Date of this Version
Damage caused by birds to ripening sunflower was evaluated in 60 fields (about 70% of all planted fields) in the Sacramento Valley, California, during 1980 and 1981. Overall monetary losses were roughly $6,800 (24 fields) and $7,400 (36 fields) in 1980 and 1981, respectively. The percentage losses estimated for the individual fields were low, ranging from 0 to 5.4% of the crop; in about two-thirds of the fields, losses were <0.5%. For the 12 fields with the highest (≥1.0%) damage, the average per acre monetary loss was roughly $18. Damage levels within local areas were relatively constant between the two years. Although several species of birds caused damage, house finches (Carpodacus mexicanus) were apparently most important. Their foraging behavior differed from that of blackbirds, which fed extensively on insects in addition to sunflower. The presence of large numbers of blackbirds or finches in fields was not always an indication of bird damage. Additional research may lead to recommendations for alleviating the moderate losses which a few growers now incur.