Bird Gard Pro Sonic Bird Repeller for 1 Acre - Woodpeckers Comes with one built in speaker and repels birds in a space up to 1 acre. Crystal-Clear Digital Sounds with many Pre-recorded Configurations The built in amplifier and speaker are durable and the unit easily mounts to a fence or post courtesy of the included mounting bracket. Comes with the Woodpecker chip to repel northern flickers, downy woodpeckers, yellow-bellied sapsuckers and house sparrows. Repel targeted birds from crops, buildings, airports - anywhere birds are a nuisance.