of red-billed leiothrix when cuckoos are present. To our knowledge, this is the one of the first examples that host antiparasitism strategies of hosts can change under a parasite-relaxed conditions and reduced selection pressure.

The maintenance of egg rejection ability is independent of cuckoos
Our results indicated no difference in egg recognition or rejection ability between the introduced and native populations of leiothrix because almost all foreign eggs were rejected on the first day of the experiment by both groups. Similar results were found by Lahti (2006) in an experiment conducted on two introduced populations of village weaverbird. These results indicate that hosts' egg recognition ability in hosts decays very slowly and can be maintained for a long time following a species' escape from brood parasitism. Rothstein (2001) also found that host populations descended from lineages likely to have been parasitized, but not parasitized currently, continue to eject nearly 100% of nonmimetic eggs. The persistence of this adaptive behavior under relaxed selection pressure may indicate that it is not costly to maintain (Kuehn et al. 2014). In line with host-parasite systems, previous studies showed that antipredation behavior requires several hundreds to even thousands of years to disappear in island populations after a relaxation in predation pressure (Magurran et al. 1992; Blumstein et al. 2000).

However, the acquisition of egg recognition can occur quite rapidly. For example, after their initial exposure to parasitism by cuckoos, the egg rejection rates in azure-winged magpies (Cyanopica cyana) increased from 0% to 30–60% in just 20 years (Nakamura 1990; Nakamura et al. 1998). Similarly, the egg rejection rate of the magpies (Pica pica) to eggs of the great spotted cuckoo (Clamator glandarius) increased from 0% to 10% in just 10 years (Soler et al. 1994). This rate of behavioral change is too rapid to be a consequence of genetic change (Davies and Welbergen 2009) and is more likely to be the result of transmission via social learning (Soler 2011); a suggestion that was confirmed by the mobbing behavior of hosts (Davies and Welbergen 2009). The acquisition of egg recognition may occur more rapidly than its loss because it occurs under strong, directional selection pressure on the particular hosts. In the absence of brood parasites, however, selection pressure is not reversed but simply released, such that the trait continues to evolve under neutral selection and only a new selective pressure can accelerate its rate of change in that particular trait. For example, strong egg rejection rates in hosts result in rejection errors, and subsequently, rejection of their own eggs and natural selection will favor reduced egg rejection behavior in hosts. While social learning may influence the uptake of egg rejection behavior, our finding of persistent egg rejection in populations free from brood parasites supports the idea that egg recognition behavior in leiothrix has a strong genetic basis.

Differences in egg color between native and introduced host populations could be the result of relaxed selection of cuckoo parasitism
We found increased interclutch variation and intraclutch consistency, but no change in the intraclutch consistency of egg background color and markings in the native population compared with the introduced populations. However, the RGB component of the hue disparity of egg markings between nests followed the opposite pattern, possibly because egg markings are not a critical cue in egg recognition. For example, a field experiment revealed that leiothrix uses egg ground-color rather than markings to recognize their own eggs and discriminate alien eggs (C. Yang, Y. Liu, and W. Liang, unpubl. data).

It has been proposed that random mechanisms such as gradual genetic drift and founder effects can result in phenotypic shifts in recently colonized island populations (Lande 1976). However, it is unlikely that such random processes alone caused the observed differences in eggs detected here (Fig. 3 and 4) because (1) current populations across the Hawaiian archipelago were introduced multiple times between 1911 and 1937 (Fisher and Baldwin 1947), and the overall population size here is estimated to be tens of thousands in Hawaii (Male et al. 1998) and regarded stable (Ralph et al. 1998); and (2) founder effects could not be the only process driving changes in egg color in the introduced population. If founder effects played a deterministic role regarding differences in egg color between introduced and native populations, the color spectrum was more disperse in the studied population than which in native populations, whereas the effect of founder effect would be more dispersed in the native population. Our results do not support this and we instead posit that release from cuckoo parasitism-driven selection pressure plays a role in driving shifts in egg color.

Hypotheses explaining intra- and interclutch variation in egg color polymorphism have spawned a cottage industry of empirical testing; however, the experimental evidence supporting this hypothesis has been mixed (Stokke et al. 1999, 2002; Karcza et al. 2003; Avilés et al. 2004). For example, Yang et al. (2010) revealed that brood parasitism from the common cuckoo exerts a disruptive selection on its host, the ashy-throated parrotbill (Paradoxornis alphonsianus), driving coevolution of polymorphic egg color in these two species. Empirical studies comparing host rejection behavior and egg color variation between native and introduced populations, with and without cuckoo parasitism, have rarely been reported before. One impressive and systematic study from Lahti (2005) showed that both the intraclutch consistency and interclutch variation in egg appearance of the village weaverbird decreased in two introduced populations which had existed without egg-mimicking brood parasites for more than 100 and 200 years, in comparison with the native population. Interestingly, in that study, the difference in interclutch variation between the source and the introduced populations was only significant when comparing the older introduced population (i.e., 200 years), although a trend in the general direction was observed in the younger introduced population (Lahti 2005). Here, we report that significant changes in interclutch variation and intraclutch consistency in egg color between native and introduced populations can occur on a timescale of approximately <100 years. These results further support the hypothesis that polymorphic egg appearance is a strongly selected trait under brood parasitism pressure of brood parasitism.

In comparison with egg rejection behavior, changes in egg color variation apparently evolve rapidly (e.g., in approximately 100 years in the present study). This disparity may be a consequence of the fact that egg appearance is also under concurrent selection to optimize factors other than minimizing brood parasitism, such as maximizing solar radiation and minimizing predation (Moreno and Osorno 2003). Egg coloration is likely to be a consequence of local adaptation to specific environments (Mathys and Lockwood 2011) and may be correlated with female's genetic quality (Moreno and Osorno 2003), which interact with each other when multiple sources of selection (natural and sexual) coexist. Thus, geographic differences between native and introduced populations are likely to have a far greater influence on egg appearance than on egg rejection behavior. As the investment of eggshell pigments is costly (Moreno and Osorno 2003; López-Rull et al. 2008; Sanz and García-Navas 2009), subsequent selection after removal of brood parasitism may favor hosts to reduce this unnecessary expenditures, resulting in decreased population variation in egg coloration. However, it remains unclear to what extent biotic and abiotic constraints shape egg color variation and egg rejection behavior. Combined, we provide rare empirical evidence that egg traits functioned as cues for recognizing alien eggs by hosts changed due to relaxed selection, as opposed to egg rejection ability per se. Since both egg coloration and recognition have a heritable basis and are probably driven by both natural and sexual selection (Moreno and Osorno 2003), an investigation into the genetic architecture of complex traits and their changes under context-dependent selection and other evolutionary processes is needed.

Monday, 12 May 2014

Bird Research this week on PubMed: May 2014 Week 1

PubMed listing for 'bird' OR 'songbird' excluding references to influenza and flu - May 2014 Week 1

1. Vaccine. 2014 Apr 30. pii: S0264-410X(14)00606-9. doi: 10.1016/j.vaccine.2014.04.068. [Epub ahead of print]

A recombinant Newcastle disease virus (NDV) expressing infectious laryngotracheitis virus (ILTV) surface glycoprotein D protects against highly virulent ILTV and NDV challenges in chickens.

Kanabagatte Basavarajappa M1, Kumar S1, Khattar SK1, Gebreluul GT1, Paldurai A1, Samal SK2.Author information:
1Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.
2Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA. Electronic address:


Infectious laryngotracheitis (ILT) is a highly contagious acute respiratory disease of chickens caused by infectious laryngotracheitis virus (ILTV). Currently, modified live ILTV vaccines are used to control ILT infections. However, the live ILTV vaccines can revert to virulence after bird-to-bird passage and are capable of establishing latent infections, suggesting the need to develop safer vaccines against ILT. We have evaluated the role of three major ILTV surface glycoproteins, namely, gB, gC, and gD in protection and immunity against ILTV infection in chickens. Using reverse genetics approach, three recombinant Newcastle disease viruses (rNDVs) designated rNDV gB, rNDV gC, and rNDV gD were generated, each expressing gB, gC, and gD, respectively, of ILTV. Chickens received two immunizations with rNDVs alone (gB, gC, and gD) or in combination (gB+gC, gB+gD, gC+gD, and gB+gC+gD). Immunization with rNDV gD induced detectable levels of neutralizing antibodies with the magnitude of response greater than the rest of the experimental groups including those vaccinated with commercially available vaccines. The birds immunized with rNDV gD showed complete protection against virulent ILTV challenge. The birds immunized with rNDV gC alone or multivalent vaccines consisting of combination of rNDVs displayed partial protection with minimal disease and reduced replication of challenge virus in trachea. Immunization with rNDV gB neither reduced the severity of the disease nor the replication of challenge virus in trachea. The superior protective efficacy of rNDV gD vaccine compared to rNDV gB or rNDV gC vaccine was attributed to the higher levels of envelope incorporation and infected cell surface expression of gD than gB or gC. Our results suggest that rNDV expressing gD is a safe and effective bivalent vaccine against NDV and ILTV.
Copyright © 2014 Elsevier Ltd. All rights reserved.
PMID: 24793943 [PubMed - as supplied by publisher]
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2. Curr Opin Neurobiol. 2014 Apr 29;28C:1-4. doi: 10.1016/j.conb.2014.04.004. [Epub ahead of print]

Communication about social status.

Fernald RD.Author information:
Biology and Neuroscience, Stanford University, Stanford, CA 94305, United States. Electronic address:


Dominance hierarchies are ubiquitous in social species and serve to organize social systems. Social and sexual status is communicated directly among animals via sensory systems evolved in the particular species. Such signals may be chemical, visual, auditory, postural or a combination of signals. In most species, status is initially established through physical conflict between individuals that leads to ritualized conflict or threats, reducing possibly dangerous results of fighting. Many of the status signals contain other information, as in some bird species that communicate both the size of their group and their individual rank vocally. Recent studies have shown that scent signaling among hyenas of east Africa is unique, being produced by fermentative, odor producing bacteria residing in the scent glands.
Copyright © 2014. Published by Elsevier Ltd.
PMID: 24793315 [PubMed - as supplied by publisher]
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3. Behav Processes. 2014 Apr 30. pii: S0376-6357(14)00112-0. doi: 10.1016/j.beproc.2014.04.010. [Epub ahead of print]

The structure of an avian syllable syntax network.

Deslandes V1, Faria LR2, Borges ME3, Pie MR4.Author information:
1Laboratório de Dinâmica Evolutiva e Sistemas Complexos, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, PR, Brazil; Pós Graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba, PR, Brazil. Electronic address:
2Laboratório de Dinâmica Evolutiva e Sistemas Complexos, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, PR, Brazil; Instituto Latino-Americano de Ciências da Vida e da Natureza, Universidade Federal da Integração Latino-Americana (UNILA), Brazil.
3Laboratório de Dinâmica Evolutiva e Sistemas Complexos, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, PR, Brazil.
4Laboratório de Dinâmica Evolutiva e Sistemas Complexos, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, PR, Brazil; Pós Graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba, PR, Brazil.


A common result in recent linguistic studies on word association networks is that their topology can often be described by Zipf's law, in which most words have few associations, whereas a few words are highly connected. However, little is known about syntactic networks in more rudimentary communication systems, which could represent a window into the early stages of language evolution. In this study, we investigate the syntactic network formed by syllable associations in the song of the oscine bird Troglodytes musculus. We use methods recently developed in the context of the study of complex networks to assess topological characteristics in the syntactic networks of T. musculus. We found statistically significant evidence for nestedness in the syllable association network of T. musculus, indicating network organization around a core of commonly used notes, small-world features, and a non-random degree distribution. Our analyses suggest the possibility of a balance between the maintenance of core notes and the acquisition/loss of rare notes through both cultural drift and improvisation. These results underscore the usefulness of investigating communication networks of other animal species in uncovering the initial steps in the evolution of complex syntax networks.
Copyright © 2014. Published by Elsevier B.V.
PMID: 24792818 [PubMed - as supplied by publisher]
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4. Mol Phylogenet Evol. 2014 Apr 30. pii: S1055-7903(14)00153-5. doi: 10.1016/j.ympev.2014.04.025. [Epub ahead of print]

A comprehensive multilocus assessment of sparrow (Aves: Passerellidae) relationships.

Klicka J1, Keith Barker F2, Burns KJ3, Lanyon SM4, Lovette IJ5, Chaves JA6, Bryson RW Jr7.Author information:
1Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Box 353010, Seattle, WA 98195-3010, USA. Electronic address:
2Department of Ecology, Evolution, and Behavior, University of Minnesota, 100 Ecology Building, 1987 Upper Buford Circle, St. Paul, MN 55108, USA; Bell Museum of Natural History, University of Minnesota, 100 Ecology Building, 1987 Upper Buford Circle, St. Paul, MN 55108, USA.
3Department of Biology, San Diego State University, San Diego, CA 92182, USA.
4Department of Ecology, Evolution, and Behavior, University of Minnesota, 100 Ecology Building, 1987 Upper Buford Circle, St. Paul, MN 55108, USA.
5Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, NY 14950, USA.
6Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA; Universidad San Francisco de Quito, USFQ, Colegio de Ciencias Biológicas y Ambientales, y Extensión Galápagos, Campus Cumbayá, Casilla Postal 17-1200-841, Quito, Ecuador.
7Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Box 353010, Seattle, WA 98195-3010, USA.


The New World sparrows (Emberizidae) are among the best known of songbird groups and have long-been recognized as one of the prominent components of the New World nine-primaried oscine assemblage. Despite receiving much attention from taxonomists over the years, and only recently using molecular methods, was a "core" sparrow clade established allowing the reconstruction of a phylogenetic hypothesis that includes the full sampling of sparrow species diversity. In this paper, we use mitochondrial DNA gene sequences from all 129 putative species of sparrow and four additional (nuclear) loci for a subset of these taxa to resolve both generic and species level relationships. Hypotheses derived from our mitochondrial (2184 base pairs) and nuclear (5705 base pairs) DNA data sets were generally in agreement with respect to clade constituency but differed somewhat with respect to among-clade relationships. Sparrow diversity is defined predominantly by eight well-supported clades that indicate a lack of monophyly for at least three currently recognized genera. Ammodramus is polyphyletic and requires the naming of two additional genera. Spizella is also polyphyletic with Tree Sparrow (Spizella arborea) as a taxonomic "outlier". Pselliophorus is embedded within a larger Atlapetes assemblage and should be merged with that group. This new hypothesis of sparrow relationships will form the basis for future comparative analyses of variation within songbirds.
Copyright © 2014. Published by Elsevier Inc.
PMID: 24792084 [PubMed - as supplied by publisher]
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Thursday, 8 May 2014

The Condor (Journal), May 2014: Volume 116 Issue 2 - Contents and Abstracts

The Condor

Published by: Cooper Ornithological Society

Table of Contents

May 2014 : Volume 116 Issue 2 


Integrating aerial and ship surveys of marine birds into a combined density surface model: A case study of wintering Common Loons Full Access

Kristopher J. Winiarski, M. Louise Burt, Eric Rexstad, David L. Miller, Carol L. Trocki, Peter W. C. Paton, and Scott R. McWilliams
pg(s) 149–161


Biologists now use a variety of survey platforms to assess the spatial distribution and abundance of marine birds, yet few attempts have been made to integrate data from multiple survey platforms to improve model accuracy or precision. We used density surface models (DSMs) to incorporate data from two survey platforms to predict the distribution and abundance of a diving marine bird, the Common Loon (Gavia immer). We conducted strip transect surveys from a multiengine, fixed-wing aircraft and line surveys from a 28 m ship during winter 2009–2010 in a 3,800 km2 study area off the coast of Rhode Island, USA. We accounted for imperfect detection and availability bias due to Common Loon diving behavior. We incorporated spatially explicit environmental covariates (water depth and latitude) to provide predictions of the spatial distribution and abundance of wintering Common Loons. The combined-platform DSM estimated the highest Common Loon densities (>20 individuals km−2) in nearshore waters <35 m deep, with an average daily abundance of 5,538 (95% CI = 4,726–6,489) individuals in the study area. The combined-platform model offered substantial improvement in the precision of abundance estimates from the ship-platform model, and modest improvement in the precision of the aerial-platform model. The combined model had relatively low predictive power, which previous research indicates is primarily a consequence of the dynamic marine environment. We show that the DSM approach presents a flexible framework for developing spatially explicit models of a marine bird from different survey protocols.

Stopover ecology of American Golden-Plovers (Pluvialis dominica) in Midwestern agricultural fields
Full Access

Kirk W. Stodola, Benjamin J. O'Neal, Mark G. Alessi, Jill L. Deppe, Tyson R. Dallas, Tara A. Beveroth, Thomas J. Benson, and Michael P. Ward
pg(s) 162–172


Stopover locations represent critical habitat in the life cycle of migratory birds and the alteration of this habitat can profoundly influence a population. American Golden-Plovers (Pluvialis dominica) migrate though the Midwestern United States each spring, where most natural habitat has been converted to row crop agriculture. We investigated the stopover ecology of the golden-plover in the agricultural matrix of east-central Illinois and west-central Indiana between 2008 and 2012. We found that golden-plovers remained in the region for ∼45 days and individuals spent on average 24 days in the area before departing to the northwest. During a period of peak migration, golden-plovers preferred fields with standing water and, to a lesser extent, soybean fields. Over the 45-day stopover duration, golden-plovers moved extensively (shown by a dynamic occupancy model and area used estimation), with some evidence for tilled fields becoming unoccupied at greater rates than untilled fields. The tendency to use fields with standing water and the movement of individuals from tilled fields suggests that food accessibility, rather than food abundance, is likely a critical factor associated with the prolonged stay, movement, and field type selection of golden-plovers. Food accessibility is important to the golden-plover because they undergo molt into breeding plumage in the region and must refuel for the next leg of their migration. The Midwest is a key stopover location for American Golden-Plovers and promoting foraging conditions by manipulating the drainage of agricultural fields, via the temporary blockage of drain tiles, should be a management focus.
Abstract & References : Full Text : PDF (318 KB) 

Nesting ecology of Marbled Murrelets at a remote mainland fjord in southeast Alaska 

Blake A. Barbaree, S. Kim Nelson, Bruce D. Dugger, Daniel D. Roby, Harry R. Carter, Darrell L. Whitworth, and Scott H. Newman
pg(s) 173–184


Studying the ecology of endangered species in portions of their range where the population remains abundant can provide fundamental information for conservation planners. We studied nesting by radio-tagged Marbled Murrelets (Brachyramphus marmoratus) during 2007 and 2008 in Port Snettisham, a relatively pristine, remote mainland fjord in southeast Alaska with high at-sea densities of Marbled Murrelets during the breeding season. Of 33 active Marbled Murrelet nest sites located during the study, we found 15 within forested habitat (tree nest sites), 16 in nonforested habitat (ground nest sites), and 2 that could not be determined. Some nests were located farther inland from the coast (range: 1–52 km) and at higher elevations (range: 42–1,100 m) than previously documented in Alaska. Nesting success to ≥20 days posthatch (0.20 ± 0.07 [SE]) was less than half of similar estimates in British Columbia and more comparable to estimates from California and Washington. A logistic regression found that nesting success did not differ between years, but nesting success was higher for tree nests than for ground nests. Conservation planners should consider that Marbled Murrelets will use certain nonforest habitat types for nesting in mainland southeast Alaska. Our reported nesting success was likely a maximum, and our results indicate that nesting success can be low even when nesting habitat is seemingly abundant and marine habitat appears excellent.
Abstract & References : Full Text : PDF (827 KB) 

Marbled Godwit migration characterized with satellite telemetry Full Access

Bridget E. Olson, Kimberly A. Sullivan, and Adrian H. Farmer
pg(s) 185–194


Marbled Godwits (Limosa fedoa) breed in 3 disparate areas: The majority breed in the prairies of midcontinental North America, but there are also 2 small and widely separated tundra-breeding populations, 1 in eastern Canada and 1 on the Alaska Peninsula, USA. The major winter ranges include the Atlantic, Pacific, and Gulf coasts of the USA and Mexico. Bear River Migratory Bird Refuge at Great Salt Lake, Utah, USA, is a major stopover site, hosting large godwit populations in the spring and fall. Although the distributions of Marbled Godwit populations and their habitats across the landscape are generally known, the linkages between them are not. We tracked 23 Marbled Godwits equipped with satellite transmitters from sites in Utah, Mexico, Canada, and coastal Georgia during 2006–2010. Our goals were to characterize the migration strategy of Marbled Godwit populations and to determine migratory connectivity of major breeding, staging, and wintering areas. We found that: 1) godwits breeding in the western USA and Canada followed an overland route to winter sites in Mexico after departing their Utah stopover site; 2) godwits tagged in eastern Canada migrated across the continental USA and wintered at sites along the Gulf of California, Mexico; and 3) godwits wintering in coastal Georgia bred in North and South Dakota. We believe this to be the first demonstration of a continental “crisscross” migration pattern in a shorebird. We identified differences in migration elements such as distances traveled, timing of migration, duration, residency, and stopover strategy between the subpopulations, but not between males and females.
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The role of landscape features and density dependence in growth and fledging rates of Piping Plovers in North Dakota, USA Full Access

Michael J. Anteau, Mark T. Wiltermuth, Mark H. Sherfy, Terry L. Shaffer, and Aaron T. Pearse
pg(s) 195–204


For species with precocial young, survival from hatching to fledging is a key factor influencing recruitment. Furthermore, growth rates of precocial chicks are an indicator of forage quality and habitat suitability of brood-rearing areas. We examined how growth and fledging rates of Piping Plover (Charadrius melodus) chicks were influenced by landscape features, such as hatchling density (hatchlings per hectare of remotely sensed habitat [H ha−1]), island vs. mainland, and wind fetch (exposure to waves) at 2-km segments (n = 15) of Lake Sakakawea, North Dakota, during 2007–2008. Hatchling growth was comparable with published estimates for other habitats. Models for fledging rate (fledged young per segment) assuming density dependence had more support (wi = 96%) than those assuming density independence (wi = 4%). Density-dependent processes appeared to influence fledging rate only at densities >5 H ha−1, which occurred in 19% of the segments we sampled. When areas with densities >5 H ha−1 were excluded, density-dependence and density-independence models were equally supported (wi = 52% and 48%, respectively). Fledging rate declined as the wind fetch of a segment increased. Fledging rate on mainland shorelines was 4.3 times greater than that on islands. Previous work has indicated that plovers prefer islands for nesting, but our results suggest that this preference is not optimal and could lead to an ecological trap for chicks. While other researchers have found nesting-habitat requirements to be gravelly areas on exposed beaches without fine-grain substrates, our results suggest that chicks fledge at lower rates in these habitats. Thus, breeding plovers likely require complexes of these nesting habitats along with protected areas with fine, nutrient-rich substrate for foraging by hatchlings.
Abstract & References : Full Text : PDF (363 KB) 

Landscape and regional context differentially affect nest parasitism and nest predation for Wood Thrush in central Virginia, USA Full Access

Matthew A. Etterson, Russell Greenberg, and Tom Hollenhorst
pg(s) 205–214


Many empirical studies have shown that forest-breeding songbirds, and Neotropical migrants in particular, suffer greater rates of nest predation and nest parasitism in smaller forest patches and in fragmented landscapes. To compare the performance of different metrics of spatial habitat configuration resulting from deforestation, we studied nest predation and nest parasitism rates at 200 Wood Thrush (Hylocichla mustelina) nests in eight forest fragments ranging from 82 to 9,171 ha in central Virginia, USA. We analyzed nest parasitism rates using logistic regression and we analyzed daily nest predation rates under a multistate competing risks design. For both analyses we compared the performance of 16 covariates, 11 of which related to the spatial configuration of habitat (e.g., patch size, distance to edge, percent core forest in proximity to nest) and 5 of which were unrelated to habitat (e.g., year, serial date, nest height). Distance to agriculture gained the greatest support in analyses of nest predation and suggested that elevated predation rates are manifest primarily within 50 m of edges; at 5, 10, and 20 m, respectively, the estimated predation rates were 87%, 76%, and 68%. In contrast, biogeographic region received the greatest support in analyses of nest parasitism, which also showed increasing rates of Brown-headed Cowbird (Molothrus ater) parasitism with percent agricultural land and road density within 500 m of a nest. Among regions, the greatest difference seemed to be a virtual absence of nest parasitism along the Blue Ridge in the absence of disturbance (agriculture or road incursion) whereas the other two biogeographic regions showed 20–50% rates of nest parasitism as background rates. Interactive models between spatial configuration metrics and region gained little support from nest predation analyses, but considerable support from the nest parasitism analyses, suggesting regional context plays a more important role in nest parasitism than in nest predation at these central Virginia sites.
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Does flooding influence the types and proportions of prey delivered to nestling Mississippi Kites? Full Access

Scott J. Chiavacci, James C. Bednarz, and Thomas J. Benson
pg(s) 215–225


Mississippi Kites (Ictinia mississippiensis) nesting in the Mississippi Alluvial Valley, USA, have consistently exhibited poor reproductive success, reduced average clutch sizes, and evidence of food stress during brood-rearing, raising concerns about population viability. Unlike populations elsewhere, kites nesting in the bottomland forests of this region face dynamic, anthropogenically altered hydrologic conditions that may be affecting the availability of important prey. Therefore, we quantified nestling diets and examined factors thought to be directly influencing the types and proportions of prey delivered to kite nestlings. Specifically, we sought to identify variables affecting the delivery of annual cicadas, the dominant prey item fed to kite chicks in numerous systems, as cicada emergence from subterranean burrows is known to be delayed by flooding. Using time-lapse video, we documented nestling diets and evaluated predictors of diet variability in east-central Arkansas, USA. We found that the delivery of cicadas increased with day of year, and was greatest during the driest of 4 study years. In contrast, the delivery of dragonflies, the numerically dominant prey item, declined with day of year, but increased with water level, and was lowest during the driest year. Although water level was not a strong predictor of the delivery of cicadas, interannual variation in the pattern of cicada deliveries suggests that flooding reduced the availability of this prey item to kites. Also, despite diverse nestling diets, the provisioning of dragonflies and a variety of other arthropods suggests that kites responded functionally to an absence of cicadas. The temporal patterns in prey deliveries that we detected imply that kite nestling diets in bottomland forests of the Mississippi Alluvial Valley may be influenced by water-level impacts on arthropod phenology and abundance.
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Land use and climate affect Black Tern, Northern Harrier, and Marsh Wren abundance in the Prairie Pothole Region of the United States Full Access

Greg M. Forcey, Wayne E. Thogmartin, George M. Linz, and Patrick C. McKann
pg(s) 226–241


Bird populations are influenced by many environmental factors at both large and small scales. Our study evaluated the influences of regional climate and land-use variables on the Northern Harrier (Circus cyaneus), Black Tern (Childonias niger), and Marsh Wren (Cistothorus palustris) in the prairie potholes of the upper Midwest of the United States. These species were chosen because their diverse habitat preference represent the spectrum of habitat conditions present in the Prairie Potholes, ranging from open prairies to dense cattail marshes. We evaluated land-use covariates at three logarithmic spatial scales (1,000 ha, 10,000 ha, and 100,000 ha) and constructed models a priori using information from published habitat associations and climatic influences. The strongest influences on the abundance of each of the three species were the percentage of wetland area across all three spatial scales and precipitation in the year preceding that when bird surveys were conducted. Even among scales ranging over three orders of magnitude the influence of spatial scale was small, as models with the same variables expressed at different scales were often in the best model subset. Examination of the effects of large-scale environmental variables on wetland birds elucidated relationships overlooked in many smaller-scale studies, such as the influences of climate and habitat variables at landscape scales. Given the spatial variation in the abundance of our focal species within the prairie potholes, our model predictions are especially useful for targeting locations, such as northeastern South Dakota and central North Dakota, where management and conservation efforts would be optimally beneficial. This modeling approach can also be applied to other species and geographic areas to focus landscape conservation efforts and subsequent small-scale studies, especially in constrained economic climates.
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Factors affecting Burrowing Owl occupancy of prairie dog colonies Full Access

Kristen M. Alverson and Stephen J. Dinsmore
pg(s) 242–250


Understanding patch dynamics can help scientists better understand metapopulations and the relationships of animals that share a habitat. The Burrowing Owl (Athene cunicularia) is a well-known associate of prairie dog colonies, thereby linking conservation measures that benefit these species. We used occupancy modeling to determine how colony attributes (e.g., size and edge effects) and the loss of prairie dog colonies to sylvatic plague affected the occupancy of those colonies by Burrowing Owls in north-central Montana. We surveyed presence–absence of Burrowing Owls during a 13-yr period (1995–2007) and analyzed the data using a robust-design occupancy model in Program MARK. The proportion of colonies occupied by Burrowing Owls ranged from 0.41 to 0.54 across years while the probability of detecting the owls ranged from 0.22 to 0.92. Contrary to our predictions, colony edge effects and plague epizootics showed only weak or no effects on Burrowing Owl occupancy. Prairie dog colony size had the greatest effect on Burrowing Owl occupancy patterns. Colonization of prairie dog colonies by owls generally increased with colony area, whereas owl extinction initially dropped and then increased as a function of increasing colony area. We found no direct link between Burrowing Owl occupancy of prairie dog colonies and plague history, but our results reaffirmed the importance of colony size. Collectively, this information will help inform future conservation efforts for Burrowing Owls that occupy prairie dog colonies.
Abstract & References : Full Text : PDF (322 KB) 

Identifying carry-over effects of wintering area on reproductive parameters in White-winged Scoters: An isotopic approach Full Access

Kirsty E. B. Gurney, Cindy J. Wood, Ray T. Alisauskas, Mark Wayland, Jean-Michel A. DeVink, and Stuart M. Slattery
pg(s) 251–264


Events during one stage of the annual life cycle of migratory birds can have lasting (i.e. carry-over) effects that influence demographic parameters in subsequent seasons. We studied migratory connectivity and potential carry-over effects in a declining population of sea ducks. We measured stable isotope values of carbon (δ13C) and nitrogen (δ15N) in head feathers to assign breeding White-winged Scoters (Melanitta fusca; hereafter scoters) to either Atlantic or Pacific winter populations. The discriminant function for δ13C and δ15N correctly classified 93% of scoters sampled from these 2 winter areas. We then applied this classification scheme to head feathers of females breeding at Redberry Lake, Saskatchewan, and Cardinal Lake, Northwest Territories, to stratify each breeding population by winter provenance. We evaluated carry-over effects associated with winter location of females breeding in Saskatchewan by testing for differences in (1) nesting phenology, (2) clutch size, (3) mid-incubation body mass, (4) nest success, and (5) concentrations of trace elements contaminants of cadmium (Cd), mercury (Hg), selenium (Se), and lead (Pb) in blood, between strata of putative winter origin. Breeding females from the Atlantic coast had later dates of nest initiation, greater mid-incubation body mass, and also had higher concentrations of Cd (one year only), Pb, and Se, relative to birds from the Pacific. Neither nest initiation date nor mid-incubation body mass, however, were related to contaminant concentrations in blood. We found no differences in clutch size or nest success between putative winter strata. Our study detected carry-over effects in the Saskatchewan population that merit further attention.
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Nest survival of a long-lived psittacid: Scarlet Macaws (Ara macao cyanoptera) in the Maya Biosphere Reserve of Guatemala and Chiquibul Forest of Belize Full Access

Charles R. Britt, Rony García Anleu, and Martha J. Desmond
pg(s) 265–276


The Scarlet Macaw (Ara macao) is a widely distributed parrot that has suffered reduced abundance and increased isolation in Mesoamerican populations. Understanding environmental and temporal factors that influence nest survival may assist efforts to increase annual recruitment for this species, improving population viability. We examined nest survival of Scarlet Macaws in the Maya Biosphere Reserve of Guatemala and Chiquibul Forest of Belize in 2010. Our results suggest that connecting tree canopies have the greatest negative influence on daily nest survival, reducing the probability of a nest surviving the entire nesting period from 0.89 to 0.42. This is likely due to facilitating nest access to predators. Nine of 20 nests in Belize, but no nests in Guatemala, were poached. The majority of poached nests were located in close proximity to a reservoir, which may facilitate access to nests. Based on previous estimates of nest survival required for this population to remain stable, our 2010 data suggest that the population in Guatemala could be growing, but that poaching has reduced nest survival below the threshold for population stability in Belize. Reducing habitat loss in Guatemala and nest poaching in Belize would most benefit this historically connected population.
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How ornithological societies can get to work for bird conservation 

Philip C. Stouffer
pg(s) 277
Citation : Full Text : PDF (59 KB) 


A vision for an expanded role of ornithological societies in conservation 

Jeffrey R. Walters, Deborah M. Brosnan, J. Michael Reed, and J. Michael Scott
pg(s) 278–289


Professional societies of biologists, including ornithological societies, have struggled to determine the appropriate way to apply the expertise of their memberships in conservation, largely because of a tension between issue advocacy and pure science. Within societies, some argue for using science to promote conservation, and others worry that such advocacy will render the science less credible in the eyes of decisionmakers. This debate excludes other important applications of science in conservation. We outline a vision for an expanded role of ornithological societies in avian conservation that includes pure science and emphasizes one of these other applications, science arbitration. Science arbitration involves evaluating the science relevant to an issue and providing the results to decisionmakers without taking a position on the outcome. We perceive a great need for science arbitration as judges, politicians, and other decisionmakers typically lack access to current, relevant scientific information in an objective form and as a result must act as their own arbiters despite a lack of appropriate expertise. The ornithological societies are in a unique position to fill this void in the area of avian conservation. We describe an additional role in which the societies may also wish to engage, Honest Broker, which is similar to Science Arbiter but also includes development of policy alternatives based on the science evaluated. We provide examples of the kinds of activities in which we envision the societies engaging, and outline a process for approaching science arbitration as the scholarly activity it should be.
Abstract & References : Full Text : PDF (167 KB)