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An animal’s pelage, feather, or skin color can serve a variety of functions, so it is important to have multiple standardized methods for measuring color. One of the most common and reliable methods for measuring animal coloration is the use of standardized digital photographs of animals. New technology in the form of a commercially available handheld digital color sensor could provide an alternative to photography-based animal color measurements. To determine whether a digital color sensor could be used to measure animal coloration, we tested the ability of a digital color sensor to measure coloration of mammalian, avian, and lepidopteran museums specimens. We compared results from the sensor to measurements taken using traditional photography methods. Our study yielded significant differences between photography-based and digital color sensor measurements of brightness (light to dark) and colors along the green to red spectrum. There was no difference between photographs and the digital color sensor measurements for colors along the blue to yellow spectrum. The average difference in recorded color (ΔE) by the 2 methods was above the threshold at which humans can perceive a difference. There were significant correlations between the sensor and photographs for all measurements indicating that the sensor is an effective animal coloration measuring tool. However, the sensor’s small aperture and narrow light spectrum range designed for human-vision limit its value for ecological research. We discuss the conditions in which a digital color sensor can be an effective tool for measuring animal coloration in both laboratory settings and in the field.

An animal's perception of predation risk varies across a heterogeneous landscape. Animals rely on indirect cues in the environment, including availability of protective cover, openness of sightlines and distance to refuge to evaluate potential predation risk. Interactions between the indirect cues that influence an animal's perception of predation risk are poorly understood, especially for prey at risk of avian and terrestrial predation. We conducted a giving-up density (GUD) study to examine how interactions between terrestrial predator presence, ceiling (canopy) cover, wall (shrub/grass) cover and distance to nearest tree influence fox squirrel, Sciurus niger, risk perception. The GUD indicates an animal's perceived predation risk, such that increased GUD (decreased foraging) corresponds to greater perceived risk. We found that fox squirrels perceived cues of predation risk in response to a synergistic interaction between ceiling and wall cover. In open canopy areas, fox squirrels increased GUD where there was also increased wall cover. However, fox squirrels reduced GUD in closed canopy areas where there was also increased wall cover. We attribute the differential effects of wall cover depending on ceiling cover to the effectiveness of open sightlines in decreasing predation risk from avian or terrestrial predators. Our study shows that the effect of vegetation structure on prey risk perception and antipredator behaviour depends on the relative risk posed by avian and terrestrial predators that use different hunting strategies.

Animals change their daily activity patterns in response to season, food availability and the presence of competitors. Competition may be an important driver of a species’ daily activity pattern, as animals manage conflict by avoiding each other temporally. We evaluated how vegetation structure and the presence of competitors changed the daily activity patterns of closely related fox squirrels, Sciurus niger, and grey squirrels, Sciurus carolinensis. We monitored squirrel activity in north and central Florida using passive game cameras at two spatial scales: local and point. To understand how seasonality and competition interact to drive behaviour, we compared squirrel activity during the leaf-off (1 January – 15 March) and leaf-on (16 March – 1 July) seasons. We tested for a relationship between squirrel activity and canopy cover by fitting a von Mises kernel distribution. To test how season and competition affected squirrel behaviour, we compared activity by computing a kernel density overlap function, ranging from 0 (no overlap: the squirrels are never active at the same time) to 1 (complete overlap: the squirrels have identical activity patterns). We found that daily squirrel behaviour was not influenced by canopy cover (P = 0.61). Fox squirrels had a single activity peak occurring around midday. In contrast, grey squirrels had a bimodal activity pattern with peaks shortly after sunrise and before sunset. The intensity of this partitioning existed on a gradient and changed with season and the presence of competitors. Fox and grey squirrel daily patterns overlapped the most when they were allopatric in the leaf-on season (overlap = 0.70, P

We observed a series of long-distance movements by an adult male Sciurus niger (Eastern Fox Squirrel). The squirrel traveled 1040 m between 25 May and 27 May, and ≥503 m on 5 separate occasions between 29 April and 25 May 2017. The individual traveled between experimental foraging sites and was photographed by remote cameras placed at each site. The time it took to travel between sites varied from 1 h and 5 min to 5 h and 7 min. The distance this squirrel regularly traveled is approximately the diameter of an average Eastern Fox Squirrel home range in the southeastern United States.

Disturbances such as fire play an important role in shaping forests and the wildlife they support. As such, forest managers employ prescribed fire to restore ecosystem function, promote forest biodiversity, and maintain wildlife habitat. To better understand how bats respond to variation in fire regime, we used acoustic recorders to quantify bat activity in forests maintained by frequent fire in southern Florida, USA and modelled this variation as a function of both fire regime and vegetation characteristics. Next, to better understand the mechanisms underlying these responses, we quantified variation in bat foraging efficiency and activity during the important early evening period. We found that even in regions historically maintained by frequent fire, bat activity was more closely associated with vegetation conditions, such as canopy cover and woody understory volume, than fire regime. When vegetation and fire frequency were considered together, the bat activity response was nuanced. Activity across the bat community was greater in forests that had burned more frequently in the previous two decades, but bats appeared more likely to encounter prey in forests that burned less frequently. Species-specific responses added additional complexity, potentially related to size and wing morphology, with larger bats responding more strongly to fire, whereas activity of smaller bats was primarily related to vegetation characteristics. Similarly, activity during the early-evening shifted as a function of fire frequency, but in different directions for different species. Our results suggest that investigations of occurrence or overall bat activity may provide an incomplete understanding of the complex responses to fire regimes that become more apparent when activity is partitioned into more refined metrics. These nuances have implications for management of fire-maintained forests. Though frequent burning may best promote the ecosystem services associated with insectivorous bat activity, a more heterogenous approach to fire management that considers bat species diversity, bat behavior, and vegetation conditions may provide additional benefits to bats.

Many sympatric species use Gopherus polyphemus (Gopher Tortoise) burrows as refugia from predators, extreme temperatures, and fire. As part of an ongoing project involving trail-camera monitoring at Gopher Tortoise burrows, we observed a Sciurus niger (Eastern Fox Squirrel) sheltering in an occupied burrow twice in a single day. Eastern Fox Squirrels primarily forage on the ground, and Gopher Tortoise burrows likely offer refuge from avian predators but could expose Eastern Fox Squirrels to increased predation risk from mammalian and reptilian predators. Alternatively, the squirrel may have been seeking refuge from higher-than-average temperatures. Our observation further demonstrates the importance of Gopher Tortoise burrows to vertebrate fauna in the southeastern United States.