Helminth parasites are reported for the first time from northern spotted owls. Seventy-one percent of a sample of Strix occidentalis caurina from western Oregon was infected. Nematodes (Porrocaecum depressum, Capillaria falconis, Microtetrameres sp. and Synhimantus hamatus) were the most prevalent parasites although cestodes (Paruterina rauschi) and acanthocephalans (Centrorhynchus conspectus) were also represented. There was an association between components of this helminth fauna and the diet of spotted owls which is dominated by small rodents. The occurrence of P. rauschi rather than P. candelabraria in this geographic region and host-species may provide additional support for recognition of a parapatric distribution in the ranges of Paruterina spp. among strigiforms in the Nearctic.
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http://dx.doi.org/10.7589/0090-3558-25.2.246 | DOI Listing |
Ecol Appl
January 2025
Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Fire shapes biodiversity in many forested ecosystems, but historical management practices and anthropogenic climate change have led to larger, more severe fires that threaten many animal species where such disturbances do not occur naturally. As predators, owls can play important ecological roles in biological communities, but how changing fire regimes affect individual species and species assemblages is largely unknown. Here, we examined the impact of fire severity, history, and configuration over the past 35 years on an assemblage of six forest owl species in the Sierra Nevada, California, using ecosystem-scale passive acoustic monitoring.
View Article and Find Full Text PDFJ Anim Ecol
December 2024
Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA.
It is widely recognized that predators can influence prey through both direct consumption and by inducing costly antipredator behaviours, the latter of which can produce nonconsumptive effects that cascade through trophic systems. Yet, determining how particular prey manage risk in natural settings remains challenging as empirical studies disproportionately focus on single predator-prey dyads. Here, we contrast foraging strategies within the context of a primary and secondary prey to explore how antipredator behaviours emerge as a product of predation intensity as well as the setting in which an encounter takes place.
View Article and Find Full Text PDFJ Ornithol
December 2023
Institute for Melanin Chemistry, Fujita Health University, Toyoake, Aichi 470-1192 Japan.
Although the evolutionary ecology of melanin pigments and melanin-based coloration has been studied in great details, particularly in birds, little is known about the function of melanin stored inside the body. In the barn owl , in which individuals vary in the degree of reddish pheomelanin-based coloration and in the size of black eumelanic feather spots, we measured the concentration in melanin pigments in seven organs. The eyes had by far the most melanin then the skin, pectoral muscle, heart, liver, trachea, and uropygial gland.
View Article and Find Full Text PDFConserv Physiol
August 2023
U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR, 97331 USA.
Body condition indices and related metrics can help assess habitat quality and other ecological processes, and ideally, these metrics are based on measures of lipids directly extracted from the species of interest. In recent decades, barred owls () have become a species of conservation concern as they invaded older forests of the US Pacific Northwest, and caused population declines of the closely related and federally threatened northern spotted owl (). A simple and effective measure of barred owl body condition could help to understand how habitat quality varies within their new range, which in turn can inform their management and other aspects of their ecology.
View Article and Find Full Text PDFEcol Appl
December 2023
Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA.
Predator populations are imperiled globally, due in part to changing habitat and trophic interactions. Theoretical and laboratory studies suggest that heterogeneous landscapes containing prey refuges acting as source habitats can benefit both predator and prey populations, although the importance of heterogeneity in natural systems is uncertain. Here, we tested the hypothesis that landscape heterogeneity mediates predator-prey interactions between the California spotted owl (Strix occidentalis occidentalis)-a mature forest species-and one of its principal prey, the dusky-footed woodrat (Neotoma fuscipes)-a younger forest species-to the benefit of both.
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