The magazine Outdoor Life and the blog Predator Hunting Info both provide reviews for predator calls. Customer reviews also appear on Amazon.com on each item's product page.
According to Outdoor Life, the best predator calls are durable, light, compact and easy to pre-program with different types of wildlife calls. Some models allow customers to add extra speakers and improve the sound output, while others can even allow for motion decoys and video cameras.
Hunters use predator calls to lure animals closer, mimicking the sound of prey to attract their attention. Gerald Stewart, a veteran hunter, suggests placing speakers in a tree to divert the predator's attention away from the hunter's hiding place. If using this tactic, however, the hunter must take care to use the appropriate sound; for example, rabbits are not likely to be hiding in trees, but birds are, so a bird call serves as the best choice in this situation.
Stewart also recommends combining different calls to attract predators. When hunting a coyote, he might start with a coyote barking followed by a rabbit squeal to make nearby coyotes think that another coyote has killed a rabbit, triggering a territorial response. An electronic caller can accomplish this because it can switch between sounds with the push of a button.