Seeds: a main source of food for birds

For a bird to fly, it needs a lot of energy or fuel. You get this fuel by eating. Just as gasoline is fuel for a jet plane, food is fuel for a bird. But the type of fuel they consume cannot be too bulky or it would add unwanted weight to their bodies and hinder their flight. The best food for a bird is something small but nutrient dense. And that food is seeds.

Seeds are some of the most nutritious foods around. In fact, the seeds tend to be so nutritious that many birds only eat seeds as long as they are available. If the seeds are scarce, many could switch to secondary food sources such as insects, fruits, and the like. And these food sources, while valuable, do not contain the condensed energy value of seeds.

Over the years, many plants that have their seeds eaten by millions of birds for their nutrients have developed defenses to thwart them. One type of defense has been to develop a hard shell around the seed that cannot be broken without great effort. In response, some of the birds that feed on these seeds have developed extraordinary, strong beaks with the ability to put hundreds of pounds on an easily broken shell.

Other plants have developed prickly needles around the husk that prick anyone who tries to extract the seed from the inside. In response to this, many birds developed special thin beaks that allow them to avoid the thorns and reach the seed inside.

Other plants have developed seeds with extremely unpleasant flavors to discourage birds from wanting to eat them. Unfortunately, most birds have a very limited number of taste buds on their tongues, so the taste doesn’t bother them much. And other plants have developed poisonous seeds. In response, certain birds have learned to eat foods that neutralize poisons along with poisonous seeds. In this way they are not affected.

Over the centuries this has resulted in an almost constant state of warfare as plants evolve defenses to protect their seeds from birds and birds evolve to counter more recent plant defenses. This, in large part, explains the large number of beak styles you will see within various species of birds.

Many veteran birders can often tell a lot about a bird, even if they are unfamiliar with it, simply by looking carefully at the shape and structure of its beak.