In my non-wildlife gardening days, I figured birds were on their own. There's generally plenty of food out there, I thought, although habitat might be in short supply.
But putting out bird feeders (sunflower seed, thistle seed, and suet) some years ago opened a new arena of observation.
All of the usual suspects (speaking in 'now' terms) appeared -- and they're great -- I know all the songs and call of our regular garden birds, and whether they eat seeds or suet, or kick up insects in the leaf litter or eat earthworms in the spring.
In the mountains, we added all of these, and it didn't take long for the seeds to be discovered. There was a parade of cardinals, tufted titmice, and Carolina chickadees at the sunflower seed feeder, and this male goldfinch loaded up.