These feeders are very easy to build (a great project for kids), and they are surprisingly effective for a variety of native birds including chickadees, nuthatches, brown creepers, many species of woodpeckers, and even juncos. I think the reason these feeders are so effective is that they mimic the trees (since they are, in fact, made of trees) that many native birds use for natural foods like insects and spider eggs. So, it is no surprise that birds have the search image of a log with treats inside.
Pictured below is everything you need to make one of these suet feeders- a log , a screw eye (I use #6), a drill bit to pre-drill the hole for the screw eye, and spade bit to drill holes for suet (1"- 1 1/4" ), and a drill.
Start with selecting a log. Any size will work (at least 8" long), the taller the better and at least 4" in diameter. It is nice to have a variety of sizes in your garden, some small ones that will only accommodate little birds like nuthatches, and some larger that will satisfy big woodpeckers.
Drill a pilot hole in one end for the screw eye.Install the screw eye. Now you are almost done!
Then, bore out holes for the suet. Place as many as you'd like, and drill them about 1" deep. Try to keep the upper holes at least 4" from the top, so non-native birds won't be able to perch on the top and reach down into the holes.
Load the cavities with suet- it is easiest, but messiest to do this when the suet is room temperature.