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Bruno Faivre - One of the best experts on this subject based on the ideXlab platform.
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carotenoid trade off between parasitic resistance and sexual display an experimental study in the Blackbird turdus merula
Proceedings of The Royal Society B: Biological Sciences, 2008Co-Authors: R Baeta, Bruno Faivre, Sebastien Motreuil, Maria Gaillard, Jerome MoreauAbstract:Many parasites depress the expression of the carotenoid-based colour displays of their hosts, and it has been hypothesized that animals face a trade-off in carotenoid allocation between immune functions and ‘degree of ornamentation’. While numerous correlative studies suggest that parasite infection decreases the intensity of carotenoid-based colour displays, the existence of this trade-off has never been demonstrated experimentally in a host–parasite model. In this study, we used the Blackbird ( Turdus merula ) and Isospora (an intestinal parasite) to assess whether this trade-off does indeed exist. Blackbirds were supplemented with carotenoids while simultaneously being exposed to parasites. Supplemented males circulated more carotenoids in the blood and developed more brightly coloured bills than unsupplemented males. In addition, supplementation slowed down the replication rate of parasites. Supplementation with carotenoids enabled infected birds to maintain their bill coloration, whereas birds that were infected but not supplemented showed reduced bill coloration. At the same time, infection slowed carotenoid assimilation in the blood. Overall, we demonstrated that bill colour reflects a bird9s health, and that only males with a carotenoid-rich diet are capable of coping with costs associated with parasitic infection. Carotenoids are thus traded off between host physiological response to parasites and secondary sexual traits. Further investigations are required to determine the physiological mechanisms that govern this trade-off.
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sensitive measure of prevalence and parasitaemia of haemosporidia from european Blackbird turdus merula populations value of pcr rflp and quantitative pcr
Parasitology, 2006Co-Authors: Sophie Bentz, Thierry Rigaud, Marco Barroca, F Martinlaurent, Jerome Moreau, Bruno FaivreAbstract:Haemosporidian parasites are common in birds in which they act as an important selective pressure. While most studies so far have focused on the effect of their prevalence on host life-history traits, no study has measured the effect of parasitaemia. We developed molecular methods to detect, identify and quantify haemosporidia in 2 natural populations of the Blackbird Turdus merula. Three different parasite genotypes were found - 1 Haemoproteus and 2 Plasmodium. A PCR-RFLP screening revealed that only approximately 3% of Blackbirds were free of parasites, compared to the 34% of uninfected birds estimated by blood smear screening. A quantitative PCR (q-PCR) assay revealed a weaker parasitaemia in microscopically undetected parasites compared to microscopically detected ones. Large parasitaemia differences were found between parasite species, suggesting either differing parasite life-histories or host resistance. Parasitaemias were also weaker in male hosts, and in urban habitats, suggesting that both host factors (e.g. immunity) and habitat characteristics (e.g. vector availability) may modulate parasite density. Interestingly, these differences in parasitaemia were comparable to differences in parasite prevalence estimated by smear screening. This suggests that previous results obtained by smear screening should be reinterpreted in terms of parasitaemia instead of parasite prevalence.
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distribution and abundance patterns of a newly colonizing species in tunisian oases the common Blackbird turdus merula
Ibis, 2003Co-Authors: Slaheddine Selmi, Thierry Boulinier, Bruno FaivreAbstract:We investigated distribution and abundance patterns of a recently arrived species in the oases of southern Tunisia: the Common Blackbird Turdus merula. In this system, we expected that the vegetation structure and geographical locations of oases would have played an important part in shaping the patterns of oasis occupancy and local abundance. Using data collected at 53 oases during two breeding seasons, we found that Blackbird occurrence in a given oasis depended mainly on its presence at neighbouring oases. However, vegetation structure did not prove to be a relevant predictor of Blackbird occurrence. Within occupied oases, local abundance was associated with vegetation structure, namely with the diversity and abundance of the two lowest vegetation layers: fruit trees and herbaceous plants. The presence of Blackbirds at neighbouring oases was not found to account for local abundance. Overall, our results suggest that the distribution and abundance of this newly colonizing species in the southern Tunisian oasis system are influenced by processes acting at two different spatial scales. Landscape-scale processes (i.e. dispersal and colonization from nearby occupied oases) are likely to play an important role in shaping the pattern of oasis occupancy, whereas local-scale factors seem to be more relevant in determining the abundance of locally established populations.
George M. Linz - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of elevated bait trays for attracting Blackbirds (Icteridae) in central
2020Co-Authors: North Dakota, George M. Linz, Jamison B. Winter, William J. BleierAbstract:Sunflower (Helianthus annuus L.) became an economically important crop in North Dakota in the 1970s, providing a major source of food for post-breeding Blackbirds (Icteridae). Reducing local Blackbird populations with rice grains treated with an avicide is one proposed alternative for reducing sunflower damage. In fall 2007 and 2008, we evaluated the idea of attracting Blackbirds to rice-baited trays attached to wire cages supplied with live Blackbirds. During our observations (1011 h), we saw 3888 birds, consisting of 25 species and 12 families, on the bait trays. Blackbirds made up 90.4% of the bird observations, whereas sparrows (Emberizidae) made up 1.6% of the birds observed. Overall risk to nontarget species appeared minimal. The bait trays, however, attracted a small number of Blackbirds compared to the source population feeding in nearby crop fields. Our results strongly suggest DRC-1339treated rice used on bait trays is unlikely to be a cost-effective method of reducing Blackbird damage to ripening sunflower. Published by Elsevier Ltd.
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Comparisons between Blackbird damage to corn and sunflower in
2020Co-Authors: Megan E Klosterman, George M. Linz, Anthony A Slowik, H. Jeffrey HomanAbstract:For sunflower producers in North Dakota, Blackbird (Icterinae) damage is a chronic problem costing millions of dollars annually. Sunflower damage surveys were last completed in the state in 1979e1980. Since the last surveys, corn plantings have increased 6-fold to 1500 � 10 3 ha, whereas sunflower hectarage has declined by >75% to 310 � 10 3 ha. Blackbirds forage on both crops, and this rapid change in North Dakota’s agricultural landscape was a sound inducement for reassessing crop damage. Field surveys are an important step in damage methods development because they are used for measuring efficacy, as well as assessing historical changes in the quality and quantity of damage. During 2009e2010, we conducted damage surveys on corn and sunflower. We surveyed 120 randomly selected 3.2 � 3.2-km plots in North Dakota’s Prairie Pothole Region. This region of numerous wetlands has historically produced the majority of the state’s sunflower crop, in addition to harboring a Blackbird population of 25 million birds. Over the 2-year study, we measured damage in 68 cornfields and 27 sunflower fields. Annual damage averaged 5.0 � 10 3 t (12 kg/ha, US $1.3 million) for corn and 7.2 � 10 3 t (45 kg/ha, US $3.5 million) for sunflower. Percentage damage was significantly greater in sunflower ðx ¼ 2:7%Þ than corn ðx ¼ 0:2%Þ. The lower per-unit cost of producing corn makes it a potential lure crop for managing Blackbird damage to sunflower. However, the two crops should be phenologically synchronized because corn matures earlier than sunflower and becomes less attractive to Blackbirds. Published by Elsevier Ltd.
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Potential Use of Perennial Sunflower to Reduce Blackbird Damage to Sunflower
Proceedings of the Vertebrate Pest Conference, 2020Co-Authors: George M. Linz, Brent S. Hulke, Michael B. Kantar, Jeffrey Homan, Robert M. Stupar, Donald L. WyseAbstract:Author(s): Linz, George; Hulke, Brent; Kantar, Michael; Homan, Jeffrey; Stupar, Robert; Wyse, Donald | Abstract: Wildlife Conservation Sunflower Plots (WCSP) have shown potential to reduce Blackbird (Icteridae) damage in commercial sunflower. Also known as lure, decoy, or trap crops, WCSP are strategically placed food plots that provide an easily available and proximate food source that entices Blackbirds away from valuable commercial crops. By providing an alternative food source, WCSP reduce direct damage to commercial fields, while also lowering indirect costs that producers incur attempting to prevent Blackbird damage. However, cost inefficiencies have deterred widespread use of WCSP. Cost-benefit ratios of using WCSP would be greatly improved if a perennial sunflower were used instead of the annual types currently available. Perennial sunflower would reduce seed cost and planting cost, and perhaps lower opportunity costs, if able to thrive on poorer quality soils. In the near-term, scientists are focused on producing a perennial sunflower sufficiently productive to replace annual WCSP plantings. In 2013, scientists from the University of Minnesota, USDA-Agricultural Research Service, and USDA Wildlife Services National Wildlife Research Center evaluated a test plot of an open-pollinated variety of perennial sunflower resulting from genetic crossing of a domesticated annual species (Helianthus annuus) and a perennial wild species (H. tuberosus). Here, we report on results from the 2013 field test and discuss the outlook for development of perennial sunflower, which would help lessen damage to commercial sunflower when used in WCSP; provide a pesticide-free food source for beneficial insects, such as honey bees; help stabilize highly erodible lands near wetlands; and provide year-round habitat for wildlife. Lastly, we provide an initial strategy for using perennial sunflower to reduce Blackbird damage in commercial sunflower.
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ARE SUNFLOWER FIELDS FOR THE BIRDS
2020Co-Authors: Heath M Hagy, George M. Linz, William J. BleierAbstract:The northern Great Plains are home to a variety of birds throughout the year, particularly during migration. Migratory species use native and restored grasslands, shelterbelts, and agricultural fields for food and shelter in North Dakota. Blackbirds (Xanthocephalus xanthocephalus) have been documented to cause economically important damage to some crops and thus, are sometimes the target of concerted harassment efforts. Few studies have assembled an inventory of nonBlackbirds using small grain fields during the fall and spring in North Dakota that may be inadvertently affected by Blackbird management. At least 94 nonBlackbird species use crop fields in the spring and fall in North Dakota. Sunflower fields appear to be a particularly important stopover habitat for a variety of migratory birds, with 78 species and 29 species using sunflower in the fall and spring, respectively. We encourage a joint Blackbird management / wildlife habitat system including Wildlife Conservation Sunflower Plots (lure plots) as part of an integrated pest management plan to reduce Blackbird damage to sunflower and provide habitat for nonBlackbirds.
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Spatially explicit modeling of Blackbird abundance in the Prairie Pothole Region
Journal of Wildlife Management, 2015Co-Authors: George M. Forcey, George M. Linz, Wayne E. Thogmartin, Patrick C. Mckann, Shawn M. CrimminsAbstract:Knowledge of factors influencing animal abundance is important to wildlife biologists developing management plans. This is especially true for economically important species such as Blackbirds (Icteridae), which cause more than $100 million in crop damages annually in the United States. Using data from the North American Breeding Bird Survey, the National Land Cover Dataset, and the National Climatic Data Center, we modeled effects of regional environmental variables on relative abundance of 3 Blackbird species (red-winged Blackbird, Agelaius phoeniceus; yellow-headed Blackbird, Xanthocephalus xanthocephalus; common grackle, Quiscalus quiscula) in the Prairie Pothole Region of the central United States. We evaluated landscape covariates at 3 logarithmically related spatial scales (1,000ha, 10,000ha, and 100,000ha) and modeled weather variables at the 100,000-ha scale. We constructed models a priori using information from published habitat associations. We fit models with WinBUGS using Markov chain Monte Carlo techniques. Both landscape and weather variables contributed strongly to predicting Blackbird relative abundance (95% credibility interval did not overlap 0). Variables with the strongest associations with Blackbird relative abundance were the percentage of wetland area and precipitation amount from the year before bird surveys were conducted. The influence of spatial scale appeared small—models with the same variables expressed at different scales were often in the best model subset. This large-scale study elucidated regional effects of weather and landscape variables, suggesting that management strategies aimed at reducing damages caused by these species should consider the broader landscape, including weather effects, because such factors may outweigh the influence of localized conditions or site-specific management actions. The regional species distributional models we developed for Blackbirds provide a tool for understanding these broader landscape effects and guiding wildlife management practices to areas that are optimally beneficial. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
William J. Bleier - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of elevated bait trays for attracting Blackbirds (Icteridae) in central
2020Co-Authors: North Dakota, George M. Linz, Jamison B. Winter, William J. BleierAbstract:Sunflower (Helianthus annuus L.) became an economically important crop in North Dakota in the 1970s, providing a major source of food for post-breeding Blackbirds (Icteridae). Reducing local Blackbird populations with rice grains treated with an avicide is one proposed alternative for reducing sunflower damage. In fall 2007 and 2008, we evaluated the idea of attracting Blackbirds to rice-baited trays attached to wire cages supplied with live Blackbirds. During our observations (1011 h), we saw 3888 birds, consisting of 25 species and 12 families, on the bait trays. Blackbirds made up 90.4% of the bird observations, whereas sparrows (Emberizidae) made up 1.6% of the birds observed. Overall risk to nontarget species appeared minimal. The bait trays, however, attracted a small number of Blackbirds compared to the source population feeding in nearby crop fields. Our results strongly suggest DRC-1339treated rice used on bait trays is unlikely to be a cost-effective method of reducing Blackbird damage to ripening sunflower. Published by Elsevier Ltd.
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ARE SUNFLOWER FIELDS FOR THE BIRDS
2020Co-Authors: Heath M Hagy, George M. Linz, William J. BleierAbstract:The northern Great Plains are home to a variety of birds throughout the year, particularly during migration. Migratory species use native and restored grasslands, shelterbelts, and agricultural fields for food and shelter in North Dakota. Blackbirds (Xanthocephalus xanthocephalus) have been documented to cause economically important damage to some crops and thus, are sometimes the target of concerted harassment efforts. Few studies have assembled an inventory of nonBlackbirds using small grain fields during the fall and spring in North Dakota that may be inadvertently affected by Blackbird management. At least 94 nonBlackbird species use crop fields in the spring and fall in North Dakota. Sunflower fields appear to be a particularly important stopover habitat for a variety of migratory birds, with 78 species and 29 species using sunflower in the fall and spring, respectively. We encourage a joint Blackbird management / wildlife habitat system including Wildlife Conservation Sunflower Plots (lure plots) as part of an integrated pest management plan to reduce Blackbird damage to sunflower and provide habitat for nonBlackbirds.
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Sunflower Growers Use Nonlethal Methods to Manage Blackbird Damage
2013Co-Authors: George M. Linz, H. Jeffrey Homan, Scott J. Werner, James C. Carlson, William J. BleierAbstract:Blackbird damage to sunflower in the Prairie Pothole Region of North Dakota, South Dakota, and Minnesota is an unyielding challenge to the industry. Large populations of Blackbirds and environmental concerns have driven the direction of research toward nonlethal methods that can be implemented locally. Currently, Wildlife Services field specialists lend propane cannons to growers and spray wetlands with glyphosate to fragment dense cattail stands used by roosting Blackbirds. After researchers demonstrated decoy crops (wildlife conservation sunflower plots), some growers have adapted the basic principles and have started diverting Blackbirds from sunflower, a high value crop, to alternative lesser-value crops, such as corn. USDA and university scientists are developing a perennial sunflower that might significantly lower the costs of planting WCSP. Growers now have access to several desiccants that hasten the crop harvest and thus avoid late-season Blackbird damage. Finally, researchers are closer to developing an effective chemical bird repellent. In this paper, we outline current nonlethal Blackbird management strategies.
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Birds Associated with Blackbird Spring Feeding Sites in South Dakota
2009Co-Authors: George M. Linz, David L. Bergman, William J. BleierAbstract:From 2 to 16 April 1993 , we conducted road-side surveys of birds using haIVested fields of small grains, soybeans, and com within 8 km of two Blackbird roosts in east central South DakOla_ Blackbirds, waterfowl, killdeer, homed larks, ring-necked pheasants, and western meadowlarks were the most common birds recorded. The frequencies of Blackbirds, nongame birds, terrestrial game birds, and waterfowl was not equally distributed within the three habitaLS (P =0.023).
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Dietary Comparisons of Adult Male Common Grackles, Red-winged Blackbirds, and Yellow-headed Blackbirds in North Central North Dakota
The Prairie Naturalist, 2009Co-Authors: H. Jeffrey Homan, George M. Linz, William J. Bleier, Robert B. CarlsonAbstract:We compared the esophageal contents of adult male common grackles (Quiscalus quiscula), red-winged Blackbirds (Agelaius phoeniceus),and yellow-headed Blackbirds (Xanthocephalus xanthocephalus) collected in north central North Dakota from JUly through October 1989. Temporal variation in the diets of all species was related to food availabilities, which were heavily influenced by crop phenology. Depending on species, mean percent dry weight of sunflower achenes during August increased 2-6 times over July. Yellow-headed Blackbirds migrated from north central North Dakota by early September, but substantial numbers of common grackles and red-winged Blackbirds remained until mid-October. Sunflower was an important component of red-winged Blackbird and common grackle diets through October. The more varied diet of yellow-headed Blackbirds, in combination with the early departure from sunflower-growing regions, makes this species less likely to cause economic impact to the sunflower producer.
Dieter Thomas Tietze - One of the best experts on this subject based on the ideXlab platform.
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does urbanization affect wing pointedness in the Blackbird turdus merula
Journal of Ornithology, 2018Co-Authors: Elisabeth Saccavino, Jan Kramer, Sebastian Klaus, Dieter Thomas TietzeAbstract:Colonization of urban habitats requires physiological, behavioral and morphological changes in many species. This is well studied in the Common Blackbird (Turdus merula), one of the most common bird species in Europe. Former studies found that urban Blackbirds show decreased migratory behavior. However, it is still a matter of debate whether this is linked to morphological changes. According to Seebohm’s rule, sedentary individuals have less pointed wings in contrast to migratory individuals. Here we assess if wing pointedness—as measured by Kipp’s index—decreases along a rural to urban gradient in Blackbirds. To determine this, Blackbirds were caught in Frankfurt am Main and Heidelberg, as well as in the neighboring uplands of the Taunus and Odenwald, along a virtual continuous urbanization gradient, ranging from nearby forests to city centers. Along this gradient, wing pointedness significantly decreased in male, but not in female, Blackbirds. However, this trend was no longer significant when considering single regions. This indicates that wing pointedness does not change uniformly across the species’ range because of different intensities of urbanization. Sex-specific differences might be due to distinct territorial and dominance behavior. Variations in wing shape of urban and rural Blackbird populations are most likely based on a combination of better climatic conditions and increased food availability, as well as behavior adjusted to urban habitats. This study shows urbanization effects on the wing morphology of Blackbirds that might coincide with reduced migratory behavior.
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characterization of a de novo assembled transcriptome of the common Blackbird turdus merula
PeerJ, 2017Co-Authors: Sven Koglin, Dieter Thomas Tietze, Daronja Trense, Michael Wink, Hedwig SauergurthAbstract:Background: In recent years, next generation high throughput sequencing technologies have proven to be useful tools for investigations concerning the genomics or transcriptomics also of non-model species. Consequently, ornithologists have adopted these technologies and the respective bioinformatics tools to survey the genomes and transcriptomes of a few avian non-model species. The Common Blackbird is one of the most common bird species living in European cities, which has successfully colonized urban areas and for which no reference genome or transcriptome is publicly available. However, to target questions like genome wide gene expression analysis, a reference genome or transcriptome is needed. Methods: Therefore, in this study two Common Blackbirds were sacrificed, their mRNA was isolated and analyzed by RNA-Seq to de novo assemble a transcriptome and characterize it. Illumina reads (125 bp paired-end) and a Velvet/Oases pipeline led to 162,158 transcripts. For the annotation (using Blast+), an unfiltered protein database was used. SNPs were identified using SAMtools and BCFtools. Furthermore, mRNA from three single tissues (brain, heart and liver) of the same two Common Blackbirds were sequenced by Illumina (75 bp single-end reads). The draft transcriptome and the three single tissues were compared by their BLAST hits with the package VennDiagram in R. Results: Following the annotation against protein databases, we found evidence for 15,580 genes in the transcriptome (all well characterized hits after annotation). On 18% of the assembled transcripts, 144,742 SNPs were identified which are, consequently, 0.09% of all nucleotides in the assembled transcriptome. In the transcriptome and in the single tissues (brain, heart and liver), 10,182 shared genes were found. Discussion: Using a next-generation technology and bioinformatics tools, we made a first step towards the genomic investigation of the Common Blackbird. The de novo assembled transcriptome is usable for downstream analyses such as differential gene expression analysis and SNP identification. This study shows the importance of the approach to sequence single tissues to understand functions of tissues, proteins and the phenotype.
Robert W Andrews - One of the best experts on this subject based on the ideXlab platform.
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reproductive interactions of the shiny cowbird molothrus bonariensis and the yellow hooded Blackbird agelaius icterocephalus in trinidad
Ibis, 2008Co-Authors: Alexander Cruz, Timothy D Manolis, Robert W AndrewsAbstract:The reproductive interactions of the Shiny Cowbird Molothrus bonariensis, a brood parasite, and the Yellow-hooded Blackbird Agelaius icterocephalus, a host of the cowbird, were studied In Trinidad, West Indies. We gathered information on the breeding biology of the Shiny Cowbird and the Yellow-hooded Blackbird, the frequency of use of the host species, and the effects of brood parasitism on host breeding success. Yellow-hooded Blackbirds are polygynous for the most part; males build nests and attempt to attract females to lay in them by means of song and visual displays directed towards the nests. This behaviour probably makes it easy for cowbirds to locate breeding birds and their nests. Cowbird eggs were found in 153 of 377 (40–3 %) Blackbird nests located before the nestling stage. Shiny Cowbird parasitism of the Yellow-hooded Blackbird had little negative impact on host reproductive success, whereas predation accounted for the majority of nest failures. Vigilant nest defense by male Blackbirds combined with colonial breeding apparently also minimized the extent of host egg damage and removal by cowbirds, and the parasitized and unparasitized nests were equally successful at producing Blackbirds. Cowbirds most frequently parasitized the first or only nesting attempts in Blackbird territories, and first or only nests were also successful more frequently than subsequent nests.