by George Ball
The beaks of birds tell their story. Technically, the term is “bill”, short for “mandible”, of which there are two, the upper and lower. Most people call them “beaks,” and birds don’t seem to mind.
A short, blunt, clearly triangular-shaped beak with an obviously sharp point allows finch-like birds to pierce, tear, and pry open the “nuts”—seeds’ thick, tough capsules or hulls—and consume the kernels within. Strong and compact, nut-cracking birds can grow large, especially in the tropics where the fruits and nuts are likewise larger.
Birds’ beaks never stop growing, as they have a lot of work to do. Because of their exceptionally high metabolism, many small birds eat 20% of their body weight daily. Hummingbirds visit as many as 1,000 flowers in a day to dine on nectar in order to maintain their 105° F body temperature. (A thousand flowers seems low somehow.) The heart rate of the Blue-Throated Hummingbird can go as high as 1360 beats per minute.
Birds with longer and wider beaks use them to swallow seeds—shell, hull, chaff, kernel and all. Also, beaks help birds in their other tasks: nest-building, worm- and larvae-picking, and extracting other invertebrate delicacies from trees, mud, sand and soil. Many styles of beaks help birds consume large insects such as beetles, or rodents, as opportunities present themselves.
Other birds, including starlings, have various sorts of “harvester”-style beaks. Starlings simply open their mandibles and fly through low brush and grass, eating insects. As they probe, sally, lunge and glean, starlings are “shooting” their large, open beaks, like the tips of stretched bi-valve throat pouches.
Starlings’ discerning eyes are located just behind their beak’s joints: the left eye perceiving color, the right eye detecting movement, which explains why certain birds tend to look at objects with one eye or the other. As a kid, I hated starlings, which we called “grackles”. They infested our house one summer, dozens of them—aggressive and making a racket with their hideous calls and wheezy songs. I’d use my BB gun to try to shoot them, with no success. My yelling was much more effective, and they eventually moved on.
Birds co-evolved with an extremely varied range of phenomena. The seed-eating birds draw the attention of gardeners and seed growers such as Burpee and its colleague companies around the world. During both the crossing (hybridizing or self-pollinating) and harvesting seasons, most of us remain “on guard”, primarily on the lookout for insects, but keeping an eye out for the more voracious, seed-loving birds. Neolithic man had to endure difficulties with birds in growing and harvesting seed crops, like the vital, all-important grass we know as wheat.
Beginning in the 19 th century, farmers found a way to take advantage of seed-eating birds; pigeons, housed in multistory towers, were used to glean stray seed from pastures after the growing season.
Water is an enormously important bird nutrient. We all know how much birds love bathing. We tend to be less aware of how much water they drink.
I am less familiar with migratory and predatory birds. I wish I had time to be a “birder”. Several hawks and one owl reside in the 60-acre research farm where I live. They hold themselves, literally, aloof and remote. Raptors use their claws rather than their beaks to capture prey. Owls frighten me a bit. Their low, deep hoots have a haunting, almost hypnotic effect. Like menacing villains, owls terrify prey with their eyes, paralyzing them with fear.
Predatory birds can be eerily clever. For instance, ravens will work in pairs as they raid seabird colonies: one bird will distract a nesting adult, allowing the other to grab an exposed egg or chick.
Since childhood I have been a fan of the small, familiar birds of home: finches, nuthatches, thrushes, wrens. Their presence around large homes and gardens is inevitable, since birds coevolved with the plants, shrubs and bushes they inhabit. These birds expand the populations and distribution of plants, helping prevent the inbreeding depression of the plants’ gene pool. They consume the fruit of various species such as winterberry, serviceberry, hawthorn, flowering dogwood, hackberry, honeysuckle, firethorn and mountain ash, to name a few. While digesting them in flight, they scarify the seed with their acidic digestive juices and gizzards, which often have small stones that help break down the seeds.
By the time the birds have flown a sufficient distance to prevent inbreeding of the plants by either wind or insects, they defecate the pre-germinated seed, now conveniently nestled in a nitrogen-rich food pack. Bird droppings—so vexing when they descend on our automobiles—are seed being sown, and evolution being maintained.
Unlike many insects, birds don’t resemble flowers. But in some species their beaks are symbolic indicators of their food seed, and some beaks look like the nuts they consume. In other birds—such as spoonbills, cormorants and pelicans—their beaks suggest both how deep or how shallow in the water their prey live.
Flying great distances, birds harness the wind, especially the great currents at about 10,000 feet and higher. In turn, these winds originate from the movement of the earth which causes the temperature variation that cause vapor, or gas, to move. While all birds like to fly dry, migratory birds like to fly bone-dry—the lighter the better. By flying so high and dry they meet with less resistance, most of which is water vapor.
The journey of most migratory birds is less than a thousand miles, one way. Their destinations are not so far, and there are plenty of dining stops along the way. Some fly south in the fall to find food: late season seeds, berries in mid-South, early season in Deep South, or year ‘round in the sub-tropics, such as Mexico. Other species fly north in early April and May to roost and reproduce. Birds are smart—they know when to leave.
One of the most extraordinary things I’ve observed was the behavior of a three-day-old pigeon. Except for its physical limitations, which weren’t so great considering its formal development, it was ready to grow, if not to go, as in get out of town. I’ve never seen such constant energetic motion—such a pure will to live. Everything was there, except size and a bit of coordination. One or two practice sessions and “game on”. The pigeon’s eyes were especially large for such a tiny, unfolded, wildly animated embryo. Birds live by their eyes.
Here I will step aside and let Mr. Darwin take over. He can carry you much farther than I. On the Origin of Species was inspired to a large extent by his observations, made in the tropics, of the differences and similarities of birds’ heads and beaks. Also, take a look at The Life of Birds by the articulate David Attenborough, the companion volume to his superb BBC nature documentary.
I shall return to this subject soon, since the composer Ralph Vaughan Williams transported me back to sweet memories of birds, particularly the songbirds’ precious calls and songs.
Finally, here’s a partial list of the great seed and berry producing plants that songbirds love and we can offer you for sale. They are sunflower (the taller the better), echinacea, rudbeckia, asters, coreopsis, poppy, marigold, zinnia, cosmos, gooseberry, hibiscus and sedum. There’s still time to plant many of them, or plan to do so in your 2013 garden.