Just mix up what I call tree goop" from peanut butter and bird seeds. I use cheap (often store brand) peanut butter - crunchy seems to work best. Into it I blend (with a sturdy utensil) a bunch of fresh birdseed containing black-oil sunflower seeds. The ratio is unimportant, except the more seed there is, the more it attracts birds.
Now, visit your bare trees and liberally spread a glop of the mixture on a patch of bark. (In north Texas most leafless trees are Post Oak and Cedar Elm). With the addition of some "tree goop", however, hungry birds should bring some life to your yard.
If you have no trees, try a section of log (pictured). It's simply a log about 3 to 5 inches in diameter. Screw an I-hook into the top, spread some "tree goop" on it and hang it outside. That's all!
You could spend a lot of money buying some costly, pre-packaged mixtures where four or five companies take a percentage of the cost. If you choose to mix your own "tree goop", however, the results will be the same.