If you feed wild birds, and you're in an area where the temps are unusually low, you may want to give the birds some water, too. Our area is in a drought, so even the little water they normally depend on is probably frozen right now. It doesn't have to be complex, I put out a little plastic bowl, and the chickadees are sipping from it.
@Jorah Does there need to be salt or sugar in the water to stop it from freezing? Or just put out warm water so they can get at it before it does? (I put out water for bees on the roof terrace in summer; winter is hardly ever very cold in N, especially not recently)
@irina I don't know if salt would hurt them. I just change it out once a day, and try to dump out the ice at night so it doesn't turn into a giant lump.
@Jorah Whoa, I'd forgotten about that. Here it's been down to -21°C at night, and there's snow that they *could* eat... but the temperature difference (plus heat of fusion) from liquid water could make the difference between life and death.
I just put out a suet feeder, but no one has shown up; I think the birds are largely sitting tight right now, and definitely not exploring for novel food sources.