162 research outputs found
American White Pelicans
American white pelicans (Pelecanus erythrorhynchos, Figure 1) threaten aquaculture producers by direct predation and the spread of disease. They are also considered competition and a nuisance by some sports fishermen. Pelicans can also damage pond levees and crops, such as rice, by trampling the vegetation and depositing guano. A combination of wildlife damage management techniques is often necessary to reduce pelican damage to these resources. Aquaculture Prior to the winter of 1992, American white pelican depredations at catfish facilities in the Delta regions of Arkansas and Mississippi were limited, and birds were easily dispersed from the area. Since 1992, however, pelicans have become more persistent in their foraging efforts and more difficult to disperse. Their increased persistence requires an equally persistent response to limit their damage. Around-the-clock harassment patrols may be necessary especially where pelicans forage at night. The most effective technique involves harassing the birds at their loafing sites near catfish farms. This often causes them to abandon the site, thus reducing or eliminating predation at nearby facilities
American White Pelicans
American white pelicans (Pelecanus erythrorhynchos, Figure 1) threaten aquaculture producers by direct predation and the spread of disease. They are also considered competition and a nuisance by some sports fishermen. Pelicans can also damage pond levees and crops, such as rice, by trampling the vegetation and depositing guano. A combination of wildlife damage management techniques is often necessary to reduce pelican damage to these resources. Aquaculture Prior to the winter of 1992, American white pelican depredations at catfish facilities in the Delta regions of Arkansas and Mississippi were limited, and birds were easily dispersed from the area. Since 1992, however, pelicans have become more persistent in their foraging efforts and more difficult to disperse. Their increased persistence requires an equally persistent response to limit their damage. Around-the-clock harassment patrols may be necessary especially where pelicans forage at night. The most effective technique involves harassing the birds at their loafing sites near catfish farms. This often causes them to abandon the site, thus reducing or eliminating predation at nearby facilities
Faith Decisions: Christian Initiation for Children of the Glenwood Church of Christ
The purpose of this study is to produce a program of instruction and events that will facilitate the initiation of children of the Glenwood Church of Christ into the full fellowship of the church. The project begins by identifying the problem of an imprecise definition of the status of children within Churches of Christ and how this uncertainty affects the process of initiating children of the church. The project continues by avowing the innocence of all children while recognizing a difference existing between children of the church and those outside the sphere of the church. The difference is community. Those who are children of the church live within the boundaries of the community and are nurtured and shaped from birth to assume their roles as adult members of that community. The model for their initiation must, by its very nature, differ from the model of initiation for those who come into the community from outside
American White Pelicans: The Latest Avian Problem for Catfish Producers
Animal Damage Control offices in Arkansas, Louisiana, and Mississippi began receiving complaints concerning American white pelicans (Pelecanus erythrorhynchos) foraging in commercial channel catfish (Ictalurus punctatus) ponds in 1990. Because of the relatively shallow pond depth and high fish stocking rates used by most producers, commercial catfish ponds provide a near perfect foraging environment for American white pelicans. Since 1993, pelicans seem to have become more persistent in their foraging efforts and therefore, more difficult to disperse from catfish farms. Damage abatement recommendations have consisted of harassment measures similar to those used for other piscivorous birds, issuance of depredation permits, and draining water from fields used as loafing sites. In order to learn more about pelican numbers and movements Animal Damage Control, Denver Wildlife Research Center (ADC/DWRC) biologists began aerial censuses in the Delta Region of Mississippi and a radio-telemetry study during the winter of 1993-1994. Information provided by these studies will be used to develop American white pelican damage management strategies in the southeastern United States and elsewhere
Foraging Behaviors of Snowy Egrets (\u3ci\u3eEgretta thula\u3c/i\u3e) and Yellow-crowned Night-Herons (\u3ci\u3eNyctanassa violacea\u3c/i\u3e) in South Louisiana
We report two previously undescribed foraging techniques used by Snowy Egrets (Egretta thula) and Yellow-crowned Night-Herons (Nyctanassa violacea) to catch crawfish (Procambarus spp.). Snowy Egrets were selecting crawfish that had recently molted their shells and Yellow-crowned Sight-Herons were targeting crawfish that were emerging from their burrows. These observations were conducted on commercial crawfish ponds near Catahoula, LA, USA
Plumage Changes in Double-crested Cormorants (\u3ci\u3ePhalacrocorax auritus\u3c/i\u3e) Within the Breeding Season: the Risks of Aging by Plumage
Scant attention has been given to the molting patterns of known-age Double-crested Cormorants (Phalacrocorax auritus). In general, subadult individuals are identified with a tan, buffy or mottled chest, and adults are identified with a black chest. While studying Double-crested Cormorant population dynamics in Ontario, Canada, with known-age birds, it was noted that the plumage of many (\u3e 75%) breeding adults changed from black to heavily mottled during the course of the breeding season. No pattern with age was observed; plumage changed in equal proportions for all ages from 2-year-olds to 7-year-olds. A similar but reverse pattern has been observed with Double-crested Cormorants roosting at sites in the southeastern USA during fall migration. Whereas the majority of the roost had juvenile/subadult plumage in September, by mid-January the roost had shifted to 75% adult black plumage. The mechanism behind the plumage change is unknown, but extreme caution is advised when using plumage to age cormorants, especially during the winter months. By describing our observations with Doublecrested Cormorants, we hope to encourage future formal research on within-season plumage changes
Seasonal climatic niche and migration movements of Double-crested Cormorants
Avian migrants are challenged by seasonal adverse climatic conditions and energetic costs of long-distance flying. Migratory birds may track or switch seasonal climatic niche between the breeding and non-breeding grounds. Satellite tracking enables avian ecologists to investigate seasonal climatic niche and circannual movement patterns of migratory birds. The Double-crested Cormorant (Nannopterum auritum, hereafter cormorant) wintering in the Gulf of Mexico (GOM) migrates to the Northern Great Plains and Great Lakes and is of economic importance because of its impacts on aquaculture. We tested the climatic niche switching hypothesis that cormorants would switch climatic niche between summer and winter because of substantial differences in climate between the non-breeding grounds in the subtropical region and breeding grounds in the northern temperate region. The ordination analysis of climatic niche overlap indicated that cormorants had separate seasonal climatic niche consisting of seasonal mean monthly minimum and maximum temperature, seasonal mean monthly precipitation, and seasonal mean wind speed. Despite non-overlapping summer and winter climatic niches, cormorants appeared to be subjected to similar wind speed between winter and summer habitats and were consistent with similar hourly flying speed between winter and summer. Therefore, substantial differences in temperature and precipitation may lead to the climatic niche switching of fish-eating cormorants, a dietary specialist, between the breeding and non-breeding grounds
Migration Patterns of Double-crested Cormorants Wintering in the Southeastern United States
Migration patterns of Double-crested Cormorants (Phalacrocorax auritus) wintering in the southeastern U.S. are poorly understood. Movement data were analyzed from 28 cormorants captured in Alabama, Arkansas, Louisiana and Mississippi and equipped with satellite transmitters. Four (three immature, one adult) cormorants did not migrate and stayed in the southeastern U.S. throughout the year. During spring, cormorants captured in Alabama migrated east of the Mississippi River and primarily west of the Appalachian Mountains. Cormorants from Arkansas, Louisiana and Mississippi migrated north along the Mississippi River Valley, the Missouri River Valley and/or the Ohio River Valley. The earliest departure for spring migration was 26 March, whereas the latest departure was 12 May. Adult cormorants departed for spring migration earlier than immature cormorants. The average departure date for fall migration was 1 October. Mean duration of spring migration was twelve days, and cormorants traveled an average of 70 km per day
Seasonal Habitat Selection by American White Pelicans
Resource utilization strategies of avian migrants are a major concern for conservation and management. Understanding seasonal habitat selection by migratory birds helps us explain the ongoing continental declines of migratory bird populations. Our objective was to compare the secondorder and third-order habitat selection by the American White Pelican (Pelecanus erythrorhynchos; hereafter pelican) between the breeding and non-breeding grounds. We tested the Lack hypothesis that habitat selection by migratory birds is stronger on the breeding grounds than on the nonbreeding grounds. We used random-effect Dirichlet-multinomial models to estimate the second-order habitat selection between the seasons with the GPS locations of 32 tracked pelicans. We used Gaussian Markov random field models to estimate the third-order habitat selection by pelicans at the breeding and non-breeding grounds, accounting for spatial autocorrelation. Pelicans strongly selected waterbodies and wetlands at both non-breeding and breeding grounds, tracking their foraging habitats between the seasons at the home range level. However, pelicans exhibited seasonal differences in the strength of the third-order selection of wetlands and waterbodies with foraging habitat selection being stronger at the breeding grounds than at the non-breeding grounds, supporting the Lack hypothesis
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