july, 1912 PRESENT AND FUTURE STATUS OF CALIFORNIA VALLEY QUAIL 139 say early in May. Let this minimum number be represented by 100. By the end of June, just after the hatching season, the maximum numbers would naturally be found. From this time on there is to be expected la decrease in numbers until the minimum of 100 is again reached. The weaker members of the flock will be killed first, and those which can survive till the later part of the winter have then a far better chance of surviving till the breeding season. Hence, the curve drops quickly until February is'reached, thus showing a greater mortality during the fall months. At the end of hatching, if forty percent produced an average of ten young, we find the numbers of quail in- creased from 100 to 500. At the beginning of the hatching season the next year, however, this number has again been reduced to the minimum number of 100. It can be seen then, that, under natural conditions, we are to expect, with a covey of 100 quail, that nearly 400 could be destroyed each year and yet equilibrium would be maintained and the birds would not decrease in numbers. Suppose that we introduce a new element, shooting. A certain number of birds would still be claimed by the natural forces at work; but if the shooting occurred during the open season, October 15 to February 15, a certain propor- tion of the birds shot would be birds which would later have died from other causes, and just so long as that particular percentage was not greater than the death rate for that period of time there would be no decrease in numbers (curve B). Of course a certain number of those vigorous birds destined to survive and breed would be claimed by the hunter. Under proper regulations these might be but a small percent, however, and even the killing of these might make the struggle for existence of less vigorous individuals so much less that their chances of surviving would become greater. Let the number shot bring down the numbers of birds to 75 instead of 100 at the time of minimum numbers, however, and a decrease would necessarily follow in the next year's crop of young (curve C). It seenas probable, moreover, that with the hunter, just as with predaceous animals, the least vigorous prey is most easily obtained; so that no selective deterioration of the quail stock can be attributed to the hunter. The dotted line C on the graph represents the conditions to be expected from an excessive amount of shooting. If the death rate could be lessened, the condition represented by D would exist, that is, there would be an increase in the numbers of quail. Such an increase could not exist for long, however, for the struggle for existence would also be increased to such an extent that a norm would soon be established. This same type of reasoning has been applied to nearly all forms of life and has been found to hold true. Summing up, then, we can say that a certain amount of shooting might in no way effect the numbers of quail; for in the shooting we might be simply making use of numbers of quail that would have perished in some other way. It should be kept in mind, however, that there is a danger point and that when the number killed approaches near to or exceeds the normal death rate, there must follow a decrease. Another point to be remembered is that this reasoning applies to ideal conditions and does not mean that 400 out of every 500 quail can be killed each year. In shooting, many birds are killed that would have survived till the breeding season; and herein lies an error in the computation that must be taken into account. Probably the number that it would be safe to kill would be very far under the 400 mark; but even then the number might be large enough to allow considerable hunting. It is safe to say that quail can withstand a certain amount of shooting without showing a decrease in mini-
