I often get asked which sounds work at different times of the year to get coyotes to respond to calls. First, you have to determine if you are going to try and trigger a territorial response, or rely on their predator instinct and play prey sounds. I have found in the cold winter months before their breeding season, prey sounds seem to work best, but after the breeding season is underway you are better off using more coyote vocalizations.
Another factor would be if they have pups of the year or not. Although pup distress works all times of the year, it might work better during the spring when you know small pups are present. Another idea is in late fall when pups start to disperse from their family groups and seek out new territory, they are more likely to respond just because they are younger dogs that aren't quite experienced yet.
As far as sounds go, you definitely can't beat rabbit in distress anywhere in the country and any time of year. Bird distress sounds also work well any time of the year and may just be the ticket in overhunted areas where most people are playing rabbit distress. Sometimes just switching sounds is all you need to do to start having success. A single howl or sounding like a pack of coyote's can sometimes trigger a response from one or more coyotes at a time.
I personally use Johnny Stewart Wildlife Calls for the wide range of sounds that they provide. That way no matter where I am or what time of year, I have a sound that I can trust to get the job done.
- Brad Biddle