Robert J. Robel

Relationships between visual obstruction measurements and weight of grassland vegetation.

As part of a long-term study of greater prairie chicken (Typanuchus cupido pinnatus) ecology in northeastern Kansas (Slade et al. 1965; Robe& 1966; Watt, 1969), an attempt was made to correlate movements and locations of prairie chickens with habitat types. In order to accomplish this, the various habitat types on a 2,500-hectare grassland study area had to be described. Species composition alone could not provide all the information necessary to evaluate the habitat potential of a grassland for prairie chickens. Emlen (1956) indicated that vegetation screening efficiency and density were as important as species present in describing avian habitats. Specifically, Hamerstrom et al. (1957) stated that height and density of grass were “clearly more important to the prairie chickens than species composition.” Various optical means have been used to measure the height and density of vegetation (Wight, 1938; Webb, 1942; Mossman, 1955).

LOCATION AND SUCCESS OF LESSER PRAIRIE-CHICKEN NESTS IN RELATION TO VEGETATION AND HUMAN DISTURBANCE

Abstract Lesser prairie-chicken (Tympanuchus pallidicinctus) populations have declined rangewide, and one of the principal causes is thought to be low nest success. Little is known about the relationship of vegetation structure and human intrusion to lesser prairie-chicken nest location and success. We conducted our study from 1997 to 2002 in southwestern Kansas, USA, on 2 sand-sagebrush (Artemisia filifolia) prairie areas managed for livestock production. We determined apparent nest success (26%) for 200 of 209 lesser prairie-chicken nests located. Nest sites had taller grass, greater sand-sagebrush density, and higher visual obstruction than random locations in the surrounding prairie. We recorded the distances from nests to 6 anthropogenic features (wellheads, buildings, improved roads, unimproved roads, transmission lines, center-pivot irrigation fields) to determine whether the features were related to nest location and success. Sand-sagebrush habitat around 5 of 6 features (all except unimproved roads) was avoided for 80 m (wellheads) to >1,000 m (buildings) by nesting lesser prairie-chickens, but distances to the features were not substantial predictors of apparent nest success. Grass height, sagebrush plant density, and sagebrush height were the most important vegetation characteristics influencing nest success.

Effects of habitat on dickcissel abundance and nest success in conservation reserve program fields in Kansas

Declining avian populations in the Midwest have increased interest in various aspects of grassland habitats and their effects on grassland birds. We studied the effects of vegetation characteristics, woody field edges, and surrounding land use on abundance and daily nest survival of the dickcissel (Spiza americana) in Conservation Reserve Program (CRP) fields in northeastern Kansas. We observed 873 dickcissels during surveys on 11 CRP fields during the summers of 1994 and 1995. In those fields, we located 186 dickcissel nests of which 13.2% were successful in 1994 and 14.9% were successful in 1995. The vertical density of vegetation in CRP fields, wooded area surrounding the fields, and amount of woody edge bordering fields were associated with dickcissel abundance (P = 0.001). Live and dead canopy cover and litter cover were associated with daily nest survival (P = 0.005). Therefore, the habitat quality of CRP fields for dickcissels might be enhanced by modifying vegetation characteristics. The outcome of any modifications of CRP habitat for dickcissels should be judged on changes in the number and success of their nests rather than on the abundance of birds.

Greater Prairie Chicken Ranges, Movements, and Habitat Usage in Kansas

Telemetry equipment was used to track 70 (34 males, 31 females, and 5 unsexed) individual greater prairie chickens (Tympanuchus cupido pinnatus) in northeastern Kansas. A total of 3,214 locations was recorded and 2,229 successive days of location data were obtained during 1964-1968. These data were used to calculate ranges of individual birds, and the distances between locations of birds on successive days were used to determine movement activity. Between 1966 and 1968, a total of 2,019 locations of 49 of the 70 birds (26 males and 23 females) was analyzed according to habitat usage. Ranges of birds were > 200 acres during the late summer and < 500 acres during fall and spring. Adult cocks exhibited the largest monthly range (1,267 acres) in March and the smallest (79 acres) in August. Ranges of juveniles were similar to those of adult males. Movement data reflected the same trends as did the range data. Occasional inter-booming ground movements were recorded for both males and females. Extensive movements (2.7-6.7 miles) of juveniles during October and November may represent population dispersal and may serve as a population regulatory mechanism. Attempts to correlate vegetation density with seasonal changes in habitat usage were futile. The shallow range site was used more by prairie chickens than were the limestone breaks and claypan vegetation complexes on the study area. Use of booming grounds was greater in spring and use of grain sorghum fields extensive in winter. Intensive use was made of booming ground areas in the morning, limestone breaks range site in midday, and wheat and oats fields in evening. At one time the greater prairie chicken was the leading upland game bird of the grasslands of central North America. Today it provides hunting in only a few areas. Even though this bird provides limited hunting opportunities and its range has been considerably reduced in recent years, the greater prairie chicken has continued to 1 Contribution No. 1056 Division of Biology, Kansas Agricultural Experiment Station, Kansas State University, Manhattan, 66502. 2Present address: Extension Service, Colorado State University, Glenwood Springs, 81601. 3 Present address: 11519 W. 61st Place, Arvada, Colorado 80002. 4Present address: Department of Zoology, Southern Illinois University, Carbondale, 62901. 5 Present address: Arizona Cooperative Wildlife Research Unit, University of Arizona, Tucson, 85721. 6 Present address: Minnesota Department of Conservation, Warroad, 56763. 286 receive the attention of several biologists. The literature contains more reports of studies conducted on remnant rather than large greater prairie chicken populations; Hamerstrom (1939), Schwartz (1945), Hamerstrom and Hamerstrom (1949 and 1955), Hamerstrom et al., (1957), Ammann (1957), Yeatter (1943), and Berger et al. (1963) to mention but a few. To obtain basic data from a large, stable population of greater prairie chickens, an extensive research program was initiated in northeastern Kansas in 1964. The determination of home range sizes and mobility patterns were two primary objectives of the original research. This paper presents data on greater prairie chicken home range and mobility gathered between 1964 and 1968. A habitable range for greater prairie This content downloaded from 157.55.39.92 on Wed, 22 Jun 2016 07:02:07 UTC All use subject to http://about.jstor.org/terms PRAIRIE CHICKEN HABITAT AND MOVEMENTS * Robel et al. 287 chickens is almost invariably defined as an extensive grassland area. Areas of extensive grasslands in the prairie regions of central North America have decreased in recent years and thus, suitable habitat for greater prairie chickens has experienced considerable attrition (Aldrich 1963:537). Much has been written about the reduction of range originally occupied by greater prairie chickens (Bennitt and Nagel 1937: 48, Schwartz 1945:90, Mohler 1952:9, Christisen 1967:182). The reduction of habitat has caused increased interest in habitat studies of greater prairie chickens (Jones 1963). To better understand habitat requirements of greater prairie chickens in a central portion of their range, bird location data from radio-tagged birds in northeastern Kansas were analyzed for habitat usage. The authors are indebted to John and the late Grover Simpson, owners of the property on which this study was conducted, for unlimited cooperation during the course of the study. This study was supported in part by grants from the National Institutes of Health, National Science Foundation, and the Penrose Fund of the American Philosophical Society.

Relationships between Husbandry Methods and Sheep Losses to Canine Predators

In this study we evaluated the efficacy of several husbandry methods in reducing sheep losses to coyotes (Canis latrans) and dogs. Findings are considered applicable to most sheep operations managed under farm-flock conditions. We monitored sheep losses of 109 producers monthly in a 9-county area of south central Kansas to assess husbandry effects. Cooperators reported deaths of 1,362 stock sheep and 2,230 lambs during the 15-month study, 229 (17%) and 278 (12%) of which, respectively, were killed by canine predators. Total annual losses of stock sheep and lambs were 6.7 and 7.9%, respectively; annual loss to predators was <1%. More than 80% of the predator-caused sheep deaths were in flocks of 22% of the producers. Sheep losses were slightly higher where coyote-abundance indices were high. Husbandry techniques that have the potential to significantly reduce sheep losses to canine predators include night confinement, lighting corrals, fall lambing, proper disposal of sheep carcasses, and killing individual predators that cause sheep losses. J. WILDL. MANAGE. 45(4):894-911 Coyote predation on sheep has been considered a major problem by stockmen of the western United States since the mid-1800s. Through the 1960s, efforts were made to reduce losses of sheep to coyotes by reducing coyote numbers by trapping, poisoning, shooting, and den hunting (Wagner 1972). Attitudes of the public toward predator control changed during the 1960s. Toxicants for predator control were banned on Federal lands (Nixon 1972), and later completely banned when the U.S. Environmental Protection Agency cancelled registrations of all predacides. Sodium cyanide was reregistered for use in the M-44 device under controlled conditions. Recent studies have focused on nonlethal methods of coyote control, including tasteaversion conditioning and olfactory repellents. Several authors have suggested husbandry methods that might reduce losses of sheep to coyotes: fencing (Shelton 1973, Thompson 1976), lights (Gier 1968), bells (Hawbecker 1939), dogs (Howard 1974), confinement at night (Gier 1968) and during lambing (Early et al. 1974a,b), and proper disposal of sheep carcasses (Boggess 1975). Few studies have been conducted to determine the relative efficacy of these methods. This study evaluated the efficacy of several sheep-husbandry methods in reducing losses of sheep to coyotes in Kansas. We acknowledge the assistance of the cooperating Kansas sheep producers who made this study possible. The study was financed by the Kansas Agricultural Experiment Station and the National Audubon Society.

Age‐Specific Survival and Probable Causes of Mortality in Female Lesser Prairie‐Chickens

Abstract Long-term population declines and habitat reductions have increased concern over the status of the lesser prairie-chicken (Tympanuchus pallidicinctus). Robust estimates of demographic parameters are essential for identifying population declines and planning effective management. We evaluated the effects of age and season on the survival of female lesser prairie-chickens at 2 sites in southwestern Kansas, USA. Using telemetry data from a 7-year field study (from 1997 to 2003), we estimated seasonal (Apr–Sep) and annual (Apr–Mar) survival. We also examined daily survival rates of females attending nests during the 26-day incubation period and young during the 14-day early brood-rearing period. We evaluated the probable mortality causes of radiomarked birds by examining evidence at recovery sites. We captured 227 female lesser prairie-chickens (87 yearlings, 117 ad, and 23 age undetermined) and fitted them with radiotransmitters. Estimates of 12-month survival were lower among yearlings (Ŝ12 = 0.429, SE = 0.117) and adults at site I (Ŝ12 = 0.302, SE = 0.080) than among yearlings (Ŝ12 = 0.588, SE = 0.100) and adults at site II (Ŝ12 = 0.438, SE = 0.083). The patterns in timing of mortality and age-specific 6-month survival were consistent with those of 12-month estimates at site I from 1998 to 2002, with a peak in mortality during May and June. Females tending to nests or to prefledged chicks had lower daily survival (DŜRtend = 0.993, SE = 0.001) than females not involved in these activities (DŜRfailed-breeder = 0.997, SE = 0.002). We recorded 92 mortalities from April 1997 to March 2003, and 59% and 11% were attributed to predation by mammals and raptors, respectively. Our research suggests that predation during the nesting season can have a major impact on lesser prairie-chicken demography, and conservation efforts should focus on enhancing female survival during the nesting and brood-rearing seasons.

Possible Role of Behavior in Regulating Greater Prairie Chicken Populations

This paper presents data on reproductive behavior gathered during a 5-year study of greater prairie chickens (Tympanuchus cupido pinnatus) in northeastern Kansas. Data were collected by direct observation and by radio-telemetry on a 6,000-acre study area. Numbers of male prairie chickens on booming grounds decreased between March and May each year. Only about 50 percent of the males were territory-owners on booming grounds during the peak of mating activity. The fate of the non-booming males was unknown. Aggressive behavior was evident in groups of females visiting booming grounds during the height of the mating season. Dominant females prevented or at least delayed the mating of subordinate females. Three instances of greater prairie chicken renesting were observed; one bird renested twice. There were two peaks of mating activity, the second may have reflected renesting activity. Success of six nests begun before May 1 was 66 percent while that for 13 nests begun after May 1 was only 8 percent. Inter-booming ground movements of both males and females indicated that booming ground areas could not be considered separate gene pools. Courtship display patterns of male greater prairie chickens have been extensively described (Breckenridge 1929, Hamerstrom 1941, Schwartz 1945, Hamerstrom and Hamerstrom 1960, Robel 1964). Essentially no data are available on the preand postnesting behavior of female greater prairie chickens. During an intensive study of prairie chickens in Kansas, data were acquired which may be helpful in determining the role of behavior in population dynamics of 1Contribution No. 1059 Division of Biology, Kansas Agricultural Experiment Station, Kansas State University, Manhattan, 66502. prairie chickens. This paper presents some pertinent behavioral data collected between 1964 and 1968. I am indebted to J. Cebula, N. Silvy, C. Viers, and P. Watt, former graduate students at Kansas State University, who assisted in collecting much of the data presented in this paper. John and the late Grover Simpson, owners of the property on which this study was conducted, provided unlimited cooperation. This study was supported in part by grants from the National Institutes of Health, National Science Foundation, and the Penrose Fund of the American Philosophical Society. This content downloaded from 157.55.39.112 on Wed, 29 Jun 2016 05:33:20 UTC All use subject to http://about.jstor.org/terms REGULATION OF PRAIRIE CHICKEN POPULATIONS * Robel 307

Avian Abundance in CRP and Crop Fields during Winter in the Midwest

Abstract We compared the abundance and species composition of birds in Conservation Reserve Program (CRP) fields with the same aspects in row-crop fields during the winter (January and February) over several years (1992–1995) for six midwestern states (Indiana, Iowa, Kansas, Michigan, Missouri and Nebraska). Field techniques were standardized in all states. CRP fields consisted of either permanent introduced grasses and legumes (CP1) or permanent native grasses (CP2), and the plant species seeded in CRP fields differed within and among states. Vegetation characteristics of CRP fields varied considerably from state to state, but vertical density and total canopy cover (primarily grasses) were particularly high in Nebraska. Mean annual total bird abundance ranged from 0.1 to 5.1 birds per km of transect in CRP fields and from 0.1 to 24.2 in row-crop fields. The total number of bird species recorded in CRP fields in the six states ranged from 6 to 32; the range for row-crop fields was 8 to 18. The most abundant species in CRP fields differed among states but included the ring-necked pheasant, American tree sparrow, northern bobwhite, dark-eyed junco and American goldfinch. The most abundant species in row-crop fields included the horned lark, American tree sparrow, European starling, mourning dove, lapland longspur, meadowlarks and Canada goose. Some of the most abundant bird species wintering on CRP fields have been undergoing long-term population declines, thus this program has the potential to mitigate population losses.

Booming territory size and mating success of the greater prairie chicken (Tympanuchus cupido pinnatus)

Summary Greater prairie chickens are social birds in which males gather and perform a group display on a mating area during the spring. On these mating areas (booming grounds) male birds establish territories. This study was initiated to determine the relationship between booming territory size and mating success of individual birds. Observations were made during fifty-three mornings at one booming ground in northeastern Kansas during 1964 and 1965. Exact locations for eight tagged males were determined at 15 min intervals during the period of study. From these location data, territories were determined for each marked male with concentric rings drawn to delineate areas of more intensive bird activity. Sixty-nine copulations were tabulated as a measure of mating success. Two males, both of which controlled large booming ground territories, accounted for 72·5 per cent of the matings observed during this study period. The size of the inner portion of the territory and the total territory size appear to be directly related to mating success in booming populations of greater prairie chickens.

SPRING BURNING : RESULTING AVIAN ABUNDANCE AND NESTING IN KANSAS CRP

Spring burning is used to control invasion by woody vegetation of rangelands in eastern Kansas and also of Conservation Reserve Program (CRP) fields planted to native grasses. We measured the effects of spring burning of CRP fields on vegetation structure and avian populations in northeastern Kansas during the summers of 1992 through 1995. Several vegetation characteristics differed between burned and unburned CRP fields in May, but few differed in July. Mean avian abundance on burned CRP fields was 5.6 birds km-1 of survey transect, significantly less (P < 0.01) than the 8.6 km-1 on unburned fields. The avian-assemblages on burned and unburned fields differed more in May/June [Morisitas Index to Similarity (MIS) = 0.86] than in June/July or July/August (MIS = 0.98 and 0.97, respectively). Avian species richness ranged from 12 to 21 on burned fields and from 10 to 19 on unburned fields. A total of 27 nests was found on burned fields, significantly less (P < 0.01) than the 372 found on unburned fields. The 22.2% nesting success on burned fields was not significantly different (P = 0.205) than the 34.1% success on unburned fields. Spring burning reduced bird-nest numbers in the summer of the same year, but did not reduce significantly (P = 0.235) the number of nests found in those fields the following summers nor the abundance of birds or nesting success. Avoidance of annual burning would reduce adverse impacts on bird populations relying on CRP fields for nesting habitat.