Southeastern Kestrel Management on Fort Polk
In 1992, Fort Polk banded its first juvenile kestrels, which were from a nest located in an enlarged RCW cavity. The kestrel nest tree was within 100 feet of an RCW nest tree, which indicates that RCWs and SAKs prefer the same type of nesting habitat. Both the RCW and kestrel had successful nests and fledged chicks.
The SAK often hunts over large openings in the forest. Fort Polk has a large number of openings in the forest, called firing ranges that are utilized by the SAK for hunting. Our most successful nest boxes are located on the edge or near firing ranges. Another favorite habitat on Fort Polk is Longleaf pine seedtree stands that have approximately 20 mature pine trees per acre. On Fort Polk, we thin our pine stands down to a basal area of 60, sometimes lower, and we have a three-year rotational prescribed fire program. Not only does this habitat management benefit the SAK and RCW, it also benefits other species of concern including Bachman’s and Henslow’s Sparrows, and the rare Louisiana Pine Snake.
Since 1993, we have placed 20-25 SAK nest boxes on Fort Polk. The boxes are placed 20 feet above the ground on pine trees. It is very important that a snag or telephone lines are located near the nest boxes; the SAK uses them for perching and hunting. Our nest boxes usually have 5-6 successful nests a year, producing 3-4 young each. In addition to our nest boxes, we usually find 3-6 nests located in natural cavities each year. Nearly all the nests are found in enlarged RCW cavities located in living or dead cavity trees. All chicks are banded with a U.S. Fish and Wildlife aluminum band and a combination of color bands. There is a lot of competition for the nest boxes from other bird species and squirrels. We usually have more Eastern Screech Owl nests than SAK nests. We have also found Great-crested Flycatchers, Tufted Titmice, and Eastern Bluebirds nesting in our boxes. If we find other bird species using the boxes, we leave them alone, but Fox Squirrels and Southern Flying Squirrels are removed. Flying squirrels are a big problem. It is not uncommon to find 4-8 flying squirrels occupying a nest box. The number one nest predator on nesting SAKs is the Texas Rat Snake, a great tree climber. We have found adults, young, and eggs consumed by the rat snake. To limit predation, we place aluminum sheeting (4 ft. wide) at the base of each nest box tree. The slick aluminum prevents the snake from climbing the trees and reaching the nest boxes.
With proper management, SAK populations should remain stable and possibly increase in the future on federal lands, including Fort Polk and National Forest Service lands. It is critical that regular prescribed fires and timber thinning continue into the future. Not only is this necessary for maintaining healthy populations of SAK, but for other rare species that share its habitat.
Contributed by: Kenneth Moore
Also by Kenneth Moore: Southeastern American Kestrel in Louisiana