Progress 08/22/12 to 11/30/16
Outputs
Target Audience:
Nothing Reported
Changes/Problems:Dr. Grovenburg has left SDSU, submitting this report to terminate this Hatch project. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Dr. Grovenburg has left SDSU, submitting this report to terminate this Hatch project.
Publications
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:Target audience reached were federal agencies (i.e., USFWS), industry (i.e., energy companies), and wildlife/conservation biologists responsible for managing avian communities. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Completed thesis was delivered to USGS and USFWS. A manuscript has been submitted to the Journal of Wildlife Management and is currently under revision. What do you plan to do during the next reporting period to accomplish the goals?Complete revision of manuscript resulting in successful publicaiton of work.
Impacts
What was accomplished under these goals?
The Northern Great Plains (NGP) contains much of the remaining temperate grasslands, an ecosystem that is one of the most converted and least protected in the world. Within the NGP, the Prairie Pothole Region (PPR) provides important habitat for >50% of North America's breeding waterfowl and many species of shorebirds, waterbirds, and grassland songbirds. This region also has high wind energy potential, but the effects of wind energy developments on migratory and resident bird and bat populations in the NGP remains understudied. This is troubling considering >2,200 turbines are actively generating power in the region and numerous wind energy projects have been proposed for development in the future. Our objectives were to estimate avian and bat mortality rates for wind turbines situated in cropland- and grassland-dominated landscapes, document species at high risk to direct mortality, and assess the influence of habitat variables on waterfowl mortality at two wind farms in the NGP. From 10 March to 7 June 2013-2014, we completed 2,398 turbine searches for carcasses at the Tatanka Wind Farm (TAWF) and the Edgeley-Kulm Wind Farm (EKWF) in South Dakota and North Dakota. We found 92 spring turbine-related mortalities comprising 33 species and documented a greater diversity of species (n = 30) killed at TAWF than at EKWF (n = 9). After accounting for detection rates, we estimated spring mortality of 1.86 (SE = 0.22) deaths/MW at TAWF and 2.55 (SE = 0.51) deaths/MW at EKWF. Our spring mortality rates were similar to previously estimated yearly mortality rates in the Great Plains, suggesting that full-year mortality rates are higher at these wind farms than others in the region. We also observed a greater diversity of species killed at turbines located in grasslands when compared to turbines located in agricultural fields. Waterfowl spring (Mar-Jun) mortality rates were 0.79 (SE = 0.11) and 0.91 (SE = 0.10) deaths/MW at TAWF and EKWF, respectively. We used a Generalized Estimating Equation (GEE) to estimate the influence of landscape variables around individual turbines on waterfowl mortality and documented cropland to have a negative influence on mortality rates. Future wind facility siting decisions should consider avoiding grassland habitats and locate turbines in pre-existing fragmented and converted habitat outside of high densities of breeding waterfowl and major migration corridors.
Publications
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience: Target audience for this project is USFWS, state game agencies, public utilities commissions, wind energy companies, and avian biologists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Graduate student presented research at the Wind Wildlife Research Meeting X in Broomfield, Colorado. How have the results been disseminated to communities of interest? Graduate student presented research at the Wind Wildlife Research Meeting X in Broomfield, Colorado. Additionally, data has been presented to USFWS, SDGFP, and disseminated to two wind energy companies associated with the project. What do you plan to do during the next reporting period to accomplish the goals? Complete land cover modeling, finish thesis, publish results, present results at additional professional meetings and to other state game agencies.
Impacts
What was accomplished under these goals?
We completed 2,398 turbine searches and found 144 avifauna fatalities. We found carcasses ranging from 4 m to 72 m (35.12 ± 1.83 SE) from turbines. We excluded 52 carcasses from mortality estimates because they were either identified as non-turbine strike or non-spring migration mortality events. We used 52 carcasses for the 2013 data analysis and 40 carcasses for the 2014 data analysis. Carcasses were comprised of at least 33 species and included 57 (62.0%) waterfowl, 19 (20.6%) passerines, 5 (5.4%) waterbirds, 5 (5.4%) upland game birds, 4 (4.3%) shorebirds, and 2 (2.2%) bats. Forty eight (52%) carcasses were intact, 25 (27%) were considered scavenged, and 19 (21%) were dismembered. Detection rates remained fairly consistent between years but differed by size class of fatality and habitat type. For both farms over both years, the average large bird (>38cm) detection rate was 67% (0.06 SE) while the average small bird (<38cm) detection rate was 24% (0.05 SE). Before adjusting mortality estimates for detection biases, we estimated 2013-2014 spring mortality at TAWF as 84 and 87 birds/bats, respectively, and 39 and 21 birds/bats, respectively, at EKWF. After adjusting for detection rates, we estimated spring mortality at TAWF to be 303 birds/bats in 2013 and 171 birds/bats in 2014. Adjusted estimates for the EKWF were 62 birds/bats in 2013 and 52 birds/bats in 2014. The number of species killed at TAWF (n = 30) was greater than at EKWF (n = 9). Orders with the greatest magnitude of mortality included Anseriformes and Passeriformes. Species most commonly found included: mallard, northern pintail (A. acuta), and redhead (Aythya americana). We combined detection trials from both years at each wind farm to estimate partial-year mortality. Fresh carcasses were found starting in April of each year, with the exception of one carcass in 2013, and mortalities remained relatively constant throughout the remainder of the field searches (Figure 3, 4). We averaged the number of carcasses found in the last 10 weeks of field seasons and then extrapolated that number for the summer and fall migration period (31 weeks total; 1 Apr to 31 Oct) to estimate partial-year mortalities. We did not include winter months because fewer species are present in the area during this time and we did not identify these species as overly susceptible to turbine-related mortality based on turbine searches in March. We estimated partial-year mortality as 2.92 (SE = 0.36) deaths/MW/year at TAWF and 3.62 (SE = 0.78) deaths/MW/year at EKWF. Confidence intervals on both estimates overlap, thus mortality rates (deaths/MW) between the farms did not differ, even though TAWF is predominantly grassland and EKWF is row-crop agriculture. Within 1 km of the TAWF turbines, we found one northern harrier nest, one great horned owl nest, and one red-tailed hawk nest. We identified one red-tailed hawk nest and one unidentified raptor nest within 2 km. At 5 km, we identified three red-tailed hawk nests and one ferruginous hawk nest. While other nests were documented, we identified them as having no reproductive activity in either year (Figure 1). Only one nest (red-tailed hawk) was found in the area surrounding the EKWF (Figure 2). No mortalities to identified nesting raptors occurred during turbine searches in either year.
Publications
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Progress 10/01/12 to 09/30/13
Outputs
Target Audience: - Wind energy companies/utilities - USFWS - SDGFP - NDGF Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Results have been disseminated to USFWS, SDGFP, and NDGF. Results will be disseminated to wind energy companies/utilities after second field season. What do you plan to do during the next reporting period to accomplish the goals? Gather additional data during second field season. Finish analyses including modeling the influence of landscape variables on mortality. Publish manuscripts and finish thesis.
Impacts
What was accomplished under these goals?
We obtained access to 53 turbines at the Tatanka Wind Farm (TWF; 40 in North Dakota and 13 in South Dakota) and 16 turbines at the Edgeley-Kulm Wind Farm (EKWF) to conduct searches. We were unable to access many turbines toward the beginning of the season due to snow and toward the end of the season due to turbine repairs, grazing cattle, and heavy rainfall on planted fields. We surveyed 24 turbines daily, based on the time needed for 1.5 ha search grids. We searched 12 turbines at TWF daily and rotated 12 turbines among remaining turbines at TWF and EKWF. Our rotation was: Day 1 – search 12 daily turbines and 12 random turbines at TWF, Day 2 – search 12 daily turbines and 12 random turbines at TWF, and Day 3 – search 12 daily turbines at TWF and 12 random turbines at EKWF. We began searching turbines on 11 March. Although we completed scavenging trials as proposed, communication with K. Shawn Smallwood (Independent Environmental Services Professions, personal communication) changed our methodology and we discontinued the traditional scavenger and decomposition bias studies: “All that matters to a fatality rate estimate is the proportion of birds (or bats) that were killed but not found by the searchers. The relative contributions of searcher error and scavenger removal to this proportion is of no consequence to […] estimates, nor are these contributions quantifiable with any reasonable accuracy due to substantial, complex interactions between the two. Therefore, [place] fresh carcasses at random locations in the search areas at a rate of about 1 carcass per 3 to 4 MW per week on a randomized day of the week. The searchers either find the carcasses or they don't. The proportion found is [the] adjustment factor. Not only [are] the biases associated with the interactions between searcher error and scavenger removal [escaped], but the error terms [carried] in the fatality rate calculation lessens and the trial is much cheaper.” Since we searched a total of 24 turbines daily (1.5 MW each; total 36 MW), we placed 8 to 12 carcasses on the wind farms each week to be included in detection trials. This not only lessened the work load associated with checking multiple scavenging and decomposition trials, but allowed us a more accurate representation of the multiple biases (Smallwood 2013). We calculated search detection rates for non-raptors classified as small-bodied or large-bodied birds (Smallwood 2007, Smallwood and Thelander 2008). To estimate adjusted mortality, we used the following equation: Fa = Fu/D, where Fu is unadjusted fatality expressed as the number of fatalities per wind turbine per period or number of fatalities per MW of rated wind power capacity per period, D is the overall detection probability determined by searcher detection trials (K. S. Smallwood, personal communication). We calculated the standard error, (SE[Fa]), using the delta method (Goodman 1960): SE[Fa] = [(1/D x SE[Fu])2 + (Fu x -1/D2 x SE[D])2]1/2 We used raptor nesting density from companion studies concurrently conducted in the TWF-EKWF study area by several of the co-principle investigators to examine dependency between nesting density and raptor mortality. Home ranges for Swainson’s hawks (Buteo swainsoni), ferruginous hawks (Buteo regalis), red-tailed hawks (Buteo jamaicensis), great-horned owls (Bubo virginianus), and northern harriers (Circus cyaneus) vary considerably and few studies have been done in the Upper Great Plains to quantify home range size. We buffered the wind turbines by 1km, 2km, and 5km as conservative estimates of raptor home ranges in the study area (Figure 1). We are currently working on estimating species-specific mortality rates for both wind farms, as well as digitizing land use. National Agriculture Imagery Program (NAIP) satellite imagery with a resolution of 1 m taken in 2012 will be used and digitizing will be done at the 1:3000 scale. Each turbine will be buffered by 1,600 meters and land use labeled as crops, roads, trees, alfalfa, pasture, farmstead, hay land, or grass. Ground mapping has already been completed. RESULTS We complete 1,317 turbine searches from 11 March to 7 June 2013; 278 in March, 388 in April, 532 in May, and 119 during the first week of June. We did not conduct searches from 1–10 March because snow cover remained on the ground. We found 84 carcasses during the monitoring period (Table 1). Approximately 88% of these were collected during April (n = 40) and May (n = 34), while only 12% were found in March (n = 2) and June (n = 8). The highest proportion of carcasses were waterfowl (Anas spp.), including mallard (33.3%; A. platyrynchos), northern pintail (9.5%; A. acuta), gadwall (2.3%; A. strepera), blue-winged teal (2.3%; A. crecca), and northern shoveler (1.2%; A. clypeata). One carcass included feathers from two different species of birds. A raptor carcass also was collected and necropsy of remaining bones and feathers were indicative of a Buteo spp. Two carcasses were deemed unidentifiable. We completed 38 individual detection trials during the first year of the study; Most (n = 30) of the detection trials were located at TWF, where a majority of the turbine searches were completed. We found 11 of the 16 large-bodied carcasses included in the detection trials (detection rate of 0.69 ± 0.12 SE). Small birds were detected at a lower rate (2 out of 11 found; 0.14 ± 0.09 SE). Large (n = 4) and small (n = 4) birds placed at EKWF were detected at rates of 0.75 ± 0.22 SE and 0.50 ± 0.25 SE, respectively. We pooled detection rates for large birds on both farms because they were not statistically different (14 out of 20 were found; 0.70 ± 0.102). After adjusting estimates for searcher detection, we estimated that wind turbine collisions between the two wind farms killed 366 total birds (80% CI = 105-627) during spring migration and initial nesting periods (11 March to 7 June). We estimate 302 birds (80% CI = 78-526) were killed on the TWF, of which 76 (80% CI = 54-98) were large-bodied birds and 226 (80% CI = 24-428) were small-bodied birds. Estimates for the EKWF are 64 (80% CI = 27-101) total birds, including 33 (80% CI = 20-46) large-bodied birds and 31 (80% CI = 7-55) small-bodied birds. Only one nest (northern harrier) was found within 1 km of the turbines. One red-tailed hawk nest, one unidentified raptor nest, and 2 nests with no activity were found within 2 km. At 5 km, one ferruginous hawk nest, one unidentified raptor nest (possible red-tailed), and 4 nests with no activity were observed. No mortalities to identified nesting raptors occurred during turbine searches. Raptor nests were not documented around the EKWF.
Publications
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Progress 08/22/12 to 09/30/12
Outputs
Target Audience: US Fish and Wildlife Service Wind Energy Industry Landowners with wind tower easements SD Game, Fish and Parks ND Game and Fish Changes/Problems: Although we completed scavenging trials as proposed, communication with K. Shawn Smallwood (Independent Environmental Services Professions, personal communication) changed our methodology and we discontinued the traditional scavenger and decomposition bias studies: “All that matters to a fatality rate estimate is the proportion of birds (or bats) that were killed but not found by the searchers. The relative contributions of searcher error and scavenger removal to this proportion is of no consequence to […] estimates, nor are these contributions quantifiable with any reasonable accuracy due to substantial, complex interactions between the two. Therefore, [place] fresh carcasses at random locations in the search areas at a rate of about 1 carcass per 3 to 4 MW per week on a randomized day of the week. The searchers either find the carcasses or they don't. The proportion found is [the] adjustment factor. Not only [are] the biases associated with the interactions between searcher error and scavenger removal [escaped], but the error terms [carried] in the fatality rate calculation lessens and the trial is much cheaper.” What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? US Fish and Wildlife has been involved in the project on a weekly basis and is aware of all results. Other parties of interest will be fully briefed after the conclusion of the second field season. What do you plan to do during the next reporting period to accomplish the goals? Continue surveying turbines. Finish digitizing land cover maps. Complete analysis and begin writing publications and thesis. Present data to interested parties as well as the general public.
Impacts
What was accomplished under these goals?
We obtained access to 53 turbines at the Tatanka Wind Farm (40 in North Dakota and 13 in South Dakota) as well as 16 turbines at the Edgeley-Kulm Wind Farm. We were unable to access many turbines toward the beginning of the season due to snow and toward the end of the season due to turbine repairs, grazing cattle, and heavy rainfall on planted fields. We surveyed 24 turbines daily, based on the time needed for 1.5 ha search grids. We searched 12 turbines at Tatanka daily and rotated 12 turbines among remaining turbines at Tatanka and Kulm-Edgeley. Our rotation was: Day 1 – search 12 daily turbines and 12 random turbines at Tatanka, Day 2 – search 12 daily turbines and 12 random turbines at Tatanka, and Day 3 – search 12 daily turbines at Tatanka and 12 random turbines at Kulm-Edgeley. We began searching turbines on 11 March and completed 1,317 turbine searches; 278 during March, 388 during April, 532 during May, and the remaining 119 during the first week of June; field season ended 7 June. We found a total of 84 carcasses with most (88.1%) collected during April (n = 40) and May (n = 34); we found 2 and 8 carcasses in March and June, respectively. The majority of the carcasses were waterfowl, including mallard (33.3%) and northern pintail (9.5%). One ‘carcass’ included feathers from two different species of birds. Two carcasses were deemed unidentifiable. Although we completed scavenging trials as proposed, communication with K. Shawn Smallwood (Independent Environmental Services Professions, personal communication) changed our methodology and we discontinued the traditional scavenger and decomposition bias studies: “All that matters to a fatality rate estimate is the proportion of birds (or bats) that were killed but not found by the searchers. The relative contributions of searcher error and scavenger removal to this proportion is of no consequence to […] estimates, nor are these contributions quantifiable with any reasonable accuracy due to substantial, complex interactions between the two. Therefore, [place] fresh carcasses at random locations in the search areas at a rate of about 1 carcass per 3 to 4 MW per week on a randomized day of the week. The searchers either find the carcasses or they don't. The proportion found is [the] adjustment factor. Not only [are] the biases associated with the interactions between searcher error and scavenger removal [escaped], but the error terms [carried] in the fatality rate calculation lessens and the trial is much cheaper.” Since we searched a total of 24 turbines daily (1.5 MW each; total 36 MW), we placed 8 to 12 carcasses on the wind farms each week. This not only lessened the work load associated with checking multiple scavenging and decomposition trials, but allowed us a more accurate representation of the multiple biases (Smallwood 2013). We completed 38 individual detection trials. Most (n = 30) of the detection trials were located at Tatanka, where a majority of the turbine searches were complete. Of the 16 large birds placed, 11 were found (detection rate of 0.69±0.12 SE). Small birds were detected at a much lower rate (2 out of 11 found; 0.14±0.09 SE). Large and small birds placed at Edgeley-Kulm (n = 8) were detected at rates of 0.75±0.22 SE and 0.50±0.25 SE, respectively. Detection rates for large birds on both farms were not statistically different, so rates were combined (14 out of 20 were found; 0.70±0.102). We calculated search detection rates for non-raptors classified as small-bodied or large-bodied birds (Smallwood 2007, Smallwood and Thelander 2008). To estimate adjusted mortality, we used the following equation: Fa = Fu/D, where Fu is unadjusted fatality expressed as the number of fatalities per wind turbine per period or number of fatalities per MW of rated wind power capacity per period, D is the overall detection probability determined by searcher detection trials (K. S. Smallwood, personal communication). We calculated the standard error, (SE[Fa]), using the delta method (Goodman 1960): SE[Fa] = [(1/D x SE[Fu])2 + (Fu x -1/D2 x SE[D])2]1/2. After adjusting estimates for searcher detection, we estimated that wind turbine collisions between the two wind farms killed 260 total birds (80% CI = 194-325) during spring migration and initial nesting periods, 11 March through 7 June. On the Tatanka Wind Farm, we estimate 197 birds (80% CI = 136-258) total were hit, of which 76 (80% CI = 54-98) were large-bodied birds and 226 (80% CI = 24-428) were small-bodied birds. Estimates for the Edgeley-Kulm Wind Farm are 62 (80% CI = 37-86) total birds, including 33 (80% CI = 20-46) large-bodied birds and 31 (80% CI = 7-55) small-bodied birds. We used raptor nesting density from a companion study concurrently conducted in the study area by several of the co-principle investigators to examine dependency between nesting density and raptor mortality. Home ranges for Swainson’s hawks (SWHA), ferruginous hawks (FEHA), red-tailed hawks (RTHA), great-horned owls (GHOW), and northern harriers (NOHA) vary considerably and few studies have been done in the Upper Great Plains to quantify home range size. We buffered the wind turbines by 1km, 2km, and 5km as conservative estimates of raptor home ranges in the study area. Only one nest (NOHA) was found with 1km of the turbines. One RTHA, one unidentified raptor, and 2 nests with no activity were found when the radius was expanded to 2km. At 5km, one FEHA nest, one unidentified raptor (possible RTHA), and 4 nests with no activity were observed. No breeding raptor mortalities were found during turbine searches. Raptor nests were not documented around the Edgeley-Kulm Wind Farm. We are currently working on estimating species-specific mortality rates for both wind farms, as well as digitizing land use. National Agriculture Imagery Program (NAIP) satellite imagery with a resolution of 1m taken in 2012 will be used and digitizing will be done at the 1:3000 scale. Each turbine will be buffered by 1600 meters and land use labeled as crops, roads, trees, alfalfa, pasture, hay land, or grass. Ground mapping has already been completed.
Publications
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