Wyniki wyszukiwania

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The effect of time of release on microhabitat use by the white-footed mouse

100%

Menzel M. A., Carter T. C., Jablonowski L. R., Laerm J.

Acta Theriologica

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2000

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tom 45

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nr 2

Fluorescent paint powders have frequently been used to determine the spatial activity patterns and microhabitat use of small mammals. The time of day that powdered animals were released differs among studies and data used in many studies were collected on the trails of powdered animals released in the morning outside the normal period of activity of many species of small mammals. We tested for differences in the characteristics of fluorescent powder trails of white-footed mice Peromyscus leucopus (Rafmesque, 1818) released using three protocols: night capture-night release, morning capture-morning release, and morning capture-delayed night-release. The night release and morning release protocols were established to replicate the extremes found in the literature. We added the third protocol to evaluate how capturing mice in the morning, holding them in captivity, and releasing them at night affected their use of microhabitat. There were no significant differences in the use of microhabitat between the night release and delayed night-release treatments. However, a significantly greater proportion of the trails of mice released in the morning were in areas of thick cover and under logs than the trails of mice released at night. Because mice released during the day used microhabitat differently than mice released at night, we caution against the interpretation of data on use of habitat collected using the fluorescent powder trails of animals released outside their normal period of activity.

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Mensural discrimination between sympatric Peromyscus leucopus and P. maniculatus in southern Illinois

100%

Sternburg J. E., Feldhamer G. A.

Acta Theriologica

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1997

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tom 42

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nr 1

A total of 383 Peromyscus was collected from southern Illinois to determine morphological characteristics useful in identifying individuals as either P. leucopus (Rafinesque, 1818) or P. maniculatus (Wagner, 1845). Polyacrylamide gel electrophoresis of salivary amylase was used to positively identify all specimens. No univariate morphological character accurately discriminated between the two species because of a high degree of intraspecific variation. Stepwise discriminant function analysis of external characters correctly classified 97.9% of subadults to species. The most important external character was the tail length/body length ratio. This ratio was also the most important factor in discrimination of adults; the function correctly classified 98.6% of individuals. Considering skull measurements of adults, 9 cranial characters were needed to differentiate between the two species, with a correct classification of 98.9%. For old adults, all specimens were classified correctly using 5 cranial characters. There was no fast, easy, accurate method to discriminate between these species 100% of the time in the fieid.

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Maximizing survivorship in cold: thermogenic profiles of non-hibernating mammals

84%

Merritt J. F., Zegers D. A.

Acta Theriologica. Supplement

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2002

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tom 47

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nr 1

Winter-active small mammals residing in seasonal environments employ many different behavioral, anatomical and physiological mechanisms to cope with cold. Herein we review research on survival mechanisms in cold employed by small mammals with emphasis on the families Soricidae, Muridae and Sciuridae. The focus of this review is on research delineating the role of seasonal changes in resting metabolic rate (RMR), nonshivering thermogenesis (NST), body mass, and communal nesting in enhancing winter survivorship of six species of small mammals (masked shrew Sorex cinereus, short-tailed shrew Blarina brevicauda, southern red-backed vole Clethrionomys gapperi, white-footed mouse Peromyscus leucopus, deer mouse P. maniculatus, and southern flying squirrel Glaucomys volans) residing in the Appalachian Mountains of Pennsylvania, USA. Each species shows good over-winter survivorship but exhibits a different suite of mechanisms to maximize survival in cold. B. brevicauda, S. cinereus, and G. volans show slight increases in RMR during winter, whereas Peromyscus and C. gapperi exhibit decreased RMR overwinter. All six species experience elevated NST in winter. The comparatively low RMR and NST of G. volans during winter was attributable to a decreased energy expenditure due to a larger body mass, coupled with communal nesting in cavities of trees that provided insulation from low ambient temperatures. Squirrels nesting singly experienced a longer period of elevated NST in winter and higher mean NST year-round than did squirrels nesting communally. Energy conservation in the form of growth retardation in winter was exhibited by C. gapperi and S. cinereus but not the other species.

4

Nest mortality in a population of small mammals

84%

Millar J. S., Havelka M. A., Sharma S.

Acta Theriologica

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2004

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tom 49

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nr 2

Female white-footed mice Peromyscus leucopus (Rafmesque, 1818) and their dependent offspring were monitored in nest boxes to determine the extent and causes of nest mortality. The mortality of dependent young was high (561 of 838; 66%) and variable among years. Most mortality involved the loss of entire litters (112 of 183 litters; 61%), with half of these losses attributed to the death of lactating females before the young were weaned (59 of 112 litters; 53%). Most mortality was from unknown causes, although infanticide, energetic constraints and prédation were identified in a small number of cases. Prédation is likely the major source of mortality in this population.

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Factors influencing perceived community structure in nearctic forest small mammals

59%

Kirkland G. L., Sheppard P. K., Shaughnessy M. J., Woleslagle B. A.

Acta Theriologica

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1998

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tom 43

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nr 2

Arrays of pitfalls and drift fences were deployed in five deciduous forest habitats in southcentral Pennsylvania to assess the characteristics, and temporal and spatial dynamics of forest small-mammal communities, and to determine the impact of precipitation, sampling method, and length of sampling period on perceived small-mammal abundance and community structure. Results revealed that soricid assemblages were more diverse and generally more abundant than rodent assemblages, which were dominated by the white-footed mouse Peromyscus leucopus. Precipitation dramatically increased the capture rates of shrews; the response was less pronounced in rodents. Individual species responded independently to precipitation. The response was more pronounced in three species of arvicoline rodents (Clethrionomys gapperi, Microtus pinetorum, and M. pennsylvanicus) than in P. leucopus, a sigmodontine. Comparisons of sampling with pitfalls and Museum Special snap-traps, with and without drift fencing, revealed that arrays of pitfalls with drift fences produced significantly higher capture rates for all small mammals, shrews, rodents, and P. leucopus, greater numbers of species, and higher Shannon indices than other sampling methods, Comparison of the results of sampling for 3, 5, 7, and 10 days revealed that extending sampling to 7 or more days yielded significantly more species, higher Shannon indices, and greater numbers of individuals than sampling for less than 7 days.

Ograniczanie wyników

4 Acta Theriologica

1 Acta Theriologica. Supplement

1 Carter T. C.

1 Feldhamer G. A.

1 Havelka M. A.

1 Jablonowski L. R.

1 Kirkland G. L.

1 Laerm J.

1 Menzel M. A.

1 Merritt J. F.

1 Millar J. S.

1 Sharma S.

1 Shaughnessy M. J.

1 Sheppard P. K.

1 Sternburg J. E.

1 Woleslagle B. A.

1 Zegers D. A.

1 2004

1 2002

1 2000

1 1998

1 1997

The effect of time of release on microhabitat use by the white-footed mouse

Mensural discrimination between sympatric Peromyscus leucopus and P. maniculatus in southern Illinois

Maximizing survivorship in cold: thermogenic profiles of non-hibernating mammals

Nest mortality in a population of small mammals

Factors influencing perceived community structure in nearctic forest small mammals