Search results for "Home range"

Spatial segregation of home ranges between neighbouring colonies in a diurnal raptor

2018

AbstractEnhancement of information transfer has been proposed as a key driver of the evolution of coloniality. Transfer of information on location of food resources implies that individuals from the same colony share foraging areas and that each colony can be associated to a specific foraging area. In colonial breeding vertebrates, colony-specific foraging areas are often spatially segregated, mitigating intercolony intraspecific competition. By means of simultaneous GPS tracking of lesser kestrels (Falco naumanni) from neighbouring colonies, we showed a clear segregation of space use between individuals from different colonies. Foraging birds from different neighbouring colonies had home r…

On the socio-sexual behaviour of the extinct ursid Indarctos arctoides: an approach based on its baculum size and morphology

2013

The fossil bacula, or os penis, constitutes a rare subject of study due to its scarcity in the fossil record. In the present paper we describe five bacula attributed to the bear Indarctos arctoides Depéret, 1895 from the Batallones-3 site (Madrid Basin, Spain). Both the length and morphology of this fossil bacula enabled us to make interpretative approaches to a series of ecological and ethological characters of this bear. Thus, we suggest that I. arctoides could have had prolonged periods of intromission and/or maintenance of intromission during the post-ejaculatory intervals, a multi-male mating system and large home range sizes and/or lower population density. Its size might also have he…

Habitat-specific ranging patterns of Dian's tarsiers (Tarsius dianae) as revealed by radiotracking

2006

Dian's tarsier Tarsius dianae, one of the smallest primates on earth, is endemic to the central regions of Sulawesi, Indonesia. To evaluate the effects of increasing land use by humans on the ranging patterns of this nocturnal insect hunter, four study plots along a gradient of anthropogenic disturbance were selected for this study. In these plots, 71 tarsiers were captured with mist nets, and 30 of these were fitted with 3.9 g radiotransmitters and subsequently tracked over the course of 2 weeks per animal. The average home ranges were 1.1-1.8 ha in size, with the smallest ranges in slightly disturbed habitat and the largest ranges in a heavily disturbed plantation. These findings coincide…

RESULTS OF RADIO—TRACKING OF DUCKS IN THE LAKE ENGURE IN SUMMER 1997

1998

ABSTRACT In summer 1997 a project of duck research using radio—telemetry was carried out on the Lake Engure, Latvia. 10 females of Mallards, 10 females of Shovelers, 9 females of Pochards and 6 females of Tufted Ducks were radio—tracked during the period from the hatching of their ducklings till fledging. Information about effect of the harness-type radio-transmitters on different species of ducks has been collected. For 15 ducks home range sizes and distances between nests and range locations were calculated. Mallards used to move further from their nest sites; one Mallard brood after one week spent near the nest site dislocated 8 km to the Southern part of the lake during one day. Problem…

Food predictability determines space use of endangered vultures: implications for management of supplementary feeding.

2013

Understanding space use of free-living endangered animals is key to inform management decisions for conservation planning. Like most scavengers, vultures have evolved under a context of unpredictability of food resources (i.e. exploiting scattered carcasses that are intermittently available). However, the role of predictable sources of food in shaping spatial ecology of vultures has seldom been studied in detail. Here, we quantify the home range of the Egyptian vulture (Neophron percnopterus), a long-lived raptor which has experienced severe population decline throughout its range and is qualified as endangered worldwide. To this end six adults were tracked by satellite telemetry in Spain d…

DIEL ACTIVITY AND HOME RANGE OF THE WHITE SEABREAM DIPLODUS SARGUS SARGUS (LINNAEUS, 1758) IN THE GULF OF CASTELLAMMARE (NW SICILY)

2011

Relationships between economic profitability and habitat quality of Siberian jay in uneven-aged Norway spruce forest

2012

Abstract In the southern and central parts of Finland, Siberian jay (Perisoreus infaustus) lives in large non-fragmented spruce-dominated forests. Due to the reduction of such forests, Siberian jay has disappeared from the southern parts of Finland. This study analyzed continuous-cover uneven-aged forest management as a way to maintain Siberian jay habitats simultaneously with timber production. Continuous cover management is able to provide the necessary spatial and temporal continuity of forest features important to the viability of Siberian jay populations. The study analyzed the relationship between habitat quality of Siberian jay and profitability of uneven-aged management of Norway sp…

Foraging site fidelity shapes the spatial organisation of a population of female western barbastelle bats

2009

Abstract Information about the spatial distribution of individual foraging habitats, which determines the space required by a population to be viable, is vitally important for the conservation of bats. Detailed knowledge of this kind is crucial for the design of nature reserves and management plans. Recent field studies that examined habitat use and home range distribution of bats largely ignored factors like traditional range use vs. intra- and interspecific competition, which may be responsible for the spatial organisation of a population home range. We investigated the home range sizes and distribution of a maternity colony of the western barbastelle bat via radio telemetry in four conse…

Social overwintering and food distribution in the bank vole Clethrionomys glareolus

1991

We studied overwintering in the bank vole Clethrionomys glareolus in four 0.5 ha enclosures in an abandoned field in central Finland in the winter 1987/88. In two of the enclosures food was offered evenly distributed over the whole enclosed area (Even Enclosures = EE), in the two others food was offered in one feeding patch with four feeding chambers 2 m apart (Patchy Enclosures = PE). Food was provided in about the same amount in both enclosures. The experiment commenced in early October, with 13 females and 11 males in EEs and 12 + 13 voles in PEs. After two months the voles in the PEs were concentrated around the feeding patches. Territoriality was not observed in EEs, instead the voles …

Spatial ecology of coastal Atlantic cod Gadus morhua associated with parasite load

2015

Acoustic tags and receivers were used to investigate the spatial ecology of coastal Atlantic cod Gadus morhua (n = 32, mean fork length: 50 cm, range: 33–80 cm) on the Norwegian Skagerrak coast in 2012. Monthly home ranges (HR), swimming activity and depth use varied considerably among individuals and through the months of June, July and August. HR sizes for the period ranged from 0·25 to 5·20 km2 (mean = 2·30 km2). Two thirds of the tagged G. morhua were infected with black spot disease Cryptocotyle lingua parasites; these fish had larger HRs and occupied deeper water compared with non-infected fish. The infected fish also tended to be more active in terms of horizontal swimming. From an e…