LETTER OF TRANSMITTAL. 
U. 8. DEpartMEeNT oF AGRICULTURE, 
Division oF BroLocicaL SURVEY, 
Washington, D. C., May 22, 1900. 
Str: I have the honor to transmit herewith for publication as Bul- 
letin No. 13 a report on ‘The Food of the Bobolink, Blackbirds, and 
Grackles,’ by Prof. F. E. L. Beal, assistant biologist. This report is 
based on a careful examination of the contents of more than 4,800 
stomachs, representing nine species and several subspecies of Amer- 
ican blackbirds. The family of orioles and blackbirds, to which the 
bobolink, cowbird, blackbirds, and grackles belong, is one of much 
economic importance. The ravages of the bobolink in the rice fields 
of the South, and of some of the blackbirds in the grainfields of the 
Upper Mississippi Valley at planting and harvesting time, are matters 
of common knowledge, but the other food of these and other species 
is not so well known. The present bulletin is devoted mainly to the 
food of the various blackbirds during the summer months; several of 
the species consume insects in such quantities at this time as to com- 
pensate in great measure for the grain they destroy. 
Respectfully 
, C. Hart MERRIAM, 
Chief, Biological Survey. 
Hon. James Wiison, 
Secretary of Agriculture. 
