Bat biologist with 26 years' experience. Specialize in acoustic monitoring and echolocation species identification, but publish natural history observations as well.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Warming climate has the potential to dramatically alter carbon and fire dynamics in high-latitude... more Warming climate has the potential to dramatically alter carbon and fire dynamics in high-latitude systems. Boreal and subarctic peatlands cover 346 million hectares of land surface and store 455 Pg-C, suggesting that changes in these systems can have regional and global-scale impacts on carbon cycling. Soil carbon release is expected to increase with more frequent fires in a warmer world.
The electricity potential from offshore wind in the United States is estimated to be more than 20... more The electricity potential from offshore wind in the United States is estimated to be more than 2000 gigawatts, roughly twice the nation's current total generation (Musail et al., 2016). Two wind farms are now in operation off the coasts of Rhode Island and Virginia (Figure 1), while 29 offshore wind farms are in varying stages of development in the United States (AWEA, 2020a), with a projected build-out of 30 gigawatts of offshore energy by the year 2030. The adverse effects of offshore wind generation on wildlife are generally acknowledged to be low relative to those of conventional electricity generation technologies (Allison et al., 2019; Gibson et al., 2017). However, adverse impacts are still possible, and understanding the ecological significance of these effects is
Quantitative methods for species identification are commonly used in acoustic surveys for animals... more Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.
The known distributions of eastern red bats and western red bats in western North America have ch... more The known distributions of eastern red bats and western red bats in western North America have changed greatly over the past 2 decades, resulting in inaccurate range maps and uncertainty regarding the presence or probable absence of these species within states and provinces. We obtained capture and specimen records from the western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.
Bats are found as fatalities at most wind energy facilities around the world, creating a challeng... more Bats are found as fatalities at most wind energy facilities around the world, creating a challenge for wind developers to predict risk to bats in an area before building a new facility. Bat echolocation activity surveys are the standard method for assessing risk, but their effectiveness has not been demonstrated. Sites with relatively low pre-construction bat activity rates are predicted to yield relatively low post-construction fatality rates (i.e., low risk), and vice-versa. To test this hypothesis, we ran simple linear regressions on bat activity rates and fatality rates from 49 paired pre- and post-construction studies across the United States and Canada. Bat activity rates did not predict bat fatality rates at wind energy facilities by detector height, by call frequency category of bats, or by season (P > 0.10). One possible explanation for the lack of a predictive relationship is that bat activity patterns may change between the pre- and post-construction periods if bats are attracted to turbines. Indeed, we found support that bat activity rates increased across call frequency category and season at four wind facilities that had measured bat activity rates before (x̄ = 1.89 bat passes/detector-night) and after turbines were built (x̄ = 4.84 bat passes/detector-night). However, simple linear regressions of post-construction activity rates and fatality rates from 25 studies found no correlation between activity and fatality rates collected concurrently by detector height (ground, raised, nacelle) or by call frequency category (P > 0.05). We conclude that the current pre-construction survey methods of collecting bat activity rates at proposed wind energy facilities do not provide reliable information on how many bat fatalities there may be once the facility is built, and advocate exploring other methods for assessing risk to bats prior to wind development.
The known distributions of eastern red bats and western red bats in western North America have ch... more The known distributions of eastern red bats and western red bats in western North America have changed greatly over the past 2 decades, resulting in inaccurate range maps and uncertainty regarding the presence or probable absence of these species within states and provinces. We obtained capture and specimen records from the western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.
Quantitative methods for species identification are commonly used in acoustic surveys for animals... more Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.
The costs and benefits of torpor may vary across the range of widespread heterothermic species, r... more The costs and benefits of torpor may vary across the range of widespread heterothermic species, resulting in different thermoregulatory patterns and other behaviours for individuals inhabiting different environments. We compared torpor use and roosting behaviour for rock-roosting populations of western longeared bats Myotis evotis living in the mountains and prairies of Alberta, Canada. We monitored body temperatures and located roosts for pregnant and lactating females using radio-telemetry. We also took roost measurements, and assessed roost microclimate using temperature dataloggers. Females in the mountains entered torpor less frequently and spent less time in torpor than bats in the prairies, supporting our hypothesis that reproductive time constraints in the mountains outweigh the benefits of torpor. Alternatively, increased torpor use in the prairies may be attributed to a greater need for water conservation. Females in the mountains minimized thermoregulatory costs and maintained homeothermy by selecting exposed roosts with warm microclimates during pregnancy, and then switching to clustering with other individuals during lactation when conditions were cooler. In the prairies, females roosted alone in cooler, less exposed roost types, which facilitate the use of torpor. Our results illustrate the importance of considering geographic variation in behaviour across the range of a species.
Entering torpor can yield significant energy savings for temperate-zone bats but can be costly fo... more Entering torpor can yield significant energy savings for temperate-zone bats but can be costly for reproductive females by slowing fetal development and reducing milk production. We studied western long-eared bats (Myotis evotis (H. Allen, 1864)) in the Rocky Mountains of Alberta to test the hypothesis that different costs of torpor result in different patterns of thermoregulation and roosting behaviour for reproductive and nonreproductive females. We radio-tracked bats to monitor body temperatures and locate roosts. We took roost measurements and inserted temperature data loggers to measure roost microclimate. Bats entered torpor frequently, but nonreproductive females spent longer periods in torpor, had lower minimum body temperatures, and entered deep torpor more often than reproductive females did, supporting the hypothesis that entering torpor is more costly for reproductive individuals. Roosts were located mainly in rock fields on steep, open, south-facing slopes. Reproductive females roosted in crevices between rocks located above or on the surface of the ground. Roosts warmed rapidly and reached warm daytime temperatures. Females roosted alone during pregnancy but formed small colonies within roosts during lactation when ambient conditions were cooler. Clustering may reduce ther- moregulatory costs for both adults and young. Nonreproductive females roosted mainly alone in crevices in the ground. These roosts had cooler, more stable microclimates, allowing females to enter deeper bouts of torpor and remain torpid longer.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Warming climate has the potential to dramatically alter carbon and fire dynamics in high-latitude... more Warming climate has the potential to dramatically alter carbon and fire dynamics in high-latitude systems. Boreal and subarctic peatlands cover 346 million hectares of land surface and store 455 Pg-C, suggesting that changes in these systems can have regional and global-scale impacts on carbon cycling. Soil carbon release is expected to increase with more frequent fires in a warmer world.
The electricity potential from offshore wind in the United States is estimated to be more than 20... more The electricity potential from offshore wind in the United States is estimated to be more than 2000 gigawatts, roughly twice the nation's current total generation (Musail et al., 2016). Two wind farms are now in operation off the coasts of Rhode Island and Virginia (Figure 1), while 29 offshore wind farms are in varying stages of development in the United States (AWEA, 2020a), with a projected build-out of 30 gigawatts of offshore energy by the year 2030. The adverse effects of offshore wind generation on wildlife are generally acknowledged to be low relative to those of conventional electricity generation technologies (Allison et al., 2019; Gibson et al., 2017). However, adverse impacts are still possible, and understanding the ecological significance of these effects is
Quantitative methods for species identification are commonly used in acoustic surveys for animals... more Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.
The known distributions of eastern red bats and western red bats in western North America have ch... more The known distributions of eastern red bats and western red bats in western North America have changed greatly over the past 2 decades, resulting in inaccurate range maps and uncertainty regarding the presence or probable absence of these species within states and provinces. We obtained capture and specimen records from the western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.
Bats are found as fatalities at most wind energy facilities around the world, creating a challeng... more Bats are found as fatalities at most wind energy facilities around the world, creating a challenge for wind developers to predict risk to bats in an area before building a new facility. Bat echolocation activity surveys are the standard method for assessing risk, but their effectiveness has not been demonstrated. Sites with relatively low pre-construction bat activity rates are predicted to yield relatively low post-construction fatality rates (i.e., low risk), and vice-versa. To test this hypothesis, we ran simple linear regressions on bat activity rates and fatality rates from 49 paired pre- and post-construction studies across the United States and Canada. Bat activity rates did not predict bat fatality rates at wind energy facilities by detector height, by call frequency category of bats, or by season (P > 0.10). One possible explanation for the lack of a predictive relationship is that bat activity patterns may change between the pre- and post-construction periods if bats are attracted to turbines. Indeed, we found support that bat activity rates increased across call frequency category and season at four wind facilities that had measured bat activity rates before (x̄ = 1.89 bat passes/detector-night) and after turbines were built (x̄ = 4.84 bat passes/detector-night). However, simple linear regressions of post-construction activity rates and fatality rates from 25 studies found no correlation between activity and fatality rates collected concurrently by detector height (ground, raised, nacelle) or by call frequency category (P > 0.05). We conclude that the current pre-construction survey methods of collecting bat activity rates at proposed wind energy facilities do not provide reliable information on how many bat fatalities there may be once the facility is built, and advocate exploring other methods for assessing risk to bats prior to wind development.
The known distributions of eastern red bats and western red bats in western North America have ch... more The known distributions of eastern red bats and western red bats in western North America have changed greatly over the past 2 decades, resulting in inaccurate range maps and uncertainty regarding the presence or probable absence of these species within states and provinces. We obtained capture and specimen records from the western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.
Quantitative methods for species identification are commonly used in acoustic surveys for animals... more Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.
The costs and benefits of torpor may vary across the range of widespread heterothermic species, r... more The costs and benefits of torpor may vary across the range of widespread heterothermic species, resulting in different thermoregulatory patterns and other behaviours for individuals inhabiting different environments. We compared torpor use and roosting behaviour for rock-roosting populations of western longeared bats Myotis evotis living in the mountains and prairies of Alberta, Canada. We monitored body temperatures and located roosts for pregnant and lactating females using radio-telemetry. We also took roost measurements, and assessed roost microclimate using temperature dataloggers. Females in the mountains entered torpor less frequently and spent less time in torpor than bats in the prairies, supporting our hypothesis that reproductive time constraints in the mountains outweigh the benefits of torpor. Alternatively, increased torpor use in the prairies may be attributed to a greater need for water conservation. Females in the mountains minimized thermoregulatory costs and maintained homeothermy by selecting exposed roosts with warm microclimates during pregnancy, and then switching to clustering with other individuals during lactation when conditions were cooler. In the prairies, females roosted alone in cooler, less exposed roost types, which facilitate the use of torpor. Our results illustrate the importance of considering geographic variation in behaviour across the range of a species.
Entering torpor can yield significant energy savings for temperate-zone bats but can be costly fo... more Entering torpor can yield significant energy savings for temperate-zone bats but can be costly for reproductive females by slowing fetal development and reducing milk production. We studied western long-eared bats (Myotis evotis (H. Allen, 1864)) in the Rocky Mountains of Alberta to test the hypothesis that different costs of torpor result in different patterns of thermoregulation and roosting behaviour for reproductive and nonreproductive females. We radio-tracked bats to monitor body temperatures and locate roosts. We took roost measurements and inserted temperature data loggers to measure roost microclimate. Bats entered torpor frequently, but nonreproductive females spent longer periods in torpor, had lower minimum body temperatures, and entered deep torpor more often than reproductive females did, supporting the hypothesis that entering torpor is more costly for reproductive individuals. Roosts were located mainly in rock fields on steep, open, south-facing slopes. Reproductive females roosted in crevices between rocks located above or on the surface of the ground. Roosts warmed rapidly and reached warm daytime temperatures. Females roosted alone during pregnancy but formed small colonies within roosts during lactation when ambient conditions were cooler. Clustering may reduce ther- moregulatory costs for both adults and young. Nonreproductive females roosted mainly alone in crevices in the ground. These roosts had cooler, more stable microclimates, allowing females to enter deeper bouts of torpor and remain torpid longer.
Uploads
Papers by Donald Solick
western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.
western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.