It depends on what kind of birds you are feeding, the type of feed you use, and your weather; I looked at your MyPage, but couldn't find where you live.

If you are feeding invasive, non-native, or common "trash birds," better not to feed them at all so they'll stop thronging to your free lunch and flooding the neighborhood with undesirables, to the detriment of native song bird populations, and the irritation of your neighbors. Wild birds are never totally dependent on human handouts, and many naturalists question the wisdom of feeding birds at all.

While you are gone your feeders could be attracting vermin-both rodent and bird. Wiser to feed small amounts of food types that don't attract the wrong critters, with careful monitoring. Remember, no matter how much food you put out, wild animals and birds-good and bad alike-will be happy to suspend their foraging efforts eat it all, flooding your yard, driving away desirable birds from the area to the frustration of your neighbors.

I live in Northern Illinois near Chicago. The birds that have been coming near the area are (in the order of numbers)

Sparrows (several variety, I can't tell them apart)
Chickadee
Cardinal
Junco
Mourning Doves
Red Wing Black Birds
Mallard Ducks
Robins
Downey Woodpecker
Hairy Woodpecker
Blue Jays
Coopers Hawk

I am guessing that sparrows may be consider invasive or trash birds, but I think the other birds are local. Which bird would be consider vermins?

There is a large Starling flock in the area, but I notice they never come to the feeder for some reason. The Mallard ducks don't come to the feeder either and I do not feed them. A hawk shows up once a week. They seemed to be different individuals, so I don't know if they are in the area or just migrating.

The tube feeder has a perch, but I notice that some cardinals can't get to it. This is why I was thinking of a hopper.

The neighbor has feeder, too but he gets finches. I rarely get them.

Paul

here the finches eat the thistle or nygier seeds before anything else. I tried the net socks but they spilt too much. so i mix the thistle with millet and put it in the tube feder.
I put a mix of cracked corn millet and boss in the small platform feeder which is mostly sparrows and juncos and a few finches and the chickadees and one lone flicker that eats from it twice a day. The other woodpeckers and the nuthatches and chickades eat on the woodpecker block mostly
but do eat some from the homemade suet tray. the big plaform tray is loose nuts and corn and raisen and dried fruits and is mostly bigger birds. During the spring and summer i have necter feeders for the hummingbirds and orioles and a fruit tray for the grosbeaks and orioles
I have some pine rounds stood on end like stumps and spread mixture of seeds and bread scraps and nuts on them and get a whole variety of birds on them. and the ground feeders cleanup everything that is spilt or dropped on the ground. the juncos and towhees normally eat on the ground but do try the stumps and feeders at times. The doves and jays and magpies eat on the stumps and the ground. I am lucky that i only get the red wing blackbirds in spring and summer because they eat a lot of everything. The starlings come through here but don't stay long and a few cowbirds are here some summers. get a rare hawk or owl and a raven or crow once in awhile.

That's a pretty good list; I consider House Sparrows to be undesirable and I don't feed Red-winged Blackbirds or Grackles, the latter because they prey on song bird nestlings. Leaving food around unsupervised is never wise-a bear, raccoon, or some other critter could take advantage of your largess and do property damage while they're at it.

Many people only put out feeders when they're home from work-the birds learn to check on the feeders and quickly return when they see the food.
When I go on vacation I let the tube feeder go empty.

House sparrows and starlings are invasive species. If they are visiting your feeders in great numbers, then they crowd out the natives, just like kudzu or buckthorn in the plant world. But don't make the mistake of lumping in the invasive house sparrow with our native sparrows. They aren't even related.

If you want to attract finches, put out a thistle feeder for them.

Although grackles and red-winged blackbirds are native, whenever they are migrating through, I don't put out sunflower, just safflower. That keeps them from congregating too much. Otherwise, I get a scene like this:

--
Liz in Bloomington, MN
Backyard weather and feedercam: http://www.overlookcircle.org
Photo gallery: http://www.pbase.com/gymell/liz_favorites
Follow me on Twitter: http://www.twitter.com/lizmstanley

My wife actually likes red wing blackbirds. In general, black birds never come in large numbers.

I guess the recent influx of sparrows are a problem. I am not sure what to do about it. I could switch to safflower seeds for a while to see if they will go away?

Paul

I think the problem may be due to the millet and cracked corn I used for ground feeding. They end up attracting large flocks of house sparrows, which then decimate the tube feeder, too.

I am suspending ground feeding for today and will try to switch to safflower seeds on the ground.

In my area we avoid feeding cracked corn at all costs. It attracts" bully" birds like starlings, doves and English/house sparrows.
Millet, while it is a favorite of sparrows, also has the same problem.
Side note: The bird we call an "English" or "house" sparrow is actually a finch. But whatever it is, it's a bother at feeders and a real nasty piece of work during breeding season.
Re: hopper feeders
While many birds like the wide platform offered by a hopper feeder, so do squirrels. And putting up a big feeder and filling it with a lot of seed won't guarantee that it will last very long, it could be empty in a couple of days.
Birds don't ration seed, they'll eat it while it's there. Fill your feeders before you leave and see if you have a neighbor that will come fill it for you once while you're gone. Or let your feeders go empty, the birds will survive.

There are a few House Sparrows and Starlings that show up on my feeders. I shoo them off if I'm around, otherwise just as Rachel suggested I don't put too much suet mixture, which they love as well as many other birds. At a minimum, I leave up a small suet cage with raw suet (House Sparrows don't eat it, Starlings occasionally) and a small tube feeder with black oil sunflower seed, which has small perches that the House Sparrows can't perch on.

Last summer, there were Bluebirds nesting in a snag in the back yard, so I suspended almost all feeding at the feeders so that the House Sparrows would disperse. They are a fierce competitor of Bluebirds for nest sites. The Bluebirds weren't bothered at all, they had no problem finding a steady supply of insects to feed the nestlings. Insects are what most terrestrial birds feed their young anyway.