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1

Digestive responses of wapiti Cervus elaphus canadensis to seasonal forages

100%
Jiang Z., Hudson R. J.
Acta Theriologica
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1996
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tom 41
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nr 4
We tested the hypothesis that seasonal differences in passage rate and digestibility of native forage in wapiti Cervus elaphus canadensis Erxleben, 1777 were due to seasonal appetence and digestive adaptation as well as plant phenology and compo­sition. To this end, we compared digestive characteristics of seasonal pasture with those of a standard alfalfa-barley pellet fed to wapiti hinds throughout the year. No evidence of seasonal effects independent of forage quality was found. Although dry matter intakes differed 2-3 fold, the digestibility of the standard pelleted diet was not signficantly different in winter (0.68 ± 0.02), spring (0,74 ± 0.01) and summer (0.71 ± 0.01). However, digestibilities of natural forages increased greatly from winter (0.51 ± 0.01), to spring (0.77 ± 0.02), with a gentle decline into autumn (0.65 ± 0.02). Because retention times of pelleted diets were not significantly different among seasons (winter 28 + 1 h, spring 24 ± 2 h, summer 22 ± 1 h), digestive kinetics also seemed to be mainly a function of seasonal composition of native forage rather than specific seasonal adaptation. The mean retention time of winter herbage (41 ± 2 h) was significantly longer than that of spring (28 + 3 h) and summer (25 ± 2 h) forages. Pasture forages were retained longer (51 ± lh) than pellets in winter but not in spring (28 ± 1 h) and summer (27 ± 1 h). Fecal moisture was a good indicator of digesta retention time despite forage type and may provide a simple index of digestive function for field studies.
2

Relationship in red deer Cervus elaphus mandibles

72%
Langvatn R., Mysterud A., Stenseth N. C.
Acta Theriologica
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2004
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tom 49
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nr 4
Growth in mammals often implies differences in body proportions and tissue development more or less characteristic for different age periods and ontogenetic stages. Mouth morphology is an important functional trait in herbivores, as it may determine both maximal intake rate and possibly level of selectivity. An untested hypothesis is that since individual bones within the skeleton are retarded in growth and development in proportion to their growth intensity at each time interval during periods of restricted nutritional supply, this may potentially affect ultimate skeletal proportions. We analysed data on mandible proportions (anterior:total) of 62 fetuses collected at different stages of growth and 16 776 red deerCervus elaphus Linnaeus, 1758 hinds from 0 to 26 years of age and 24026 males from 0 to 22 years of age harvested during autumns 1965–2001 along the west coast of Norway. At the fetal stage, the mandible proportion was negatively related to body weight and, therefore, declined with age of the fetus. The anterior part of the mandible was initially longer than the posterior part; the mandible proportion was between 0.75–0.8 at the fetal stage, but declined with increasing age. The relationship between mandible proportion and weight was strong for calves, but decreased with increasing age, and the relationship was almost flat when reaching 5 years of age. From 5 years, the anterior and posterior part of the mandible was approximately equal in length and this mandible proportion (0.50–0.51), which was unrelated to weight, remained stable for the rest of the life in both hinds and stags. After they were fully-grown, early conditions (cohort density and climate as measured by the North Atlantic Oscillation) had no measurable effect on ultimate mandible proportions after the effect of body weight was removed.
3

Foraging ecology and spatial behaviour of the red fox (Vulpes vulpes) in a wet grassland ecosystem

58%
Meisner K., Sunde P., Clausen K. K., Clausen P., Faelled C. C., Hoelgaard M.
Acta Theriologica
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2014
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tom 59
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nr 3
We investigated diet composition, habitat selection and spatial behaviour of the red fox (Vulpes vulpes) in relation to the availability of wader nests in a coastal polder area in southwest Denmark. The predatory role of the red fox in wet grassland ecosystems has profound implications for conservation status of declining populations of grassland breeding waders. However, few studies have focussed on the foraging ecology and behaviour of the red fox in these landscapes. Faecal analyses revealed that fox diet consisted of birds (43 % of prey remains / 32 % of biomass), rodents (39 % / 21 %), sheep (mainly as carrion, 14 % / 41 %) and lagomorphs (4 % / 7 %). Charadriiformes (including waders) comprised 3–12 % of prey remains throughout the year. Telemetry data and spotlight counts indicated that foxes did not select areas with high densities of breeding waders, suggesting that foxes did not target wader nests while foraging. Foxes maintained stable home ranges throughout their lives, indicating that the area sustained a permanent fox population all year round. The population densities, estimated from spotlight surveys, were 0.74 visible foxes km−2 (95 % CI; 0.34–1.61) on the preferred breeding habitat for waders and 1.21 km−2 in other open habitats such as cultivated fields. Our results indicate that red fox predation on wader nests is incidental, consistent with the notion that red foxes are generalist predators that opportunistically subsist on many prey groups.
4

Sympatric fruit bat species (Chiroptera: Pteropodidae) in the Comoro Islands (Western Indian Ocean): diurnality, feeding interactions and their conservation implications

58%
Trewhella W. J., Rodriguez-Clark K. M., Davies J. G., Reason P. F., Wray S.
Acta Chiropterologica
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2001
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tom 03
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nr 2
The fruit bats Pteropus livingstonii and Pteropus seychellensis comorensis coexist on two of the Comoro Islands, in the Western Indian Ocean. Pteropus livingstonii is more diurnally active than P. s. comorensis. Differences exist in the feeding strategies exhibited by both species when feeding together on kapok (Ceiba pentandra), with P. livingstonii dominant in aggressive interactions with P. s. comorensis. Preliminary investigations suggest that, although there may be some overlap in feeding ecology, with both species feeding on native forest plants, there may be little evidence of overlap in the native fruits eaten. These differences complement known differences in the roosting ecology, flight behaviour, morphology and timing of reproduction of the two sympatric Pteropus species, and suggest that P. s. comorensis does not act as a major limiting factor on P. livingstonii. The implications for the conservation of the Critically Endangered P. livingstonii are discussed.
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