Author Archive | Dan Greaney

Plants for Birds

By Dan Greaney on October 9, 2017 in BirdWords

Cedar Waxwing on Toyon by Jay Thesken

After the long heat, the season for planting approaches. The local CNPS will hold its fall sale of native plants at the Shasta College Horticulture area on October 14, 8am-2pm. It may be an opportunity to dress up both your yard and the birds!

We only survive and flourish because of photosynthesis, the green-plant magic that turns solar energy into food energy. Without plants we would lack the wit to see a bird, as well as any birds to see. None would sing, or sprout a golden feather.

Praying Mantis

Fortunately, many plants survive our summer droughts and winter frosts. Trees, shrubs, forbs, and grasses provide a feast of seeds, nuts, berries, leaves, and nectar. Native plants support insects—caterpillars, leaf-hoppers, aphids, and more. Buckwheats, sages, coffeeberry, and toyon are among the many plants that support our pollinators—native bees, wasps, flies and beetles. The insects become food for so much of animate life, including our local fledglings who this month are fueling their first flights south.

Western Bluebird Fledglings Waiting to be Fed

Many birds are strongly associated with oaks. Besides making nesting sites, oaks make acorns, which are devoured by jays, magpies, crows, ravens, turkeys, and band-tailed pigeons. Acorn woodpeckers store the acorns in rotting branches for winter dining. Lewis’s woodpeckers do the same, but meticulously shell and split the acorns first!

Acorn Woodpecker Granary

And oaks pass storms of insect energy on to hungry birds! Woodpeckers, titmice, and nuthatches dine on the beetles, ants, and spiders of the woody branches, and on the wasp larvae in oak galls. A stunning 534 species of butterflies and moths are known to lay their eggs in oaks, and those caterpillars feed orioles, warblers, vireos, mockingbirds, and bushtits. Bluebirds and flycatchers hawk the insects that take wing, and robins, sparrows, and towhees pick dinner from the detritus under the trees. Oaks are the crowning gem of many a lively yard!

Oak Titmouse with Insect

Quail will roost in the oaks, but will gladly poke about at ground level in the thick protection of Ceanothus bushes, where foraging wrens and towhees may join them. Nearby lupines, after their bright show of blue flowers, will draw the quail out to dine on their nutritious seed pods.

California Quail Female with Chick

The fruits from Coffeeberry, Toyon, and Elderberry attract robins, bluebirds, mockingbirds, waxwings, and nuthatches. Currants will also draw these berry-loving birds.

Goldfinches flock to sunflowers and thistles. Milkweed supports not just monarchs but eleven other species of butterflies and moths, too. Colorful grosbeaks dine on their seeds, and hooded orioles use the plant fibers to weave their nests.

Swallowtail On Western Vervain

Four species of hummingbirds are regularly seen in our area, and many flowers sustain them—woolly blue curls, larkspurs, penstemons, monkeyflower, fuschia, currants, and salvia. Some of these plants bloom through the winter, sustaining the resident Anna’s hummingbirds.

Anna’s Hummingbird on Thistle

For the adventurous, poison oak provides fruit and cover for quail, thrushes, sparrows, goldfinches, flickers, juncos, kinglets, sapsuckers, wrens, titmice, and a host of other songbirds. Don’t get carried away with toxic adventures, though. Nandina, known as heavenly bamboo, is a colorful but dangerous invasive that poisons birds with its cyanide-laced berries.

Gardening for birds is best done with a dose of indolence. Leave those dead-heads on the plant; they’ll feed the finches. Leave the leaves on the ground. Towhees and sparrows will breakfast on the bugs that turn them into mulch. Native plants are generally a great bet. Together with the birds they form a beautiful gift to yards all over. Enjoy!

pH for Public Health, and Dinner, too

By Dan Greaney on August 8, 2017 in BirdWords

Turkey Vulture Juvenile

Most of us observe external adaptations—the vulture’s naked head, its sharp beak, its capacity to soar. But the MD’s among us develop a familiarity with internal adaptations. Redding’s own Dr. Lang Dayton has provided further details in response to last month’s article on turkey vultures.

He refers to pH, the chemists’ and pool-owners’ 0-14 scale. In this scale, seven is neutral, like pure water. The extremes, as they are in much of life, are toxic. High numbers are alkaline, also called basic: ammonia measures eleven, and bleach twelve. Low numbers are acidic—think lemon juice, which stings, or sulfuric acid, used in drain cleaners, or Iron Mountain runoff, which has been measured at sub-zero pH levels.

Dr. Dayton writes:

The main reason vultures can eat almost anything is that they have the lowest gastric pH in the animal kingdom. Stomach acid protects all animals because it digests bacteria and other living organisms along with other proteins. Human stomach acid has a pH of two. It kills 99% of bacteria in contact with it, but people still get sick and can die if they eat enough contaminated or rotten food.

Turkey vultures’ stomach acid has a pH slightly above zero, lower than car battery acid and 100 times as concentrated as human gastric juice. It can dissolve metal, e.g. shovels, as well as digest nearly all organisms, including those that cause botulism, anthrax, rabies, cholera, hepatitis, and polio, along with other proteins. Vultures can eat just about anything that is dead and rotten, including animals that died from infections that, in turn, would kill most people who ate them.

By consuming rotten and diseased meat they decontaminate it, which helps to prevent the spread of disease to both humans and other animals.

When India experienced a massive vulture die-off in the 1980s, feral dog populations exploded and, with them, the incidence of anthrax, rabies, and other communicable diseases. Unlike vultures, dogs do not so thoroughly disinfect what they eat. Feral pets that eat carrion can acquire and spread disease from their meals.

One of the things that I used to teach Interns and Residents in the Mercy Medical Center Family Practice Program was that stomach acid protects all animals as it digests swallowed organisms along with other proteins, and that it is a bad idea to take medicines that suppress gastric acid when going to 3rd world countries. People lacking stomach acid get sick on 1/100th the dose of ingested organisms as normal people. Vultures, on the other hand, could feed on botulinum toxin. Give them enough gastric acid suppressants, however, and they would likely die after their next putrid meal.

Turkey Vulture

So thanks again to vultures for their good work, which seems to take both soaring on wings and going low on pH, and to Dr. Dayton for teaching us about the vultures’ gastro-intestinal virtue.

Vultures Soar to do the Dirty Work

By Dan Greaney on July 3, 2017 in BirdWords

Turkey Vulture Adult and Juvenile

Summer is the season for soaring. Thermals, the warm air rising from the earth’s heated surface, can lift birds thousands of feet into the air with no more effort than spreading their wings. Larger birds, particularly raptors, for whom the quick flutter of small-bird wings would be physiologically impossible, are particularly famous for riding on thermals. The reigning champions of hot-air flight are, arguably, turkey vultures.

They’re ungainly, maybe disgusting. They can’t sing, only argue over food with a breathy hiss. They’re folklore symbols of doom and death. But supremacy in the air helps vultures prosper and decorate the sky through our sultry summer days. Some 90% of the soaring birds we see are apt to be not birds of prey but turkey vultures.

These vultures can be identified at a great distance. They hold their wings up in a V, a gift of their initial letter that hawks and eagles cannot replicate. The V shape, known in aviation as a dihedral, helps stabilize the birds in windy weather. When winter buffets the north state, the resident vultures ride the winds that replace the lazier-seeming currents of summer. Other turkey vultures will honor autumn tradition and head south—but they will still sail the winds, as they can ride as far down-continent as ever-blustery Tierra del Fuego.

Wherever they are, turkey vultures must soar to find their food with the most efficiency. Unlike most birds, they hunt with a keen sense of smell. Eagle-eyed predators can spot a salmon below the river’s ripple. Owls can hear a mouse squeak a football-field away. Vultures’ food, already dead, will not squeak or scurry for the ear or eye. Turkey vultures hunt mainly by smell. Their acute olfactory sense will not only find their carrion dinner, but will tell them whether it is too rotten to interest a civilized vulture. Indeed, while large owls, with their absent sense of smell, may gulp down a skunk, vultures will regularly discard at least the skunk’s scent gland.

But they really are not delicate diners. Vulture beaks are sharp and strong, but when particularly tough hides must be pierced, they may need to wait for early decay or a bigger predator to open the carcass. Since they will then be eating meals past their expiration date, and since they seem to prefer eating entrails from the anus up, vultures are heavily exposed to toxins. Fortunately, they are adapted to the dangers. Their naked heads not only keep feathers from being matted with contaminants, but also allow their skin bacteria, thicker and harsher than our own, to attack microbes in the meat, averting facial infection. The birds seem to be immune to effects from many biotoxins, and their own exceptionally virulent intestinal bacteria help them finish the job.

Their job is in fact a substantial service. Vultures find and scavenge about 90% of sizable dead animals in their range, reducing both disease and cleanup costs we would otherwise face.

Their condor cousins, with the rise of lead shot in carcasses and, longer term, no more mega-fauna to clean up, have been teetering on the edge of extinction for some time. Turkey vultures, on the other hand, perhaps responding to clearing of forests, an increase in roadkill, and a warming climate, have been extending both their breeding and wintering ranges northward.

Numbers Matter for These Birds

By Dan Greaney on May 27, 2017 in BirdWords

Tricolored Blackbird photo by David Bogener

Last month local birders joined in a state-wide survey of tricolored blackbirds. These birds look much like their more common and widespread relatives, the red-winged blackbirds, and they are even found in similar marshy habitats. But the two speak different languages and have markedly different lifestyles.

These are the sounds of the Red-winged Blackbird:

These are the sounds of the Tricolored Blackbird:

The survey is conducted statewide in just three days. This all-at-once survey approach minimizes recounting the birds as they move. And move they do!

Tricolors begin nesting in early spring in southern California and the San Joaquin Valley. Then they move northward and by late spring and early summer are ready to undertake a second nesting, much of it in the Sacramento River watershed. This year the survey in early April found no tricolored blackbirds in southern Shasta County. Two weeks later the nesters moved in: 10,000+ were reported.

Those birds were descending on a field of Himalayan blackberry. Tricolors have been versatile, and as historical marshes of tules and cattails have gone dry, they have adopted a wide range of nesting vegetation, including nettles, mallows, triticale, and blackberries. When they find a field that looks promising, they swarm into it by the hundreds, thousands, and tens of thousands.

If you visit a local pond this time of year, you are apt to see a sprinkling of red-winged blackbirds perched on the tules, perhaps singing their reedy but musical song and showing off their bright epaulettes, vermillion edged with yellow. Below them are the females, hidden with their brown plumage as they warm their eggs in reed-hung hide-aways.

These red-wing colonies might stretch thirty feet from one perched male to the next. Tricolors, on the other hand, go for high-density. The males are likely perched a mere yard from one another, and there are probably two females on two nests beneath each male. This high-density nesting offers a potential advantage.

While the bright and busy colony, along with the tricolors’ raucous, obnoxious blatting, may draw predators, the sheer number of birds overwhelms most local predators. The nearby cats and snakes can only eat so many nestlings. The vast majority survive.

Unless the killing is mechanized. The flock of over 10,000 that arrived in our county seems huge, but surveys in the 1930’s documented colonies with a quarter to a half million nests! Since then, numbers have steadily tumbled. When triticale replaced tules, tricolors adopted the new fields; farmers reacted to the hungry hordes with poisoned grain and market hunts. Those actions are now outlawed, but, despite many positive farmer-conservationist collaborations, harvesting of grain while birds are still in their nests sometimes continues, wiping out entire reproductive colonies. Most irrevocably, the inexorable conversion of marshes into row crops, orchards, homes, and shopping centers reduces habitat on a wide and lasting scale.

Still, 10,000 birds is enough to make a successful colony. Enough, in fact, to raise the seamy side of reproductive abundance. Tricolors try to nest near plenty of grain and insects, but their numbers can overwhelm not only local predators, but also local food supplies. This creates hunger at home, a problem that different species face differently. Underfed eagle and owl chicks eat their younger siblings. Wolves reduce their offspring by limiting reproduction to one pair in the pack. Observations indicate that tricolored blackbird mothers, rather than starve their whole broods, will remove some chicks to be able to feed the others. It’s not a pleasant reality, but one that successful reproduction can force.

Never Out of Season

By Dan Greaney on May 1, 2017 in BirdWords

Northern Mockingbird Displaying

You’ve heard them. Maybe in the day, maybe all day. Maybe at night, when it seems decent creatures should be in bed. Maybe they’ve added sweet melody to your spring morning. Maybe they’ve kept you wondering at night. Northern Mockingbirds are singers.

They have their own style of delivery, but Mimus polyglottos, the many-tongued mimics, learn their songs from other birds, animals, and even machines around them. They sing their playlists round and round, a wheel of chirps, chortles, squawks and trills that dominate the local soundwaves. With age and experience, they keep learning new songs. Males, the louder and more relentless singers, may learn up to 200 songs in their lives. Their musical variety, then, can attract long-term mates who know that they have been around and have the stuff to survive.
The trilling you’ve heard through the night is usually a less satisfied bird, a lovelorn bachelor still seeking someone to nest with.

Mockingbirds’ feathers seem less flamboyant than their songs, but they hold their own surprises. Wings folded, the birds are nondescript tan and gray, as unremarkable as newsprint. But then, when the birds fly, bold black-and-white abruptly flashes out on wings and tail, a sort of optical shout, like a meaningful story. Then the birds land and go visually mute once more, like a pause for thought.

Dull colors might seem like useful camouflage, but mockingbirds don’t settle for dull. Even standing on the ground they frequently flash their wings out. The standard explanation for this display is that the bright white wing patches startle bugs, causing them to move and be more easily seen and eaten. But this effect is unobserved. Test it, with, say, a small piece of paper. Do bugs move when you flash it at them? Apparently other species of mockingbirds who lack the bright patches also flash their wings. So it seems the biggest known effect of flashing wing patches is to make people wonder why they do it.

As forward as these birds can be with just borrowed songs and black-and-whites, mockingbirds are no less shy in tending their territories. They dive-bomb cats, dogs, and crows who wander too near. Less riskily, with encroachments from their own kind males have developed a bill-up and chest-to-chest dance at their territorial border. That ritual rarely deteriorates into a pecking battle, and allows both birds to make peace and move on without too much loss or humiliation.

The successful male mockingbird chooses a nesting site. Several of them, actually, where he frames several nests of twigs. Then the female makes her choice, and finishes the one she’ll use with grasses and other soft linings. She lays a handful of eggs, which in 12-13 days hatch into blind, naked nestlings. Both parents help the young into their first feathers, and then she will often start a second brood while he continues to tend the first.

In the 19th century, before radios or today’s Pandora, mockingbirds were captured to provide music in people’s homes. Those nearly year-round singers—the literature lists them as singing February to August, and then again September to November—were so popularly caged that they began to disappear from East Coast yards. Since then they have rebounded, doing well in suburbia’s mix of open areas and trees with fruits and berries. Now, in the era of expanded pesticide use and domestic cats, they are declining again, but their song remains the headline show in gardens across America.

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