TEMPORAL AND SPATIAL PATTERNS OF REST-SITE USE BY 4 FEMALE OTTERS LUTRA-LUTRA ALONG THE SOUTH-WEST COAST OF PORTUGAL

Data from four radio-tracked female otters (Lutra lutra) were used to describe the temporal and spatial patterns of resting-sites by the spe cies along the south-west coast of Portugal. Two female otters were tr acked during 24-h periods, showing a continuous resting period in dayl ight, whereas during the night there were several hunting bouts in the sea interspersed with periods ashore. These otters spent most of the time each day in daytime rest-sites (72.1%), and devoted only a small time to hunting (18.3%) and other activities (9.6%). The onset of fish ing activity was monitored for three animals, starting on average 45.4 min after sunset; this was largely independent of the degree of human disturbance close to the rest-sites. Most rest-sites were located wit hin dense thickets of Rubus sp. along coastal and estuarine streams, a nd sometimes they were near areas disturbed by human activities. Three otters were captured along the coast and they were found in eight day time rest-sites on 116 occasions, each otter using regularly a small n umber of sites (2.7); the mean re-use rate of sites was high (9.5 days per site), and the sites were spread over 4.2-15.0 km of coast, with 0.20-0.71 sites/km. One otter was captured in an estuarine stream, whe re she was found on 70 occasions in 13 daytime rest-sites spread over 6.0 km of streams; the density of rest-sites was 2.2 sites/km and the re-use rate was 5.4 days/site. The results of this study suggest that rest-sites are scarce for marine-feeding otters in south-west Portugal . This is probably because rest-sites used by these otters have an obl igatory association with freshwater sources, and these are infrequent and scattered along this coast. Conservation implications of this stud y are discussed.