may become still more contoured and, if pressed, the owl will like back and attempt to slash with its large talons. The threat displays of males are generally more emphatic than those of females. Although snowy owls have been considered as semi-colonial, they do not appear to fit this mold well. Nesting sites can be loosely clustered but this is a coincidental response to concentrated prey and each pair tends to be somewhat intolerant of each other. During winter, snowy owls are usually solitary but some aggregations have been recorded, especially nearer the Arctic when more narrow food selection can lead to up to 20–30 owls gathering in an area of about . Congregations were also recorded in the winter in Montana, where 31–35 owls wintered in a area, owls mostly grouped in loose aggregations of 5–10 owls each or occasionally side-by-side or about apart. In extreme cases in Utqiaġvik, the owls may have exceptionally close active nests that may be down to only apart. Juvenile males appear to be especially prone to loose associations with one another, appearing to be non-territorial and able to hunt freely in front of one another. In a area in and around Utqiaġvik, productive years may have about 54 nests while none may be found in poor years. Utqiaġvik may have about 5 owls in early summer every , have a nest spacing of and the owls territory size is about . In Churchill, Manitoba, nest spacing averaged about . In Southampton Island in a year when the owls nested there, nest spacing averaged , with the closest two apart and density per nest was . In Nunavut, densities could go from 1 owl per in a productive year to 1 owl per in a poor year and from 36 nests in a area to none at all. Owl density on Wrangel Island in Russia was observed be a single bird each . The first known study of winter territories took place in Horicon Marsh where owls ranged from each. In Calgary, Alberta, mean territory size of juvenile females in winter was and adult females was . Wintering owls in central Saskatchewan were radio-monitored, determining that 11 males had an average range of , while that of 12 females was with the combined average being . Migration It is fair to say that the snowy owl is a partial, if fairly irregular, migrant, having