ASSEMBLED DATA
Age and sex of trapped squirrels
| females | males | total number | per cent males | |
| Adult squirrels | 29 | 26 | 55 | 47 |
| Young squirrels | 15 | 19 | 34 | 127 |
| Total | 44 | 45 | 89 | 102 |
Reproduction in terms of the season as determined by lactation of adult females
| July 21-August 7 | August 8-22 | August 23-Sept. 8 | September 9-15 | |
| Lactating | 6 | 2 | 1 | – |
| Not lactating | 2 | 4 | 10 | 4 |
Number of times squirrels were retaken
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
| Adults | 44 | 8 | 1 | 1 | 1 | 1 | ||||
| Young | 20 | 9 | 3 | 2 |
SUMMARY
- Seventy-three squirrels were trapped between the Crater Wall Trail and the Lodge in a strip of territory about 150 feet broad. This represents a very dense population.
- Squirrels do not, in a season, move around much. They may repeatedly be taken in the same territory, rarely are found more than 100 feet away from it.
- The sexes are equal in number in the population; an excess of young males balances an excess of old females. This is the situation to be found in other rodent populations such as the deer mouse.
- All young squirrels taken in the vicinity of a mother’s burrow were found to have traveled only a short distance away after weaning. This is a tentative inference and awaits further trapping data.
- Young are born during the months of June, July, and August and emerge from the mother’s burrow during July, August, and September. At the Rim Area in 1939, the first newly emerged young were seen July 15th and the last September 20th. A lactating female was taken as late as August 24th. In 1938 the first young were noted in the Rim Area on July 31st and the last on September 15th. This seems to suggest that occasionally a mother may have a second brood.
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