Conception dates in relation to age and condition in two populations of Red deer in Scotland

The conception dates of wild Red deer ( Cervus elaphus L .) in two parts of Northern Scotland (the Isle of Rhum in the Inner Hebrides, and Glen Feshie in the Central Highlands) were estimated from foetus weights and from the known birth dates of calves. In both localities, the conceptions were spread over periods of about 100 days from late September to late December with a peak in October. The median conception date was seven to ten days earlier on Rhum than at Glen Feshie. The conception data from shot hinds showed distinct patterns in relation to age, whether or not the hinds had current year's calves, and to body condition. Body condition may be the most important “secondary factor” influencing the time of conception; hinds in poor condition tended to conceive later than those in good condition. Body condition could also account for year to year fluctuations in the time of breeding; hinds tended to breed earlier in years when they were in better condition.