Daily and seasonal activity patterns of the dorcas gazelle,scimitar-horned oryx,north-African ostrich and canids in an arid habitat

North Africa's megafauna has developed behavioural adaptations to reduce energetic and fitness costs under harsh arid land conditions. Animal behaviour and activity patterns are difficult to study in the wild, but remote camera traps provide a solution to collecting data without the presence of a researcher influencing outcomes. Here, we report results from a study comprising over 20,382 camera-trap days during a 34-month period in Dghoumes National Park, Tunisia. We aimed to evaluate temporal activity patterns and their overlap and explore opportunities for niche partitioning. Our focal species were the reintroduced scimitar-horned oryx, north-African ostrich, dorcas gazelles and extant regional top-order predators, African wolf and red fox. We found differences in activity patterns between seasons across the focal species, with the most noticeable change being an increase in dawn activity from 1% to 33% between winter and summer for the red fox. Consequently, higher summer temperatures limit opportunities for temporal niche partitioning and push focal species towards dawn-time activity peaks resulting in higher intra-guild overlap values at dawn. Arid antelopes have physiological adaptations that enable them to better exploit ecological resources in hotter time periods than the carnivores, and this reduces inter-guild overlap during summer days.     

Habitat Use of Fox Squirrels in an Urban Environment

Abstract: Tree squirrels are one of the most familiar mammals found in urban areas and are considered both desirable around homes and, conversely, a pest. We examined fox squirrel (Sciurus niger) habitat use in inner city and suburban areas using radiotelemetry. We estimated habitat selection ratios at differing scales by season and fox squirrel activity. Telemetry data suggests that during periods of inactivity radiocollared fox squirrels (n = 82) selected 1) areas with greater tree canopy, 2) live oaks (Quercus fusiromis and Q. virginiana), and 3) trees with larger diameters and canopies. When inactive during the winter and spring, fox squirrels also preferred, within their core areas, to use the inside of buildings, and during periods of activity in the autumn and spring, fox squirrels preferred grassy areas. During periods of activity, fox squirrels avoided using pavement but did not exclude it from their core-area movements. Fox squirrels' ability to use buildings and to tolerate pavement in core-area movements make vast areas of the urban environment available to fox squirrels. In evaluating habitat variables that increased fox squirrel activity in urban areas, we found the number of large and medium trees, amount of pavement and grassy areas, canopy cover, number of oaks, and the area covered by buildings were all important factors in predicting fox squirrel activity in an urban environment. Our data suggests urban planners, animal damage control officials, wildlife managers, and landscapers who want to control urban fox squirrel populations through habitat manipulation should consider the reduction of oaks trees, a reduction of the canopy cover, and restricting the access of fox squirrels to buildings. Alternatively, home owners and squirrel enthusiasts hoping to bolster fox squirrel populations in urban areas should consider increasing the number of large mast—bearing trees and canopy cover and providing nest boxes.     

The daily cycle of activity in the mole (Tabu europaea) and its seasonal changes, as revealed by radioactive monitoring of the nest

The daily cycle of activity in the mole (Talpa europaea) and its seasonal changes, as revealed by radioactive monitoring of the nest
Published information on the activity rhythm of the mole ( Talpa europaea ), although limited to observations on a very few moles during February-April, had indicated a basic short-term cycle of approximately 8 hours. The technique used, manual tracking of radioactively tagged individuals with portable monitors, was modified for the present study to record automatically the presence or absence of the tagged mole at its nest site. Data were obtained for all months of the year, with a total of 797 days of records from 14 male and 13 female animals. The most characteristic feature of the records, irrespective of the time of year and thus daylength, was the sharpness of the transition from inactivity to activity at dawn and the reverse shortly prior to dusk. During midwinter, when daylength was short the animals tended to be active throughout the day, with few or no rest periods at the nest, and there was only one other active period, during the night. With increasing daylength there was usually a short rest period about midday so that the animals had the classical 3-cycle daily rhythm. In summer, with the longest days and shortest nights the timing of the daytime rest period was variable and there was often no active period during the night so that the short-term cycles were less distinct.     

Usefulness and limitation of a tiny light-temperature logger to monitor daily activity levels of arboreal squirrels in temperate areas

Owing to recent advances in technology, biologging has revealed in-depth animal behavior at a level of detail that previously could not be obtained. However, previous studies were limited to relatively large species due to constraints caused by the size of data loggers. Some recent studies, however, applied tiny light loggers (geolocator) to monitor daily activity levels of small rodents in the southern arctic and far north Holarctic. In this study, we tested whether a similar method can be applied to arboreal squirrels in temperate regions, by combining light intensity and temperature data. Inside the squirrel’s nest was dark enough during daylight hours to capture out of nest activity with light intensity, clearly showing daily and seasonal changes in diel activity patterns. The new temperature function on the device showed consistently high temperature within the nests (35–37 °C) and suggested additional activity before sunrise; the squirrels were primarily diurnal, but occasionally left their nest for short periods (an average of 13 min) during the night. We also found that estimates of daily activity time changed depending on the threshold cut-off values of light intensity and provide a recommendation of 5 to 25 lx for future studies. In addition, temperature loggers were not always effective during summer when warmer ambient temperature approached the squirrel’s body temperature. While the inexpensive and tiny light-temperature logger has potential to monitor activity levels of small mammals, care should be taken when analyzing the output.     

Seasonal variations in basal metabolic rate, lower critical temperature and responses to temporary starvation in the arctic fox (Alopex lagopus) from Svalbard

Metabolic rates of four resting, post-absorptive male adult summer- and winter-adapted captive arctic foxes (Alopex lagopus) were recorded. Basal metabolic rates (BMR) varied seasonally with a 36% increase from winter to summer, while body mass was reduced by 17% in the same period. The lower critical temperature (T _1c) of the winter-adapted arctic fox was estimated to −7°C, whereas T _lc during summer was 5°C. The similarity of these values, which are much higher than hitherto assumed (e.g. Scholander et al. 1950b), is mainly due to a significantly (P<0.05) lower BMR in winter than in summer. Body core (stomach) temperature was stable, even at ambient temperatures as low as −45°C, but showed a significant (P<0.05) seasonal variation, being lower in winter (39.3±0.33°C) than in summer (39.8±0.16°C). The thermal conductivity of arctic fox fur was the same during both seasons, whereas the thermal conductance in winter was lower than in summer. This was reflected in an increase in fur thickness of 140% from summer to winter, and in a reduced metabolic response to ambient temperatures below T _lc in winter. Another four arctic foxes were exposed to three periods of forced starvation, each lasting 8 days during winter, when body mass is in decline. No significant reduction in mass specific BMR was observed during the exposure to starvation, and respiratory quotient was unchanged at 0.73±0.02 during the first 5 days, but dropped significantly (P<0.05) to 0.69±0.03 at day 7. Locomotor activity and body core (intraperitoneal) temperature was unaltered throughout the starvation period, but body mass was reduced by 18.5±2.1% during these periods. Upon re-feeding, locomotor activity was significantly (P<0.05) reduced for about 6 days. Energy intake was almost doubled, but stabilised at normal levels after 11 days. Body mass increased, but not to the level before the starvation episodes. Instead, body mass increased until it reached the reduced body mass of ad libitum fed control animals. This indicates that body mass in the arctic fox is regulated according to a seasonally changing set point.     

Mountain hare populations on islands: effects of predation by red fox

Summary On islands off the west coast of Sweden the density of mountain hares (Lepus timidus L.) is very high. One of the main predators on hares, the red fox (Vulpes vulpes L.), is only present during short periods. Data on hare density and predation by red fox and eagle owl (Bubo bubo (L.)) has been analyzed from five islands over several years. Winter mortality in years with low predation pressure was independent of hare density. But when red fox or eagle owl were present on islands (i.e., high predation pressure) winter mortality became density dependent. Thus, at low density, winter mortality did not increase through red fox predation. But at densities up to two hares/ha, predation pressure was increasing and could be limiting for these populations. At still higher hare density predation pressure became less intensive. The functional response for foxes preying on hares showed a type II or a sigmoid type III response pattern. In normal summers, the population increase due to reproduction was at least two-fold. When a fox was present there was instead a sharp decrease in hare numbers. Fox predation had a stronger effect in summer than in winter. By switching between islands and mainland areas from winter to summer, a fox can stabilize fluctuations in hare numbers on the islands. This is dependent on how often the ice permits a fox to reach an island and the lack of numerical response by predators.     

Seasonal variation of activity patterns in roe deer in a temperate forested area

We investigated the activity patterns of a European roe deer (Capreolus capreolus) population living in a forested Apennine area in central Italy, in order to shed light on the environmental and biological factors that were expected to account for the observed activity patterns on daily and yearly bases. Daily and seasonal activity patterns of 31 radio-collared roe deer were assessed through sessions of radio tracking for a total period of 18 consecutive months. Roe deer showed bimodal activity patterns throughout the year, with the two highest peaks of activity recorded at dawn and dusk. Activity patterns of males and females differed during the territorial period (from early spring to late summer), whereas they did not during the nonterritorial period. Most likely, behavioral thermoregulation can be held responsible for variation of daily activity patterns in different seasons. In winter, for instance, activity during the dawn period was significantly higher than in other seasons and daylight activity was significantly higher than at night. Nocturnal activity was highest in summer and lowest in winter. During the hunting season, moreover, roe deer showed lower activity levels than during the rest of the year. The prediction that roe deer would show lower activity levels during full moon nights, when the predation risk was assumed to be higher, was not confirmed by our data. Activity rhythms in roe deer were thus subjected to both endogenous and environmental factors, the latter working as exogenous synchronization cues. Accordingly, in changing environmental and ecological conditions, a circadian cycle of activity could be seen as the result of complex interactions among daily behavioral rhythm, digestive physiology, and external modifying factors.     

Summer and winter torpor use by a free-ranging marsupial

Torpor is usually associated with low ambient temperatures (T(a)) in winter, but in some species it is also used in summer, often in response to limited food availability. Since the seasonal expression of torpor of both placental and marsupial hibernators in the wild is poorly documented by quantitative data, we investigated torpor and activity patterns of the eastern pygmy-possum Cercartetus nanus (17.4 g) over two seasons. We used radio telemetry to track animals during winter (n=4) and summer (n=5) in a warm-temperate habitat and found that torpor was used in both seasons. In winter all animals entered periods of short-term hibernation (from 5 to 20 days) containing individual torpor bouts of up to 5.9 days. In summer, torpor bouts were always <1 day in duration, only used by males and were not related to daily mean T(a). Pygmy-possums entered torpor at night as T(a) cooled, and rewarmed during the afternoon as T(a) increased. Individuals interspersed torpor bouts with nocturnal activity and the percentage of the night animals were active was the same in summer and winter. Our study provides the first information on torpor patterns in free-ranging C. nanus, and shows that the use of torpor throughout the year is important for energy management in this species.     

Some aspects of the metabolism of hibernating and recently aroused common dormouse Muscardinus avellanarius L. (Rodentia,Gliridae)

Summary A dormouse found in hibernation in its winter nest on January 26 was studied continously from February 5 until May 11 by recording ambient temperature, temperatures inside the nest ball and 5 cm from it, and by recording any possible motor activity. The first emergence from hibernaculum occurred on April 3 after which the animal was active each day with the exception of April 11, 13 and 14. Activity mainly occurred during evening and night hours and lasted on average 4 hrs (2–8 hrs) per day. Outside periods of activity the winter nest was consistently used as a place of shelter and for sleep.The ambient temperature ranged from-0.5° to 21.0°C being chiefly 1°C less the nestbox temperature. The difference between the nest-box and nest temperature was also about 1°C when the animal was inactive, thus clearly indicating torpidity. Steep increases in nest temperature, amounting to 14–18°C and raising nest temperature up to 30°C, were recorded on four occasions. This is interpreted as shallow torpor, since no activity occurred on these days.The spontaneous warming up from deep hypothermia to shallow torpor lasted on average 40 min (30–70 min), while the duration of passive cooling when returning to the hypothermic condition amounted to 5 hrs. In the weeks following continuous hibernation the dormouse alternated between activity, shallow torpor, and relatively deep torpor each day. The species should be considered as a true aestivator.     

A test of non‐kin social foraging in the southern flying squirrel (Glaucomys volans)

It can be challenging to understand the evolution of sociality, particularly the occurrence of co‐operation by non‐kin. Southern flying squirrels (Glaucomys volans) are an interesting example of non‐kin co‐operation because of the mutual benefits obtained by social thermoregulation during winter. Because group survival confers benefits to the entire group, flying squirrels may also follow an aggregation economy, whereby co‐operative foraging during winter is advantageous. However, the extent of such social foraging in flying squirrels is unknown. We tested for social foraging of southern flying squirrels, and also for relatedness among foraging groups. To determine the structure of foraging groups, we set up and remotely monitored feeding stations and nest cavities. All squirrels at the study site were tagged with passive integrated transponder (PIT) tags and nests and feeding stations were monitored with automated PIT‐tag recorders for a 24‐month period. Squirrels were found most often foraging alone. Squirrels that were recorded foraging together comprised unrelated individuals that were also found to share nest cavities. Squirrels were also recorded travelling farther distances between nest cavity and feeding station in the winter season than in the summer season, suggesting that, during winter, squirrels trade‐off proximity to food caches for membership in a nest group. Our data suggest that squirrels forage and cache alone in their summer home range and make solitary returns to this summer range to collect their cache during the winter months, despite exhibiting social winter nesting. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 1126–1135.     

Identifying activity patterns from activity counters in ETHOSYS® collars on red deer

Identifying activity patterns of animals from activity counts recorded by sensors in the storage-telemetry-system ETHOSYS^® requires to calibrate activity counters to field activities. We continuously observed from dawn to dusk during days 1, 3 and 5 three collared red deer hinds introduced into a 1-ha enclosure for five consecutive days in February (winter), May (spring) and July (summer) 2001. On the basis of concurrently count data collected every 5 min for each hind and each season, we selected the threshold sensor values which best allowed separation of inactive (mainly in the lying position) and active bouts. In winter and spring, the threshold sensor values ranged from 5 to 20 counts per 5 min, which allowed to correctly classified 90.1–98.5% of diurnal sampling intervals. However, higher threshold values (from 55 to 110 counts per 5 min) were found in summer, because foraging and lying periods occur more frequently together within the 5-min interval counts. So, only 76.9–81.4% of sampling intervals were correctly discriminated. To compare the daily activity patterns of hinds in each season, the percentage of time spent active was calculated on a hourly basis. Synchronized periods of activity occur among the three hinds throughout a 24-h period both in winter and summer. However, especially during daytime, the activity patterns of hinds differed significantly in spring. This could affect interpretation of activity patterns of animals from activity counts averaged from several individuals, even if having similar status and environmental conditions or over periods longer than the interval count adopted in the present study.     

Seasonal variation in freezability of buffalo semen

Fifty-six buffalo semen ejaculates of mass activity greater than plus three on a five-point scale (28 each in summer and winter seasons) were frozen in Tris yolk glycerol (TY-G) extender with four hours equilibration time. Motility of semen was checked after first extension (initial motility), after equilibration time, 15 minutes after freezing, and 30 days after freezing. Motility increased during winter season. Significant differences (P<0.01) in motility after freezing were observed between summer and winter seasons.     

The locomotory activity patterns of a functionally complete colony of Cryptomys hottentotus hottentotus (Rodentia: Bathyergidae)

The locomotory activity patterns of a colony of eight field-captured mole-rats housed in a transparent burrow system were monitored for a total of 240 hours. Movement along the burrow system was recorded for all hours of the 24-hour chronological day for 10 days. Intermittent periods of activity were characteristic for all the mole-rats in the colony. The lack of a distinct sleeping period reflects the asynchrony of each mole-rat's activity cycle with that of other colony members. There are four major peaks of activity during the 24-hour cycle and an absence of a well-defined diurnal or nocturnal phase to the activity cycle.
The nest area is a focal point in the burrow system with individuals spending between 36 and 81% of the day there. There is a positive correlation between the size of a group of sleeping mole-rats in the nest and the frequency of occurrence.     

Seasonal changes in the composition of titin isoforms in muscles of hibernating ground squirrels

An electophoretic study of changes in the content of intact titin isoforms, N2B-, N2BA-, N2A-titins and T2 in skeletal and cardiac muscles of ground squirrel (Spermophillus undulatus) is made in different periods: summer activity, autumnal activity, hibernation, arousal, and winter activity. In atria and ventricles of ground squirrels in the period of autumnal activity an increase (by ～1.5 times) in the N2BA to N2B ratio was observed, in comparison with that in cardiac muscle in summer activity. During hibernation, the decrease in the relative content of N2B-, N2BA-titins and T2 in cardiac muscle as well as of N2A-titin and T2 in skeletal muscles was determined against the background of preservation of the relative amount of intact titin isoforms. At waking of ground squirrels and in a short period of winter activity, a rapid restoration of the content of N2B-, N2BA-, N2A-titisns and T2 in muscles was observed. In the myocardium of hibernating, waking ground squirrels and of those during winter activity the increased N2BA to N2B ratio was retained. The changes in the titin content are discussed in the aspect of adaptation of ground squirrels to hibernation.     

A QUANTITATIVE STUDY OF THE DAILY ACTIVITY OF THE UGANDA DEFASSA WATERBUCK

Waterbuck activity was recorded at four-minute intervals for continuous periods of 12 hours on two or three consecutive days, and for single nocturnal periods. Feeding patterns of the male and female were similar and during the day there was no hour during which some feeding did not take place. Only male activity was recorded at night. This showed more intensive feeding but with periods of no feeding just after dark and just before dawn. The use of a four-minute recording interval was found to work well in practice.     

New findings in body mass regulation in zebra finches (Taeniopygia guttata) in response to photoperiod and temperature

Small birds in temperate zones increase body mass in winter (Lehikoinen, 1987). We investigated daily and annual variation of body mass and fat reserves of locally-reared Australian zebra finches Taeniopygia guttata , by exposing them to different photoperiods, feeding periods, and temperatures.
Experiments with long and short photoperiods and long and short feeding periods, showed that long photoperiods increased body mass and fat reserves of the zebra finches, and readiness to breed, independently of the actual feeding period.
Furthermore, the zebra finches in indoor aviaries with constant temperature (22-24°C) and in outdoor aviaries with ambient temperature, both exposed to the natural daylength changes of Bielefeld, Germany (52 °N), had high dawn body mass in summer (12.9 and 12.0-12.4g, respectively) and low in winter (10.7 and 11.1 g, respectively). Thirty to sixty percent of these mass changes were related to changes in fat reserves, so that the finches had only 0.1-0.2g of metabolizable fat reserves in short photoperiods (or in winter), which increased up to 1.5g in long photoperiods (or in summer).
Indoor finches consumed more seeds in summer than in winter (3.3 vs. 2.7g/day), while outdoor finches consumed 4-5g of seeds per day throughout the year, which probably represented the limit of energy intake for a 11-13g bird (Kirkwood, 1983). Nightly mass loss, increasing from 0.7g in summer up to 2.0g in winter, was highly positively correlated with night length, not influenced by ambient temperature. Foraging before dawn and after dusk, roosting with well-filled crops, and decreasing body mass and fat reserves, seem to be adaptations of zebra finches for survival in winter. The summer fattening probably accelerates reproduction in this opportunistic breeder, by allocating more time to reproductive behaviour and more endogenous nutrients to egg-formation.     

Seasonal variation in daily activity patterns of free-ranging European ground squirrels (Spermophilus citellus)

Daily aboveground activity of European ground squirrels (Spermophilus citellus) in their natural habitat was recorded with a visual scanning procedure during the active seasons of 1992 and 1993. Activity patterns were analyzed with respect to time of year and to the animal's reproductive state. Aboveground activity started on average 3.9 h (SD 0.6 h, n = 37 days) after civil twilight at dawn and ended on average 3.2 h (SD 0.9 h, n = 37 days) before civil twilight at dusk. Between onset and offset of activity, 54% was spent aboveground, of which 73% was spent foraging. Activity patterns were influenced by photoperiod, rainfall, and by reproductive state. During mating, reproductively active males started activity earlier than females and reproductively inactive males. For females, time spent foraging was high during lactation. The midpoint of daily activity was at 12:16 h (SD 0.37 h, n = 37 days). Activity patterns of European ground squirrels thus appear robustly positioned in the middle of the photoperiod.     

Daily and seasonal activity patterns of the muskrat Ondatra zibethicus as revealed by radiotelemetry

Activity patterns of the muskrat Ondatra zibethicus L. were examined during summer and winter in Delta Marsh, Manitoba, Canada (50°11'N, 98°23'W). Animals exhibited intermittent activity throughout the day with a mean periodicity close to 6 h in both seasons. The 24-h activity pattern in summer was typically bimodal with major peaks occurring between sunset and sunrise. Muskrats were more diurnal in winter when maximal levels of activity occurred in late afternoon and early evening (1500–2000). Pronounced inter- and intra-individual variability in daily activity ensured continuous, or nearly continuous occupation of winter shelters by a variable number of muskrats, and thus enchanced microclimate stability. Daily variation in activity and weather were weakly correlated both summer and winter. Of the environmental variables tested, only photoperiod and wind speed in summer, and photoperiod and air temperature in winter correlated significantly with total time spent in lodge or burrow per day.     

Seasonal changes of locomotor activity patterns in the desert isopod Hemilepistus reaumuri

The locomotor activity rhythm of the desert woodlouse Hemilepistus reaumurii was monitored as individuals over the four seasons, under entraining and constant darkness conditions. Results indicated that individuals exhibited an endogenous rhythm of locomotor activity with a circadian period longer in spring than the other seasons whatever the regimen. Due to the important inter-individual variability, no significant difference in period was found between seasons as well as between regimens. Periodogram analysis revealed also an ultradian period around 12 h. Activity was mostly confined to the hours of the photophase or to those of subjective day. The activity pattern showed two main peaks. This bimodal circadian rhythm persisted for as long as the experiments were run, and was clearer in summer and autumn than in winter. The most clearly defined rhythms were found in spring and summer recordings, respectively, under entraining and free running conditions. The variation of activity patterns according to the seasons will be discussed.     

Diel activity of the pink shrimp Penaeus duorarum

Twelve juvenile pink shrimp, Penaeus duorarum Burkenroad, were tested individually for 3-day periods in electronic shuttleboxes to determine their diel patterns of locomotor activity, in relation to a natural summer photoperiod. Nocturnal activity was twice that exhibited during the daytime; however, a bimodal pattern was evident with crepuscular peaks occurring at dawn and dusk. The dusk peak was more pronounced, with activity increasing markedly before sunset (indicative of an endogenous circadian rhythm component), and continuing during the initial hours of darkness, gradually declining later during the night with a secondary peak at dawn falling off to minimal activity during daylight. Crepuscular activity (mean of dawn and dusk) was twice the nocturnal average.