Revealing the behavioural ecology of the elusive hairy-eared dwarf lemur (Allocebus trichotis)

In this study we followed hairy-eared dwarf lemurs (Allocebus trichotis), a small nocturnal strepsirrhine primate, using radio-tracking during a one year study. Our aim was to clarify the behavioural ecology of the species and in particular to determine habitat use, social organisation and seasonal activity cycle. We conducted field work between January and December 2007 in the Analamazaotra Special Reserve, Andasibe, central eastern Madagascar. After capturing and measuring eleven individuals, we followed two males and two females for eight months and two additional females for three months. Adults weighed about 77 g, measured 13-14 cm and had a 12-15 cm tail. The much larger home range of Allocebus trichotis compared to other Cheirogaleidae (mean: 15 ha (MCP), 5 ha (kernel)) could be due to the highly insectivorous diet or the use of patchily distributed gum-trees. Each focal animal used four or five different tree holes and shared these with conspecifics and occasionally with white-tailed tree rats (Brachytarsomys albicauda). Tree holes were in living trees with average diameters at breast height of 32 cm, at median heights of 7 m. Tree holes could have antipredator and thermoregulatory functions and might be a limiting resource. Hairy-eared dwarf lemurs mainly used the small branch niche, five to ten meters above ground. Their diet was gummivore-insectivore. We propose a dispersed pair-bonded multi-male/multi-female social system with a monogamous or slightly promiscuous mating system. During the colder drier season, most animals decreased activity and entered periods of daily torpor, especially the heavier ones. The mating season probably lasted from October to December with births between December and February. Although this study presents crucial data on a rare nocturnal species, its small sample sizes call for additional research. Continued efforts are needed to assess the conservation status of this Data Deficient species. Fortunately, this and recent studies prove the feasibility of research on small nocturnal strepsirrhine primates in the eastern rainforests of Madagascar

Defining the Low End of Primate Social Complexity: The Social Organization of the Nocturnal White-Footed Sportive Lemur (Lepilemur leucopus)

Whereas other species of sportive lemurs (genus Lepilemur) have been described as living in dispersed pairs, which are characterized by spatial overlap but a lack of affinity or affiliation between one adult male and female, existing reports on the social organization of the white-footed sportive lemur (Lepilemur leucopus) are conflicting, describing them as either living in dispersed one-male multifemale systems or pairs. We conducted this study in the spiny forest of Berenty Reserve, southern Madagascar, to clarify the social organization and to characterize the level of social complexity of this species. We combined 1530 h of radio-telemetry and behavioral observations over a period of 1 yr to describe the spatiotemporal stability, size, and interindividual overlap of individual home ranges as well as interindividual cohesiveness. Results revealed low intra- and high intersexual home range overlap. Although most of the social units identified consisted of dispersed pairs (N = 5), males were associated with two adult females in two cases. Furthermore, members of a social unit were never observed to groom each other or to share a daytime sleeping site, and Hutchinson’s and Doncaster’s dynamic interaction tests indicated active avoidance between pair partners. Low cohesiveness together with extremely low rates of social interactions therefore arguably places Lepilemur leucopus at the low end of primate social complexity

Time of day and flightiness in flocks of semipalmated sandpipers

Environmental light intensity is known to exert a strong influence oil antipredation behavior by influencing prey Vulnerability. However, an association between low light levels and increased predation risk is not well established empirically. For species that rely on Visual detection of their predators, low light levels call hinder predator detection and thus increase predation risk. We examined the foraging behavior of migrating Semipalmated Sandpipers (Calidris pusilla) on a mudflat in the Bay of Fundy in New Brunswick, Canada as a function of time of day from dawn to dusk. Time of day was used as a surrogate for light intensity, assuming that, oil average, light levels Would be lower near sunrise and sunset. Sandpipers forage both day and night at low tide, which occurs at different times each day, thus disentangling the effect of light intensity from energy levels. Falcons make surprise attacks on sandpipers by leaving forest cover and flying low over the mud flat, rendering detection difficult against the dark forest background. The propensity for sandpipers to leave a foraging patch by taking flight was higher earlier and later in the day, controlling for temperature and sandpiper density. Pecking Success was similar whether a focal sandpiper stayed in the Current patch or took flight at the end of a focal observation, suggesting that the choice to leave abruptly was not related directly to food availability. We conclude that increased flightiness likely represents a response by sandpipers to a perception of higher predation risk from falcon attacks at low light level