Introduction Barn owls (Tyto alba) are the most widely distributed species of owls in the World, but...
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Introduction Barn owls (Tyto alba) are the most widely distributed species of owls in the World, but their population is experiencing a decline in Pennsylvania. Habitat loss, followed by the structural change of foraging habitat from pasture to row crop for farming practices, negatively affects barn owl foraging, perching and nesting. In order to prevent population declines, suitable foraging and nesting habitats need to be preserved. Currently, very little is understood about the home range size and type of habitat used by foraging barn owls. For successful habitat and species conservation, local studies are needed to assess species-specific habitat requirements for Pennsylvania barn owls. Due to their nocturnal and secretive nature, information about local barn owl home ranges and foraging habitats is very limited. This project proposes the use of radio telemetry and GIS to determine the habitat size and type used by foraging barn owls. This information can then be used to create conservation planning polygons that identify suitable foraging habitats and determine appropriate home range size necessary for barn owls. Ultimately, the results from this study can be used in management and conservation efforts to ensure the barn owls’ continued survival in Pennsylvania. Review of Literature Habitat and nest site qualities are considered to be the most important factors in determining barn owl distribution, breeding success and diet (Bond et al. 2004). Availability of foraging habit (i.e., selected prey resources) should be considered the crucial limiting factor on barn owl populations (Colvin 1985). Bond et al. (2004) assessed the landscape mosaic and structure on the breeding success of barn owls using a landscape GIS approach. Their analysis was based on a six-year data set and results indicated landscape features that should be considered for barn owl habitat conservation. Successful sites had fewer patches of improved grassland and suburban land, a smaller proportion of wetlands, a more regular patch shape, and more homogeneity than unsuccessful sites (Table 1). 35.33 6.33 3.33 Woodland edges Hedge “headlands” Field crops Radio telemetry is needed to guarantee unbiased information on barn owl habitat selection (Taylor 1994). Taylor (1994) utilized radio telemetry to study the habitat selection of barn owls during the summer months in farmland habitats of Scotland. Edges around woodlands were strongly preferred (Figure 1). A strong preference for grassland and edge habitats has also been established from radio telemetry studies in several states of the U.S. including, New Jersey, Virginia, and Texas (Colvin 1984, Rosenburg 1986, and Byrd 1982). Previous studies have observed foraging patterns of adult barn owls (radio telemetry) or have assessed barn owl habitat quality (landscape GIS). However, no combination of these methods has been attempted. This proposal combines the use of radio telemetry and landscape GIS to asses both habitat type and home range size of foraging barn owls in Pennsylvania. Research Design Radio Telemetry Home Is Where The Heart Is: Understanding the Home Range and Habitat Use of Barn Owls (Tyto alba) in southeastern Pennsylvania Kathleen A. Kolos and Karl Kleiner Department of Biological Sciences, York College of Pennsylvania Objectives 1) What is the foraging range for nesting barn owl adults? 2) What type of habitat is used for foraging? Putting It All Together GIS Land Use Summaries •Created land use summaries using ArcGIS of proposed study site •Created 3km 2 home range buffer based on previous literature (Bond et al. 2004) •Used air-photo imagery to manually digitize and define land use polygons •Determined percentage of habitat types Literature Cited Bond, G., Burnside, N., Metcalfe, D., Scott, D., and Blamire, J. 2004. The effects of land-use and landscape structure on barn owl (Tyto alba) breeding success in southern England, U.K. Landscape Ecology 20: 555-566. Colvin, B. 1985. Common barn owl population declines in Ohio and the relationship to agricultural trends. Journal of Field Ornithology 56(3): 224-235. Taylor, I. 1994. Barn Owls: Predator-prey relationships and conservation. Cambridge University Press, Cambridge, U.K. Proposal The overlay of radio telemetry foraging data onto GIS land use summaries will allow researchers to create conservation planning polygons that identify suitable foraging habitats for preservation and determine appropriate home range size necessary for barn owls. Table 1. Differences in landscape variables between successful and unsuccessful nest site 3km 2 home range buffers (Bond et al. 2004) Habitat Parameter P value Mean (+/-1 sd)/median Successfu l Unsuccess ful Improved grassland Patches 0.023 9.81 (3.08) 11.47 (3.45) Improved grassland Perimeter: area 0.035 0.019 0.022 Wetlands Proportion 0.014 0.003 0.016 Figure 1. Average spot location of three radio- tagged foraging barn owls in enclosed farmland, Esk study area, south Scotland (Taylor 1994). Overlay location polygons onto land use summaries to analyze habitat use Choose a local study site in York County Fit a pair of breeding barn owls with backpack transmitters Record the nocturnal movements of the hunting owls using triangulation Create two-dimensional polygons of the owl’s locations GIS analysis showed that the proposed study nest site in York County was dominated by row crops, followed by woodlands as the most abundant habitat types. ^ ^ N estSite D eveloped Fallow M ow ed Field O pen C reek Area R ow C rop W ooded C reek Area Woodlands HabitatType A rea (ha) 33.5 37.63 41.08 114.49 297.4 401.36 1,926.01 Proportion of Habitat Type at Proposed Study Site Northern Saw-whet owl night activity at King’s Gap State Park, 2008. Location of a signal (LOAS) data is displayed. Habitat types of proposed York County study site, 3km 2 home range buffer displayed.
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Transcript of Introduction Barn owls (Tyto alba) are the most widely distributed species of owls in the World, but...
Introduction
Barn owls (Tyto alba) are the most widely distributed species of owls in the World, but their population is experiencing a decline in Pennsylvania.
Habitat loss, followed by the structural change of foraging habitat from pasture to row crop for farming practices, negatively affects barn owl foraging, perching and nesting. In order to prevent population declines, suitable foraging and nesting habitats need to be preserved.
Currently, very little is understood about the home range size and type of habitat used by foraging barn owls. For successful habitat and species conservation, local studies are needed to assess species-specific habitat requirements for Pennsylvania barn owls.
Due to their nocturnal and secretive nature, information about local barn owl home ranges and foraging habitats is very limited. This project proposes the use of radio telemetry and GIS to determine the habitat size and type used by foraging barn owls.
This information can then be used to create conservation planning polygons that identify suitable foraging habitats and determine appropriate home range size necessary for barn owls. Ultimately, the results from this study can be used in management and conservation efforts to ensure the barn owls’ continued survival in Pennsylvania.
Review of Literature
Habitat and nest site qualities are considered to be the most important factors in determining barn owl distribution, breeding success and diet (Bond et al. 2004). Availability of foraging habit (i.e., selected prey resources) should be considered the crucial limiting factor on barn owl populations (Colvin 1985).
Bond et al. (2004) assessed the landscape mosaic and structure on the breeding success of barn owls using a landscape GIS approach. Their analysis was based on a six-year data set and results indicated landscape features that should be considered for barn owl habitat conservation. Successful sites had fewer patches of improved grassland and suburban land, a smaller proportion of wetlands, a more regular patch shape, and more homogeneity than unsuccessful sites (Table 1).
35.33
6.33 3.33Woodland edges
Hedge “headlands”
Field crops
Radio telemetry is needed to guarantee unbiased information on barn owl habitat selection (Taylor 1994). Taylor (1994) utilized radio telemetry to study the habitat selection of barn owls during the summer months in farmland habitats of Scotland. Edges around woodlands were strongly preferred (Figure 1). A strong preference for grassland and edge habitats has also been established from radio telemetry studies in several states of the U.S. including, New Jersey, Virginia, and Texas (Colvin 1984, Rosenburg 1986, and Byrd 1982).
Previous studies have observed foraging patterns of adult barn owls (ra-dio telemetry) or have assessed barn owl habitat quality (landscape GIS). However, no combination of these methods has been attempted. This proposal combines the use of radio telemetry and landscape GIS to asses both habitat type and home range size of foraging barn owls in Pennsylvania.
Research Design
Radio Telemetry
Home Is Where The Heart Is: Understanding the Home Range and Habitat Use of Barn Owls (Tyto alba) in southeastern Pennsylvania
Kathleen A. Kolos and Karl KleinerDepartment of Biological Sciences, York College of Pennsylvania
Objectives
1) What is the foraging range for nesting barn owl adults?
2) What type of habitat is used for foraging?
Putting It All Together
GIS Land Use Summaries
•Created land use summaries using ArcGIS of proposed study site
•Created 3km2 home range buffer based on previous literature (Bond et al. 2004)
•Used air-photo imagery to manually digitize and define land use polygons
•Determined percentage of habitat types
Literature Cited
Bond, G., Burnside, N., Metcalfe, D., Scott, D., and Blamire, J. 2004. The effects of land-use and landscape structure on barn owl (Tyto alba) breeding success in southern England, U.K. Landscape Ecology 20: 555-566.
Colvin, B. 1985. Common barn owl population declines in Ohio and the relationship to agricultural trends. Journal of Field Ornithology 56(3): 224-235.
Taylor, I. 1994. Barn Owls: Predator-prey relationships and conservation. Cambridge University Press, Cambridge, U.K.
Proposal
The overlay of radio telemetry foraging data onto GIS land use summaries will allow researchers to create conservation planning polygons that identify suitable foraging habitats for preservation and determine appropriate home range size necessary for barn owls.
Table 1. Differences in landscape variables between successful and unsuccessful nest site 3km2 home range buffers (Bond et al. 2004)Habitat Parameter P value Mean (+/-1 sd)/median
Successful Unsuccessful Improved grassland Patches 0.023 9.81 (3.08) 11.47 (3.45) Improved grassland Perimeter: area 0.035 0.019 0.022 Wetlands Proportion (%) 0.014 0.003 0.016 Wetlands Perimeter: area 0.043 0.051 0.037 Suburban Patches 0.022 3.73 (2.54) 5.25 (3.13)
Figure 1. Average spot location of three radio-tagged foraging barn owls in enclosed farmland, Esk study area, south Scotland (Taylor 1994).
Overlay location polygons onto land use summaries to analyze habitat use
Choose a local study site in York County
Fit a pair of breeding barn owls with backpack transmitters
Record the nocturnal movements of the hunting owls using triangulation
Create two-dimensional polygons of the owl’s locations
GIS analysis showed that the proposed study nest site in York County was dominated by row crops, followed by woodlands as the most abundant habitat types.
^^ Nest Site
Developed
Fallow
Mowed Field
Open Creek Area
Row Crop
Wooded Creek Area
Woodlands
Habitat Type
Area (ha)
33.537.6341.08
114.49297.4
401.361,926.01
^ Nest Site
Developed
Fallow
Mowed Field
Open Creek Area
Row Crop
Wooded Creek Area
Woodlands
Habitat Type
Area (ha)
33.537.6341.08
114.49297.4
401.361,926.01
^ Nest Site
Developed
Fallow
Mowed Field
Open Creek Area
Row Crop
Wooded Creek Area
Woodlands
Land Type
Area (ha)
33.537.6341.08
114.49297.4
401.361,926.01
Proportion of Habitat Type at Proposed Study Site
Northern Saw-whet owl night activity at King’s Gap State Park, 2008. Location of a signal (LOAS) data is displayed.
Habitat types of proposed York County study site, 3km2 home range buffer displayed.
