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Shovelers Don’t Shovel

By on January 31, 2023 in Birds, BirdWords

Northern Shoveler Pair

Who would have thought it? Shovelers have been around much longer than shovels! The oldest known shovels, rough tools made of wood and sometimes a shoulder blade, are less than 4000 years old, whippersnappers like the folks who made them. Shovelers, on the other hand, are ducks, which, allowing for some evolution, date back to sixty-five million years ago, about the time dinosaurs proper were going extinct.

Of course, for purposes of our understanding and communication, we are the ones giving out names, and shoveler bills are broad, reminding us of our digging tools, and thus the name we use for them.

Northern Shoveler Drake

But shoveler bills are not for digging. Their broad bills, like those of many dabbling ducks, are edged with comb-like ridges. No, ducks don’t have teeth. Crowns and root canals are not required. Rather their bills are bony cores covered in keratin sheathes–think fingernail material. The keratin edge is scalloped into ridges that catch small aquatic crustaceans and seeds as the ducks squeeze water through, just as on a larger scale whales net krill in their baleen. Shoveler bills are for filter-feeding, not digging.

In their long history of acquiring food, shovelers have learned a further trick: the benefit of cooperation. As they  squeeze water through their bills they often paddle in a tight circle with a friend, or twenty or more friends. Apparently this action creates a tornado-current that pulls up foodstuff from deeper in the water, making the foraging more profitable for everyone involved. One can only imagine how they learned that stratagem.

It seems to have worked. Our species, the northern shoveler, prospers at mid-northern latitudes around the globe, mainly from western North America through Siberia to Scandinavia. Each summer a mated pair settles on a quiet pond or wetland. As with other ducks, the female raises the young on her own. She forms a scrape in the reeds or fields nearby, and there lays about ten eggs, which she incubates for over three weeks. When the young hatch, she quickly leads them to the water, where they feed and grow under her watchful eye, until they fledge after about seven weeks more.

Now that winter and water have returned to the North State, so have the northern shovelers. You can spot them, in small groups or by the hundreds, on quiet waters–the males with rusty red flanks and tuxedo-white breasts, the females in dappled browns. Her bill is orange, his black. The bills of  both are noticeably large–but they remain bills, not shovels.

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An Avian Santa Claus

By on January 3, 2023 in BirdWords

Pileated Woodpecker Female

Santa Claus isn’t the only one in a pointy red cap who flies around in winter handing out presents. Pileated woodpeckers do, too. As a matter of fact, they fly year round, delivering gifts through large swaths of North American forests, mostly south of the reindeer.

Pileated woodpeckers thrive among big trees. They prosper in west coast conifers and arc across Canada into deciduous forests throughout the eastern US. Among the big trees, they build and deliver their gifts as only these largest woodpeckers in North America can.

Their gifts are staples of life–food and shelter. Their tools for delivering them are those of carpentry, or maybe jack-hammering–tools of woodpeckers generally, but writ large in these crow-sized birds.

First they need a firm foundation for their hammering. The three toes forward and one back that most birds have would be comparatively unstable. Woodpeckers instead have on each foot two toes forward and two back. This allows a solid grip at the variety of angles at which woodpeckers work.

Further, woodpeckers have stiff tails that function with their feet to create a sturdy tripod from which to work.

Well anchored, woodpeckers still need a stout, strong bill to pound and pry. These birds regularly punch wood at about fifteen miles per hour. With what are probably the continent’s most heavy-duty natural chisels, pileated woodpeckers excavate gaping holes in dead trees. However, the abrupt deceleration of smacking their heads into solid wood creates impacts up to fifteen times what humans can sustain–impacts that would shut down the NFL with concussion injuries. All their concussive pounding requires some protection for these bird brains. Fortunately, they have it.

Human hyoid bones, which anchor our tongues, are firmly based at the top of our throats. Woodpecker hyoid bones are anchored at the base of their upper bill and flex in two bands over and around the brain before curving up under it to root the tongue. This limber anatomy creates extra elastic length for the tongue, allowing woodpeckers to probe deeply after insects in their excavations. It also lets the hyoid bone act as a sort of seat belt around the brain, tightening against destructive sloshing inside the skull.

The hyoid can’t reduce the pounding to zero, however, and woodpeckers have another brain-protecting design. Their brains are oriented more vertically than ours. That spreads out the force of frontal impact over a larger area of the brain, effectively dissipating the blow of each whomp on wood.

With these tools for effective and sustainable wood-carving, the woodpeckers can make their gifts–presents not wrapped up with a bow but offering vitals to their forest neighborhoods.

The large, often rectangular feeding holes that pileated woodpeckers create expose their prime food, carpenter ants, to not just themselves but to wrens and other birds, too, a feast any time of year.

And their nesting cavities? The excavations of smaller woodpeckers often end up as homes for smaller birds–swallows, titmice, nuthatches, chickadees, bluebirds, etc. But pileated woodpecker cavities are super-sized, and can provide homes for bigger forest and woodland residents: numerous ducks–mergansers, buffleheads, and wood ducks; owls of various kinds; other woodpeckers that are upsizing; and many mammals, including squirrels, flying squirrels, different bat species, pine martens, and raccoons.

The efforts of pileated woodpeckers are a boon to the forests. Each year mated pairs select one of their many holes and there raise their brood of three to five young, ensuring that this avian Santa Claus keeps giving.

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Cinnamon Teal – spice on the water

By on November 23, 2022 in BirdWords

Seasonal colors, check! Pumpkin spices, check! Plentiful food and gathering with family? Check and check! Cinnamon teals are birds of the season! Turkeys notwithstanding.

Their color is brilliant autumn rust, a very red cinnamon.

The spice, of course, is in their name.

Feasting? That’s what the season is for: they dine and rest in preparation for raising young next spring.

And gathering with family? Cinnamon teals often feed together in tight groups, but they are not so numerous that they cover lakes the way some ducks and geese do. Fortunately, they seem to have an inclusive attitude, and readily paddle among other ducks on the ponds– adding spice to the mix, one might say.

Cinnamon Teal Drake

Cinnamon Teal Drake

Teals are small dabbling ducks. The dabblers are ducks who feed not by diving but by skimming aquatic plants and insects from the surface or tipping tail-up to stretch below water to gather snails from the bottom of their shallow ponds. Cinnamon teal, with relatively large bills perfect for filtering surface water, often skim the top of a pond near the cattails and tules that ring it.

Along those tules a male may establish a favored resting spot, perhaps in the morning sun. There his fiery eye and brilliant rust-colored head and lower body can shine. If he stretches a wing he shows a green patch at the hind end of his upper wing, the teal color that defines this group. Forward of that color patch, known as a speculum, he shows an even larger strip of powdery blue feathers. But he does not always shine so brightly.

Ducks are heavy birds, and their aerodynamics require them to fly fast or not at all. That requires all their feathers to be in good form. Most birds molt, or replace their feathers, piecemeal, but ducks doing so would be flight-compromised for a long time. Instead they lose all their large feathers at once, becoming completely flightless for a much shorter period. Male ducks typically enter this phase after their young have hatched. They lose their bright colors and their flight feathers. Brown camouflage feathers grow in, and they retire from public life for a couple months. By mid to late fall they will grow colorful new feathers, including flight feathers

Cinnamon Teal Female

The timing works well. The females have raised their ducklings, and the young have fledged and flown. She is ready to start looking for a mate for next year just as he is freshly dressed to impress. She will study the males as they preen and strut for her attention, and make her selection. The pair will bond over the winter.

The female runs nesting. She builds her nest in dead pond-side vegetation, often under overhanging reeds that require her to tunnel into the den. There she will incubate 4-16 eggs, sometimes including eggs donated by a female from another species. When the young hatch in about three weeks she will guide them for a couple months, until they take wing to spread their own spice.

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Ravens – gotta love ‘em, but–

By on October 30, 2022 in BirdWords

Common Raven

Raven wings rake the air around the Northern Hemisphere, so it is not surprising that they are also tucked into an extensive array of human mythologies.

In Pacific Northwest traditions, the raven is the creator and, in what seems a wry pairing of roles, a trickster. For the Norse, two ravens scour the Earth each morning and provide to Odin the wisdom and knowledge they find. In China, ravens are credited with feeding their parents, and thus they symbolize filial gratitude and respect. Modern Londoners maintain an aviary of ravens at the Tower in respect to the legend that their loss would signal the end of the Empire. In the US, Edgar Allen Poe gave the raven the repeated knell of the finality of death’s parting, “Nevermore.”

Ravens are the planet’s largest songbird–loud, bold, and conspicuous. They are not, however, musical geniuses. Songbirds are defined by having a finely-muscled syrinx, a voice box that allows the variety and complexity of birdsong that humans enjoy around the world. With all that potential, ravens seem to have undersold themselves, settling on a range of croaks and clucks, generally burrier than the caws of crows, that support their communication but lack musicality as we understand it.

Music notwithstanding, avian scientists recognize ravens as among the most intelligent of birds. Like at least most of the warm-blooded world, ravens share in the social and biological intelligence that supports care for their young and getting along with one another. They are versatile, with the powerful bill and analytic capacity to adapt to new situations. Lab tests for some sorts of intelligence–mechanical and numerical–place them on par with chimpanzees and orangutans, roughly the level of human toddlers. Common observation shows another feature that indicates intelligence: ravens dive and roll through mountain airstreams for no apparent reason other than what in humans we call play.

If population is an adequate measure, ravens are highly successful. In this time when most songbirds are declining, their numbers are increasing. They are rather like us, drawing sustenance from beach to mountaintop, from desert to arctic, from trash piles to pristine wilderness.

Their triumphs, of course, come at a cost. Living things survive on other living things, and ravens are no exception to that rule. Patrolling highways through forests opened up by development, by burns and logging, and by the roads themselves, ravens dine not just on roadkill and human refuse, but also on the more exposed eggs and young of other birds, many of whom are already dwindling. Condors, despite their daunting size, have probably long suffered from the bolder and more clever ravens; beginning in the 1980’s era of condor conservation, officials found the need to haze and cull ravens to protect the larger birds’ nests. In the Arctic, whether warming is yet prompting increased raven predation on the world’s nesting shorebirds and ducks is something that research is still determining, but in 1913 camera technology allowed the first observation of a pair of ravens killing and subsequently feeding to their own nestlings a litter of four arctic fox pups.

A Conspiracy of Ravens

We don’t know how much ravens will impact other species in a warmer and less verdant world, but we do know that they are opportunistic predators. Fortunately, their harm to other species is individual, not systemic; raven proliferation is just one small facet of the broader harm posed by development and climate change. But we should recognize that ravens, for all their intelligence, operate with the short-sighted and self-centered adaptations that evolution writes for survival in a more stable world. We cannot expect them to curb their reproduction or their appetites. Intriguing as ravens are, each year a mated pair raises its handful of offspring and adds to the world its own version of a dubious “ever more.”

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Small Hawks Arriving for Winter

By on September 30, 2022 in BirdWords

Sharp-shinned Hawk

The raptors are coming, the raptors are coming!

Fall is upon us, and migration is in full swing.  The cliff swallows and orioles were moving in July, with warblers and vireos on their heels. Now, as their exodus southward continues, look for birds that have nested north of us to arrive. One of our winter residents, down from nesting in mountain conifers and Canada’s boreal forest, is the sharp-shinned hawk.

Raptors are birds of prey. Among the many North American raptors–eagles, hawks, falcons, etc.–the sharp-shinned is the smallest in the group called accipiters, stealth hunters that prey mainly on birds in fairly dense woods. They are well adapted to that habitat and lifestyle. Let’s start with their eyes.

Sharp-shinned Hawk Close

Sharp-shinned hawks, or “sharpies,” have the front-facing eyes typical of vertebrate predators. That positioning creates a blind spot behind, but allows two eyes to focus forward–the binocular vision that supports depth perception and successful hunting. Relative to our eyes, the hawks have about eight times as many rods and cones, providing their innate version of HD viewing. Further, where our eyes each have one fovea, or focal point, sharpie optical nerve endings are arranged to form two foveae–a central one that can focus on a fleeing bird and a peripheral one that can help the hawk avoid crashing into branches.

Forest hunting has also helped design sharpie body form. Their short, round wings sacrifice the soaring ability of larger hawks but gain mobility and quick acceleration for sudden attacks. Their long tails serve as rudders for abrupt maneuvering through forest obstacles.

One of the sharpie’s hunting styles is to perch low and explode upon an unsuspecting sparrow that happens by. If you see this small hawk perched, you may be able to observe its yellow, pencil-thin legs and fluffy white feathers under the base of the tail. Adults have red eyes, a slate-gray cap and back, gray-barred tail, and cinnamon-red barring on the breast. Juveniles have yellow eyes and are generally mottled brown, with thick streaks on the breast.

Sharp-Shinned Hawk in Flight courtesy Tom Murray

Sharpies also hunt by cruising low through brush and trees and, with sudden acceleration, pouncing on a potential meal. If you see this, it’s hard to discern more than a dark blur rushing by.

They hide their nests below the canopy in their forest homes, and tucked against a trunk. The female incubates her handful of eggs for a month. The male brings in food for the hatchlings, and later, the female, half again larger than the male, brings in larger prey to feed the growing chicks. The young will fledge at about a month old, and must develop their coordination and skills before striking out on their own and facing their first winter.

Sharpies are often seen at windy passes and peaks during migration. Perhaps their wings, so good for forest navigation but not for distance flying, benefit from the Earth’s corridors of air.

Through the winter they have no nests to hide and are less committed to being in forests. They can be found in suburbs and will frequently visit bird feeders, providing a twist on the definition of “bird feeding,” and generally stirring a mix of dismay and intrigue in their human neighbors.

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