This weather is tough on the wildlife. Most people don't think about that, or think too much on it. There's a lot of suffering going on out there in the big world, both in human-created civilizations, the outskirts, and in the animal kingdom. It's a balancing act. There's no way to make all the animals in your area happy and safe and warm and fed, and they're never going to weave your hair into a braid or sweep your porch for you. But it is nice, as a fellow living creature, to look out for our companions on this planet when resources are thin on the ground and the weather is nasty.
Salt licks for deer. Yeah, the fuzzy, sweet-faced, big-eyed and big-eared vermin drive me nuts, but they are adorable and it's great fun to watch them hang out in your yard. When it's cold, the molasses in those licks gives them a few extra calories plus needed minerals when the plant life all around them has sucked most of the nutrients down to the roots for winter.
Suet cakes for birds. Lots of calories, and not as much waste as plain ol' seed. Hang up multiple cakes so that bully birds have a harder time hoarding the cakes, although I've noticed that different species of birds come to the cakes at different times, so the bully birds aren't always going to be there every second of the day. That gives other birds a chance to supplement their regular winter diet too.
Hummingbird nectar. One part sugar, four parts water. I usually do a 1/2 cup of water and 1/8 cup of sugar, but if you have lots of them in your neighborhood you may have to do more than that, or even have more than one feeder. Hummingbirds go into torpor overnight and during the worst parts of the day. They'll usually come to the feeder first thing in the morning when able. They'll also return later in the day during warmer or lower-wind stretches if weather allows. My mom puts a regular light bulb in an outdoor-rated socket near the feeder to keep it thawed. Another friend activates a hand-warmer and tapes it to the bottom of the feeder. Still another takes the feeder in overnight so that it's at house temperature and then puts it out in the morning. Unless the weather is exceptionally cold, sugar water will remain thawed for several hours if it starts at room temperature. The clear boxes with the red lids that have holes in them are the easiest to keep sanitary, but I find that the suction cups that hold them to the window become detached more easily in winter than in summer, so I use one of the hanging bottles with fake flowers around the red base. Protect your hummingbird feeder from wind if you can, both to help the birds and to keep the feeder from smashing to bits, but don't overdo it. The birds need space to approach and depart from the feeder safely, and they feel safer if they have a clear sightline in as many directions as possible. Yes, cats can catch hummingbirds. A friend of mine told me about a cat who caught hummingbirds almost every day out of her yard until she strung up a feeder up high to divert the birds from feeding in her flowerbeds and raspberry bushes where the cat could easily sneak up on them.
If you've seen wild bunnies in your area, you can try to put out sunflower seeds and/or cracked corn in pans on the ground for them. (Doves will also help themselves to cracked corn if it's left on the ground–they're ground feeders and very rarely go to regular bird feeders unless you have a large one with a flat bed they can hop around in.) I avoid attracting bunnies, and in fact try to deter them in the summer, but I like to see them in the wintertime because I don't have vegetable gardens for them to raid, and feeding them keeps the pressure off of my dormant roses. I used to put a pan of sunflower seeds and chunks of dried, stale bread out on a defunct wood stove we have in the garden and the bunnies would hop right up to feast. They've also hunted around for fallen stuff under the bird feeders before. The jays, of course, also help themselves (which will keep them out of your regular bird feeders so the little birds can have their share.) Don't leave pans of bunny food on the ground overnight. It'll attract rats.
Squirrel mix, peanut butter smeared on dried corn cobs, unsalted peanuts in the shell, etc. for squirrels. Hate squirrels because they get into the bird feeders? Try giving them their own spot with their own food. Bully birds tend to focus on whole peanuts too. They can only carry one at a time, and tend to fly off with their loot rather than pick at it at the feeder, so it majorly reduces competition for those seeds you put out for smaller birds.
Got any winter wildlife feeding tips? Post 'em in the comments.