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Martina Carrete - One of the best experts on this subject based on the ideXlab platform.
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Burrowing Owl data sets
2019Co-Authors: Álvaro Luna, Antonio Palma, Ana Sanz-aguilar, José Luis Tella, Martina CarreteAbstract:Data are organized in two independent files: (1) “Burrowing_Owl_Data.xlsx” records all the information of Burrowing Owls ringed during a monitoring program at Bahia Blanca (Argentina) during the breeding seasons 2005/2006 - 2017/2018. Each line corresponds to one individual. The dataset includes the year of birth and the year of first resight, the natal dispersal distance, the sex, the flight initiation distance (FID) and the breeding productivity both in the first breeding attempt and during the entire life for each individual. We also provide information about the habitat type, the conspecific density and the conspecific productivity both for their natal area and for their first breeding territory.-- (2) “dispnatalsurvival.inp” records the recaptures of each marked Burrowing Owls during a continuous monitoring program, grouped by sex and habitat. Each line corresponds to one individual. The first 11 columns represent the history of life of the individuals by years (with 0 = no resight and 1= resight). The following 4 columns are the groups (urban males, urban females, rural males, rural females), and the last column is the natal dispersal distance (log transformed) covered by each Burrowing Owl.
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urban conservation hotspots predation release allows the grassland specialist Burrowing Owl to perform better in the city
Scientific Reports, 2017Co-Authors: José Luis Tella, Martina Carrete, Natalia ReboloifranAbstract:Although habitat transformation is one of the main causes of biodiversity loss, there are many examples of species successfully occupying and even proliferating in highly human-modified habitats such are the cities. Thus, there is an increasing interest in understanding the drivers favoring urban life for some species. Here, we show how the low richness and abundance of predators in urban areas may explain changes in the habitat selection pattern of a grassland specialist species, the Burrowing Owl Athene cunicularia, toward urban habitats. Predation release improves the demographic parameters of urban individuals, thus favoring an increment in the breeding density of the species in urban areas that accounts for the apparent positive selection of this habitat in detriment of the more natural ones that are avoided. These results suggest that traditional habitat selection analyses do not necessarily describe habitat choice decisions actively taken by individuals but differences in their demographic prospects. Moreover, they also highlight that cites, as predator-free refuges, can become key conservation hotspots for some species dependent on threatened habitats such as the temperate grasslands of South America.
Courtney J. Conway - One of the best experts on this subject based on the ideXlab platform.
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Agriculture creates subtle genetic structure among migratory and nonmigratory populations of Burrowing Owls throughout North America.
Ecology and evolution, 2020Co-Authors: Alberto Macías-duarte, Courtney J. Conway, Melanie CulverAbstract:Population structure across a species distribution primarily reflects historical, ecological, and evolutionary processes. However, large-scale contemporaneous changes in land use have the potential to create changes in habitat quality and thereby cause changes in gene flow, population structure, and distributions. As such, land-use changes in one portion of a species range may explain declines in other portions of their range. For example, many Burrowing Owl populations have declined or become extirpated near the northern edge of the species' breeding distribution during the second half of the 20th century. In the same period, large extensions of thornscrub were converted to irrigated agriculture in northwestern Mexico. These irrigated areas may now support the highest densities of Burrowing Owls in North America. We tested the hypothesis that Burrowing Owls that colonized this recently created Owl habitat in northwestern Mexico originated from declining migratory populations from the northern portion of the species' range (migration-driven breeding dispersal whereby long-distance migrants from Canada and the United States became year-round residents in the newly created irrigated agriculture areas in Mexico). We used 10 novel microsatellite markers to genotype 1,560 Owls from 36 study locations in Canada, Mexico, and the United States. We found that Burrowing Owl populations are practically panmictic throughout the entire North American breeding range. However, an analysis of molecular variance provided some evidence that Burrowing Owl populations in northwestern Mexico and Canada together are more genetically differentiated from the rest of the populations in the breeding range, lending some support to our migration-driven breeding dispersal hypothesis. We found evidence of subtle genetic differentiation associated with irrigated agricultural areas in southern Sonora and Sinaloa in northwestern Mexico. Our results suggest that land use can produce location-specific population dynamics leading to subtle genetic structure even in the absence of dispersal barriers.
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Genetic Variation among Island and Continental Populations of Burrowing Owl (Athene cunicularia) Subspecies in North America
Journal of Raptor Research, 2019Co-Authors: Alberto Macías-duarte, Courtney J. Conway, Geoffrey L. Holroyd, Héctor E. Valdez-gómez, Melanie CulverAbstract:Burrowing Owls (Athene cunicularia) have a large geographic range spanning both North and South America and resident populations occur on many islands in the eastern Pacific Ocean and the Caribbean Sea. Many Owl populations are isolated and disjunct from other populations, but studies on genetic variation within and among populations are limited. We characterized DNA microsatellite variation in populations varying in size and geographic isolation in the Florida (A. c. floridana), the Western (A. c. hypugaea), and the Clarion (A. c. rostrata) subspecies of the Burrowing Owl. We also characterized genetic variation in a geographically isolated population of the western subspecies in central Mexico (near Texcoco Lake). Clarion Burrowing Owls had no intrapopulation variation (i.e., fixation) at 5 out of 11 microsatellite loci, a likely outcome of genetic drift in an isolated and small population. The Florida subspecies had only polymorphic loci but had reduced levels of genetic variation compared with the more-widespread western subspecies that occurs throughout western North America. Despite the extensive geographic distribution of the Western Burrowing Owl, we found genetic differentiation between the panmictic population north of the Trans-Mexican Volcanic Belt and the resident Texcoco Lake population in central Mexico.
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Spatial and Temporal Patterns In Population Trends and Burrow Usage of Burrowing Owls In North America
Journal of Raptor Research, 2018Co-Authors: Courtney J. ConwayAbstract:Abstract Many researchers have suggested that abundance of Burrowing Owls (Athene cunicularia) has declined in many portions of their breeding range, but a thorough review of their population trends over time is lacking. Published population trends from the North American Breeding Bird Survey program suggested that Burrowing Owl populations in the US have declined over the past 60 yr, but the declines were not considered significant until 2014. However, accurate trend estimates and the statistical significance of those estimates were hampered by low relative abundance of Owls. Moreover, many authors have suggested that eradication of Burrowing animals is a major cause of Burrowing Owl declines, because burrows dug by Burrowing animals are a critical resource for Western Burrowing Owls (A. cunicularia hypugaea). Despite this, we currently lack a range-wide summary of the Burrowing animals on which Western Burrowing Owls depend. To help fill these two information gaps, my objectives were to: (1) use Breedin...
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depth of artificial Burrowing Owl burrows affects thermal suitability and occupancy
Journal of Field Ornithology, 2015Co-Authors: Christopher P. Nadeau, Courtney J. Conway, Nathan RathbunAbstract:Many organizations have installed artificial burrows to help bolster local Burrowing Owl (Athene cunicularia) populations. However, occupancy probability and reproductive success in artificial burrows varies within and among burrow installations. We evaluated the possibility that depth below ground might explain differences in occupancy probability and reproductive success by affecting the temperature of artificial burrows. We measured burrow temperatures from March to July 2010 in 27 artificial burrows in southern California that were buried 15–76 cm below the surface (measured between the surface and the top of the burrow chamber). Burrow depth was one of several characteristics that affected burrow temperature. Burrow temperature decreased by 0.03°C per cm of soil on top of the burrow. The percentage of time that artificial burrows provided a thermal refuge from above-ground temperature decreased with burrow depth and ranged between 50% and 58% among burrows. The percentage of time that burrow temperature was optimal for incubating females also decreased with burrow depth and ranged between 27% and 100% among burrows. However, the percentage of time that burrow temperature was optimal for unattended eggs increased with burrow depth and ranged between 11% and 95% among burrows. We found no effect of burrow depth on reproductive success across 21 nesting attempts. However, occupancy probability had a non-linear relationship with burrow depth. The shallowest burrows (15 cm) had a moderate probability of being occupied (0.46), burrows between 28 and 40 cm had the highest probability of being occupied (>0.80), and burrows >53 cm had the lowest probability of being occupied (<0.43). Burrowing Owls may prefer burrows at moderate depths because these burrows provide a thermal refuge from above-ground temperatures, and are often cool enough to allow females to leave eggs unattended before the onset of full-time incubation, but not too cool for incubating females that spend most of their time in the burrow during incubation. Our results suggest that depth is an important consideration when installing artificial burrows for Burrowing Owls. However, additional study is needed to determine the possible effects of burrow depth on reproductive success and on possible tradeoffs between the effects of burrow depth on optimal temperature and other factors, such as minimizing the risk of nest predation. RESUMEN Profundidad de la madriguera de Athene cunicularia influencia la idoneidad en la temperatura y la ocupacion Muchas organizaciones han instalado madrigueras artificiales para ayudar a incrementar las poblaciones locales de Athene cunicularia. Sin embargo, la probabilidad de ocupacion y el exito reproductivo de estas madrigueras varia dentro y entre las instalaciones. Evaluamos la posibilidad que la profundidad bajo la tierra pudiera explicar las diferencias en la probabilidad de ocupacion y exito reproductivo, debido a que afectan la temperatura de las madrigueras artificiales. Medimos las temperaturas de las madrigueras desde Marzo hasta Julio de 2010 en 27 madrigueras artificiales en el sur de California que fueron enterrados 15–76 cm debajo de la superficie (medido entre la superficie y la parte mas alta de la camara de la madriguera). La profundidad de la madriguera fue una de muchas variables que afectaron su temperatura. La temperatura de la madriguera disminuyo 0.03°C por cada cm de suelo sobre la madriguera. La cantidad de tiempo en el cual la temperatura era optima para las hembras en incubacion vario entre 27–100% entre madrigueras y la cantidad de tiempo que la temperatura fue optima para los huevos vario entre 11–95%. No encontramos efecto de la profundidad de la madriguera sobre el exito reproductivo en 21 intentos de anidacion. Sin embargo, la probabilidad de ocupacion tuvo una relacion no linear con la profundidad de la madriguera. Las madrigueras mas cercanas a la superficie (15 cm) tuvieron una probabilidad moderada de ser ocupadas (0.46), madrigueras entre 28 y 40 cm tuvieron la mas alta probabilidad de ser ocupadas (>0.8) y madrigueras >53 cm tuvieron la probabilidad mas baja de ocupacion (<0.43). Athene cunicularia puede preferir madrigueras a profundidades moderadas debido a la necesidad de temperaturas mas bajas. Esto, con el fin de proveer un refugio termal y minimizar el costo por termorregulacion para los adultos, juveniles y las hembras en incubacion durante los periodos de temperaturas extremas sobre la tierra. Sin embargo las temperatura no puede ser tan baja como en las madrigueras mas profundas. Estas madrigueras profundas se encuentran con frecuencia a temperaturas por debajo de la temperatura critica de Athene cunicularia, lo cual incrementa los costos de termorregulacion. Nuestros resultados sugieren que es importante considerar la profundidad cuando se instalen madrigueras para Athene cunicularia. Sin embargo, se requieren estudios adicionales que determinen los posibles efectos de la profundidad de la madriguera en el exito reproductivo ademas de los posibles compromisos entre los efectos de la profundidad de la madrigueras sobre las temperaturas optimas y otros factores, como la necesidad de minimizar el riesgo de depredacion de nidos.
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Depth of artificial Burrowing Owl burrows affects thermal suitability and occupancy
Journal of Field Ornithology, 2015Co-Authors: Christopher P. Nadeau, Courtney J. Conway, Nathan RathbunAbstract:Many organizations have installed artificial burrows to help bolster local Burrowing Owl (Athene cunicularia) populations. However, occupancy probability and reproductive success in artificial burrows varies within and among burrow installations. We evaluated the possibility that depth below ground might explain differences in occupancy probability and reproductive success by affecting the temperature of artificial burrows. We measured burrow temperatures from March to July 2010 in 27 artificial burrows in southern California that were buried 15–76 cm below the surface (measured between the surface and the top of the burrow chamber). Burrow depth was one of several characteristics that affected burrow temperature. Burrow temperature decreased by 0.03°C per cm of soil on top of the burrow. The percentage of time that artificial burrows provided a thermal refuge from above-ground temperature decreased with burrow depth and ranged between 50% and 58% among burrows. The percentage of time that burrow temperature was optimal for incubating females also decreased with burrow depth and ranged between 27% and 100% among burrows. However, the percentage of time that burrow temperature was optimal for unattended eggs increased with burrow depth and ranged between 11% and 95% among burrows. We found no effect of burrow depth on reproductive success across 21 nesting attempts. However, occupancy probability had a non-linear relationship with burrow depth. The shallowest burrows (15 cm) had a moderate probability of being occupied (0.46), burrows between 28 and 40 cm had the highest probability of being occupied (>0.80), and burrows >53 cm had the lowest probability of being occupied (0.8) y madrigueras >53 cm tuvieron la probabilidad mas baja de ocupacion (
Natalia Reboloifran - One of the best experts on this subject based on the ideXlab platform.
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urban conservation hotspots predation release allows the grassland specialist Burrowing Owl to perform better in the city
Scientific Reports, 2017Co-Authors: José Luis Tella, Martina Carrete, Natalia ReboloifranAbstract:Although habitat transformation is one of the main causes of biodiversity loss, there are many examples of species successfully occupying and even proliferating in highly human-modified habitats such are the cities. Thus, there is an increasing interest in understanding the drivers favoring urban life for some species. Here, we show how the low richness and abundance of predators in urban areas may explain changes in the habitat selection pattern of a grassland specialist species, the Burrowing Owl Athene cunicularia, toward urban habitats. Predation release improves the demographic parameters of urban individuals, thus favoring an increment in the breeding density of the species in urban areas that accounts for the apparent positive selection of this habitat in detriment of the more natural ones that are avoided. These results suggest that traditional habitat selection analyses do not necessarily describe habitat choice decisions actively taken by individuals but differences in their demographic prospects. Moreover, they also highlight that cites, as predator-free refuges, can become key conservation hotspots for some species dependent on threatened habitats such as the temperate grasslands of South America.
Margaret A. Skeel - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of voluntary habitat stewardship in conserving grassland case of operation Burrowing Owl in saskatchewan
Environmental Management, 2004Co-Authors: Robert G. Warnock, Margaret A. SkeelAbstract:There have been no published performance evaluations of nongovernmental, voluntary habitat stewardship programs. The Operation Burrowing Owl (OBO) stewardship program, initiated in 1987, was evaluated for its effectiveness in conservation of grassland habitat during 1986-1993. The 108 OBO sites from 1987 to 88 and 98 randomly selected non-OBO sites that were grassland in 1986 in the Regina-Weyburn, Saskatchewan study area were classified by size and agricultural soil suitability. By 1993, 41 (38%) of the 108 OBO sites had been withdrawn from the program. The 1986 area of grassland was compared with grassland area calculated from digitized 1993 LANDSAT imagery. A correction for satellite inaccuracies was determined. Grassland retention in 1993 was significantly higher at OBO sites (66%) than at random sites (49%), demonstrating that the OBO voluntary program effectively conserved habitat. Also, grassland retention was significantly lower on sites with better agricultural soils, and for sites <12 ha in size. Site type (OBO or random), size and their interaction, followed by agricultural soil suitability, had the greatest effects on grassland retention. During an era of accelerated grassland loss, OBO strongly and positively (statistically significant) affected conservation of grassland sites most at risk: sites <12 ha in size and with good to excellent agricultural soils. This suggests that grassland conservation efforts focus on vulnerable sites (small size and/or good agricultural soils) to provide nesting habitat for Burrowing Owls. Our study demonstrates that a voluntary stewardship program can significantly increase conservation of habitat.
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Effectiveness of Voluntary Habitat Stewardship in Conserving Grassland: Case of Operation Burrowing Owl in Saskatchewan
Environmental Management, 2004Co-Authors: Robert G. Warnock, Margaret A. SkeelAbstract:There have been no published performance evaluations of nongovernmental, voluntary habitat stewardship programs. The Operation Burrowing Owl (OBO) stewardship program, initiated in 1987, was evaluated for its effectiveness in conservation of grassland habitat during 1986–1993. The 108 OBO sites from 1987 to 88 and 98 randomly selected non-OBO sites that were grassland in 1986 in the Regina-Weyburn, Saskatchewan study area were classified by size and agricultural soil suitability. By 1993, 41 (38%) of the 108 OBO sites had been withdrawn from the program. The 1986 area of grassland was compared with grassland area calculated from digitized 1993 LANDSAT imagery. A correction for satellite inaccuracies was determined. Grassland retention in 1993 was significantly higher at OBO sites (66%) than at random sites (49%), demonstrating that the OBO voluntary program effectively conserved habitat. Also, grassland retention was significantly lower on sites with better agricultural soils, and for sites
Troy I Wellicome - One of the best experts on this subject based on the ideXlab platform.
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Evaluating cropland in the Canadian prairies as an ecological trap for the endangered Burrowing Owl Athene cunicularia
Ibis, 2019Co-Authors: Corey A. Scobie, Erin M. Bayne, Troy I WellicomeAbstract:Anthropogenic development may influence the choices animals make and their resulting reproductive success and survival. If such choices are maladaptive, the impact of anthropogenic change can be catastrophic to small or declining populations. Over the past century, Canada's prairie landscapes have been altered dramatically, with over two‐thirds of its native grasslands now having been converted to cropland. The decline of the endangered Burrowing Owl Athene cunicularia population is assumed to have resulted from this landscape change, yet no causal link has been demonstrated. One hypothesis to explain this population decline is that Owls get caught in an ecological trap, whereby they prefer to establish nests at the start of each breeding season in landscapes that later confer lower reproductive success. Agricultural landscapes represent a plausible potential ecological trap because the short and sparse vegetation in annual crops (seeded each spring) is predicted to be attractive nesting/foraging habitat for Burrowing Owls when they arrive from northward migration, yet crops become substantially taller and denser over the growing season so prey are predicted to become less accessible by the time broods have hatched. We tested this ecological trap hypothesis in a 3‐year study, involving 379 Burrowing Owl pairs, across the agricultural landscapes of southern Alberta and Saskatchewan. In support of the hypothesis, Burrowing Owls did prefer to settle in breeding home‐ranges that contained a higher proportion of cropland, and their prey‐delivery rates during brood‐rearing were lower at nests with a higher proportion of cropland growing in the surrounding landscape. However, in contradiction to a key prediction, the number of fledglings produced (range = 0–9) was higher, not lower, for pairs with more actively growing cropland in their landscapes. Therefore, the decline of the Burrowing Owl in Canada does not appear to result from cropland forming an ecological trap during the breeding season. We also found a significant positive relationship between the amount of summer fallow within Burrowing Owl home‐ranges and the quantity of vertebrate prey delivered to the nest and the number of juveniles fledged, highlighting the importance of this declining land use in raptor conservation.
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Influence of anthropogenic features and traffic disturbance on Burrowing Owl diurnal roosting behavior
Endangered Species Research, 2014Co-Authors: Corey A. Scobie, Erin M. Bayne, Troy I WellicomeAbstract:Birds that forage nocturnally should select daytime roosts that minimize predation risk to themselves, maximize their ability to warn mates or young about predators, and reduce their exposure to inclement weather. The objective of this study was to identify landscape features used by Burrowing Owls Athene cunicularia hypugaea during the day and to determine if traffic disturbance altered patterns of daytime space use. We tracked 17 adult male Owls for 0.6 to 2.8 d each with GPS dataloggers and used resource utilization and resource selection functions to examine the response of each Owl to nest burrows, perches, and roads. Selection for roads de - creased as average vehicle speed increased. Roads with vehicle speeds > 80 km h −1 were avoided. Owls may avoid roads with high traffic speeds because auditory disturbance from passing vehi- cles interferes with their ability to communicate the presence of predators to their mates and young. Owls also spent more time near fences and posts, likely because these elevated perches are good vantage points for predator detection. Perches near Burrowing Owl nests should be main- tained, and speed limits on roads near Burrowing Owl nests should be set to
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influence of anthropogenic features and traffic disturbance on Burrowing Owl diurnal roosting behavior
Endangered Species Research, 2014Co-Authors: Corey A. Scobie, Erin M. Bayne, Troy I WellicomeAbstract:Birds that forage nocturnally should select daytime roosts that minimize predation risk to themselves, maximize their ability to warn mates or young about predators, and reduce their exposure to inclement weather. The objective of this study was to identify landscape features used by Burrowing Owls Athene cunicularia hypugaea during the day and to determine if traffic disturbance altered patterns of daytime space use. We tracked 17 adult male Owls for 0.6 to 2.8 d each with GPS dataloggers and used resource utilization and resource selection functions to examine the response of each Owl to nest burrows, perches, and roads. Selection for roads de - creased as average vehicle speed increased. Roads with vehicle speeds > 80 km h −1 were avoided. Owls may avoid roads with high traffic speeds because auditory disturbance from passing vehi- cles interferes with their ability to communicate the presence of predators to their mates and young. Owls also spent more time near fences and posts, likely because these elevated perches are good vantage points for predator detection. Perches near Burrowing Owl nests should be main- tained, and speed limits on roads near Burrowing Owl nests should be set to <80 km h −1 to help ensure Owls are able to effectively detect and react to predators.
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does doramectin use on cattle indirectly affect the endangered Burrowing Owl
Rangeland Ecology & Management, 2008Co-Authors: Kevin D. Floate, Geoff Holroyd, Ray G Poulin, Patrice Bouchard, Troy I WellicomeAbstract:Doramectin is one of several endectocide compounds widely used to treat nematode and arthropod pests affecting cattle. Insecticidal residues in dung of endectocide-treated cattle can reduce numbers of dung-breeding insects. Concerns have been raised that use of endectocides may adversely affect birds that rely on dung-breeding insects as food. However, these concerns have not been specifically addressed in previous studies. We performed two studies to collectively assess whether doramectin adversely affects Burrowing Owls (Athene cunicularia Molina), which are listed as ‘‘Endangered’’ in Canada. In the first study, insect emergence was monitored from dung of cattle treated with a recommended topical dose of doramectin. Experiments replicated in each of 3 yr showed residues reduce the number of insects developing in dung of cattle treated up to 16 wk previously. In the second study, we identified prey items from regurgitated pellets collected at 206 Burrowing Owl nests in southern Alberta and Saskatchewan, Canada. A total of 50 213 prey items were identified, of which 90% were invertebrates. Beetles (Coleoptera) comprised 54% of the total prey items, followed next in abundance by grasshoppers (Acrididae, 20%) and crickets (Gryllidae, 16%). Of the beetles, 1 381 specimens were identified as breeding in dung (mainly species of Aphodius, Canthon, Onthophagus). The dung beetles comprised an estimated 2.8% of the total prey items or 0.1% of total prey biomass. Results of the first study validate initial concerns that doramectin use can reduce numbers of insects breeding in dung of treated cattle. Results of the second study show reliance of Burrowing Owls on dung beetles is sufficiently low that use of doramectin on cattle is unlikely to appreciably affect the food supply of co-occurring Burrowing Owls.
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Report on the Western Burrowing Owl (Speotyto cunicularia) conservation workshop
1997Co-Authors: Geoffrey L. Holroyd, Troy I WellicomeAbstract:This workshop was convened to review the current status of the Western Burrowing Owl (Speotyto cunicularia hypugaea) in North America, to discuss means by which we can improve our knOwledge of this Owl, and to initiate conservation action to benefit the species.
