For many years, I've fed the squirrels where I work. Once upon a time, long ago as a New England winter was approaching making life difficult for many (if not most) creatures great and small, I started feeding the birds as well. I had squares of suet with bird seed that I'd place in a cage that would hang with suction cups holding it to the window, a free-standing type of device.
That worked fine for all the little birds until some of the larger birds took over the feeder, dive-bombing the suet cages and scaring off the smaller birds. The simplest (if not also the cruelest) solution was to stop putting suet out and removing the cages. After awhile, the raiders took the hint and moved on.
In the meantime, my wife had gotten me a small plasticine feeding shelf with a roof. It secures to the window with suction cups and the feeder itself is attached by the hooks. It's all clear so the birds can see the seed, and in this case, because it's on my outer office window, the biped in the dress shirt and tie on the inside, where we keep the carpeting and the fluorescent light, can look at them instead of my computer screen.
On colder days during the winter I'd have waves of little birds, and some not so small ones, landing and gobbling seed (which we bought in those forty pound bags). My favorite birds were the male Cardinals--I'm not sure if birds see in color (Animal Planet is a premium channel on my cable system) but I suspect they can, and the Cardinal is one reason why. I got Lady Cardinals, too, and was impressed with how well both sexes seem to coexist with the other birds at the feeder.
Not so the Blue Jays. They're more or less a special creature since, according to the pamphlet that came with the feeder, it was designed specifically to thwart their efforts and to discourage them from using the feeder. When I read that the first time after putting up the feeder, the pamphlet made me feel bad, except, the birds themselves are unable to read and will not sit still long enough for me to read the pamphlet aloud to them. Ignorance is bliss with feathers.
All day long, there was a coming and going at the feeder and a pattern of hustle and bustle on the suet cages as a waiting area would form there to get at the feeder and grab some seed. But as you may have noticed I'm writing in the past tense, because it's all over now. I came out one night to head home and the usual gaggle of little sparrows was in the area of the feeder and on the sidewalk flanking the parking lot in front of the building where I park and on the hood of my car were three or four (or more) piles of poop, starkly white against the clear coat paint job.
As a card-carrying Auto-American, I turned to the little birds sitting on the sidewalk looking in my direction and warned them 'not MY car! I'm the biped who feeds you! Poop on the Armada or on the Ram truck (he eats chicken for lunch. Where's your sense of solidarity?) But leave my car alone." I don't know how many warnings the Audobon Society recommends, nor do I care. Let's just say they had plenty. My feathered former friends learned too late that my animus now extended to them and while they may continue to be free birds, their free lunch was history.