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Richard T. Reynolds - One of the best experts on this subject based on the ideXlab platform.
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Northern Goshawk (Accipiter gentilis)
Birds of the World, 2020Co-Authors: John R. Squires, Richard T. Reynolds, Jaume Orta, Jeffrey S. MarksAbstract:The Northern Goshawk (hereafter referred to as Goshawk) is a large forest raptor, occupying boreal and temperate forests throughout the Holarctic. In North America, it breeds from Alaska to Newfoundland and south (Fig. 1). This partial migrant winters throughout its breeding range including occasionally the Great Plains and southeastern states; some individuals undergo short movements to lower elevations during winter, apparently in search of food. Irruptive movements of Northern birds to the south occurs at approximately 10-year intervals that coincide with population lows of snowshoe hare (Lepus americanus) and grouse.
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long term demography of the Northern Goshawk in a variable environment
Wildlife Monographs, 2017Co-Authors: Richard T. Reynolds, Jeffrey S Lambert, Curtis H Flather, Gary C White, Benjamin J Bird, Scott L Baggett, Carrie Lambert, Shelley Bayard De VoloAbstract:The Nearctic Northern Goshawk (Accipiter gentilis atricapillis) is a resident of conifer, broadleaf, and mixed forests from the boreal to the southwestern montane regions of North America. We report on a 20-year mark-recapture investigation (1991–2010) of the distribution and density of breeders, temporal and spatial variability in breeding, nestling sex ratios, local versus immigrant recruitment of breeders, breeding age structure, age-specific survival rates, and rate of population change (λ) of this species on the Kaibab Plateau, a forested sky island in Northern Arizona, USA. We used an information-theoretic approach to rank models representing alternative hypotheses about the influence of annual fluctuations in precipitation on the annual frequency of Goshawk breeding and fledgling production. We studied 125 Goshawk breeding territories, representing approximately 87% of an estimated 144 total territories based on a mean distance of 3.8 km between territory centers in a 1,728-km2 study area. The salient demographic feature of the population was extensive annual variation in breeding, which manifested as large inter-annual variation in proportions of pairs laying eggs, brood sizes, nest failure rates, and fledgling production. The percent of territories known in a prior year in which eggs were laid in a current year ranged from 8% to 86% (x¯ = 37%, SE = 4.51), annual mean nest failure rate (active nests that failed) ranged from 12% to 48% (overall x¯ = 23%, SE = 2.48), and mean annual brood size of successful nests (fledged ≥1 fledgling) ranged from 1.5 young to 2.5 young (overall x¯ = 2.0 young, SE = 0.03). Inter-annual variation in reproduction closely tracked inter-annual variation in precipitation, which we hypothesize influenced primary forest productivity and bird and mammal prey abundance. The best breeding years (1992–1993, 77–87% of pairs laid eggs) were coincident with a record-long El Nino-Southern Oscillation (ENSO) wet period and the worst breeding year (2003; 8% of pairs laid eggs) was the last of a 3-year record drought. Overall breeding success was 83% with most failures occurring during incubation; once eggs hatched, Goshawks tended to fledge young. The pooled 20-year nestling sex ratio did not differ from unity (53% M; n = 410 M, 366 F) but was significantly male-biased in 2 years and female-biased in 1 year. Nonetheless, the overall greater production of male fledglings followed a strong trend of greater male production in other Goshawk populations, suggesting that breeders might have been adaptively adjusting their offspring sex ratio, perhaps to produce more of the rarer (male) sex. Annual recruitment of new individuals into the breeding population averaged 43% during the study. Study area recruitment rate of hawks locally born (in situ) and banded was 0.12. Both sexes had equal tendencies to return to the Kaibab Plateau to breed (no differences in philopatry) and there were no differences in natal dispersal distances (natal to first breeding site) between the sexes. During the final years of study (1999–2010), an estimated 46% of breeding recruits were locally born and 54% were immigrants from distant forests. Minimum age at first breeding was 2 years and mean age at first breeding by known-age hawks (banded as nestlings or aged on plumage at first breeding) was 3.7 years for males and 3.5 years for females. Mean lifespan (yr from first banding as nestling to last resighting) of known-age Goshawks was 6.9 years for both sexes. Mean minimum apparent lifespan of breeders aged ≥4 years based on plumage at first capture was 6.5 years for both sexes. Average age of Goshawks at their first detection was 3.9 years old, at which time apparent survival was estimated at 0.77 for both sexes, which was just slightly less than the peak survival of 0.78 as a function of age. Age-specific survival estimates showed a steady decline after 9 years old and approached 0 at 20 years of age. Estimates of λ for breeding adults (M, 0.94, SE = 0.037; F, 0.98, SE = 0.038) provided only weak evidence for a population decline during the study. Although sex was not in the top survival model, models including age + sex were competitive, evidencing lower male than female survival, a finding corroborated by the occurrence of sex effects in the top λ model. Lower male survival may result from higher mortality associated with hunting agile prey in vegetation-filled environments during long breeding seasons when they are the primary forager. Lower survival may be compensated by the more frequent production (53%) of male fledglings. High-severity crown fire was an existential threat to the population. In addition to 4 large high-severity fires that burned roughly 3,770 ha (equal to 3 Goshawk territories) in the 30 years preceding 1991, 6 high-severity fires burned another 30,945 ha during our study and killed most (>64%) of the forests in 8 known territories and possibly another 2 that were burned before we completed surveys. Based on a lack of any recent demographic perturbations in age structure, a relatively high and time-constant annual adult survival rate, confidence intervals around adult λ estimates overlapping 1.0, and a study area saturated with territories, we surmise that the Goshawk population on the Kaibab Plateau was stable during the 20-year study. Nonetheless, uncertainty remains regarding the population's future status because of a declining trend in breeding frequency, uncertain status (dead, alive, emigrated) of non-breeding adults, extensive temporal and spatial variation in breeding, and high frequency of immigrant recruits to the breeding population on the Kaibab Plateau. If the century-long decline in precipitation persists, especially at the increased rate seen since 1980, and manifests as deeper droughts, diminished wet periods, and weaker pulses in forest productivity, then the Kaibab Plateau Goshawk population would be expected to show unambiguous evidence of decline. Evidence would include reduced local and regional Goshawk reproduction and survival, reduced frequency of immigration, and further habitat loss to catastrophic fire. © 2017 The Wildlife Society.
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Appendix A. A table showing the ranking of the full set of juvenile Northern Goshawk survival models considered for the post-fledging and post-independence developmental stages.
2016Co-Authors: David J. Wiens, Barry R. Noon, Richard T. ReynoldsAbstract:A table showing the ranking of the full set of juvenile Northern Goshawk survival models considered for the post-fledging and post-independence developmental stages
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Northern Goshawk and its prey in the Black Hills: Habitat assessment
2015Co-Authors: Russell T. Graham, Shelley Bayard De Volo, Richard T. ReynoldsAbstract:The Northern Goshawk is classified as a Sensitive Species in all USDA Forest Service regions, including on the Black Hills National Forest in western South Dakota and northeastern Wyoming. An assessment was conducted of the quality of Northern Goshawk nesting and foraging habitat, along with the habitat quality of 22 of the Goshawk’s prey species. A Delphi (expert panel) evaluation of Goshawk and prey habitat in 3,414 watersheds averaging 449 acres (182 ha) in size was completed by wildlife biologists from the Black Hills National Forest. The quality of Goshawk nesting and foraging habitat and of prey group habitats was reported individually, then combined for each watershed. The optimum Goshawk and prey habitat, totaling 67 watersheds or 34,427 acres (13,932 ha), was distributed throughout the nearly 1.5 million-acre (about 607,000-ha) Black Hills National Forest. Panel members found that the Bear Lodge Mountains, located in northeastern Wyoming, proportionally had the most optimum, high-, and medium-rated habitat. Wildfire, bark beetles, urban encroachment, and timber harvest can negatively affect Northern Goshawks and their prey’s habitat. However, increasing the amount and presence of quaking aspen forests within the Black Hills will most likely improve the habitat of the Goshawk by improving the habitat for many of its prey. Using previously articulated conditions as a template in the Forest Vegetation Simulator, we designed an example 100-year silvicultural system to create and maintain forest conditions for the Northern Goshawk and its prey on the Black Hills Experimental Forest.
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Integrating single-species management and landscape conservation using regional habitat occurrence models: the Northern Goshawk in the Southwest, USA
Landscape Ecology, 2014Co-Authors: Brett G. Dickson, Richard T. Reynolds, Thomas D. Sisk, Steven E. Sesnie, Steven S. Rosenstock, Christina D. Vojta, Michael F. Ingraldi, Jill M. RundallAbstract:Conservation planners and land managers are often confronted with scale-associated challenges when assessing the relationship between land management objectives and species conservation. Conservation of individual species typically involves site-level analyses of habitat, whereas land management focuses on larger spatial extents. New models are needed to more explicitly integrate species-specific conservation with landscape or regional scales. We address this challenge with an example using the Northern Goshawk ( Accipiter gentilis ), a forest raptor with circumpolar distribution that is the focus of intense debate regarding forest management on public lands in the southwestern USA. To address Goshawk-specific habitat conservation across a management area of 22,800-km^2 in Northern Arizona, we focused on the territory scale rather than individual nest sites. We compiled a 17-year database of 895 nest sites to estimate territory locations. We then estimated the likelihood of territory occurrence for the entire management area using multiple logistic regression within an expert-driven, spatially balanced, and information-theoretic framework. Our occurrence model incorporated forest structure variables that were derived from USFS Forest Inventory and Analysis plots and high-resolution satellite imagery. Results indicated that high canopy-bulk density, intermediate canopy-base heights, and low variation in tree density were strong predictors of territory occurrence. We used model-averaged parameter estimates for these variables to map and explore patterns of territory distribution across multiple land jurisdictions and ecological subregions. Our iterative modeling approach complements previous demographic studies in the region. It also provides a robust framework for integrating species conservation and landscape management in ongoing and future regional planning efforts.
Patricia L. Kennedy - One of the best experts on this subject based on the ideXlab platform.
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The Northern Goshawk (Accipiter gentilis atricapillus) in the Western Great Lakes Region: A Technical Conservation Assessment
2003Co-Authors: Aimee M. Roberson, David E. Andersen, Patricia L. KennedyAbstract:This conservation assessment is a summary of the information currently available regarding the Northern Goshawk (Accipiter gentilis) in the Western Great Lakes Region (WGLR), including the states of Minnesota, Wisconsin, and Michigan and the forested southern portion of the Canadian province of Ontario. Because relatively few scientific studies of the Goshawk in the WGLR have been conducted and even fewer published, information that may be relevant from studies conducted in other parts of North America and Eurasia have also been summarized. The purpose of this assessment is to present information relevant to the formation of a conservation and management strategy for the Goshawk in the WGLR. This assessment describes the species’ systematics, physical characteristics, distribution, and abundance. It also includes information regarding the foraging ecology, habitat characteristics, population ecology, potential threats, and monitoring of the Northern Goshawk, summarizes ongoing research, and identifies additional research needs for this region.
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Do Some Northern Goshawk Nest Areas Consistently Fledge More Young Than Others?
The Condor, 2002Co-Authors: Erica L. Mcclaren, Patricia L. Kennedy, Sarah R. DeweyAbstract:Abstract In long-lived raptors, research suggests that some nest areas consistently fledge more young than others, with the majority of young in the population being produced by a few females. If this claim were true for Northern Goshawk (Accipiter gentilis) populations, it would benefit land managers to identify high-quality Goshawk breeding habitat. We examined whether the number of young fledged varied spatially among Northern Goshawk nest areas within three study areas where long-term reproductive data from Goshawks were available: (1) Vancouver Island, British Columbia; (2) Jemez Mountains, New Mexico; and (3) Uinta Mountains, Utah. A mixed-model ANOVA indicated there was minimal spatial variation in nest productivity among nest areas within the three study locations. Rather, nest areas exhibited high temporal variability in nest productivity within each study area. These results suggest that temporal patterns such as local weather and fluctuating prey populations influenced Northern Goshawk reproduction more than spatial patterns such as habitat characteristics. Nest productivity may inadequately reflect spatial patterns in Goshawk reproduction and so it would be premature to assume that habitat quality for Northern Goshawks was equal among nest areas within these study areas. Future research should examine spatial variability among nest areas in adult and juvenile survival rates to gain a complete picture of population responses to habitat change. ¿Se Producen Consistentemente Más Volantones de Accipiter gentilis en Algunos Sitios de Anidación que en Otros? Resumen. Investigaciones en aves rapaces longevas sugieren que consistentemente más polluelos empluman en algunos sitios de anidación que en otros y que la mayoría de los juveniles en la población son producidos por unas pocas hembras. Si esto fuera cierto para poblaciones de Accipiter gentilis, ayudaría a las autoridades ambientales a identificar hábitat reproductivo de alta calidad para la especie. Evaluamos si el número de polluelos emplumados varió espacialmente entre sitios de anidación de A. gentilis dentro de tres áreas de estudio para las cuales había datos reproductivos de largo plazo disponibles: (1) Vancouver Island, British Columbia; (2) Jemez Mountains, New Mexico; y (3) Uinta Mountains, Utah. Un modelo mixto de análisis de varianza indicó que la variación espacial en la productividad de los nidos entre sitios de anidación dentro de las tres áreas de estudio fue mínima. En cambio, los sitios de anidación presentaron una alta variabilidad temporal en la productividad de los nidos dentro de cada área de estudio. Estos resultados sugieren que los patrones temporales como el clima y las fluctuaciones de las poblaciones de presas influencian la reproducción de A. gentilis más que los patrones espaciales como las características del hábitat. La productividad de los nidos puede reflejar inadecuadamente los patrones espaciales de la reproducción de A. gentilis, de modo que sería prematuro suponer que la calidad de hábitat fue igual entre los sitios de anidación dentro de las áreas de estudio. Para tener una perspectiva completa de la respuesta de las poblaciones a cambios en el ambiente, investigaciones futuras deberían examinar la variabilidad espacial entre sitios de anidación en las tasas de supervivencia de aves adultas y juveniles.
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DO SOME Northern Goshawk NEST AREAS CONSISTENTLY FLEDGE MORE YOUNG THAN OTHERS
The Condor, 2002Co-Authors: Erica L. Mcclaren, Patricia L. Kennedy, Sarah R. DeweyAbstract:Abstract In long-lived raptors, research suggests that some nest areas consistently fledge more young than others, with the majority of young in the population being produced by a few females. If this claim were true for Northern Goshawk (Accipiter gentilis) populations, it would benefit land managers to identify high-quality Goshawk breeding habitat. We examined whether the number of young fledged varied spatially among Northern Goshawk nest areas within three study areas where long-term reproductive data from Goshawks were available: (1) Vancouver Island, British Columbia; (2) Jemez Mountains, New Mexico; and (3) Uinta Mountains, Utah. A mixed-model ANOVA indicated there was minimal spatial variation in nest productivity among nest areas within the three study locations. Rather, nest areas exhibited high temporal variability in nest productivity within each study area. These results suggest that temporal patterns such as local weather and fluctuating prey populations influenced Northern Goshawk reproduc...
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RESEARCH AND MONITORING PLAN FOR Northern GoshawkS (Accipter gentilis atricapillus) IN THE WESTERN GREAT LAKES REGION, 1999
1999Co-Authors: Patricia L. Kennedy, David E. AndersenAbstract:Because the Northern Goshawk (Accipiter gentilis atricapillus; hereafter referred to as Goshawk) often nests (Siders and Kennedy 1996; Squires and Ruggiero 1996) and hunts (Bright-Smith and Mannan 1994; Beier and Drennan 1997) in mature forests, potential conflicts between timber harvest and maintenance of viable Goshawk populations concerns various publics (Kennedy 1997). Due to these concerns, the U. S. Fish and Wildlife Service (FWS) recently conducted a status review of Goshawk populations west of the 100th meridian to determine if listing this population as threatened under the Endangered Species Act (ESA) was warranted (Clark 1997).
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Siblicide at Northern Goshawk Nests: Does Food Play a Role?
The Wilson Journal of Ornithology, 1999Co-Authors: A. F. Skutch, W. S. Clark, D. A. Boyce, R. Straneck, Patricia L. KennedyAbstract:Siblicide as a mechanism for brood reduction has been reported in a number of asynchro- nously hatching bird species. Although researchers have documented the occurrence of facultative sibli- cide in several raptor species, its cause is still debated. Most hypotheses relate incidences of siblicide to food availability. The food-amount hypothesis predicts a negative relationship between the amount of food available and nestling aggression. While the food- amount hypothesis has received much attention, few studies show more than correlational support for this activity in raptors. Our observation of a siblicide event at a Northern Goshawk (Accipiter gentilis) nest used as a control in a supplemental feeding experiment, and a similar incident where a nestling Goshawk's death can be attributed to siblicide provide support for the negative correlation between food amount and sibling aggression. These observations and the lack of any re- ported sibling aggression at seven supplementally fed nests showing extreme hatching asynchrony also in- dicate a relationship between food resources and brood reduction. Our observations are consistent with the idea that Goshawks exhibit facultative siblicide, and that resource levels as predicted by the food-amount hypothesis directly influence it. Received 7 Oct. /998, accepted 16 Feb. 1999.
David E. Andersen - One of the best experts on this subject based on the ideXlab platform.
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Factors Related to Northern Goshawk Landscape Use in the Western Great Lakes Region
Journal of Raptor Research, 2014Co-Authors: Jason E. Bruggeman, David E. Andersen, James E. WoodfordAbstract:Abstract Northern Goshawks (Accipiter gentilis) are a species of special conservation concern in the western Great Lakes bioregion and elsewhere in North America, and exhibit landscape-scale spatial use patterns. However, little information exists about Northern Goshawk habitat relations at broad spatial extents, as most existing published information comes from a few locations of relatively small spatial extent and, in some cases, short durations. We used an information-theoretic approach to evaluate competing hypotheses regarding factors (forest canopy cover, successional stage, and heights of the canopy top and base) related to odds of Northern Goshawk landscape use throughout the western Great Lakes bioregion based on an occupancy survey completed in 2008 (Bruggeman et al. 2011). We also combined these data with historical data of Northern Goshawk nest locations in the bioregion from 1979–2006 to evaluate the same competing hypotheses to elucidate long-term trends in use. The odds of Northern Goshawk ...
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Northern Goshawk Monitoring In the Western Great Lakes Bioregion
Journal of Raptor Research, 2011Co-Authors: Jason E. Bruggeman, David E. Andersen, James E. WoodfordAbstract:Abstract Uncertainties about factors affecting Northern Goshawk (Accipiter gentilis) ecology and the status of populations have added to the challenge of managing this species. To address data needs for determining the status of Goshawk populations, Hargis and Woodbridge (2006) developed a bioregional monitoring protocol based on estimating occupancy. The goal of our study was to implement this protocol and collect data to determine Goshawk population status in the western Great Lakes (WGL) bioregion, which encompasses portions of Minnesota, Wisconsin, and Michigan, and is a mixture of private and public property. We used 366 Goshawk nest locations obtained between 1979 and 2006 throughout the WGL bioregion to develop a model of landscape use consisting of forest canopy cover and land-cover covariates. We then used the model to develop a stratified sampling design for selecting 600-ha Primary Sampling Units (PSUs) to survey for Goshawks. Project collaborators surveyed 86 PSUs for Goshawk presence using br...
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The Northern Goshawk (Accipiter gentilis atricapillus) in the Western Great Lakes Region: A Technical Conservation Assessment
2003Co-Authors: Aimee M. Roberson, David E. Andersen, Patricia L. KennedyAbstract:This conservation assessment is a summary of the information currently available regarding the Northern Goshawk (Accipiter gentilis) in the Western Great Lakes Region (WGLR), including the states of Minnesota, Wisconsin, and Michigan and the forested southern portion of the Canadian province of Ontario. Because relatively few scientific studies of the Goshawk in the WGLR have been conducted and even fewer published, information that may be relevant from studies conducted in other parts of North America and Eurasia have also been summarized. The purpose of this assessment is to present information relevant to the formation of a conservation and management strategy for the Goshawk in the WGLR. This assessment describes the species’ systematics, physical characteristics, distribution, and abundance. It also includes information regarding the foraging ecology, habitat characteristics, population ecology, potential threats, and monitoring of the Northern Goshawk, summarizes ongoing research, and identifies additional research needs for this region.
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RESEARCH AND MONITORING PLAN FOR Northern GoshawkS (Accipter gentilis atricapillus) IN THE WESTERN GREAT LAKES REGION, 1999
1999Co-Authors: Patricia L. Kennedy, David E. AndersenAbstract:Because the Northern Goshawk (Accipiter gentilis atricapillus; hereafter referred to as Goshawk) often nests (Siders and Kennedy 1996; Squires and Ruggiero 1996) and hunts (Bright-Smith and Mannan 1994; Beier and Drennan 1997) in mature forests, potential conflicts between timber harvest and maintenance of viable Goshawk populations concerns various publics (Kennedy 1997). Due to these concerns, the U. S. Fish and Wildlife Service (FWS) recently conducted a status review of Goshawk populations west of the 100th meridian to determine if listing this population as threatened under the Endangered Species Act (ESA) was warranted (Clark 1997).
Michael Lierz - One of the best experts on this subject based on the ideXlab platform.
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sarcocystis calchasi sp nov of the domestic pigeon columba livia f domestica and the Northern Goshawk accipiter gentilis light and electron microscopical characteristics
Parasitology Research, 2010Co-Authors: Philipp Olias, Hafez M Hafez, Alfred Otto Heydorn, Achim D Gruber, Heinz Mehlhorn, Michael LierzAbstract:A novel highly pathogenic Sarcocystis species has been shown to cycle between the Northern Goshawk (Accipiter gentilis) as definitive host and the domestic pigeon (Columba livia f. domestica) as intermediate host. However, genetically based characteristics are only available from very few bird-infecting Sarcocystis species. We therefore further characterised morphological properties of this protozoan in both hosts. Using light and electron microscopy, oocysts and sporocysts as well as schizonts and sarcocysts were characterised and compared with available morphological features of previously reported Sarcocystis species of Northern Goshawks, Columbidae and genetically closely related species of other avian hosts. Sporocysts shed from day 6 on after experimental infection by the Northern Goshawk were of ovoid appearance (11.9 × 7.9 μm). Ultrastructurally, schizonts of all developmental stages were found in the liver, spleen and next to or in endothelial cells of various organs of domestic pigeons 7 to 12 days after experimental infection. The cyst wall surface of slender sarcocysts (1 to 2 mm in length and 20 to 50 μm in width) was smooth and lacked protrusions. Cystozoites were lancet-shaped and measured 7.5 × 1.5 μm in Giemsa stain smears. The morphological findings, when combined with data of experimental infection and genetic studies, convergently indicate that the recently discovered Sarcocystis species represents a new species. We therefore propose to name this parasite Sarcocystis calchasi species nova.
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Pathogenicity of Mycoplasma lipofaciens (Strain ML64) for turkey embryos
Avian Pathology, 2008Co-Authors: Michael Lierz, Achim D Gruber, Sebastian Brokat, Stefanie Deppenmeier, Hafez Mohamed HafezAbstract:Mycoplasma lipofaciens (strain ML64), isolated from an egg of a Northern Goshawk (Accipiter gentilis), was found to be pathogenic for chicken embryos causing mortality during first two weeks of incubation. The same strain was inoculated in turkey embryos to evaluate its pathogenicity and its ability to be laterally transmitted in the hatchery. The strain was found to be pathogenic to turkey embryos causing a high mortality (88.9%) during late incubation as well as haemorrhages of the legs, dwarfing, curled toes and a severe, multifocal, purulent to necrotizing broncho-pneumonia. In addition, lateral transmission between turkey poults hatched from infected eggs and poults from non-infected controls, was observed in the incubator.
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Pathogenicity of Mycoplasma lipofaciens strain ML64, isolated from an egg of a Northern Goshawk (Accipiter gentilis), for chicken embryos
Avian pathology : journal of the W.V.P.A, 2007Co-Authors: Michael Lierz, R. Stark, Sebastian Brokat, Hafez M HafezAbstract:Some Mycoplasma species are well-known avian pathogens and are of importance in poultry breeder flocks due to their pathogenic potential for embryos. Mycoplasmas are regularly detected in birds of prey, and a strain of Mycoplasma lipofaciens that was isolated from an egg of a Northern Goshawk (Accipiter gentilis) was examined for its pathogenicity in specific pathogen free chicken embryos since birds of prey eggs were not available for this purpose. The strain was found to be pathogenic, causing a high mortality as well as dwarfing, curled toes and infiltrations of heterophils in the liver, kidney, intestine and chorioallantoic membrane.
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Pathogenicity of M. lipofaciens (strain ML64), isolated from an egg of a Northern Goshawk (Accipiter gentilis), for chicken embryos
Avian Pathology, 2007Co-Authors: Michael Lierz, R. Stark, Hafez Mohamed Hafez, Sebastian BrokatAbstract:Some Mycoplasma species are well known avian pathogens and are of importance in poultry breeder flocks due to their pathogenic potential for embryos. Mycoplasmas are regularly detected in birds of prey and a strain of M. lipofaciens that was isolated from an egg of a Northern Goshawk (Accipiter gentilis) was examined for its pathogenicity in specific pathogen-free chicken embryos since birds of prey eggs were not available for this purpose. The strain was found to be pathogenic, causing a high mortality as well as dwarfing, curled toes and infiltrations of heterophils in the liver, kidney, intestine and chorioallantoic membrane.
Sam-rang Song - One of the best experts on this subject based on the ideXlab platform.
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Did genetic lineage divergence or spatial environmental variance lead to global subspecies differentiation of Northern Goshawk (Accipiter gentilis)?
Animal Biology, 2020Co-Authors: Sam-rang SongAbstract:Abstract When a widely distributed species undergoes ecological or geological isolation, it tends to divide into subspecies. In general, subspecies differentiation is affected by environmental variance and genetic divergence. But the extent to which these two factors influence subspecies differentiation in species with different distribution ranges and modes of living, might be different. Despite having high breeding habitat fidelity, Northern Goshawk is a forest raptor that is widely dispersed. We investigated morphological traits in combination with the genetic background of Northern Goshawk individuals at a large global scale. We also collected genetic, palynological and climatic data to reveal what caused global subspecies differentiation in Northern Goshawk. Eurasian and North American subspecies populations are thought to have diverged approximately 660 000 years ago to undergo different evolutionary routes, which remarkably facilitated intercontinental subspecies differentiation through genetic lineage divergence. During the last glacial period (18 000 years ago) the different isolation levels of Northern Goshawk refugia on the continents caused genetic lineage divergences, which, however, are unlikely to have led to subspecies differentiation directly. Spatial environmental variance due to the wide distribution of Northern Goshawks made an important contribution to subspecies differentiation throughout continents.
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Did genetic lineage divergence or spatial environmental variance lead to global subspecies differentiation of Northern Goshawk (Accipiter gentilis)
Animal Biology, 2020Co-Authors: Sam-rang SongAbstract:When a widely distributed species undergoes ecological or geological isolation, it tends to divide into subspecies. In general, subspecies differentiation is affected by environmental variance and genetic divergence. But the extent to which these two factors influence subspecies differentiation in species with different distribution ranges and modes of living, might be different. Despite having high breeding habitat fidelity, Northern Goshawk is a forest raptor that is widely dispersed. We investigated morphological traits in combination with the genetic background of Northern Goshawk individuals at a large global scale. We also collected genetic, palynological and climatic data to reveal what caused global subspecies differentiation in Northern Goshawk. Eurasian and North American subspecies populations are thought to have diverged approximately 660,000 years ago to undergo different evolutionary routes, which remarkably facilitated intercontinental subspecies differentiation through genetic lineage divergence. During the last glacial period (18,000 years ago) the different isolation levels of Northern Goshawk refugia on the continents caused genetic lineage divergences, which, however, are unlikely to have led to subspecies differentiation directly. Spatial environmental variance due to the wide distribution of Northern Goshawks made an important contribution to subspecies differentiation throughout continents.