Page:Condor13(6).djvu/40

208 THE CONDOR Vol. XIII (Slumella neg?lecla), western kingbird ( 7?vrannus verticalis), 'blue-fronted jay (C?anocilla slelleri??onlalis), and Say phoebe (Sayornis sayus). 4. Four out of five species found to feed on the butterfly are numbered among the birds whose usual food habits justly subject them to severe criticism from the farmer. 5. The Brewer blackbird (Euphag?us cyanocephalus) was found to be the most efficient check both on account of numbers and food habits. When the dom- parative number of individuals of the different species of birds were considered, it was found that the Brewer blackbird took 95 percent of all the butterflies eaten by birds. In this particnlar outbreak, therefore, one species of bird rather than birds in general, played the greatest part in the destruction of the insect. 6. The examination of thirteen stomachs of the red-winged blackbird (Ag?e- laius phoeniceus, subspecies?) showed over 93 percent of its food to be vegetable matter, thus bringing out the vast difference in food habits between this bird and the Brewer blackbird (Euphag?us cyanocephalus), 83 percent of whose food was animal matter. 7. Eugonia californica in the butterfly stage, probably on account of its large size, was not eaten by any species of bird smaller than the Say phoebe. The smaller birds probably had a more intimate relation to the outbreak when the in- sect was in the larval and pupal stage. 8. The birds in feeding on the butterfly attacked the insect at a critical l?oint in its life history and were therefore of more value as a check than they would have been had they fed on the larva or pupa. 9. A comparison of the food of birds taken before the plague with that of birds taken while the plague was at its height, showed that birds had varied their food habits and had taken advantage of the abundant supply of insect food in the form of butterflies. Their value as checks in this particular insect outbreak, there- fore, was real. 10. The data collected shows of what value birds may be in the checking of an insect outbreak rather than their value in the prevention of an outbreak. LITERATURE CITED Aughey, S. 1878. Notes on the nature of food of the birds of Nebraska. United States Ento- mological Commission, First Report, Appendix II. Beal, F. E. L. 1907. Birds of California, Part I. U.S. Dept. Agric., Div. Biol. Surv. Bull., No. 30, pp. 1-100, $ pls. 1910. Birds of California, Part II. Ibid., No. 34, pp. 1-96, 6 pls. Weed, C. M., and Dearborn, N. 1903. Birds in their relation to' man (Philadelphia, Lippincott), viii, 380, pls. and text figs. FURTHER NOTES FROM SANTA CRUZ ISLAND By ALFRED B. HOWELL and A. VAN ROSSEM HE topography of Santa Cruz Island is more varied than that of any other of the islands comprising the Santa Barbara group, and it has a corresponding diversity of bird life. Its greatest altitude is nearly three thousand feet; for the most part it is grass land with extensive barren stretches, and canyons filled