Grackles are messy, black to brown colored birds that flock in large numbers in certain areas of central Texas. They feed on garbage, generally out of dumpsters, and are extremely messy when they roost in dense trees in or near parking lots and defile the parking areas, vehicles, bus stops, etc . Grackles are becoming a vastly more severe pest problem as the years go by in Central Texas, and various methods are being explored to control them.
Years ago I attended an interesting seminar on grackle control by a Texas State Park official who worked in the Dallas area. His area was so badly infested with grackles, that he was actually imlementing shooting off ‘whistlers’ to control grackles. These ‘whistler’s are actually a type of shotgun shell that is fired into the air, creating a whistling sound culminating in a explosion that temproarily scares off grackle flocks from their roosting areas. Although effective, it is loud and disruptive, and there are certain areas where this simply cannot be employed.
I have found thinning dense trees in high impact areas to be quite effective at controlling grackles. Thinning needs to be done anyway, not only to reduce potential storm damage to landscape trees, but can also be highly effective in reducing grackle roosting problems.
For example, in several instances in 2010, we thinned trees out in several different shopping centers that were having grackle infestations. After the trees were thinned, the grackles no longer had the cover of the dense foliage, and have since moved their roosts elsewhere. At the Tech Ridge Center at Parmer and I-35, the property manager was looking at installing an extremely expensive grackle control misting system to all affected trees.
This system had to be hot-wired into the ground at all tree islands in the parking lot, and was supposed to expel an irritant at certain times to repel the pests. After thinning out the landscape trees early in 2010, we are now experiencing such a decline in grackle activity that they are not considered to be a major problem at this time.