Normally birds will feed on crop grain twice a day given non critical weather conditions. When temps are good birds will fly as far as 50 miles to feed. When temps start to drop birds will look for shorter flight times. Also during colder weather birds will feed as long as they can, stuffing themselves with as many calories as possible. In extreme cases I have seen geese sit on a frozen lake for days burning as little energy as they can. They'll wait out the bad weather flying out when the qeather brakes. Birds key on three things during their mirgation shelter, food, soft water (as in, not frozen). Birds that arent lunar migrators, that is, those that dont migrate due to changes in the length of days will migrate when food gets covered with snow and or their water freezes up. Look for ponds or lakes tucked in the woods that may have acorns near by, beaver ponds, access to rivers hopefully with an island you can wade to, or grain feilds that tend to hold some sheet water. Many birds are lunar migrators and the heaviest migration around here seems to be around Thanksgiving time. Still many other birds resist migrating until they cant take the bad weather. On clear nights with bright moons I will be hitting beaver ponds and small streams in the morning. On dark nights I'll be in the fields. Later in the seasonI'll be looking for concentrations of birds on gravel pits, large lakes, and rivers.