Ecology of a Maryland Population of Black Rat Snakes (Elaphe o. obsoleta)

Stickel, Lucille F.; Stickel, William H.; Schmid, Frederick C.

doi:10.2307/2425033

Cited by 39 publications

(29 citation statements)

References 11 publications

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“…First, SFS show a strong selection for cavities with small entrances and appear to avoid cavities that have been enlarged by other species (Loeb ). Natural cavities with small entrances presumably provide greater protection from predators (e.g., black rat snakes [ Pantherophilis obsoletus ]; Stickel et al ) and may reduce accessibility (and thus competition) via arboreal routes from other larger sciurids such as fox squirrels ( Sciurus niger ) and gray squirrels ( S. carolinensis; Muul , Bendel and Gates ). Our results corroborate previous hypotheses regarding nest‐tree use by SFS and Siberian flying squirrels ( Pteromys volans ) in Finland, whereby cavities with small entrance holes were the most common nest source and prevented access by most natural predators (e.g., owls [ Strix uralensis ], pine marten [ Martes martes ]; Selonen et al , Selonen and Makelainen ).…”

Section: Discussionmentioning

confidence: 99%

Nest tree use by southern flying squirrels in fragmented midwestern landscapes

et al. 2018

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Southern flying squirrels (Glaucomys volans; SFS) nest in naturally formed cavities in snags and hardwoods found in mature, oak (Quercus spp.)–hickory (Carya spp.) forests. Intensive forest fragmentation of the Midwest United States limits the number of available nesting trees. We quantified annual nest‐site selection patterns by southern flying squirrels across fragmented landscapes of west‐central Illinois, USA. We used radiotelemetry to measure nest‐tree use by 55 SFS (30 males, 25 females) captured during 2014–2016. Of 105 nest trees used by SFS, live trees and snags comprised 75% and 25%, respectively. Probability of diurnal nest‐tree use increased 1.08/1.00‐cm increase in diameter‐breast‐height and by 1.50/1‐unit increase in the number of overstory mast trees between random and nest‐tree habitat areas (i.e., 300‐m2 circular plots). Similarly, probability of diurnal nest‐tree use increased 1.29/1‐unit increase in the number of snags between random and nest‐tree habitat areas. Our results revealed no intersexual differences in patterns of nest‐site selection, which may reflect the tendency for SFS to compensate for reduced availability of key structural attributes (i.e., snags, overstory trees) across fragmented forests by exhibiting similar intersexual patterns of nest‐tree use. Use of natural cavities for denning is encouraging, but also underscores the importance of unharvested oak–hickory forests in contributing essential habitat to SFS populations in fragmented Midwestern landscapes. © 2018 The Wildlife Society.

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Section: Discussionmentioning

confidence: 99%

Nest tree use by southern flying squirrels in fragmented midwestern landscapes

et al. 2018

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“…Black rat snakes feed mostly on rodents (Fitch 1963, Stickel et al 1980. Black rat snakes feed mostly on rodents (Fitch 1963, Stickel et al 1980.…”

Section: General Patterns Of Thermoregulationmentioning

confidence: 99%

Thermal Ecology of Black Rat Snakes (Elaphe obsoleta) in a Thermally Challenging Environment

Blouin‐Demers¹,

Weatherhead²

2001

Ecology

106

178

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A general model in thermal ecology predicts that ectotherms should stop thermoregulating when the costs outweigh the benefits. Support for this model comes from studies of warm-temperate species, but the extent to which the model can be extrapolated to species living in climatic extremes is unknown, because of the lack of information regarding the thermoregulatory behavior of such species. We tested the applicability of this cost-benefit model using data for black rat snakes (Elaphe obsoleta obsoleta) studied at the northern extreme of their range in Ontario. During 1997-1999, we used automated temperature-sensitive radiotelemetry to collect ϳ150 000 body temperatures from 53 freeranging rat snakes. Simultaneously, we used physical models of snakes to measure the environmental operative temperatures available to black rat snakes, and we determined their preferred body temperature range in a laboratory thermal gradient. The mostly forested habitats inhabited by rat snakes in Ontario were more thermally challenging than the habitats of other species studied to date. The preferred body temperature ranges of male, nongravid female, and gravid female black rat snakes were not significantly different (preferred body temperature averaged across all individuals, 28.1ЊC). However, free-ranging gravid females tended to maintain higher body temperatures in order to thermoregulate more effectively as well as exploit their thermal environment more than males and nongravid females. This difference was most pronounced during the day and prior to egg laying, and constituted the first documentation of such a phenomenon in an oviparous snake. Black rat snakes had indices of thermoregulation effectiveness similar to other species but tended to exploit opportunities for thermoregulation less. Overall, our data provided support that was at best ambiguous for the current cost-benefit thermoregulation model, suggesting that this model may generally be less applicable to species inhabiting climatic extremes. We propose that, for species in extreme climates, the costs associated with thermoconformity may be more important than previously recognized. We identified several problems associated with the index of thermoregulation effectiveness used by previous researchers, and we propose a mathematically simpler alternative that circumvents these problems. We also make recommendations regarding the future use of the various indices of thermoregulation developed in recent years.

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“…Because our study site was relatively small (460 ha), a 1000 m home range ensured that any individual snake was able to reach and explore a large percentage of the study area comprised of a mix of habitat patch types. Consistent with the reported range of rat snake densities (Fitch, 1963;Stickel et al, 1980), for our model we assumed there were 100 ratsnakes at the site. All snake movements were independent of other snakes on the landscape.…”

Section: Ratsnake Movementmentioning

confidence: 85%