Radiotelemetry Data Research Articles

Using Radio-Telemetry for Mark-Recapture Studies with Edge Effects

(1) Radio-telemetry provides a technique for estimating population abundance of species that move on and off a study plot during a survey period. (2) Monte Carlo simulations indicate that either a bias-corrected version of the 'mean Petersen' or a Petersen estimate based on the means of the observations may be suitable for estimating abundance from radio-telemetry data. (3) The proposed bias correction may make it possible to obtain useful abundance estimates for very small populations, given sufficiently high probabilities of marking and recapture.

Summer-Fall Survival of American Woodcock in Maine

We estimated summer-fall (15 Jun-20 Oct) survival for 32 adult and 96 fledged young American woodcock (Scolopax minor) radiotagged in eastern Maine during 1982-84 using single-interval, multipleinterval, and nonparametric (product-limit) methods. Single-interval survival estimates were 0.90, 0.88, 0.57, and 0.73 for adult males, adult females, young males, and young females, respectively. Multiple-interval survival estimates (0.93, 0.88, 0.63, and 0.71) and product-limit estimates were similar (0.92, 0.90, 0.60, and 0.69). Within each age class, male and female period survival was not significantly different for any method. However, point estimates of survival for young females exceeded those of young males by 0.08-0.16. Regardless of sex, adults exhibited higher summer-fall survival (range = 0.89-0.92) than young woodcock (range = 0.64-0.68). Age-specific variation in survival was caused by different predation rates that may be related to age-specific differences in mobility. The survival rates sustained by young woodcock during our study were similar to 4-month rates derived from annual survival estimates that assume constant mortality throughout the year. The high summer-fall survival estimates exhibited by adult woodcock suggest that most of their annual mortality occurs during another season. J. WILDL. MANAGE. 54(1):97-106 Because of the long-term decline of American woodcock in the eastern United States (Tautin et al. 1983) the U.S. Fish and Wildlife Service (USFWS) implemented woodcock harvest restrictions in 1985. Changes in habitat conditions, through forest succession and urbanization, are believed largely responsible for the decline (Dobell 1977, Coulter and Baird 1982, Dwyer et al. 1983). However, the exact mechanisms that have resulted in lower recruitment or survival remain largely unexamined. To define the relationship between woodcock survival and habitat conditions, information is needed on timeand causespecific mortality factors. Estimates of annual survival for American woodcock relied on return rates of breeding birds (Sheldon 1956, 1967), life tables (Godfrey 1974), or band recoveries from hunters (Martin et al. 1969, Krohn et al. 1974, Dwyer and Nichols 1982). Analysis of band recoveries is least biased with the development of band-return and markrecapture models (Brownie et al. 1978). However, precise estimates of annual survival of woodcock are difficult to obtain because of the large sample sizes required by banding models (Dwyer and Nichols 1982). Fortunately, application of more rigorous statistical methods used in conjunction with radio-telemetry data permit relatively unbiased time-specific survival estimates from studies of free-ranging animals (Mayfield 1961, 1975; Trent and Rongstad 1974; Ri gleman and Longcore 1983; Cowardin et al. 1985; Heisey and Fuller 1985; Kirby and Cowardin 1986; Kurzejeski et al. 1987; Pollock et al. 1989). Our objectives were to estimate ageand sex-specific survival of American woodcock from June to October and compare survival estimates among 3 statistical methods with differing assumptions on survival constancy within the study period. We acknowledge C. M. Bunck, S. R. Winterstein, and G. L. Hensler for statistical consultation and thank G. L. Storm, T. J. Dwyer, M. A. Howe, C. M. Bunck, J. R. Sauer, R. H. Yahner, and W. M. Tzilkowski for thoughtful reviews of the manuscript. Support was providby the Patuxent Wildlife Research Center, the Moosehorn National Wildlife Refuge, the Pennsylvania Cooperative Wildlife Research Unit, the Ruffed Grouse Society, and the National Rifle Association.

Movements and Temperatures of Radiotagged Salmonines in Lake Ontario and Comparisons with Other Large Aquatic Systems

Abstract We used six years of radiotelemetry data (1980–86) to compare movements and temperatures occupied by four introduced salmonine species (174 fish) in the nearshore region of Lake Ontario. Movement patterns (64% moved east initially with prevailing currents; 68% reversed direction one or more times), net movement rates (ave. −4.7 km/d), water temperatures occupied (ave. = 10.7 C) and harvest rates by anglers (ave. = 23% of radiotagged salmonines) were generally similar among species and seasons. However, Pacific salmon (coho, Oncorhynchus kisutch and chinook, O. tshawvtscha) moved against prevailing currents and were caught by anglers more often than brown trout (Salmo trutta) and rainbow trout (O. mykiss, formerly S. gairdneri). The movement patterns and thermal habitats of salmonines in Lake Ontario generally were in the mid-range of those reported for conspecifics in other large lakes and the North Pacific Ocean.

Dispersal Distance and the Range of Nightly Movements in Merriam's Kangaroo Rats

Lifetime dispersal distances in Merriam's kangaroo rat, Dipodomys merriami , ranged from 0 to 265 m in males and from 0 to 158 m in females. Radiotelemetry data on nightly movements detected males ≤146 m and females ≤123 m from home-range centers. Eighty-nine percent of lifetime dispersal distances and 96% of moves between consecutive censuses were within the radii of familiarity indicated by radiotelemetry. Most effective “dispersal” appears to occur as a series of shifts in centers of activity within familiar areas. Occasional excursions beyond the usual area of activity and frequent moves to new burrows may contribute to the ability of the D. merriami to shift home ranges. The traditional view of dispersal as high-risk movement into unfamiliar areas does not apply to effective dispersal in D. merriami . Neither is dispersal in this species described precisely by models in which investigators assumed that individuals move to the nearest vacant site at a particular age or season.

Survival of Wild Turkey Hens in North Missouri

Survival and cause-specific mortality of wild turkey (Meleagris gallopavo silvestris) hens were investigated in north Missouri during 1984-85. Survival estimates and distributions were calculated using the Kaplan-Meier product-limit method from a sample of 60 radio-marked hens. The annual survival rate was 0.435 ? 0.073. Predation and poaching were the major causes of mortality, accounting for 54.9 and 38.7% of the losses, respectively. Legal fall harvest was responsible for only 3.2% of the deaths and was considered a minor cause of mortality. Seasonal losses were highest during spring. Forty-two percent of the illegal hen kills occurred during the spring gobbler season. Survival probabilities with poaching or predation as the only source of mortality followed similar patterns. J. WILDL. MANAGE. 51(1):188-193 Wild turkey populations in the mixed timber-agricultural regions of the Midwest have been reported to exceed 30 birds/km2 of timber (Hanson 1984, Lewis and Kurzejeski 1984). Effective management of these populations requires quantitative data on hen turkey survival. Radio-telemetry data have been used to examine survival in reintroduced turkey populations (Swank et al. 1985), expanding turkey populations (Porter 1978), and indigenous turkey populations in the traditional southern range (Everett et al. 1980, Holbrook and Vaughan 1985). Data on survival rates and causes of turkey mortality are scarce, and estimates of hen wild turkey survival are lacking for established populations in the Midwest. Estimates of hen turkey survival are important in the formulation of fall harvest recommendations and as an indication of reproductive potential. Furthermore, determining seasonal and cause-specific survival provides inference as to the relative importance of natural, illegal, and where appropriate, legal harvest mortality. The objectives of this study were to determine annual and seasonal survival and causes of mortality for hen wild turkeys in north Missouri during March 1984-March 1985. We thank V. L. Kimmel for coordinating and conducting the fieldwork, and E. A. Keyser, J. S. Fleming, D. J. Neuswanger, and B. J. Otten for assistance in trapping turkeys. C. J. Scriven, M. E. Wade, C. Turner, E. R. Jayne, and numerous others provided access to their private lands that was essential in conducting this study. S. R. Winterstein, C. Bunck, and S. L. Sheriff provided assistance with data analyses. Partial funding for this study was provided by the Mo. State Chapter and various local chapters of the Natl. Wild Turkey Fed. This study also was supported, in part, by funds supplied by the Fed. Aid to Wildl. Restor. Act, under PittmanRobertson Proj. W-13-R-38. S. S. Sapp typed drafts of the manuscript. The manuscript was reviewed by K. C. Sadler, O. A. Torgerson, R. W. Cannon, S. R. Winterstein, and L. M. Smith. STUDY AREA AND METHODS Hen wild turkeys were captured, radio instrumented, and released in a 52-km2 area in Adair County, Missouri, about 8 km west of Kirksville. The topography is rolling with elevations ranging from 226 to 297 m. Forested land comprises 59.6% of the area. Agricultural lands comprise the remainder, with 16.2% of the area in row crops and 24.2% in pasture. The timber component is 2nd growth oak (Quercus spp.) and hickory (Carya spp.) predominated by pole-sized stands. The floodplain of the Chariton River, which bisects the study area, contains a majority of the cropland. The upland portions of the area are a mosaic of timber interspersed with pastures and hayfields. Trapping was conducted using cannon nets during 2 periods (1 Aug-15 Oct 1983 and 1 Jan-13 Mar 1984). Hens were aged, radio instrumented, and released at the capture site. Transmitters were attached using a backpack harness. The 140-g radio package included a

Density, Home Range, Habitat Use, and Reproduction in Feral Pigs on Santa Catalina Island

A feral pig population on Santa Catalina Island, California, was studied for 17 months beginning in July 1980. A total of 136 pigs was marked and 188 recaptured during capture-recapture studies at two sites. Density was estimated to be 21 to 34 pigs/km2 (95% confidence interval). Dry season home ranges determined from radio-telemetry data were small and differed significantly between boars (2.04 ± 0.20 km2—95% ellipse; 2.44 ± 0.30 km2— harmonic mean method) and sows (0.90 ± 0.23 km2—95% ellipse; 1.46 ± 0.14 km2—harmonic mean method). During the dry season, pigs preferred cool moist canyon bottoms, the result of both a physiological need for free water and behavioral responses to high environmental temperatures. Patterns of utilization during the wet season appeared to be primarily a function of food availability. Seasonality in time of birth was evident, with piglets born in winter and spring (1980) or spring and summer (1981). Litter size as measured by fetal counts was 5.00 ± 0.36 and sows averaged 0.86 ± 0.17 litters over a 12-month period. Most sows were older than 1 year when they first conceived, and litter size increased from puberty and peaked at 2–3 years of age. Intrauterine mortality of fetuses averaged 25% and piglet mortality was estimated to be 58% prior to weaning. Mortality rates appeared to be higher for piglets born in summer than in winter or spring.

Selection and Availability of Dens for Black Bears in Tennessee

Radiotelemetry data indicated that black bears (Ursus americanus) in the Great Smoky Mountains National Park, Tennessee, prefer tree cavities above ground as winter dens. Adult females and subadults of both sexes selected tree dens more frequently (P < 0.078) than did adult males. Because parturition and lactation occur in winter dens, secluded and well-insulated tree cavities, which provide better protection than ground dens, appear to enhance survival and reproduction. A greater proportion (P < 0.010) of adult females and a higher bear density were found in the primary tree-denning area of the Park. Analysis of vegetation showed no absolute shortage of tree dens; however, their clumped distribution due to logging before the Park was established resulted in tree dens being less available in certain watersheds and especially at low elevations. Site and vegetation differences at dens enabled classification, through discriminant function analysis, of areas with the highest potential availability of dens. Tree dens may afford the extra protection necessary to maintain bear populations within marginal habitats of the southern Appalachian Mountains. J. WILDL. MANAGE. 45(1):111-119 Black bears use a wide variety of sites for winter dens. The most common den types include excavated and natural depressions under tree roots, stumps, fallen logs (Erickson 1964:100, Lindzey and Meslow 1976), boulders (Jonkel and Cowan 1971:22, LeCount 1977), or inside the bases of hollow trees (Jonkel and Cowan 1971:22, Bromlei 1973:94). Occasionally bears den in unsheltered depressions (Erickson 1964:100, Hamilton and Marchinton 1977) or man-made structures such as drainage culverts (Barnes and Bray 1966) and under buildings (Jonkel and Cowan 1971:22). Use of radiotelemetry has resulted in reports of bears selecting tree cavities above ground as dens (Taylor 1971:67; Ernst, unpubl. rep., Ga. Fed. Aid Proj. W-37-R, 1972; Conley 1976; Lindzey and Meslow 1976; Hamilton and Marchinton 1977; Pelton et al. 1977). However, lack of information on the relative availability of different types of dens has precluded determination of preferences by bears among the types. The broad range of den types reported in the literature indicates that specific den requirements may not be important to the survival of black bears. However, most reports are from northern regions where snow plays an important role in concealment and insulation of denning bears. The natural sealing of entrances to ground dens by snow in Minnesota decreased the bears' winter energy requirements by 27% (Maxwell and Thorkelson, unpubl. rep., North Cent. For. Exp. Stn., 1975). Southern regions are generally free of snow cover but experience heavy winter rains. Hammel (1955) showed that moist pelts have 5-20% greater conductivity than dry pelts, and that small amounts of water vapor can produce this variation. Open ground dens also would result in greater heat loss due to air turbulence. Thorkelson and Maxwell (1974) found that an air turbulence of 150 cm/ second increased total heat loss of a raccoon (Procyon lotor) in an open den by 33%. Free-ranging dogs and human encroachment pose additional threats to southern bear populations. These factors plus frequent winter flooding (Landers et J. Wildl. Manage. 45(1):1981 111 This content downloaded from 157.55.39.253 on Wed, 08 Jun 2016 06:04:28 UTC All use subject to http://about.jstor.org/terms 112 BEAR DENS IN TENNESSEE * Johnson and Pelton

Analysis of Radio Telemetry Data in Studies of Home Range

In home range studies of wild animals and birds, statistical analysis of radio telemetry data poses special problems due to lack of independence of successive observations along the sample path. Assuming that such data are generated by a continuous, stationary, Gaussian process possessing the Markov property, then a multivariate Ornstein-Uhlenbeck diffusion process is necessarily the source and is proposed here to be a workable model. Its characterization is given in terms of typical descriptive properties of home range such as center of activity and confidence regions. Invariance of the model with respect to choice of an observational coordinate system is established, while data for twin deer are used to illustrate the manner in which the model may be used for study of territorial interaction. An approximate maximum likelihood procedure is proposed with results being reported for deer, coyote, and bird tracking data.

Automated Recordings of Body Temperature from Free-Ranging Yellow-Bellied Marmots

A simple, portable system for the automatic collection and storage of radio-telemetry data is described. Data on the deep body temperatures of two yellow-bellied marmots (Marmota flaviventris) are reported for 3 days. The advent of radio-telemetry has initiated the development of few automated recording and tracking systems (Cochran et al. 1965, Cochran 1967). While telemetry methods provide the potential of gathering vast amounts of data on the behavior and physiology of animals, most of these data are not collected or used because datagathering techniques are inadequate. This paper describes the design of a portable, self-contained receiving and recording system for the automatic collection of telemetered data and reports some data retrieved by that system. The study was supported by an NSF Grant to K. B. Armitage, the University of Kansas. 1Present address: Section of Neurobiology and Behavior, Cornell University, Ithaca, New York. advent of radio-tel metry has inithe development of ew automated ding and tracking systems (Cochran l. 1965, Cochran 1967). While telemetry ods provide the potential of gathering METHODS Our design criteria were as follows: (1) portability; (2) low maintenance; (3) 100200 m range; (4) high reliability. A block diagram of this system is given in Fig. 1. An incoming signal from a temperaturesensitive, pulsed transmitter (Pauley et al. 1968) is received by a portable receiver (Shirer and Downhower 1969). The receiver runs continuously; its output is connected to a battery-operated, portable tape recorder. (The tape recorder should have a capstan drive and an effective AGC (Consumer's Reports 1969) through a switching circuit controlled by a windup clock.) The switching circuit turns on the tape recorder for about 80 seconds every 30 minutes and allows the output from the This content downloaded from 40.77.167.51 on Tue, 04 Oct 2016 05:07:34 UTC All use subject to http://about.jstor.org/terms 640 Journal of Wildlife Management, Vol. 34, No. 3, July 1970