july, 1912 PRESENT AND ]?UTURE STATUS OF CALIFORNIA VALLEY QUAIL 135 l?cality. They are as follows: Food supply, cover, predatory animals and birds, disease, weather conditions, and the hunter. There is an old biological law which states that birds and ?animals under 'natural conditions will increase up to the limit of ? their food supply. On any given area there is food and protection for a certain population of plant and animal life. Just as soon, therefore, as the food or protection or both are di- minished the given area will support less numbers of individuals and vice versa. This law is one of the most fundamental of all natural laws and most of the fluctuations of numbers of a given species can be traced either directly or 'indirectly to the working out of this law. Such factors as disease, predatory animals and birds, and climatic conditions are usually minor external factors. If it can be shown, then, that the food supply or cover of the California Valley quail has greatly decreased in the last twenty years, we should naturally expect a decrease in the numbers of quail. If, on the other hand, it can be shown that the food 'supply and cover, or both, has Rot decreased, or has increased, we should naturally expect to find the quail holding their own or increasing in numbers; that is, barring other factors such as disease, an increase of predatory mammals and birds, or hunting. Outside disturbances in the'baance, such as the hunter, may or may not have a decided influence on numbers, depending upon the extent of the destruction. A certain small amount .?f destruction probably would have littie or no effect on the numbers, as this d?..pletion would simply leave more room for others and a larger percent of the birds hatched would live. Under natural conditions, therefore,' the :food supply of a birc probably has more to do with the numbers 'than any other thing. The cultivation of land, which is becoming more and more general each year, causes t?e destruction of the natural food of many of our birds. In a fe?v instances cex?tain birds are profiting by a new supply of food furnished by the crops raised; l?ut in most in- stances the intensive cultivation of land brings a diminution in tl?e numbei's of birds very largely due to a destruction of their natural food. It is',pleasing to note that the quail are among the birds which have, to some extent at least, adapted themselves to the ne?v conditions. It has been stated that no birds flourish under so many varied conditions as do the California valley quail; for they can be found from sea level to a mile above the sea, and from the humid coast belt to the desert. They have been found breeding in rules, in vineyards, in the weeds along fences, in orchards, and?even in suburban gardens. Vine- yards furnish them not only acceptable food but good cover. The quail being largely a seed eater, Will turn to grain, grapes, and other cultivated products when its natural food is not available. In spite of this fact, however; the cul- tivation of great tracts of wild land accompanied With the'destruction of such plants as the burr clover, alfilaria, lupine, tarweed, pigweed, and mustard, has diminished the food supply of the quail to such an extent that doubtless it has bad a considerable effect on the numbers. The habits of the quail show them to be closely dependent on cover. There are many places in the state where it could be definitely shown that the destruc- tion of cover has been the primary factor in the diminishing of the numbers of quail. Not only is that cover, destroyed in the clearing of land, of impor- tance, but also the large areas destroyed by fire each year. As the land becomes cultivated, but a small amount of cover is furnished in place of that destroy-?d'.
The weeds and shrubs growing along the fences, and the vineyards, probably
furnish the best of the new cover.
