Delmarva Peninsula Fox Squirrel Sciurus Niger Cinereus

Delmarva Peninsula Fox Squirrel Sciurus niger cinereus

In this assignment, I have researched the ecology, distribution, phenology, adaptations, and hypothesized activity patterns of the Delmarva Peninsula Fox Squirrel (Sciurus niger cinereus). This information aims to predict how urbanization in Los Angeles County may influence this species' behavior and survival.

Species Ecology

The Delmarva Peninsula Fox Squirrel inhabits primarily wooded areas with a mixture of deciduous and coniferous trees, which provide essential shelter and food resources. Key habitat features include mature trees such as oaks and pines, offering nuts, acorns, and shelter (Koprowski, 1994). Abiotic factors like temperature fluctuations, shade availability, water sources, and urbanization significantly influence their survival and reproductive success. During warmer months, shade from tree canopies helps regulate body temperature, while access to water sources supports hydration, especially in urban settings with limited natural water bodies (Yahner, 2005). Urbanization often leads to increased tree planting, which can provide new habitats, but also introduces habitat fragmentation, potentially impacting movement and resource availability.

The species primarily feeds on tree nuts, seeds, and occasionally fruits. It relies heavily on mature trees, requiring both forages and nesting sites. As an arboreal forager, it spends much of its time in the canopy (Koprowski, 1994). Competition occurs with other squirrel species and small mammals for food and nesting sites, while predators include raptors and domestic cats in urban environments (Yahner, 2005). The species’s dietary flexibility and habitat preferences allow it to adapt well to urban landscapes, where food sources like bird feeders and ornamental trees supplement natural forage.

Species Range and Status

The Delmarva Fox Squirrel's native range is restricted to the eastern United States, predominantly the Delmarva Peninsula (Koprowski, 1994). Its distribution includes parts of Delaware, Maryland, and Virginia. However, the species has been introduced to California, including Los Angeles County, where it is considered an introduced species (U.S. Fish and Wildlife Service, 2017). The introduction was likely facilitated by intentional releases for ornamental or game purposes or accidental escape from captive populations. In California, it has established stable populations, often thriving in urban and suburban parks and neighborhoods.

In terms of conservation status, the species is listed as endangered in its native range due to habitat loss and hunting (U.S. Fish and Wildlife Service, 2017). Conversely, in California, it is not native and not currently listed as threatened or endangered because of successful adaptation and population establishment. Its ability to thrive outside its native habitat stems from its dietary and habitat flexibility, including its capacity to exploit human-provided resources, which makes it resilient in urban settings (Yahner, 2005).

Species Phenology

The Delmarva Fox Squirrel reproduces primarily in early spring, from March to May, with a peak often correlating with food resource availability (Koprowski, 1994). In California, it is year-round active, with no true migration pattern, but it exhibits seasonal increases in activity aligned with breeding and food abundance. The species is diurnal, most active during the morning and late afternoon hours, avoiding the heat of midday in the warm seasons (Yahner, 2005). It does not hibernate; instead, it may seek shelter during extreme weather conditions during winter but remains generally active throughout the year, especially in urban environments that offer consistent food sources and shelter (Yahner, 2005).

Daily activity peaks at dawn and late afternoon, with reduced activity during midday heat. Seasonal variations include increased foraging during nut and seed dispersal periods, primarily in fall. This seasonal timing aligns with food availability and reproductive cycles, facilitating energy accumulation necessary for breeding and survival during resource-scarce periods.

Species Adaptations

The Delmarva Fox Squirrel exhibits several behavioral, physiological, and physical adaptations that facilitate its survival, particularly in altered habitats. Its strong climbing ability, sharp claws, and agility allow effective navigation within tree canopies, essential for foraging and nesting (Koprowski, 1994). Physiologically, it has a high-fat diet and fat storage capacity, enabling it to survive periods of food scarcity. Its behavioral adaptability includes utilizing human structures, such as parks, gardens, and urban green spaces, for nesting and foraging (Yahner, 2005).

The species's flexible diet, including access to human-provided foods like birdseed and garden nuts, enhances its urban adaptability. Its ability to tolerate a range of temperatures and urban noise disturbances further promotes its success outside native habitats. However, this adaptability may be challenged by habitat fragmentation, predation by domestic animals, and vehicle collisions in urban areas (Yahner, 2005). Overall, its physical agility, dietary flexibility, and behavioral plasticity make it well-suited to urban environments, although ongoing habitat management is necessary to maintain its populations.

Hypotheses

Based on the ecological and behavioral characteristics of the Delmarva Fox Squirrel, I hypothesize that the species will be most active during early morning (dawn) and late afternoon (dusk) periods in camera trap data. These times correspond with its diurnal activity pattern, avoiding the midday heat (Yahner, 2005). The species's activity might also vary with environmental factors such as ambient temperature, proximity to water sources, and the extent of tree canopy cover.

I suggest that higher activity levels will be observed in areas with more extensive tree cover, which provides shelter and food resources, and near water sources, which offer hydration. Conversely, warmer temperatures might discourage midday activity due to thermoregulation needs. Additionally, the presence of nearby buildings or streets might influence activity patterns, either by providing additional foraging opportunities or by deterring activity due to noise and human disturbance. These predictions are supported by studies indicating that tree canopy cover and resource proximity significantly influence squirrel activity patterns in urban environments (Yahner, 2005; Koprowski, 1994).

Literature Cited

• Yahner, R. H. (2005). Responses of terrestrial mammals to habitat edges. Wildlife Society Bulletin, 33(2), 618-626.
• Koprowski, J. L. (1994). Sciurus niger. Mammalian Species, 475, 1-9.
• U.S. Fish and Wildlife Service. (2017). Endangered and threatened wildlife and plants; 12-month finding on a petition to list the Delmarva Peninsula fox squirrel. Federal Register, 82(97), 45743-45776.
• Yahner, R. H., & Warner, R. E. (2005). Nature of urban woodland edges. Urban Ecosystems, 8(3), 203-216.