Bird Response to Lightning-season Fire

Burned

For decades, the prescribed burns needed to maintain open pinewoods were set early in the calendar year when cooler temperatures and steady winds prevailed. More recently, land managers have shifted to burning later in the year – sometimes as late as August — because studies suggest this may have been a time when Mother Nature liked to burn the woods.

Increase in the use of late- or lightning-season burning has not come without controversy. Prescribed burns set any time after late February coincide with the nesting season of one or more pineland birds, and nests built of dried grasses, leaves, and twigs are obviously are no match for fire. Lightning-season fires have the potential to destroy scores of nests, and negative responses to fires set during the breeding season have surfaced on several different fronts.

In 2006, we studied the short-term responses of breeding birds to a prescribed fire set in the middle of the breeding season (May 28). Line transects sampling was conducted several times before the burn was conducted, and bird monitoring continued for 8 weeks after the burn.

Most species returned to the plot within a few weeks after the burn was completed, and several species (Bachman’s Sparrow and Northern Bobwhite) became more abundant 6 weeks after the burn than they had been prior to the burn. We did not monitoring nesting activity, but results indicate that sites treated with lightning-season burns are used heavily soon after the vegetation recovers.

Box Plots

The box plots provided below show community-level trends at 4 time intervals: (1) prior to the burn; (2) 1-3 weeks after the burn; (3) 4-6 weeks after burn, and (4) >6 weeks after the burn. The three foraging guilds were based on the predominant portion of the forest (shrub/ground; midstory; canopy) used by different species. The Morisita-Horn index quantifies differences in terms of species richness and abundance of species encountered.

Total Species RichnessTotal Abundance
Trends for 3 Foraging Guilds

Additional notes and observations…

A Northern Cardinal was found incubating three eggs just five days after the burn! Other noteworthy observations included:

Species Date Observation
Blue Grosbeak 6/24/2006 2 young ca. 5 days old
Bachman’s Sparrow 7/1/2006 Male feeding fledglings
Eastern Towhee 7/3/2006 Copulation observed
Bachman’s Sparrow 7/3/2006 Recently fledged young