Sex Adult silver fox females spend much more time on the platforms than males in the winter (20-35 YV 0-2 %) but not in the summer (both sexes about 55 % of daily time) (Korhonen and Niemelä 1996a). Juvenile silver fox females have be seen to use the platforms more (Korhonen and Niemelä 1995, 1996a), less (Mononen et al. 1996b) and equal amount than the males. Size/design/material Juvenile silver foxes in cages with U-bottomed platforms spent 65 % of daily time on the platforms in September and 20 % of daily time in November (Korhonen and Niemelä 1995). In the study by Mononen et al. (1996b), respective figures for a flat-bottomed platform were 70 and 40 % of daily time. No clear-cut preferences have been observed in adult silver foxes between concrete and wire mesh floor (Jeppesen and Pedersen 1990) or between wood and wire mesh floor. Similarly in juvenile silver foxes in the autumn was not observed differences in the preferences for wire mesh and wooden platforms (Mononen 1996). The use of resting platforms without walls in silver foxes decreased from 73 % in September to 27 % in November if the view from the cage floor was open (Mononen et al. 1996b). The respective decrease was from 70 to 46 % of daily time if the view from the cage floor was obstructed. Platforms for blue foxes Age Adults Foxes that are provided with platforms at the age of one year or more, rarely use the platforms. The platforms are used most by animals that have experiences of the platforms from less than four months of age continuously onwards (Korhonen and Niemelä 1993, Korhonen et al. 1995). Juveniles Blue foxes may spend up to 70 % of their daily time on resting platforms. There is also individuals that do not use platforms. The platforms are used mainly for resting, but the platforms are visited also during active periods (Korhonen and Niemelä 1993, Mononen et al. 1996a). The use of the platforms is at its peak in the late evening and early hours, L H during the main resting phase of the day (Korhonen and Niemela 1996). The platforms are used more during summer and the use decreases towards winter (Korhonen and Niemelä 1994a, 1994b, 1996b, Korhonen et al 1995). In the study of Harri et al. (1991) blue foxes used the platforms more during the working day if there was some extra human activity (H J blood sampling) on the farm compared with routine farm days (11 YV 5 % of time). Sex In the adult blue foxes the difference between the sexes is not as clear as in silver foxes and not at all detectable in the winter, since foxes of both sexes rarely use the platforms (Korhonen and Niemela 1996).
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