This thesis describes the social organization of a home range
group of Scottish Blackface sheep occupying an area known as the Howlet
in the Pentland Hills, Midlothian, Scotland. Evidence to support the
contention that these sheep constitute a home range group is presented.
The home range occupied by the group was found to be at a minimum
in winter (the winter range) and at a maximum in summer (the summer
range). Using cluster analysis on individuals' location data it was
shown that in autumn and winter there was little individual variation in
home range behaviour in comparison to summer. Variability in home range
size showed a similar trend. Ewes in summer could occupy home ranges
differing by as much as 40 ha. It was further illustrated that in
winter ewes showed increased gregariousness, forming large sub -groups
and being readily influenced by the movements of other sheep, whilst in
summer the converse was true. It was concluded that these seasonal
variations in social organization occurred largely in response to
ecological changes; in winter a reduction in the variability in the
quality of the hill swards and the worsening weather; in summer the
increase in the dispersion of resources through the growth of the widley
distributed Agrostis-Festuca swards. The presence of a lamb in summer
would seem to satisfy the ewe's proximal motivation to group, thus
allowing her greater flexibilty of movement between Agrostis-Festuca
In contrast to the findings of previous workers, the ewe-daughter
bond was found to be of little significance beyond 7 to 8 months.
Around this age ewe-lambs formed peer groups that during their first
winter moved independently of other group members. In their second
summer ewe-lambs became integrated into the larger social group. Early
experience was found to be important in determining summer home range
patterns of individual ewe-lambs. The cohesion of the home range group
seemed to result from the animals' preference for an area and their
motivation to form sub-groups; specific bonds between individuals were
not of importance in this respect.
Social organization was shown to negate supposed advantages of
feedblocks, fed as a supplement to the group during winter. Ewe -lambs
did not follow older ewes to the feedblock; 2 and 3 year old ewes did
not compete successfully with older ewes when feeding at the block;
further the feedblocks apparently decreased the size of ewes home
ranges, which it seems must have led to the overuse of the lower parts,
and conversely underuse of upper parts of the range.
The results are discussed in relation to literature on wild, feral
and domestic sheep. It is concluded that whilst in general terms the
social behaviour of domestic sheep remains close in form to that found
in feral and wild populations, that there remain unresolved questions
over the function of aspects of social behaviour in domestic ungulates.
It is argued that that a better understanding of the effects of
domestication on, for example, anti -predator behaviour in domestic sheep
would help in the construction of a theoretical framework for the study
of the ethology of farm animals.