Indirect assessment of avian damage to agriculture.
Estimates of damage to maize by individual red-winged blackbirds (Agelaius phoeniceus) were derived from energetics and life history information and independently using captive birds. Combining these estimates with a breeding season population census of red-winged blackbirds in the agricultural zone of Quebec produced similar regional damage estimates. Energetics estimates of damage of 0.41% of total production were consistent with damage sampling in 9 other regions (range 0.25-0.80%). The energetics estimate of damage of $ 279 357 damage was well below a 1975 estimate of $ 16 470 000. The speed, economy and apparent reliability with which indirect assessments can be made once the baseline data have been collected suggests this approach as a valuable tool in avian pest management.