Crop Depredation Research Articles

Effectiveness of crop protection methods against wildlife damage: A case study of two villages at Bardia National Park, Nepal

Conflicts due to damage caused by wildlife pose serious threats to conservation. In addition, wildlife damage incurs severe economic loss to communities living in the close vicinity of the park, affecting the livelihoods and well-being of locals. While different studies have emphasised identification and quantification of crop damage problems, studies highlighting the means used for crop protection and their effectiveness are limited. This study aimed to examine the effectiveness of means used by communities to protect their crops against wildlife. 117 households were visited at two Buffer Zone villages of Bardia National Park, Nepal. Findings suggested that crop depredation by wildlife was a function of several factors, such as the distance of the farmland from the park, the size of the crop raiding animals and the frequency of attacks on the farmland, and the type of crops. Ten different means were identified by communities which were used regularly to prevent crop damage. Households combined both traditional and modern means to guard their crop against the wild animals. Means differed according to the animals as well as crops being protected. Among all these means, Machan (i.e. watch towers) combined with other means such as throwing flaming sticks and group shouting were the most effective and safest modes of crop guarding for all kinds of animals and crops. Trench and Bio-fencing were effective mostly for deer species. However, crop guarding was an intensive process and no means were able to completely prevent crop damage. Problem animals differed according to the villages and crops being damaged, which suggests that employment of single means would be ineffective. Site-specific management strategies and economic as well as technical support from funding organisations would be most useful to minimise crop loss. In addition information exchange and learning between farmers and the park management about different mitigating means could support and prepare farmers for improvement in the means.

A Note on Daily Movement Patterns of a Female Asiatic Black Bear (Ursus thibetanus) in a Suburban Area of Iwate Prefecture, Northeastern Japan

As urban areas sprawl and natural environments are modified, human-bear conflicts are becoming increasingly more common and significant management concerns throughout the United States (Peine 2001; Beckmann and Lackey 2008) and other countries (Mattson 1990; Huygens et al. 2004; Sangay and Vernes 2008). In North America, nuisance activities by American black bears (Ursus americanus) include raiding crops and orchards, feeding on human food and garbage, and attacking livestock and humans (Herrero 2002). However, management policies for black bears vary according to the status of the species, which ranges from pest to threatened (Pelton 2003). American black bears are generally crepuscular but may shift to diurnal or nocturnal activities depending on human activity (Pelton 2003). Several studies have reported such behavioral changes of black bears in British Columbia (Reimchen 1998), Nevada (Beckmann and Berger 2003), and California (Ayres et al. 1986; Lyons 2005; Matthews et al. 2006). Recently, crop damage and human injuries have also been caused by Asiatic black bears (U. thibetanus) in Japan (Hazumi 1994). Most of these disturbances occur in suburban landscapes surrounded by forests and farmlands with obscure boundaries (Ozaki and Kudo 2002). In Japan, only a few behavioral studies have addressed such problems with black bears. In Nagano Prefecture, central Japan, Huygens and Hayashi (1999) constructed an electric fence around corn fields to test its effect on crop depredation by black bears. In the Experimental Farm of Tohoku University, northeastern Japan, Deguchi et al. (2003) placed infrared cameras near a corn field to observe nuisance behavior by black bears. Despite these studies, little is known of the movement patterns of Asiatic black bears in suburban areas of Japan. Detailed monitoring of active Asiatic black bears near suburban areas is required to reduce human-bear interactions. Therefore, to characterize bear movement and resource selection patterns during the crop harvest season, we monitored the movement of a female Asiatic black bear, which was tagged in a forest adjacent to a suburban area, using global positioning system (GPS) technology.

Beehive fence deters crop‐raiding elephants

AbstractPrevious work has shown that African elephants Loxodonta africana will avoid African honeybees Apis mellifera scutellata. Here we present results from a pilot study conducted to evaluate the concept of using beehives to mitigate elephant crop depredation. In Laikipia, Kenya, we deployed a 90‐m fence‐line of nine inter‐connected hives, all empty, on two exposed sides of a square two‐acre farm that was experiencing high levels of elephant crop depredation. Compared with a nearby control farm of similar status and size, our experimental farm experienced fewer raids and consequently had higher productivity. Socioeconomic indicators suggest that not only was the concept of a beehive fence popular and desired by the community but also that it can pay for its construction costs through the sale of honey and bee products. We are calling for experiments testing this concept of a ‘guardian beehive‐fence’ to be conducted rigorously and scientifically in as wide a range of agricultural settings as possible to evaluate jointly its effectiveness and efficiency.

Home range and habitat use of female brown bear (Ursus arctos) in Urahoro, eastern Hokkaido, Japan

ABSTRACT We examined the home range and habitat use of three female brown bears (Ursus arctos) in the Urahoro region, eastern Hokkaido, Japan, where crop depredation by bears has increased since 1996. The average annual home range size calculated by the minimum convex polygon method was 43.04 ± 9.52 km2 (mean ± SD, N = 5). Summer (June–September) home ranges were larger than spring (April–May) and fall (October–December) ranges. The home range of brown bears in the region was larger than those in other areas of Hokkaido, such as the Oshima and Shiretoko Peninsulas. This suggests that habitat quality and population density are lower in the Urahoro region than in other areas. One of two bears for which we examined habitat preferences depended on crop fields during the late summer, whereas the other bear remained in the forest throughout the year. Brown bears in this area preferred mixed forest and avoided deciduous broadleaf forest and conifer plantations.

Valuing mangrove ecosystem services: linking nutrient retention function of mangrove forests to enhanced agroecosystem production

Mangroves are highly productive wetland ecosystems strategically located at the interface between land and sea. They play an important role in the biogeochemical cycles of the coastal environment, acting as sources of nutrients to adjacent marine and terrestrial ecosystems through active and passive transport. We examined the nutrient contents in mangrove and nonmangrove soils in and around the Bhitarkanika National Park, India and assessed whether the local agricultural producers were aware of and placed a value on this contribution of mangrove forests in enhancing agroecosystem productivity. Soil samples from both mangrove and nonmangrove areas were analysed and quantity of organic carbon, total nitrogen, available phosphorus and potassium were derived. The replacement cost method was used to derive the value of nutrients in mangrove soils. We estimated that each hectare of mangrove contains additional nutrients worth US$232.49 in comparison to nonmangrove areas. The difference in nutrient content in mangrove versus nonmangrove areas gave the value of US$3.37 million for the nutrients in 145 km2 of mangrove forests. The agricultural producers were aware that mangrove forests act as a source of nutrients and were willing to pay a higher price for the land adjoining mangrove forests. Around 92% of the producers ranked nutrient retention as a secondary function of mangrove forests. Despite crop depredation from wild ungulates and conflict with salt water crocodiles the agriculturist finds the benefit to cost ratio of mangrove forests high and more than 76% were in favour of mangrove restoration. This study provides an opportunity to highlight the importance of mangrove ecosystems to the livelihoods of the local people and the urgent need to sustain these through proper policy and market interventions.

Role of NTFPs Among Forest Villagers in a Protected Area of West Bengal

People of rural India especially forest dwellers extract non-timber forest produces (NTFPs) from forest for both commercial as well as consumption purposes. Various studies showed that poorest forest dwellers are highly dependent on NTFPs to sustain daily requirements of family needs. In protected areas, people's access to collect NTFPs has been either prohibited or restricted as per Wildlife Protection Act. The present study is an attempt to assess the extent of dependency on NTFPs after declaration of Buxa as protected area, dynamics of collection of NTFPs , people's perception about NTFPs collection etc. The study reveals that more than half of total families are dependent on NTFPs to supplement their daily requirements. Moreover, tribal populations are most dependent on NTFPs at BTR among all the social categories. It is observed that number of species as well as quantity of NTFP collection for sale increased considerably over the years. This might be due to the fact that villagers are increasingly dependent on NTFPs as potential income source as employment opportunity reduced drastically due to ban on clear felling coupes and artificial regeneration of plantations with the creation of Tiger Reserve. It is revealed that primary collectors i.e. local villagers are not getting remunerative price though secondary and tertiary collectors, in particular, are making maximum profits from NTFPs. Forest villagers of BTR regard NTFPs as more consistent and stable source of income with declining forest departmental works and crop depredation by wild animals.

Stomach contents of brown bears Ursus arctos in Hokkaido, Japan

We determined the seasonal food habits of brown bears Ursus arctos in three regions of Hokkaido, Japan, over eight years (1991–1998) by analysing the stomach contents of 556 bears killed for nuisance control or sport hunting. Seasonally dominant food items changed from herbaceous plants (61–80% in volume) in spring, to herbaceous plants (53–97% in volume) and ants (0–18% in volume) in early summer, crops (32–46% in volume) and herbaceous plants (26–31% in volume) in late summer, and berries (25–39% in volume), acorns and nuts (8-16% in volume) in autumn. These diet shifts were consistent among the three investigated regions. Crop depredation by brown bears in late summer occurred extensively in Hokkaido and was probably driven by a shortage of alternative food sources during this season. The proportion of sika deer Cervus nippon yesoensis in the diet increased during the 1990s in eastern Hokkaido (25.2% in frequency), where bears consumed deer throughout the year. Bears probably acquired deer meat from carcasses left in the fields after the deer were shot for nuisance control and sport hunting. In the Oshima Peninsula of southern Hokkaido, bears consumed large amounts of anthropogenic waste (16% in frequency).

Assessment of crop depredation by wild turkeys in the United States and Ontario, Canada

The wild turkey (Meleagris gallopavo) repatriation in the United States and Canada has been a major achievement in wildlife management. This success has led to increasing wild turkey populations and calls to wildlife professionals complaining about wild turkeys causing agricultural damage. A mail survey was distributed to state, federal, and provincial agencies that respond to wildlife crop-damage complaints. Survey recipients were asked to report the number of crop-damage complaints and their severity received from farmers, how many of these complaints were investigated and by what means, how often damage was confirmed when investigated, the severity of actual damage observed, and how frequently the damage was caused by other species. We wanted to compare farmers' perceptions of crop-depredation levels to actual damage as observed by experts. We further assessed the number of complaints received, the severity of the damage, and the economic impact relative to specific agricultural crops. Twenty-three different crops were reported as having confirmed damage caused by wild turkeys. In the majority of these cases (93%) damage was reported as light. In 46% of inspected cases, investigators reported most of the damage (76–100%) was caused by another species. Our results provide wildlife managers with an understanding of the nature of crop depredation relative to the wild turkey.

Living amidst large wildlife: livestock and crop depredation by large mammals in the interior villages of Bhadra Tiger Reserve, South India.

Conflict with humans over livestock and crops seriously undermines the conservation prospects of India's large and potentially dangerous mammals such as the tiger (Panthera tigris) and elephant (Elephas maximus). This study, carried out in Bhadra Tiger Reserve in south India, estimates the extent of material and monetary loss incurred by resident villagers between 1996 and 1999 in conflicts with large felines and elephants, describes the spatiotemporal patterns of animal damage, and evaluates the success of compensation schemes that have formed the mainstay of loss-alleviation measures. Annually each household lost an estimated 12% (0.9 head) of their total holding to large felines, and approximately 11% of their annual grain production (0.82 tonnes per family) to elephants. Compensations awarded offset only 5% of the livestock loss and 14% of crop losses and were accompanied by protracted delays in the processing of claims. Although the compensation scheme has largely failed to achieve its objective of alleviating loss, its implementation requires urgent improvement if reprisal against large wild mammals is to be minimized. Furthermore, innovative schemes of livestock and crop insurance need to be tested as alternatives to compensations.

Focus groups as a human dimensions research tool: Three illustrations of their use

Through a discussion of our experiences with focus groups in Michigan, we illustrate the application of focus groups in human dimensions research. Focus groups aided in hypothesis generation and development of conceptual frameworks in a project on the deer crop depredation issue, and they provided insights for the design of questionnaires in research on black bear management and ecosystem management. Focus groups have proven to be a useful exploratory tool and are perhaps underutilized in the study of natural resources‐related issues.

Conservation of biodiversity within Canadian agricultural landscapes: Integrating habitat for wildlife

Industrialized agriculture currently substitutes many of the ecological functions of soil micro-organisms, macroinvertebrates, wild plants, and vertebrate animals with high cost inputs of pesticides and fertilizers. Enhanced biological diversity potentially offers agricultural producers a means of reducing the cost of their production. Conservation of biodiversity in agricultural landscapes may be greatly enhanced by the adoption of certain crop management practices, such as reduced pesticide usage or measures to prevent soil erosion. Still, the vast monocultures comprising the crop area in many Canadian agricultural landscapes are often of limited conservation value, thus the inclusion of appropriate wildlife habitat in and around arable lands is a fundamental prerequisite for the integration of wild species within agricultural landscapes. This review of current literature considers the potential for non-crop areas within agricultural landscapes to be reservoirs of agronomically beneficial organisms including plants, invertebrates, and vertebrate species. Non-crop habitats adjacent to crop land have been identified as significant for the maintenance of plant species diversity, for the conservation of beneficial pollinating and predatory insects, and as essential habitat for birds. A key component for enhancement of biodiversity is the reintroduction of landscape heterogeneity by (1) protection and enhancement of key non-crop areas, (2) smaller fields and farms, and (3) a greater mixture of crops, through rotation, intercropping and regional diversification. The benefits of increased biodiversity within arable lands are reviewed for various species groups. In the Canadian context, any serious attempt to derive significant agronomic benefit from increased biodiversity will require considerable changes in the agricultural programs and policies which shape mainstream industrialized agriculture. The problems of crop depredation by vertebrate species, weed and insect competition, which still represent significant impediments to the creation and proper management of wildlife habitat, are also discussed.

Evaluation of ReJeX-iT AG-36 as a Canada Goose Grazing Repellent

Effective methods to manage Canada geese (Branta canadensis) implicated in habitat destruction, crop depredation, and nuisance are needed. In july 1993, we applied ReJeX-iT AG-36 (a methyl anthranilate [MA] formulation) to 14- × 14-m grass plots within a 40- × 120-m enclosure to evaluate its effectiveness as a repellent for Canada geese. An application rate of 59 kg/ha of ReJeX-iT AG.-36 reduced (P < 0.001) goose activity on treated grass plots for ≤4 days. Improvements in encapsulating or entrapping MA may extend the effectiveneff of ReJeX-iT AG-36

Fall Flock Behavior and Harvest of Canada Geese

We studied fall flock behavior and harvest of locally breeding Canada geese (Branta canadensis) and those that use the area as a migration stopover at the Talcot Lake Wildlife Management Area (TLWMA) in southwest Minnesota in 1980-81. We used neckbands and radio transmitters to measure movements and survival of geese. We conducted aerial and ground surveys to estimate the size of goose populations. The 800-ha TLWMA refuge provided hunting season sanctuary for geese breeding in a 1,500-km2 area surrounding the refuge. Fidelity of local geese to feeding and roosting sites was strong throughout the fall. Prehuntingseason flight patterns to feeding sites off the refuge continued despite heavy hunting pressure. Marked families from a given brood-rearing site fed and roosted together at rates greater than would have been expected by chance. This subflock behavior, combined with consistent flight patterns, resulted in differential mortality among brood-rearing groups. In contrast, migrants remained at TLWMA briefly, fed independently from local geese when off the refuge, and were harvested at a lower rate (P < 0.05) than local geese. J. WILDL. MANAGE. 52(4):679-688 The giant Canada goose (B. c. maxima) has been restored over much of its former midwestern range (Nelson 1963, Brakhage 1965, Dill and Lee 1970, Cooper 1978). This race has steadily increased to an estimated 108,000 birds in the Mississippi Flyway in 1981 (U.S. Fish and Wildl. Serv. and Can. Wildl. Serv. 1982). Although less numerous than subarctic and arctic goose populations (Bellrose 1976), resident populations of giant Canada geese provide recreation where geese were once rare or absent (Hine and Schoenfeld 1968). Management programs for local geese have included establishing additional populations, improving breeding habitat, and establishing refuges. Refuges have also contributed to an increase in subarctic and arctic nesting Canada geese stopping in the upper midwest (Vaught and Kirsch 1966, Reeves et al. 1968). Concurrent use of refuges by migrant geese and locally breeding geese is common. Goose concentrations on refuges have resulted in high hunter densities, firing lines, and crop depredations. These issues, and a goal to apportion the harvest of geese equitably in the Mississippi Flyway, have led to a search for methods to distribute migrant geese (Reeves et al. 1968). Sherwood (1968) identified hunting as an important limiting factor for restored populations; therefore, techniques are needed for managing the harvest of migrant and locally breeding geese concurrently using a refuge. An understanding of the behavior of migrant and resident geese during fall is necessary to attain this objective. Migratory and wintering subpopulations or subflocks of Canada geese have been described by Kennedy and Arthur (1974), Koerner et al. (1974), and Raveling (1969, 1978, 1979). Zicus (1981a) documented subflock behavior on the breeding grounds in summer and fall. Zicus (1981a) suggested that resident geese rearing young at specific sites associated with each other and differed from other subflocks in their use of a refuge for feeding and roosting; he speculated that subflocks may differ in their vulnerability to hunting. Our study examined behavior of resident and migrant Canada geese using a refuge concurrently during fall in southwest Minnesota. We studied chronological changes in size and composition of migrant and local flocks, use of feeding sites, family associations and mortality rates among local geese, composition of the Canada goose harvest, and factors affecting vulnerability of these geese to hunting. We thank J. R. Kitts and F. B. Martin, University of Minnesota, for reviewing the manuscript and for assisting with statistical procedures, respectively. R. J. Peterson, J. G. Beech, D. G. Opdahl, L. M. Koster, E. L. Larson, and other personnel of the Minnesota Department of Natural Resources (MDNR) helped with banding, observations, and bag checks. Additional banding assistance was provided by S. J. 1 Present address: Section of Wildlife, Minnesota Department of Natural Resources, 231 E. Second Street, Redwood Falls, MN 56283.

Effects of Jackrabbit Grazing, Clipping, and Drought on Crested Wheatgrass Seedlings

The effects of black-tailed jackrabbits on crested wheatgrass (Agropyron desertorum) seedling establishment and utilization were monitored on a mesic and 2 xeric Wyoming big sagebrush (Artemisia trdentata spp. wyomingensis) sites in Nevada. Although jackrabbit densities (1.4 to 2.9/ha) and utilization were high, seedling survival was not significantly different (p?0.05) inside or outside rabbitproof exclosures even on the xeric sites during drierthan-normal springs. Seedling density was greater on the mesic than xeric sites, but good grass stands were produced on all sites. The smaller seeded areas (less than 60 ha) and the edge of the large seeded area (400 ha) had the greatest forage utilization by rabbits. To determine the effects of defoliation and drought on seedling survival, seedlings in small tubes (3.8 cm diameter and 20 cm deep) and in large tubes (10 cm diameter and 1 m deep) were watered and clipped at 7 different intervals. Seedlings grown in the smaller volume were more sensitive to clipping and drought than those grown in the larger soil volume. Seedlings watered less than weekly showed a trend toward higher survival when clipped every 3 or 4 weeks than when clipped more or less frequently. Clipping weekly and watering less than weekly greatly reduced root growth and seedling survival. Although infrequent grazing by rabbits could slightly increase seedling survival in a dry year, the additive effects of frequent grazing and drought could result in stand failure, especially on shallow or rocky soils with a small soil volume that limits water retention and root growth. Rangelands of western North America are inhabited by several species of hares of the genus Lepus, commonly known as jackrabbits. The black-tailed jackrabbit (Lepus californicus) is probably the most abundant and widely distributed of the jackrabbits and therefore, most generally responsible for damage to crops and forage plants. Jackrabbit populations are very cyclic and virtually every western state has gone through severe crop depredation during population peaks (McAdoo and Young 1980). Large populations of jackrabbits have been considered a result and symptom of overgrazed rangelands (Fichter 1952) and a threat to crested wheatgrass seeded for range improvement (Goodwin 1960). High consumption of range forage by jackrabbits has been well documented (Taylor et al. 1935, Currie and Goodwin 1966, Westoby and Wagner 1973). Although Westoby and Wagner (1973) suggested and Goodwin (1960) observed that jackrabbits affected crested wheatgrass seedling establishment, these effects have not been quantified. McGinnies (1973) showed that clipping crested wheatgrass seedlings to ground level once during the 5month period following germination can reduce seedling survival by 50%o. However, for many years and clipping dates, clipping caused little or no seedling mortality, while for other years and clipping dates, high mortality was observed. Cook and Stoddart (1953) suggested that crested wheatgrass clipped early in the season would not produce regrowth under arid conditions. Mohammad et al. (1982) found 40% defoliation increased production of crested wheatgrass grown at -0.5MPa water potential while 80% defoliation resulted Authors are range scientist, formerly with USDA/ ARS, Reno, Nev., now at School of Renewable Natural Resources, University of Arizona, Tucson 85721; range agronomist, formerly with University of Nevada, Reno, now at Department of Crop and Soil Science, University of New Mexico, Las Cruces; wildlife scientist, Renewable Resources Center, University of Nevada, Reno; and range scientist, USDA/ ARS, Reno, Nev. Manuscript accepted March 19, 1985. in 100% mortality of plants at -l.5MPa water potential. The purpose of this study was to determine the effects of black-tailed jackrabbits and clipping on crested wheatgrass seedling survival in relation to precipitation.

Methiocarb-Induced Aversion to Grapes by Gray-Backed White-Eyes

Gray-backed white-eyes (Zosterops lateralis) formed a conditioned aversion to grapes sprayed with methiocarb but not when a visual mimic, calcium phosphate, was substituted. The birds did not use a visual cue to distinguish between treated and untreated grapes, but probably used a taste cue. White-eyes that had previously eaten grapes formed a specific aversion while those that had not eaten grapes formed a nonspecific aversion. This suggests methiocarb can be successfully used as a border treatment for protection of crops from 1st-year birds. If invading birds are older and therefore at eating grapes, the entire crop would need to be treated. J. WILDL. MANAGE. 48(2):444-449 Damage to grapes by the gray-backed white-eye was a problem of economic proportions in Western Australia during the early development of the colony (Hallack 1891, Anonymous 1904, Milligan 1904). Despite the continuing loss of production and the lowering of wine quality caused by this bird, there has been little scientific effort devoted toward alleviating the problem. Apart from the limited use of a promising acoustic device that interferes with the birds' communication system (Knight and Robinson 1978a,b), methods of control have advanced little beyond shooting the birds and picking the crop early. Investigations were initiated in southwest Western Australia, near Margaret River (34?00'S, 115000'E), to ascertain the efficacy of the insecticide, molluscicide, and avian emetic, methiocarb [4-(methylthio)-3,5-xylyl N-methyl carbamate] in protecting ripening grapes from whiteeyes. Methiocarb repels birds from crops (Guarino 1972, Stone et al. 1974, Porter 1977, Henkes 1979, Ruelle and Bruggers 1979). It can also protect grapes from depredations by white-eyes (Bailey and Smith 1979, Menzies 1979). A recent study has shown, however, that methiocarb reduces crop depredations by birds because, in some instances, it reduces insect numbers; thus the birds find a crop with few insects an unacceptable area in which to forage (Woronecki et al. 1981). Some evidence is available which suggests that the reported crop protection provided by methiocarb has a more direct, physiological-psychological basis. Rogers (1974) demonstrated that methiocarb causes a response to feeding in redwinged blackbirds (Agelaius phoeniceus) similar to that caused by lithium chloride, an agent well known for forming conditioned aversions. Rogers (1978) also found that redwings form a specific conditioned aversion to two foods, a formulated product and finely ground rice, treated with methiocarb and that the cue used in the formation of the aversion is probably taste. Rooke (1983) demonstrated that whiteeyes develop a specific conditioned aversion to their food when it has methiocarb added if a visual cue is provided. In the absence of a visual cue, food consumption decreased due to a nonspecific aversion or to debilitation caused by methiocarb. Thus, methiocarb has the potential to directly deter white-eyes from eating grapes rather than merely reducing damage in a vineyard by making the area unaccept444 J. Wildl. Manage. 48(2):1984 This content downloaded from 157.55.39.177 on Tue, 15 Nov 2016 04:02:18 UTC All use subject to http://about.jstor.org/terms METHIOCARB-INDUCED AVERSION IN WHITE-EYES * Rooke 445 able for foraging because of methiocarb's insecticidal properties. The present study was conducted to determine whether white-eyes develop a conditioned aversion to grapes sprayed with methiocarb (experiment I). If the cue used by white-eyes in the formation of a specific aversion to treated grapes is visual, then it should be possible to use a visual mimic of methiocarb to form an aversion in birds that have previously eaten grapes treated with methiocarb. Such a mimic could be cheaper and nontoxic and, therefore, more compatible with the grape and wine industries. To test this possibility, a second experiment was conducted to determine whether calcium phosphate would act as a visual mimic of methiocarb in the formation of an aversion (experiment II). The two experiments were conducted using white-eyes whose previous experience with eating grapes was unknown. In a vineyard there would be two classes of birds: adults that had eaten grapes in previous seasons, and 1st-year birds that had not had the opportunity to eat grapes. Because it is well known that animals readily form aversions to novel food but not to familiar food (Revusky and Bedarf 1967, Wittlin and Brookshire 1968, Shettleworth 1972), it is likely that experienced grape-eaters would not as readily form an aversion to treated grapes as animals to which grapes were novel. To test this hypothesis, experiments were conducted to determine the difference in aversive behavior between these two classes of white-eyes (experiments III, IV).

Field-Feeding Ecology of Waterfowl Wintering on the Southern High Plains of Texas

ecology of field-feeding dabbling ducks wintering on the Southern High Plains was investigated on a 50-km2 study area in Castro County, Texas, from September to March 1980-82. Most ducks participated in two feeding flights/day to harvested cornfields, which occupied about 45% of the study area. average morning flight was initiated 52 ? 1.5 minutes before sunrise and terminated 23 ? 1.4 minutes later. Evening flights began 25 ? 2.0 minutes after sunset and ended 37 ? 4.2 minutes later. duration of evening flights increased as the season progressed, and birds fed longer and participated more in the evening flight compared to the morning flight of the same day. Colder temperatures and snowfall were associated with longer evening, but not morning, flights. Feeding flocks selected fields based on an abundance-availability hierarchy, apparently attempting to minimize foraging time. Burned fields were preferred when available, followed by disked fields, especially those containing >60 kg waste corn/ha. J. WILDL. MANAGE. 48(1):63-71 Field-feeding by waterfowl is a widely documented occurrence (Bellrose 1976). However, most studies have focused on crop depredation by aggregations of postbreeding waterfowl on the Canadian prairies or in the northern United States prior to fall migration (Bossenmaier and Marshall 1958, Anderson 1959, Winner 1959). Fredrickson and Drobney (1979) emphasized the urgent need for information on the ecology of postbreeding waterfowl, especially from wintering areas where some waterfowl may spend 6-7 months of their annual cycle. Anderson and Batt (1983: 24) summarized a recent workshop on wintering waterfowl and stated, The consensus was that our knowledge of the ecology of wintering habitats is still embryonic .... Field-feeding on waste grain may be of increasing importance to survival of wintering waterfowl as wetland destruction continues and natural food resources decline. However, until the ecology of wintering waterfowl using agricultural habitats is understood, effective management practices will be difficult to implement. This study was initiated to (1) identify the temporal and spatial aspects of field-feeding by dabbling ducks on the Southern High Plains of Texas (SHP); (2) identify factors affecting field selection by fieldfeeding waterfowl; and (3) assess these observations in relation to the quantity and quality of waste grain resources as a means of attracting and supporting populations of wintering waterfowl. This study was conducted on private farmland in Castro County, Texas, and we thank farmers for access privileges to their properties. We especially acknowledge C. L. and C. L. Lee, T. J. and W. J. Hill, J. D. Myrick and family, J. R. Davis and family, D. W. Brown, H. A. McLain, Mr. and Mrs. E. E. Davis, Mr. and Mrs. H. H. Buchanan, F. A. Smith, P. W. Upshaw, W. T. King, H. and R. W. Mitchell, and G. E. Bennett. E. E. Quinlan, G. E. Huber, R. H. Lunn, and R. J. Whyte assisted in all phases of the fieldwork. K. J. Reinecke and S. L. Paulus provided helpful comments on the manuscript. This study was supported by the U.S.D.A. For. 'Present address: Department of Zoology and Entomology, Auburn University, Auburn, AL 36830. J. Wildl. Manage. 48(1):1984 63 This content downloaded from 157.55.39.92 on Tue, 21 Jun 2016 05:07:38 UTC All use subject to http://about.jstor.org/terms 64 WATERFOWL FIELD-FEEDING * Baldassarre and Bolen Serv., Rocky Mountain For. and Range Exp. Stn. through the Great Plains Wildl. Res. Lab., the Caesar Kleberg Found. for Wildl. Conserv., and the Dep. of Range and Wildl. Manage. at Texas Tech Univ. This paper is contribution T-9-292, Coll. of Agric. Sci., Texas Tech Univ.

Fall Food Habits of Canada Geese in Wisconsin

The Mississippi Valley Population (MVP) of Canada geese (Branta canadensis) is one of the most intensively managed waterfowl populations in North America. Although one of the major management problems for these birds in Wisconsin has been agricultural crop depredation, their food habits have not been investigated beyond small samples analyzed in 1973 and 1974 (R. Ziegler, unpubl. rep., Wis. Dep. Nat. Resour., 1975). From 1965 to 1974, depredation complaints from farms surrounding Horicon Marsh averaged 108/ year, and claims for damage compensation payments from the State of Wisconsin averaged $5,040/year, with an annual range of $450-23,500 (Wis. Dep. Nat. Resour.). Not every complaint for depredation abatement resulted in a claim for

Crop Depredation by Waterfowl: Is Compensation the Solution?

This article examines the apparent failure of public programs which provide reimbursement for agricultural losses in order to quell opposition to concentrations of migratory waterfowl. A theoretical model and case study are employed to investigate the complex economic incentives arising from the presence of waterfowl, the availability of compensation, and public assistance with prevention of loss. It is concluded that compensation and dispersal assistance generate conflicting incentives, and that the limited success of the former could also be due to satiation in consumption and to administrative inefficiencies.The paper examines an alternative to compensation — institutional change which would enable farmers to capture willingness to pay for the opportunity to hunt waterfowl—and concludes that it is worthy of greater attention from policymakers.Cet article examine l'échec apparent des programmes publics destines à rembourser les agriculteurs des penes dues aux oiseaux aquatiques migrateurs. Un modèle théorique et une étude de cas sont utilisés pour examiner les motifs économiques compliqués qui résultent de la presence de ces oiseaux, les fonds de dédommagemenl disponibles, et l'action publique pour la prévention des pertes. II est conclu que dédommagemenl et assistance pour la dispersion des oiseaux produisent des conflits d'intérêl, el que l'insuccès partiel de la première mesure pourrai êire clûà I'incompétence administrative et à un effet de sur‐consommation.Cet article examine une alternative au dédommagement: un changement d'institutions qui permettrait au fermier de récupérer la valeur de la chasse aux oiseaux aquatiques migraleurs. On conclut que cetle solution mérite plus d'attenlion de la pan des agents de decision.

Movement and Migration Patterns of Red-Winged Blackbirds: A Continental Overview

From 1924 through 1974, about 11,000 recoveries accumulated from the banding of over 700,000 Red-winged Blackbirds (Agelaius phoeniceus) in North America. A few studies have examined some of these data for specific localities during certain times of the year; however, no attempt has been made to examine the total recovery data to compile a general picture of continental movement and migration patterns. Increasing attention is being given to blackbird (Icteridae) and Starling (Sturnus vulgaris) populations in North America because of their reported crop depredations, health hazards, and nuisance aspects, especially when congregating in large roosts (Meanley, 1975; Graham, 1976). Solutions to these problems are difficult to find because the problems are widespread and the populations are highly mobile. Management measures necessary in one area may have effects in areas far removed. Thus, effective management requires a thorough knowledge of the overall movement and migration pattern of each species. The objectives of this study are to: (1) determine the general continental movement and migration patterns of the Red-wing during the annual cycle, and (2) examine banding and recovery numbers in relation to population numbers on a regional basis to pinpoint areas where additional banding and/or recovery effort is needed.

On Assessing the Economic and Ecological Impact of Winter Blackbird Flocks

Species composition of the Fort Campbell, Kentucky 1974-75 winter blackbird flock, was found to be dynamic both in size and relative abundance of species. Carefully planned and executed sampling is required to determine species composition due to clumping of species in various parts of the roost. Stomach analyses revealed that in addition to the consumption of some economically important grain, blackbirds were feeding on weed seeds and insect pests such as army worms and corn borers. Since food habitats change during the winter season, extensive sampling is required to determine accurate estimates of economic and ecological impact of blackbird roosts. J. WILDL. MANAGE. 42(1):53-60 Crop depredation by blackbirds (Icteridae) and starlings (Sturnus vulgaris) in North America has prompted experimental control techniques. These efforts have been centered in the northeast and northcentral United States where concentrated cultivation of vulnerable crops coincides with locations where flocks of blackbirds congregate in the fall prior to their migration south (Stone et al. 1972, Wiens and Dyer 1975). In these areas the high cost and logistic impracticality of implementing widespread controls has suggested the need for modifying agricultural practices instead (Wiens and Dyer 1975). More recently, attention has been focused further south, particularly in Kentucky and Tennessee where winter roosts of mixed flocks of blackbirds and starlings commonly number several million birds. These highly localized concentrations have prompted concern for both agricultural damage and danger to human health (Department of the Army 1975). A major difference between the problem in the south and that further north is that in the south the birds present themselves as much more accessible targets for control measures. By virtue of their tremendous concentrations they make the potential for large scale extermination very real. It is remotely conceivable that a significant proportion of the entire North American populations of these birds could be eliminated if extermination efforts were maintained for several years at the major winter roosts. Before such extermination is allowed to proceed, a number of questions must be answered. These can be divided into 2 areas. The first area deals with whether or not the control measures are actually justified-how much agricultural damage is done by the birds and how real is their threat to human health? The second area of questioning concerns the environmental impact of both the control measures themselves as well as the effect of suddenly removing such large numbers of birds from the ecosystem. This paper presents the results of a preliminary study aimed not at answering these questions so much as providing some insight into the factors which 1 This study was supported by funds from the Canadian Wildlife Service and the National Research Council of Canada. 2 Present address: Box 1343, Banff, Alberta TOL OCO. 3 Present address: University of Sussex, Brighton, Sussex, England. J. Wildl. Manage. 42(1):1978 53 This content downloaded from 157.55.39.159 on Sun, 18 Sep 2016 05:54:03 UTC All use subject to http://about.jstor.org/terms 54 ASSESSING WINTER BLACKBIRD FLOCKS Robertson et al. must be considered if accurate answers are