Mustela Õison : implications for the assessment of behavioural priorities

Consumer demand studies of animal preference commonly involve the imposition of costs on access to resource compartments rather than direct costs on resource consumption. The aim of this study was to analyse how such increasing access costs alter the scheduling of behaviour, in order to investigate some potential problems with using this technique to measure behavioural priorities. Ž . We investigated the effect on mink of placing a cost a weighted door on the access to resources. Six mink were individually housed in closed economy test arenas. Each consisted of a home cage Ž . containing food, water and a nest box , an empty compartment and six resource compartments with access to a box of hay, a water bath, a raised platform, a wire cylinder, a novel object, and small toys. Door weights were increased from 0 to 1000 g and the minks’ behaviour was recorded on video for 8 h per day. As expected, increasing door weight reduced the number of visits to each compartment but lengthened each visit. Furthermore, as costs on access increased, there were changes in how mink behaved during each visit to resource-compartments. They became increasingly likely to interact with each resource during a visit, and they showed shorter latencies to interact with the resources. The time spent in compartments not interacting with the resources also declined. Overall, these changes in within-visit behaviour meant that the greater the cost on access, the greater the proportion of time spent with a resource devoted to actually interacting with it. Thus, the time spent with a resource over-estimated the actual use of that resource, particularly at lower access costs. These results illustrate the dangers of simply using time spent with a ) Corresponding author. School of Agriculture and Horticulture, De Montfort University, Caythorpe Court, Caythorpe, Lincolnshire, NG32 3EP, UK. Tel.: q44-1400-275678; fax: q44-1400-275686; E-mail: