Seasonal variations in the time–activity budget of Royle’s pika in the Western Himalaya,India

ABSTRACT

The time–activity budget of a species has ecological relevance because natural selection often favours individuals that utilise their time most efficiently. Details of time–activity budgets can provide information on how animals allocate time to their various activities through the day and during different seasons to most efficiently cope with varying energy demands and environmental changes that may threaten their survival. Efficient use of time–activity budget is also crucial for alpine small mammals, which live in a highly seasonal environment with restricted periods in which to gain energy and successfully reproduce. Hence, variations in the time–activity budget of the high-elevation lagomorph Royle’s pika (Ochotona roylei) were analysed during different seasons over 2 years across an elevational gradient (2900–3680 m). Seven behavioural conditions were recorded in adult and juvenile pikas through daily focal sampling between 0600 and 1900 hrs. Royle’s pika had bimodal activity: animals were most active during the morning and early evening and relatively inactive during midday hours. Adult pikas allocated the largest proportion of their time–activity budget to foraging and the smallest proportion to vocalisation. Greater food availability during the monsoon season encouraged pikas to spend more of their time foraging than on other activities. In the autumn, pikas spent more time on locomotory and musing activities. Vigilance activities were most frequent during midday hours, possibly due to a high risk of predation. Locomotion and foraging were the predominant behaviours of juveniles during the summer and monsoon seasons. Prominent food hoarding activities were not observed in either adult or juvenile pikas. Information on time allocation to different activities during different seasons should provide a baseline for future behavioural ecology and bioenergetic analyses of pikas and help to understand their potential for adaptation to climate change.     

Conservation in a changing landscape: habitat occupancy of the critically endangered Tennent’s leaf-nosed lizard (Ceratophora tennentii) in Sri Lanka

Landscape modification is a key driver of global species extinction. Thus, understanding how species react to changes is essential for effective conservation management in modified landscapes. We examined the impact of selected land use patterns on the critically endangered Ceratophora tennentii in the Knuckles mountain range of Sri Lanka where lizards occupy patches of both natural undisturbed forests and modified plantations – evidently, those with a forest canopy. We tested three potential explanations for non-random habitat selection: availability of suitable microhabitat pockets, availability of prey and direct threats from humans. The microhabitat pockets occupied by the lizards were characterised by shade, humidity and the density of perches. Most lizards were found in mixed cardamom forests followed by natural forests and cardamom plantations, but none were observed in the pine plantations. Food availability showed similar patterns among habitats. Direct mortality by humans did not influence the distribution of this species. Our work indicates that habitat modifications that retain the structural complexity of the vegetation would still permit the existence of the species in densities equal to or greater than that of undisturbed forest patches. It adds to a growing body of literature that signifies the importance of disturbed habitats (intermediate disturbance hypothesis) in protecting threatened species of fauna. It is highly unlikely that some disturbed habitats will be ever be returned to their former pristine state in time frames that are important for species’ conservation. Hence, attention is needed in developing suitable approaches to manage and conserve species across disturbed habitats.     

Nesting territory characteristics of a migratory South American forest hawk,the White-throated Hawk (Buteo albigula) (Aves: Accipitridae), in temperate rainforest remnants of Araucanía,southern Chile

During four successive breeding periods (2007–11) we characterized the nesting territories of the white-throated hawk (Buteo albigula) in southern Chile. Territories were located in mountainous areas with mature native forest (n = 17) or mature pine plantations (n = 1). Most of the territories were distant from urban centres (>2 km). Only one or two adult hawks and one young per pair/year were observed in each territory. All nest sites were located in the upper parts of ravines. Nests were built on large, living mature trees. Platforms were bulky (>50 cm diameter) and oval or round. Eggs were white and subelliptical in shape (40.0 × 50.0 mm). Hawk pairs reproduced asynchronically extending the reproductive period for 6 months. Although some white-throated hawk pairs were tolerant of human-modified habitats, it is possible that decline in forest cover represents a potential threat for the population viability of this migratory forest hawk.     

The diet of the Eleonora’s falcon (Falco eleonorae) in the Aegean archipelago (Greece)

ABSTRACT

In the present study we investigated the diet of Eleonora’s falcons in Greece and assessed the regional dietary pattern of 16 breeding colonies of the Aegean. Overall 224 nests were visited and a total of 8067 prey items were collected which contained two mollusca classes, seven insect orders, one reptile family, two mammalian taxa and at least 54 avian species. Cicadas were the most common insects found in pellets (45.1%) followed by flying ants (34.8%) and beetles (15.8%) while just 20 species (33.3%) accounted for over 90% of the avian prey items identified in bird remains dominated (>50%) by the Willow Warbler (Phylloscopus trochilus), the Red-backed Shrike (Lanius collurio) and the Whitethroat (Sylvia communis). Insect feeding peaked in late August (39.8%) and late September (20.8%), whereas bird remains built up in falcon nests from mid-August onwards, culminating in late September (57.2%) and declined abruptly afterwards. Overall the falcons’ diet diversity increased as the breeding season progressed and from the north towards the south Aegean. The avian prey species richness was negatively influenced by the distance of the colonies from the mainland and the weather conditions during September which coincides with the fledgling period of the young and the autumn peak of passerine migration.