How do I reuse gallon water containers for bird/squirrel feeders?

https://www.hometalk.com/diy/outdoor/garden/thistle-bird-feeder-927656

Put a hole in front large enough for the birds to get in towards the bottom and put in a couple of small dowels for them to perch on to eat that stick out a few inches. I would make sure that it hangs level so less snow will get in. I don't know how I would do it, but the piece you cut out could be used to put a roof over the hole for more protection. Make sure you put in a number of small holes in the bottom for drainage of melting snow/rain, etc. Check it to make sure the feed doesn't get covered with snow and freeze into a block. I have to do that frequently to my bird feeders to keep the food loose for them to be able to eat.

I found this on google!

If you cut off side below the handle, at angle down to the base you can make a scoop. Some could be made into houses for wrens.

What size hole does a wren house need?

Diameter of Hole, Floor, Size. Wrens prefer a house that has an entry hole dimension of 1 1/8 inches, any larger and house sparrows and other less desirable birds will use them. The floor should be 4 inches square and 3-6 inches below the entry hole.