Which Bird Seeds Are Best?

Scientists provide tips for choosing foods that attract the most birds--and keep them the healthiest

11-01-2010 // NWF staff
cardinal at seed feeder

As the weather turns cooler, it’s time for backyard birders to start cleaning out feeders and stocking up on supplies for winter feeding.

Trying to decide which bird seed to buy? Surprisingly, the answer is not clear-cut. Despite our enthusiasm for backyard feeding—more than 50 million people feed wild birds in the United States alone—very little science has gone into understanding the nutritional needs of wild birds or even which seeds they like to eat.

David Horn, associate professor of ecology at Millikin University and a leading expert on the subject, is trying to fill that gap. Recently, he established the National Bird-Feeding Society. Many of the group’s recommendations will be based on Project Wildbird , a 2005–2008 study led by Horn in which several thousand volunteers contributed observations from their backyard feeders.

Some conclusions so far:

1. Birds require foods with high nutritional content, especially protein and fat.

 A bird’s diet must fuel a metabolism that can require up to a whopping 10,000 calories a day (equivalent to a human consuming 155,000 calories). A bird’s inner furnace burns especially hot during flight and the breeding season and on the coldest days.

This means birds must make highly efficient choices about what they eat. A backyard feeder is an especially efficient place to forage because it mimics what scientists call a “resource patch,” a cluster of food much like a fruit-laden apple tree.

But don’t worry that birds will become too dependent on your feeders. Evolutionary pressures encourage birds to continuously sample a wide variety of foods because any bird that becomes dependent on a single patch or type of food will perish if it runs out.

2. Birds must have high-quality food.

 Birds are remarkably proficient at assessing potential food items for nutritional content and quality. If you watch your feeder closely, you may observe the animals lightly rattling individual seeds in their bills to weigh and taste them before deciding whether to drop them to the ground or eat them.

Low-quality foods are discarded and a consistently low-quality food patch may be avoided for a while—a behavior called “neophibia” that explains why birds learn to avoid your feeder if you put out old, moldy or inedible seeds.

3. Birds choose seeds that are easily handled and digested.

 This finding emphasizes that for birds, eating is not only about nutrition but about consuming a lot of food very quickly while avoiding predators. Research has shown that given a choice between high-quality, cumbersome seeds or low-quality, easily handled seeds, birds consistently choose the latter.

The bottom line:

For these reasons and others, the study found that the most highly sought after seeds are: black oil sunflower, white proso millet, nyjer (thistle) seed and sunflower chips.

Whichever seeds you buy, a growing body of evidence shows that backyard feeding helps wild birds—the animals’ growth rates, survival rates, breeding success and clutch sizes all improve markedly when they have access to feeders.

Adapted from “ For the Birds: Which Seeds Are Best ?” by David Lukas, National Wildlife , October/November 2009.

Learn more about bird feeding: NWF’s Certified Wildlife Habitat™ program provides homeowners with all the information they need to create quality outdoor spaces for birds using native plants as well as bird feeders.

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