Avifaunal Response to the 1977 La Mesa Fire

Johnson, Terrell; Wauer, Roland

Three of 4 breeding bird transects in habitats ranging from mixed conifer to pinyon-juniper were burned by the 1977 La Mesa Fire. Large portions (25-80 percent) of the 3 burned transects suffered forest loss from crown fire or scorching, but the pinyon-juniper transect did not burn. The transects were surveyed during the breeding season before the fire and 1, 2, 4, 6, and 14 years afterwards. Species diversity increased after the fire, but breeding populations generally declined for several years before increasing above prefire levels. This temporary population decline was more pronounced and lasted longer on the more severely burned transects. Conversely, the population on the unburned pinyon-juniper transect temporarily increased after the fire. After 14 years, avian diversity and populations in the burn remained well above prefire levels, except on the transect with 80% forest loss, where the population was 22% lower due to a reduction in insectivores. Populations of seed-eating birds and raptors were consistently higher than before the fire. All 3 burned transects experienced both immediate and successional changes in species composition. Even an uncontrolled crown fire such as the La Mesa Fire can increase the diversity and population of breeding birds. High fire intensity appears to delay recovery of avian populations from short-term postfire declines, and extensive crown fire appears to reduce populations after most snags have fallen, but even the most severely burned areas of the La Mesa Fire generally retained some live trees and snags and supported diverse, substantial populations of breeding birds after the fire. Application of moderate intensity prescribed fire to relatively dense stands such as those burned by the La Mesa Fire can enhance avian diversity and populations without the disadvantages of high intensity crown fires.