Filters: Tags: diet (X) > Categories: Publication (X)
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To investigate whether Northern Goshawk textit(Accipiter gentilis) reproduction is food-limited, we evaluated the reproductive output from 401 goshawk breeding opportunities on the Kaibab Plateau, Arizona during 1999-2002. Concurrently, we estimated densities of 10 goshawk prey species (seven birds, three mammals) using distance sampling. We then assessed the relationship between goshawk productivity (number of fledglings produced) and prey density within and among years by relating the contribution of individual prey species and total prey density to goshawk productivity. We also estimated the proportion of total diet and biomass for each species that contributed ?3% of all prey items. Total prey density was highly...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal Of Raptor Research,
Predator?prey dynamics,
accipiter gentilis,
diet,
distance sampling,
We investigated the bioavailability via diet of spiked benzo[a]pyrene (BaP) and 2,2',5,5'-tetrachlorobiphenyl (PCB-52) from different carbonaceous (non-carbonate, carbon containing) particle types to clams (Macoma balthica) collected from San Francisco Bay. Our results reveal significant differences in absorption efficiency between compounds and among carbonaceous particle types. Absorption efficiency for PCB-52 was always greater than that for BaP bound to a given particle type. Among particles, absorption efficiency was highest from wood and diatoms and lowest from activated carbon. Large differences in absorption efficiency could not be simply explained by comparatively small differences in the particles' total...
Categories: Publication;
Types: Citation;
Tags: Absorption,
Animals,
Benzo(a)pyrene,
Biological Availability,
Bivalvia,
Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha (Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground sloth species not yet represented by skeletal material in the region, and not closely related to any of the four previously sequenced extinct and extant sloth species. Analyses of pollen and plant cuticles, as well as analyses of the chloroplast DNA, show that the Cuchillo Curá...
We studied Mexican spotted owl (Strix occidentalis lucida) diets and the relative abundance and habitat associations of major prey species in a ponderosa pine (Pinus ponderosa)-Gambel oak (Quercus gambelii) forest in north-central Arizona, USA, from 1990 to 1993. The owl's diet was comprised of 94% mammals by biomass and consisted of primarily the deer mouse (Peromyscus maniculatus), brush mouse (P boylii), Mexican woodrat (Neotoma mexicana), and Mexican vole (Microtus mexicanus). Spotted owl prey in our study area were smaller on average than prey in other locations, and the total biomass of potential prey was less than that reported in other areas within the owl's geographic range. Although all prey populations...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of Wildlife Management,
Mexican spotted owl,
Mexican woodrat,
Neotoma mexicana,
P. maniculatus,
Many wildlife species ingest soil while feeding, but ingestion rates are known for only a few species. Knowing ingestion rates may be important for studies of environmental contaminants. Wildlife may ingest soil deliberately, or incidentally, when they ingest soil-laden forage or animals that contain soil. We fed white-footed mice (Peromyscus leucopus) diets containing 0-15% soil to relate the dietary soil content to the acid-insoluble ash content of scat collected from the mice. The relation was described by an equation that required estimates of the percent acid-insoluble ash content of the diet, digestibility of the diet, and mineral content of soil. We collected scat from 28 wildlife species by capturing animals,...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: JSTOR,
Journal of Wildlife Management,
contaminants,
diet,
nutrients,
This investigation evaluated effects of exposure of larval razorback sucker to waterborne and dietary selenium and other contaminants that occur in nursery habitats. Site waters were collected from three localities on the Colorado River near Grand Junction, CO; a total of five test waters (including control) were studied. Razorback sucker larvae were exposed to site-water contaminants via waterborne and dietary exposure using a laboratory food chain (algae, rotifer, razorback sucker). Fish were exposed for 28 days to site waters and food organisms cultured in site waters. Survival data were analyzed by inspection. Growth data were analyzed using analysis of variance to describe the response of fish in each site...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Animals,
Archives of environmental contamination and toxicology,
Cypriniformes,
Cypriniformes: growth & development,
Diet,
Seasonal forages of desert bighorn sheep (Ovis canadensis nelsoni) were analyzed for dry matter, crude protein, in vitro digestibility, and cell wall content. Qualitative nutrient intake was estimated by combining chemical analyses with diet-composition data. Composite diets were also analyzed for the above parameters as well as for phosphorus and calcium. Dietary quality generally declined from spring to winter. Diet digestibility was good to excellent year-round, indicating that desert bighorn were receiving adequate energy. Protein levels were high in spring but were probably deficient for lactating ewes and young lambs in summer and fall. Diets were deficient in phosphorus in all seasons. Forbs had higher protein...
Categories: Publication;
Types: Citation,
Thesis Citation;
Tags: Ovis canadensis,
Utah,
diet,
food,
national parks,
Few dietary studies of pronghorn (Antilocapra americana) have been conducted in semidesert grasslands and little mention has been made of Mexican-tea or ephedra (Ephedra spp.) as a browse species. During summer 2003, we estimated the mortality rate of a pronghorn population in southwestern New Mexico to be nearly 75%. As the severity of the summer drought progressed, pronghorn used ephedra (Ephedra torreyana) until many plants showed signs of heavy browsing. Perennial browse is limited in this area, and we suspect this normally winter forage species was used as an emergency food. If pronghorn carrying capacity in semidesert areas is limited by insufficient forage during dry years, browse occurrence and condition...
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