In much of North America, winter is a difficult time for birds. Days are often windy and cold; nights are long and even colder.

The lush, berry-laden vegetation of summer and fall has withered and been consumed and most insects are dead or dormant.

Birds may have difficulty finding enough food during the short winter days to fuel their internal furnaces.

Setting up a backyard bird feeder makes their lives easier and ours more enjoyable.

During spring and summer months, the diet of most songbirds is composed mainly of insects and spiders. These tiny creatures are highly nutritious, abundant, and, for the most part, easily captured.

During fall and winter, however, non-migratory songbirds must shift their diets to fruits and seeds to survive.

This is the time of year when winter bird-feeding enthusiasts should roll out the welcome mat and set the table.

The question is what to serve for dinner.

The shelves of many supermarkets and specialty bird-feeding stores are stocked with bags, buckets and cakes of many food types.

One key to attracting a diversity of bird species is to provide a variety of food types, but that doesn’t mean you need to purchase one of everything on the shelf.

Different birds prefer different types of seeds, but the seeds that attract the greatest number of species are black-oil sunflower. These seeds have a high meat-to-shell ratio, they are nutritious and high in fat, and their small size and thin shells make them easy for small birds to handle and crack.

Striped sunflower seeds are larger and have a thicker seed coat.

Several studies show that this high-energy food is the flock-pleasing favorite of the majority of birds that visit feeders. In fact, if you fill a feeder with a standard mix, a blend of sunflower, milo, millet, oats, wheat, flax and buckwheat seeds, you’ll see many birds kicking out the smaller seeds to get to the prized sunflower seeds.

Whole-kernel corn, a favorite food for jays, pigeons and doves, is perhaps the least expensive of all birdseeds.

Cracked corn, however, is easier to eat for blackbirds, finches and sparrows.

“Millet” comes in red and white varieties, but most birds prefer white proso millet over red.

“Niger,” or thistle seed, is a delicacy for small finches such as goldfinches and siskins. Because Niger seeds are small and expensive, it’s best to offer them in a special Niger feeder which has tiny ports that prevent the seeds from spilling out.

Safflower is another seed that many birds like, most notably, cardinals. As an added bonus, it has limited appeal to starlings, house sparrows and squirrels.

Peanuts are another readily available food that many backyard birds will eat.

Suet feeders at the right time of year are very beneficial.

You should hang suet feeders in the fall, keep them filled in the winter, and put them away in the spring. If you keep your suet out in the spring and summer, as the suet heats up, its fat can go rancid and harbor fungus and bacteria that can be harmful to birds.

While most birds will not eat food that has spoiled, they may be unable to tell when suet first starts to decay or there may not be other food sources available, so they inadvertently consume the unhealthy suet.

Suet is ideal for birds that like meat: the chickadee, titmouse, nuthatch and woodpecker. Birds will nest near this excellent food source in the winter and then take up with insects when the suet feeders are empty.

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613