Arthur D. Dayton

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.

Carbaryl residues in tissues and cholinesterase activities in brain and blood of rats receiving carbaryl

Abstract The diagnostic value of measuring insecticide levels and cholinesterase activity in carbaryl-poisoned rats was studied. Mature, male rats received 450, 800, or 1200 mg carbaryl/kg orally, and carbaryl residues in liver, heart, and brain and/or cholinesterase (ChE) activity in brain, red blood cells, and plasma of sacrificed, moribund, and dead rats were compared. Significant tissue residues were still present 24–48 hr after dosing. The lowest liver, heart, and brain carbaryl levels were 11.7, 3.6, and 5 ppm, respectively, in fatally poisoned rats. The brain ChE activity of fatally poisoned rats was less than 35% of normal, while surviving rats had greater than 55% of normal ChE activity 48 hr after dosing. Following dosing, red blood cells and plasma ChE activity was near 30% of normal. Cholinesterase activity in brain, red blood cells, and plasma was back to 70% of normal 96 hr after dosing. Blood studies on gastrointestinal tract absorption of carbaryl indicated that prolonged absorption may account for extended clinical signs observed. Whole blood was superior to plasma for carbaryl determination.

Preferences and Influence of Paired Food Items on Energy Intake of American Robins and Gray Catbirds

Seed selection by avian granivores has been studied intensively in laboratories (Willson 1971, Willson and Harmeson 1973, Gass 1978, Browning et al. 1981), but comparable studies have not been reported for frugivores. Kantak (1979) and Baird (1980) both postulate that conspicuous color may play a more important role in food selection by frugivores than the size or nutritional quality of the fruit. Knowledge of fruit preferences may increase the effectiveness of habitat im-

APPARENT METABOLIZABLE ENERGY CONTENT OF FOODS USED BY MOURNING DOVES

We collected metabolic efficiency and consumption data on 12 seed diets fed to captive mourning doves (Zenaida macroura) under simulated winter conditions. Doves consumed 7-17 g/day of 8 diets (i.e., acceptable) and 0.8-3.5 g/day of 4 diets (i.e., unacceptable). Metabolic efficiencies of doves on the 8 acceptable diets ranged from 69 to 94%. The foods differed in apparent metabolizable energy value to doves.

Effects of carbamates on bobwhite food intake, body weight, and locomotor activity

Food intake, body weight, and locomotor activity were monitored on adult male bobwhites (Colinus virginianus) which were provided diets that contained sublethal levels of carbaryl or carbofuran typical of natural exposure under agricultural conditions in Kansas. Diets containing 237 or 1,235 ppm of carbaryl, or 26 ppm of carbofuran did not alter food intake, body weight, or locomotor activity of adult bobwhites. Diets containing 131 ppm of carbofuran significantly (P < 0.05) reduced food intake, body weight, and locomotor activity.

Effects of Dieldrin on operant behavior of bobwhites 1

Bobwhites (Colinus virginianus) were trained to peck a green lighted key to receive food. Bird response performance was monitored for 14 days, then birds were dosed with five levels of dieldrin (50 to 300 micrograms every other day) for 42 days while their response performance was monitored. At the end of the 42-day dosage period, mean brain concentrations of dieldrin ranged from 2.6 ppm to 11.8 ppm; lower concentrations associated with lower dosage levels. All dieldrin dosage levels altered cage behavior of bobwhites, dieldrin dosage levels greater than 100 micrograms resulted in slower and less accurate responses by dosed birds during the 42-day trial period.

Comparative Preferences of Field Sparrows and Cardinals among Four Propagated Seeds

Both Willson (1971) and Robel et al. (1974) reported that wild birds eat the most abundant seeds available, regardless of energy content. A contrary view is held by Pulliainnen (1965), Moss (1968), and Gardarsson and Moss (1968), who report that some gallinaceous birds select food on the basis of nutritional quality. Selection for dietary items with higher nutritional qualities has obvious survival value (Royama 1970, Smigel and Rosenzweig 1974). Studies by Willson (1971) and Willson and Harmeson (1973) found that seed selection by finches was related to bill size, and that ease of handling was the most important factor related to seed preferences of finches. The controversy surrounding seed selection by birds, and the desire of the U.S. Soil Conservation Service (SCS) to establish wildlife plantings preferred by song birds, led us to study preferences of cardinals (Cardinalis cardinalis) and field sparrows (Spizella pusilla) among seeds of 4 plant species being propagated at the SCS Plant Materials Center, 10 km south of Manhattan, Kansas.

EPA small pen tests I. Effects of pen and group sizes, sex combinations, and feeding levels on bobwhite activity

ConclusionsSix-bird groups of bobwhites in large pens exhibited significantly more movement than did corresponding pairs of bobwhites in small pens, indicating a need to standarize pen and bird-group sizes in EPA small pen tests if results are to be comparable. Although in this study we did not detect any statistically significant differences in activity levels of bobwhites attributable to pen or bird-group size, the fact that the activity of pairs of bobwhites in small pens were consistently higher than those of 6-bird groups in larger pens reinforces the need to standardize pen and bird-group sizes in EPA small-pen tests. High er levels of aggression noted in the 6-bird groups compared with the 2-bird groups further substantiate this need. Additionally, the all-male 6-bird groups traveled significantly less distance than did male-female 6-bird groups, suggesting the need to also standardize sex combinations of birds used in EPA small pen tests. Dietary levels did not appear to affect either activity levels or movements of birds. Therefore this study produced no data to support the need to standardize dietary levels provided birds used in EPA small pen tests.Additional research is needed to separate the effect of group size and pen size on bird activity and movements before these parameters are standardized in EPA small pen test protocol.

Effects of Dietary Carbofuran on Bobwhite Activity Patterns

Early pesticidal research focused primarily on the determination of LD~ 0 concentrations and measuring changes in D reproductive performance and/or number and survival of offspring (BROWN 1978). More recently, research has evaluated effects of pesticides on aggression, motor activity, stress, growth response, susceptibility to disease, and other nonletha! impacts. Because of the complexity of natural ecosystems and strong selective forces operating within them, slight pesticide-induced behavioral changes could be extremely important to the survival of certain organisms. Physiological and behavioral rhythms are part of the phylogenetic make-up of an organism and have obvious ecological and biological significance (PITTENDRIGH 1961, ASCHOFF 1964). Earlier we reported on the effects of carbaryl and carbofuran on bobwhite (Colinus virginianus) food intake, body weight, and locomotor activity (ROBEL et al. 1982). Herein we report on the effect of sublethal levels of carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) on activity patterns of bobwhites.

Bioavailability of alfalfa calcium

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