Movement Behavior of Radio-Tagged European Starlings in Urban, Rural, and Exurban Landscapes Page E

Human–Wildlife Interactions 14(3):398–408, Winter 2020 • digitalcommons.usu.edu/hwi

Movement behavior of radio-tagged European starlings in urban, rural, and exurban landscapes Page E. Klug, USDA, APHIS, Wildlife Services, National Wildlife Research Center, North Dakota Field Station, Department of Biological Sciences, North Dakota State University, Fargo, ND 58108, USA [email protected] H. Jeffrey Homan, USDA, APHIS, Wildlife Services, National Wildlife Research Center (retired), North Dakota Field Station, Department of Biological Sciences, North Dakota State Univer- sity, Fargo, ND 58108, USA

Abstract: Since their intentional introduction into the United States in the 1800s, European starlings (Sturnus vulgaris) have become the fourth most common bird species and a nuisance bird pest in both urban and rural areas. Managers require better information about starling movement and habit-use patterns to effectively manage starling populations and the damage they cause. Thus, we revisited 6 radio-telemetry studies conducted during fall or winter between 2005 and 2010 to compare starling movements (n = 63 birds) and habitat use in 3 landscapes. Switching of roosting and foraging sites in habitat-sparse rural landscapes caused daytime (0900–1500 hours) radio fixes to be on average 2.6 to 6.3 times further from capture sites than either urban or exurban landscapes (P < 0.001). Roosts in urban city centers were smaller (<30,000 birds, minor roosts) than major roosts (>100,000 birds) 6–13 km away in industrial zones. Radio-tagged birds from city-center roosts occasionally switched to the outlying major roosts. A multitrack railroad overpass and a treed buffer zone were used as major roosts in urban landscapes. Birds traveling to roosts from primary foraging sites in exurban and rural landscapes would often pass over closer-lying minor roosts to reach major roosts in stands of emergent vegetation in large wetlands. Daytime minimum convex polygons ranged from 101–229 km2 (x̄ = 154 km2). Anthropogenic food resources (e.g., concentrated animal feeding operations, shipping yards, landfills, and abattoirs) were primary foraging sites. Wildlife resource managers can use this information to predict potential roosting and foraging sites and average areas to monitor when implementing programs in different landscapes. In addition to tracking roosting flights, we recommend viewing high-resolution aerial images to identify potential roosting and foraging habitats before implementing lethal culls (e.g., toxicant baiting).

Key words: agriculture, concentrated animal feeding operations (CAFO), European starling, invasive species, radio-tracking, spatial ecology, Sturnus vulgaris, urban ecology, wildlife damage, winter roost

European starlings (Sturnus vulgaris; star- cause inordinate economic damage (Linz et al. lings; Figure 1) are a medium-sized, Old World 2018; Figure 2). Starling damage reported to passerine species introduced in the United the U.S. Department of Agriculture, Animal States in the late 1800s. The North American and Plant Health Inspection Service, Wildlife starling population was recently estimated at Services (USDA APHIS WS) averages <$2 mil- 140 million (Jernelöv 2017) and ranked fourth in lion USD per year, but this is a fraction of total the United States in total numbers tallied during damage (Homan et al. 2017). Agricultural dam- the 2018 North American Breeding Bird Survey age alone was estimated at nearly $1 billion per (Pardieck et al. 2019). Starlings are abundant and year in the United States (Pimentel et al. 2005). have exhibited a swift expansion throughout Other damage costs are unknown, including North America (Kessel 1953, Bodt et al. 2020), costs of cleaning and maintaining city centers, but they along with many other avian species loss of production and increased veterinary are exhibiting population declines in both their care at concentrated animal feeding opera- introduced and native ranges (Chamberlain et tions (CAFO), and public health care (Shwiff al. 2000, Rosenberg et al. 2019). Still, large con- et al. 2012). Starlings, rather than rock doves gregations of starlings at fall and winter roosts (Columba livia), may be the most economically result in flocks being drawn to foraging sites harmful bird species in the United States (Lowe in human-modified environments, where they et al. 2004). Movement behavior of European starlings • Klug and Homan 399

1,000 starlings using a CAFO for 60 days will eat about 1.5 tons of cattle feed, representing a loss of $200 to $400 (Homan et al. 2017); perhaps more importantly, starlings contaminate feed and nutritionally deplete mixed-rations, effectively reducing dairy cow (Bos taurus) performance and weight gains in beef livestock (Depenbusch et al. 2011, Medhanie et al. 2014, Carlson et al. 2017). Large flocks of starlings are correlated with poorer herd health (Carlson et al. 2011a, b, c; Carlson et al. 2015, 2020) and probably amplify and transmit pathogens within and among CAFO (Gaukler et al. 2012, Chandler et al. 2020). Figure 1. European starling (Sturnus vulgaris; Night roosts are likely point sources for patho- photo courtesy of U.S. Department of Agriculture, genic dissemination among CAFO (Swirski et Animal and Plant Health Inspection Service, Wild- life Services). al. 2014). Lastly, starlings cause damage to fruit crops (Conover and Dolbeer 2007, Anderson et al. 2013, Campbell et al. 2016) and are found in mixed flocks of blackbirds (Icteridae) damaging mature and sprouting grains (Stickley et al. 1976, Dolbeer et al. 1986). Understanding the movement behavior and habitat use of starlings associated with large fall and winter aggregations among different regions in the United States will inform the implementation of management strategies at landscape scales. We describe the distances traveled by starlings to forage and roost and the Figure 2. Flock of European starlings (Sturnus habitats used to fulfill these behaviors in 3 land- vulgaris) at a dairy (photo courtesy of N. Dunlop, scapes. Better information regarding differences U.S. Department of Agriculture, Animal and Plant in starling behavior among urban, exurban, and Health Inspection Service, Wildlife Services). rural landscapes may help wildlife managers adopt effective plans for managing pest birds Starlings are attracted to urban environments and address various human–wildlife conflicts because of anthropogenic foods and sheltered ranging from nuisance complaints and agricul- roosting sites (Peach and Fowler 1989, Clergeau tural damage to public health threats. and Quenot 2007). A city-center roost will number about 30,000 starlings spread out over several Study area buildings (Potts 1967). Urban roosts draw the We conducted 5 radio-telemetry studies at the most complaints because the roosts’ metabolic request of USDA APHIS WS state directors after wastes despoil buildings, city infrastructures, receiving nuisance complaints from the private and public amenities that affect the ambience sector. We completed a sixth study in conjunction and attractiveness of commercially active areas with an epidemiological study done through the (Bernardi et al. 2009). Starling roosts also cause Ohio Agricultural Research and Development public health issues including the increased risk Center, Food Animal Research Program (The of histoplasmosis, a respiratory fungal infection Ohio State University, Wooster Campus). We (Clark and McLean 2003). In rural areas, com- conducted 2 studies on night roosts in urban plaints about starlings arise because massive centers (Indianapolis, Indiana and Omaha, flocks, some in the hundreds of thousands, for- Nebraska, USA) and 4 studies at CAFO, includ- age on livestock feed at CAFO, particularly those ing dairies (Ohio, USA), beef feedlots (Texas with open feeder troughs (Glahn et al. 1983, and Kansas, USA), and a gamebird farm (New Homan et al. 2010, Gaukler et al. 2012). A flock of Jersey, USA; Homan et al. 2006, 2010; Gaukler et 400 Human–Wildlife Interactions 14(3)

Figure 3. A map of the 6 study sites across the United States used to evaluate the habitat use and movement behavior of European starlings (Sturnus vulgaris) during fall or winter between 2005 and 2010. The sites incorporated 2 studies at night roosts in urban centers (circles; Indianapolis, Indiana and Omaha, Nebraska) and 4 studies at concentrated animal feeding operations, including dairies (Ohio) and a gamebird farm (New Jersey) in exurban landscapes (diamonds) and beef feedlots (Texas and Kansas) in rural landscapes (squares). al. 2012; Homan et al. 2012, 2013; Figure 3). From based on the population size at multiple capture the total 17 capture sites used for radio tagging, sites (2–5) per study area. We aged and sexed we selected 2 roosting sites and 6 foraging sites the birds according to external characteristics for evaluation. We pooled locations (n = 7) from (Kessel 1951, Schwab and Marsh 1967, Smith 5 birds at the Indianapolis roost with 6 birds (n = et al. 2005), and the sex ratio of radio-tagged 12 locations) captured at a foraging site used by birds matched that of captured birds. We used most of the roost’s radio-tagged birds. We pooled spring-loaded box traps and hoop nets to cap- 2 foraging sites that were 1 km apart in the Ohio ture starlings at urban roosts and drop-in traps CAFO study because of high rates of exchange and mist nets at CAFO. We also used drop-in between radio-tagged cohorts. We selected the traps to capture urban starlings at foraging sites foraging site where the most birds were radio- with trappable populations, which were found tagged at the remaining 3 CAFO studies. through monitoring of radio-tagged birds. We assigned each of the 6 studies to the pre- We used very-high frequency radio transmit- dominant landscape of the study area (i.e., ters (mass with harness = 2.2 g; frequency range urban, rural, and exurban). We defined an exur- = 164.000 – 167.999 MHz; radio pulses = 40 min-1; ban landscape as an amorphous boundary lying warranted battery life = 50 days). The transmit- between suburban and rural landscapes. The ter was mounted on the anterior dorsal surface exurban landscapes were characterized by large of the bird’s fused pelvic region using a leg single-residence tracts surrounded by farms, harness made of 0.8-mm elastic beading cord fields, and recreational parks. We divided the 4 (Rappole and Tipton 1991; Figure 4). We fol- CAFO studies into rural (beef feedlots in Texas lowed the U.S. Geological Survey (USGS) Bird and Kansas) and exurban (dairy in Ohio and Banding Laboratory guidelines indicating the gamebird farm in New Jersey) landscapes. radio and harness pack must be ≤3% of body mass (i.e., starling mass >73 g). We released the Methods radio-tagged birds at the capture site immedi- Our target sample size was 50 radio-tagged ately after banding them on the left leg with a birds for each study, allocated proportionately, No. 2 USGS aluminum band. We collected radio Movement behavior of European starlings • Klug and Homan 401

strength, radio pulse, and decimal degree coordinates of the mobile unit. We self-entered a description of the location (e.g., residence, park, airport). If multiple fixes per bird were made on the same day, we required them to be sepa- rated by >1 hour for spatially independent fixes (White and Garrott 2012). Nighttime fixes on roosting birds consisted of a single fix >1 hour past local sunset. We cleaned the raw data generated from the Figure 4. European starling (Sturnus vulgaris) data recorder by culling false positives using being fitted with a radio-telemetry harness (photo ® courtesy of U.S. Department of Agriculture, Animal Visual Basic for Applications. We only used and Plant Health Inspection Service, Wildlife fixes obtained between 0900 and 1500 hours Services). and ≥1 km from the capture site because we wanted to focus on offsite daytime activities. frequency, capture date and site, mass, sex, We considered hours outside the 6-hour time leg-band number, and date and time of loca- frame as periods for transiting to and from tions for each bird. Birds not radio tagged were roosts (Homan et al. 2013). We measured the banded with a USGS leg band and released. We distances of mobile locations from the capture provided a minimum 2-day acclimation period sites using the haversine-distance formula or prior to collecting movement data. the great-circle distance between 2 points on a We used 2 mobile receiving units consist- sphere given longitudes and latitudes (Sinnott ing of a rotatable set of dual 6-element Yagi 1984). We discarded bearings emanating from antennas attached to an aircraft aluminum pole the direction of a capture site if <1 km. We mounted through the roof of a pickup truck imported the fixes into Google Earth® for iden- and cabled to a null-peak box, a data recorder, tification of habitat, distances to roosts and and global positioning system. We attached a foraging sites, and minimum convex polygons compass rose to the pole aligned to the North (MCP) of cohorts. The base map was a mosaic Magnetic Pole and used the antenna null to of high-resolution (1 m), digital orthoimage acquire bearings. The optimum line-of-sight quadrangles, with roadways. transmission range was 2–3 km, but field testing We used geographical coordinates of the showed ranges were generally ≤1 km (Homan urban roosts and CAFO capture sites as center et al. 2006). The mobile units were operated 5–7 points for measuring offsite distances to the days per week from 6–10 hours per day. Search respective foraging and roosting sites. We used routes included all drivable roads and trails in means (±SE) to describe average distances trav- the study area. An onboard PC-laptop with a eled, whereas means (±SD) were used for MCP Geographical Information System was used and distances from major (primary) and minor to store the mobile unit’s unique route, direc- (secondary) roosts to the most-used (primary) tional track, and geographical coordinates of foraging sites in the urban studies and vice prior detections. Search radii from capture sites versa in the CAFO studies. By the nature of our were 50 km in urban and exurban and 100 km study designs, the CAFO capture sites were pri- in rural landscapes. mary foraging sites (PFS), so we designated the We defined a valid radio-frequency signal next-most used foraging site as the PFS to those (fix) as the logging of ≥3 signals per minute capture sites. We used a 1-way analysis of vari- averaging ≥100 dBm in strength (maximum sig- ance (ANOVA) on ranked-transformed data to nal strength: 155 dBm). If signal strength was test differences P( ≤ 0.05) among landscapes in <130 dBm, we attempted to move closer to get a offsite average distance measurements between sighting on the bird or its flock. When multiple fixes and capture sites. We used Tukey-Kramer signals from the same frequency were received multiple comparisons to compare differences within 60 minutes, we used the strongest signal among landscape means with distance (single to determine the radio fix. The data recorder fix) or average distance (multiple fixes) of each stored the radio frequency, time, date, signal bird from its capture site. 402 Human–Wildlife Interactions 14(3)

Table 1. Movements and habitats used by 63 radio-tagged European starlings (Sturnus vulgaris) in 6 behavioral studies done between 2005 and 2010 in the United States. Movements included (1) average linear distance (km) between capture sites and geographic points where birds were detected between 0900 and 1500 hours, (2) linear distances (km) from primary (1⁰) and secondary (2⁰) roosts to primary foraging sites (PFS), (3) minimum convex polygons (km2) with (MCP+) and without (MCP) roosts, and (4) dominant habitat of the PFS. State Date Landscape Birds Radio Avg. 1⁰ Roosta 2⁰ Roost MCP+ MCP PFS fixes dist. ↔ 1⁰ ↔ 1⁰ habitatb (SE) PFS PFS IN Dec–Jan Urban 11 19 7 (3.2) 7 8c 131 116 LF NE Dec–Jan Urban 18 33 6 (3.6) 1 6c 229 229 AB NJ Dec–Jan Exurban 10 21 5 (3.7) 34 6 485 172 RT OH Sep–Oct Exurban 11 34 3 (3.3) 23 7 282 101 DA KS Dec–Feb Rural 11 61 19 (9.2) 13 6 273 146 GR TS Dec–Jan Rural 2 54 18 (1.4) 39 7 461 157 DA 63 222 10 (7.0) 20 7 310 154 aPrimary and secondary roosts were those attended by the largest and next largest populations, respectively. bPrimary foraging sites were those attracting the largest populations. In exurban and rural concentrated animal feeding operations (CAFO) studies, where the CAFO themselves were PFS, PFS represent those sites second in intensity of use. Abbreviations are as follows: LF = landfill, AB = abattoir, RT = residential tracts, DA = dairy, GR = granary. cSecondary roost was the capture site

Results scapes, primary roosts were >10 km (x̄ = 27 km, Movements SD = 11.6) from PFS with sizable variation in dis- Of 176 radio-tagged birds, 63 individuals (male tances (Table 1). In contrast, secondary roosts in = 31, female = 30, and unknown = 2) provided data all landscapes were <10 km (x̄ = 6 km, SD = 0.6) after passing our entry criteria. Linear distances from PFS with little variation. The average MCP traveled from capture sites during daytime activi- size was 154 km2 (SD = 45.3). The Ohio study, ties in rural landscapes (x̄ = 19 km, SE = 8.4, n = 2) conducted in early fall, had the smallest daytime were 2.6–6.3 times further than urban and exur- MCP (Table 1). The area of the daytime MCP ban landscapes (F2, 60 = 40.27, P < 0.001; Table 1). We doubled when we included locations of primary did not detect differences in distances traveled in roosts (MCP+; Table 1). urban and exurban landscapes (x̄ = 5 km, SE = 2.0, n = 4; P > 0.05). The greater distances traveled in Habitat use and food sources rural landscapes were primarily from birds using In urban landscapes, primary roosts were or switching to other feedlots 15–20 km from cap- under a multitrack railroad overpass and in ture sites; 19% and 10% of radio-tagged birds in a treed buffer zone surrounding an airport. the Kansas and Texas studies, respectively, tem- In exurban and rural landscapes, all primary porarily used or switched CAFO. roosts were in large wetlands (x̄ = 196 ha, SD = Both capture sites in urban landscapes were 89.7) with dense stands of emergent vegetation, secondary roosts (≤30,000 birds). These urban- including cattail (Typha spp.) and phragmites centered roosts averaged 9 km (SD = 4.9) from (Phragmites australis). Secondary roosts in urban primary roosts (≥100,000 birds) in outlying centers extended throughout downtown areas industrial zones with less public access. Radio- on building ledges and facades, fire escapes, tagged birds from urban-center roosts would monuments, decorative conifer plantings, sig- intermittently use the primary roosts. The- pri nage, and central air units atop multistoried mary roost in Omaha was only 1 km from the buildings. Expansive industrial structures (e.g., PFS; otherwise, distances between PFS and both power plants, refineries, and shipping-yard roost classes in urban landscapes were similar granaries) were also used as secondary roosts (x̄ = 7 km, SD = 1.0). In exurban and rural land- in urban and rural landscapes. In exurban land- Movement behavior of European starlings • Klug and Homan 403 scapes, we located starlings in numerous small ments on the outskirts of Akron, Ohio. The roosts (100–5,000 birds) scattered among barns, unique characteristics of the roost were likely the outbuildings, CAFO, and tree stands in parks, sole cause for it being preferred; the roost was residences, university grounds, and along large and had stable water depths and expan- roadways. sive emergent cover, making it more attractive Sources of directly or indirectly supplied than woodlot habitats, which were available anthropogenic foods were foci of PFS across all and used but at magnitudes far less than the landscapes. The PFS in urban landscapes were primary roost. The birds may have preferred the landfills and abattoirs (Table 1). Other lesser- wetland’s seclusion or perhaps derived some used sites were zoos, water treatment plants, thermal benefits from the aquatic roost. The grassy tracts of industrial and business parks, secondary roost was also a secluded, emergent- and shipping-yard granaries. All of these sites dominated wetland but was only 40 ha. This were <15 km from urban roosts. In exurban land- secondary roost held ≤30,000 birds and thus its scapes, CAFO were often PFS; lesser-used sites smaller area likely explained its status as a sec- included groomed lawns of residential tracts ondary roost. and business parks, fields, roadsides, and grassy Our observations of strong site fidelity for extents of airports, fairgrounds, and recreational specific CAFO indicates that morning - depar parks. In rural landscapes, most PFS were large, ture lines taken by roosting flocks to foraging open-troughed CAFO (≥5,000 head); lesser-used sites from primary and secondary roosts are not sites in rural areas were small towns and cities, random. However, we found birds did switch small CAFO (≤500 head), and granaries. CAFO foraging sites, which indicates some mixing of flocks at roosting sites, either prior to Discussion roosting (e.g., staging) or upon departure the We demonstrated that the distribution of next morning. In the Texas study, we followed food and roosting resources across landscapes the flightline emanating from the primary roost affected starling movements between foraging and never witnessed diverging flightlines for and roosting sites. The feedlot studies in Kansas the entire 40-km flight to the CAFO. However, and Texas were conducted in the Interior Plains a secondary roost (an abandoned refinery) 7 km physiographic region, known for its large away from the CAFO capture site supported sev- swaths of scrublands, grasslands, and grain- eral thousand birds and was used sporadically fields. These are not ideal habitats for wintering by 11 of our 20 radio-tagged birds. Thus, birds starlings, which have few foraging options but from our cohort probably followed birds from to use cities, towns, CAFO, and the industries this roost that were using another CAFO. In the serving CAFO (e.g., granaries). In the vastness Kansas study, radio-tagged birds that we cap- of the Interior Plains, CAFO used by starlings tured at another CAFO used the same primary lie far apart in comparison to the availability roost as members of our radio-tagged cohort. As of anthropogenic food resources in urban and in Texas, a few members of our cohort joined the exurban landscapes. flock that was using the unselected CAFO about Although strong fidelity was shown for major 20 km away and the nearby town of Great Bend, roosts as indicated by consecutive days of use Kansas, USA. The switching of CAFO has impli- per individual and overall use by cohorts, roost cations for distribution of bacterial and viral site choice was not rigid. Similarities in distances pathogens that impact herd health. Of the total from primary roosts to PFS in exurban and rural 51 birds radio tagged at the 2 CAFO in Kansas landscapes indicated starlings spent more time and Texas, 8 (16 %) established temporary or and energy to join primary roosts, usually pass- permanent residence at a feedlot different than ing over smaller secondary roosts. For example, the capture-site feedlot. With an average MCP+ in the Ohio study the distance between the of 367 km2 in rural landscapes, disease transmis- primary roosting site and the PFS was 23 km, sion among neighboring CAFO is likely. whereas the secondary roost was only 7 km Basically, no adventurism was displayed away. The primary roost was a phragmites- other than movement within the confines of dominated, 100-ha wetland in a wooded com- daytime MCP, which were small for birds plex of industrial sites and suburban develop- capable of flying 60–80 km/hour (Feare 1984). 404 Human–Wildlife Interactions 14(3)

For example in New Jersey, starlings continued composition (e.g., pasture) influences population to use the same foraging area, despite a switch density, nest box occupancy, reproductive success, to a less preferred food at the gamebird CAFO. foraging distances, and winter roost distribution Although starlings curtailed their use of the of starlings (Smith and Bruun 2002, Bruun and CAFO after a switch from high-protein meal to Smith 2003, Clergeau and Fourcy 2005, Heldbjerg whole kernel corn (Zea mays), they continued et al. 2016, Pfeiffer et al. 2019). Seasonal - varia foraging on nearby residential lawns, a habitat tion in temperatures may also influence move- capable of providing abundant prey resources, ment and habitat-use behaviors of starlings. We especially during a mild and open winter observed instances of starlings foraging in lawns, (Morrison and Caccamise 1985, Olsson et al. parks, fields, and roadsides during all studies, but 2002). This type of starling behavior, wherein a mostly in the New Jersey and Ohio studies. Given small-sized activity area is maintained and used we started the Ohio study in late September and consistently over time, has been observed pre- experienced a mild winter in New Jersey, star- viously in several different studies (Morrison lings were able to exploit foraging habitats that and Caccamise 1985, 1990; Caccamise 1991, would have otherwise been unavailable during 1993; Homan et al. 2013). Long-term use of colder periods. Starlings are omnivorous, with a small-sized areas may confer a survival advan- natural diet of invertebrates and wild fruits (Feare tage through increased foraging efficiency and 1984). A major portion of their invertebrate diet reduced predation (Tinbergen 1981, Caccamise consists of coleopteran (beetle) and lepidopteron and Morrison 1986). In some instances, it may (butterfly and moth) larvae foraged from soils have roots in a desire to remain near reproduc- (Fischl and Caccamise 1987). Starlings encounter- tive territories (Morrison and Caccamise 1985, ing harsher fall or winter conditions would have Caccamise 1993). In our study, the presence quickly lost access to soil invertebrates and wild of reliable anthropogenic food resources may fruits found in pastures, fields, and lawns, likely have also contributed to small activity areas. forcing them to expand their MCP to acquire reli- We do believe that the small-sized MCPs able sources of anthropogenic foods. Starlings are were not an artifact of inefficient sampling but attracted to sites where human-produced foods indeed a result of strong site fidelity (Caccamise are processed (e.g., distiller’s grain, suet, pet food, 1991). In the Ohio study, we traversed over and livestock feed). During colder periods, star- 8,500 km of roads, illustrating the intensive lings develop a preference for high-energy fatty nature of our searches for radio-tagged birds. foods, which are available at landfills and food The extent of our searches in Ohio far exceeded processing plants (Homan et al. 2011). starling movements and MCPs as evidenced Caccamise and Morrison (1988) hypothesized by minimal mixing of the cohorts from 5 cap- that large communal roosts develop over time ture sites. We only found the daytime mixing by passive convergence of individual flocks of cohorts at a maximum distance of 6 km. staging and foraging at sites adjacent to the roost Birds seldom visited dairies >5 km away from (“patch-sitting”). The birds gather at these sites the capture sites unless transiting to roosts, and because they are forced to forage outside the these visits were usually of short duration com- usual confines of their breeding home ranges pared to the time spent at the capture sites. In because of seasonal changes in food preference the New Jersey study where the average dis- from invertebrates to plant materials, the latter tance of all capture sites from the average of being unavailable in the diurnal home ranges. their geographical coordinates was 20 km, we However, the communal roost in Ohio did not did not observe interactions among cohorts at apparently develop by “patch-sitting,” poten- any of the capture sites (n = 3), alternate forag- tially due to various seasonal, agricultural, and ing sites, or secondary roosts. Thus, our study landscape differences between the Ohio study areas were effectively sampled by our mobile area and the New Jersey study area used by receiving units as evidenced by the lack of find- Caccamise and Morrison (1988). Those differ- ing intermingled cohorts during the daytime ences included an Ohio landscape with (1) high- (i.e., mingling of cohorts occurred at roosts and energy foods or supplemental feedings areas not foraging sites). provided at the dairies; (2) abundant inverte- Previous studies have shown how landscape brates on a heterogeneous landscape containing Movement behavior of European starlings • Klug and Homan 405 numerous dairy farms juxtaposed among large exurban areas) if starling populations are not pastures, extensive lawns of rural homes, hous- controlled (Zufiaurre et al. 2016). ing developments, and towns; (3) availability of maturing cultured and wild fruits in orchards Acknowledgments and roadsides; and (4) availability of corn, small We thank the U.S. Department of Agriculture, grains, and weed seeds in pastures and fields Animal and Plant Health Inspection Service, surrounding the dairy operations. Indeed, the Wildlife Services state directors, the USDA roosting behavior we observed was inverse APHIS WS National Wildlife Research Center of that observed by Morrison and Caccamise (NWRC), and the Ohio Agricultural Research (1985), where birds used a roost in rural habi- and Development Center, Food Animal tat and left to forage in suburban habitats. Research Program for their help and sup- Ultimately, the availability, distribution, and port of this research. We thank all of the many environmental and physical quality of roosting USDA-WS and NWRC personnel that worked sites combined with consistency in availabilities in the field with us. We thank the CAFO busi- of anthropogenic food resources are important ness owners and the city and business leaders factors in explaining fall and winter movements that allowed us access to their properties and and habitat use of starlings across all landscapes, buildings. The research was approved by the urban, exurban, and rural. USDA-APHIS-WS NWRC Quality Assurance (QA) in Fort Collins, Colorado under the fol- Management implications lowing protocols: QA-1324 (Omaha), QA-1413 Starling roosts in urban centers remain a (Indianapolis), QA-1464 (Ohio), QA-1592 (Texas), chronic problem in the United States because and QA-1695 (New Jersey) with H. J. Homan as of the lack of management options. Even if the the study director and QA-1414 (Kansas) with use of physical frightening agents (e.g., alarm G. M. Linz as the study director. Research was calls, pyrotechnics, and lasers) is feasible, their conducted under the U.S. Geological Survey efficacy is generally short-lived. Roosts that Master Banding Permit (#21672) and the U.S. develop on multistoried buildings in commer- Fish and Wildlife Scientific Collecting Permit cial districts are generally inaccessible, and (MB019065-4). Animal care and use procedures removal of starlings is complicated by proxim- were followed in accordance with USDA APHIS ity to heavily used public areas. In the Omaha, WS NWRC Institutional Animal Care and Use Nebraska study, we used radio telemetry to Committee guidelines. Any use of trade, firm, or find secluded areas where birds concentrated product names is for descriptive purposes only after departing the roost that could be used for and does not imply endorsement by the U.S. lethal control (i.e., Judas technique; Woolnough Government. Comments provided by G. Linz, et al. 2006). We avoided additional public HWI associate editor, and 2 anonymous review- encounters with sick or dead birds by collect- ers greatly improved a previous version of this ing carcasses early in the morning at the urban manuscript. roosts. Daily movement radii of birds in rural and exurban landscapes can be so large that Literature cited they include small towns, suburbs, and urban Anderson, A., C. Lindell, K. M. Moxcey, W. Siemer, areas. Resource managers should be aware of G. M. Linz, P. Curtis, J. Carroll, C. Burrows, this when conducting toxicant baiting (e.g., J. R. Boulanger, and K. Steensma. 2013. Bird DRC-1339) on starlings in these landscapes damage to select fruit crops: the cost of dam- for effective public notification of lethal- man age and the benefits of control in five states. agement activities (Homan et al. 2017). Small Crop Protection 52:103–109. activity areas also suggest that localized con- Bernardi, E., D. J. Bowden, P. Brimblecombe, H. trol of starlings may be achievable if immigra- Kenneally, and L. Morselli. 2009. The effect of tion is limited (Rollins et al. 2009, Campbell et uric acid on outdoor copper and bronze. Sci- al. 2016), but well-established populations can ence of the Total Environment 407:2383–2389. act as sources of individuals that disperse short Bodt, L. H., L. A. Rollins, and J. M. Zichello. 2020. distances into nearby favorable landscapes Contrasting mitochondrial diversity of Euro- (e.g., proliferation of human development in pean starlings (Sturnus vulgaris) across three 406 Human–Wildlife Interactions 14(3)

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