Category Archives: Archosaurs

Flocks of locally-grown red junglefowl arrive in McClurg Hall

Thanks to the work of University of the South Executive Chef Rick Wright, along with his colleagues, local foods are gracing our dining hall. This year, the University will use about 20% of the food-purchasing budget in the local farm economy, a flow of $300,000. A few years ago, that number was zero. Next year, we’re on track for 30%.

This Sunday, fried chicken, along with squash from the University farm, was on the menu, a celebration of the fall harvest. Thank you Chef Rick Wright, Farm Manager Carolyn Hoagland, and the many staff, students, and administrators whose work is reorienting campus dining away from the outlet pipe of the industrial food system and toward Tennessee’s fields.

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Light, sound, hummingbird wings

From the dawn-light series (see also silk and moth wings)…

There is a moment in the early morning when the sun catpaws through the forest’s tangled blankets, illuminating my hummingbird feeder. The touch is gentle. The claws of midday are withheld. For two or three minutes, sun fires the blur of wings. For the rest of the day, the lights are off and wings move in gray-green, almost invisible.

hummer0hummer1hummer4Unlike other birds that power their flight with only the downstroke of the wing, hummingbirds flip their wings after the downstroke and generate more lift as they pull back their arms. The feather tips therefore scribe a figure-of-eight as the bird crams more gravity-fight into each back-and-forth. They do this fifty or more times every second. Humans can perceive only ten “images” per second and most movies are shot at twenty-four frames per second. To get an acoustic sense of the birds’ frenzy, I slowed a sound recording of the hummingbird in the photograph by one hundred times. The heart-beat thuds are the slowed wings, the strange wind is the sound of insects singing in techno-molasses:

(email subscribers, click on the header link to get to the sound file)


Silhouette: a short hawk quiz

A fuss of blue jays and robins. Look up:


Some clues:
unhappy songbirds
a tail that extends beyond the wing tips, but not too far
stout chest

Red-shouldered hawk. Not a Cooper’s Hawk? The tail is too short and the body too chunky. (Birders: let loose with corrections as needed!)

I used the computer to zip down the brightness of the photograph:

hawk3Coarse streaking: an immature bird. It took off after a young robin… and so the next generation relearn the old ways.

Bass Rock gannets

A view from the bull’s eye of the target, right before the release of a uric acid/digested fish bomb. The splattering impact is impressive. The smell lingers.

gannet1170,000 gannets (with 75,259 nests) make their summer homes on the Bass Rock, just off the Scottish coast.

Like Arthur’s Seat in Edinburgh, the Bass Rock is a volcanic plug, an erosion-resistant intrusion into softer rocks, now standing exposed. The Rock’s lighthouse was built by the family of Robert Louis Stevenson, as were many of Scotland’s nineteenth century lighthouses. Before the lighthouse, the Rock served variously over the centuries as a castle, prison, and hermitage. Now, birds have run of the place.

bass rockgannet2 Gannets are plunge-feeders, diving with wings folded onto their prey (cam-on-human video here; cam-on-bird video here, the green is marking paint on the bird’s feathers).

Gannets fly up to 100 km from the colony in search of food. Unlike most other northern seabirds, gannet populations have grown lately, perhaps because the birds are no longer hunted for meat and eggs (except for a small hunt on the Outer Hebrides). The fishing industry leaves plenty of edible “by-catch” and removes larger fish that would compete with gannets for food.

Nests are perched on every available rock ledge. A seaweed base and rim gives the eggs and nestlings a suitably salty start to life, spiced with plastic flotsam.


Puffin launch

puffinAn Atlantic puffin (Fratercula arctica) pounding the sea with its feet as it builds enough speed to get airborne. I photographed this bird near the Bass Rock in southeastern Scotland. Puffin wings are designed both for rapid aerial flight (exceeding 50 mph) and for underwater diving (200 feet down). Take-off is therefore cumbersome, as the wings only generate lift at high speeds.

This bird likely had chicks in a burrow on the islands nearby. Peregrine falcons patrolled the cliffs. Two good reasons for agility.

Dead wood and the woodpecker’s g-force

About fifteen years ago, the local electrical company hired a crew of subcontractors to cut and trim any trees that were deemed a threat to powerlines. The crew gave the sugar maple in our front garden a lop-sided haircut, slicing away all the branches on the south side. Regrettably, the equipment they used must have carried spores from a diseased tree: fungus swarmed over the cut branches, then killed the whole maple.

The dead tree stood next to the house, so its upper trunks had to be cut down. We left the lower ten feet standing, though. This part, even if it fell, presented no danger to the house. Ever since, the stump has gradually rotted away, occasionally calving chunks of bark, but mostly turning slowly, slowly to punk and duff.

The birds love to perch atop the tall stump, as have two generations of housecats. Woodpeckers also include the rotting maple on their rounds and this week a pileated woodpecker made a stop. I poked a microphone out of the cat-flap and recorded the bird’s hammering and the powerful sound of its thirty inch wingspan as it took flight.

As you listen, imagine the slamming impact of beak on wood. Human brains are concussed by forces ten times weaker than those that pileated woodpeckers experience. They’d make a fine mascot for a football team. The woodpeckers’ heads attain speeds of 6-7 meters per second before impact, they then hit the trunk and decelerate at 13,000 meters/second^2 or 1000 g (see Wikipedia for interesting comparative examples of “g”).  The birds tolerate this pounding because their multi-million dollar contracts specify that they must. And because they are protected by the angle of beak to brain, the shock-absorbing design of the skull, the tightness of the brain in its case, and the elasticity of muscles.

The spectrogram gives a visualization of the sound, with time moving left to right, and frequency (pitch) shown on the vertical: woodpeckerfull

These two clips show short segments, one from the beginning and one from the end of the recording:knockknock


What is a “seahawk” anyway?

A sports team of ambiguous nomenclature and symbolism takes the field today. The seahawk logo matches the appearance of no Seattle bird that I know of. The logo design itself appears not to be a hawk, but an eagle, a design taken from the Kwakwaka’wakw transformation mask of the Coastal Indians. Even though the NFL knows all about property rights and branding, no Indian got any royalties, to my knowledge.

The captive bird that flies out before games is an Augur hawk from Africa, a distant relative of the red-tailed hawk, in the Buteo genus. It is not a seabird, but feeds in mountains and grasslands. Thanks to the Smithsonian Magazine for that interesting tidbit. This captive needed some serious training to prepare it to face the whooping Seattle fans.

“Seahawk” might refer to either an osprey (not a hawk, but a bird in its own family, a relative of hawks and eagles) or a skua (a fierce cousins of gulls). The osprey has a bold eyestripe, not a two-tone head, so the color match with the sports team logo is imperfect, as is the size of the beak. Ospreys feed by swooping down on fish with great skill and elegance. Skuas, our other contender for “seahawk,” look nothing like the logo. They feed by robbing other birds, eating the afterbirth of marine mammals, preying on the eggs and young of other seabirds, scavenging dead meat, and generally scraping the barrel of respectable behavior. We’ll see how the game goes, then decide which bird is the better fit.

Sandhill Cranes at Hiwassee Wildlife Refuge, TN

2015-01-16 Sandhills 037Tens of thousands of cranes gather at Hiwassee. Gruuu gruuu: sound resonates within the trachea coiled within their sternum. Horn section of the avian band. An ancient sound; Sandhill Cranes have flown across North America for at least ten million years.

In this recording, made on my phone, you’ll hear the cranes overhead, and the ack-ack artillery of photographers shooting their pixel flak skyward:

2015-01-16 Sandhills 028“…not quite the world’s” William Stafford, Watching Sandhill Cranes

“…so stears the prudent Crane/Her annual Voiage, born on Windes;/the Aire
Floats, as they pass, fann’d with unnumber’d plumes…” John Milton, Paradise Lost

“The crane’s legs/have gotten shorter/in the spring rain” Basho (Matsuo Kinsaku)

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Sounds from the edge of Boreas’ kingdom

A raven flies to its roost at dusk, wingbeats audible between the calls. Just before this flight, the bird was amusing itself with half a dozen others of its kind by harassing a sluggard-winged eagle. The ravens wove and swooped; the eagle flopped its great wings, finally passing out of sight on the horizon.

I think the squealing call at the end is a younger raven, greeting its homeward-bound parent.

Spectrogram of the same sound. Time moves left to right, pitch increases along the vertical.

Spectrogram. Time moves left to right, pitch increases along the vertical. “Stacked” lines are harmonics.

Night came and with it a frost.

Fir at nightI lingered and was rewarded by the sounds of Northern Saw-whet Owls. These tiny owls are common in dense forests of Canada and the Western US, especially forests with rotten trees to supply nesting holes. In the winter, some birds move south, so Saw-whets can be found all the way to Florida in the right season. The bird gets its name from the supposed resemblance between its repeated whistled call and the action of whetting a saw. The analogy is stretched, unless your saw comes with a flute.

The owls were a distance away, so the following recording has some lower and higher sounds filtered out to make the call come through more clearly.