Dinosaurs Developed Feathers To Attract Mates, Not Fly

 In news that shouldn't surprise anyone who finds them so irresistible, paleontologists are now claiming that the earliest dinosaurs to develop feathers did so for courtship purposes and not to soar like giant, sexy eagles.

"They may have initially evolved as a secondary sexual characteristic," says a paper published Thursday in the prestigious journal Science.

 "Because they're in these large dinosaurs, (wings) haven't evolved for flight," Zelenitsky says. "(And) because these wing-like structures develop later in life, that suggests they were used for purposes like display or courtship or egg-brooding."

Peacock in flight

Albatrosses achieve "Dynamic Soaring"

Albatrosses perform a fascinating and complicated flight maneuver called dynamic soaring, in which energy can be extracted from horizontally moving air and transferred to the bird so that an energy gain is achieved which enables it to fly continuously without flapping. Dynamic soaring is possible when the wind speed changes with altitude. This type of wind, which is called shear flow, exists in the boundary layer above the ocean surface in areas in which albatrosses are found.

Dynamic soaring is energetically efficient. The heart rate of a Wandering Albatross was recorded over a two-day period and its heart rate was just above resting rates when soaring, suggesting that dynamic soaring requires little more energy than resting on land.

From: http://people.eku.edu/ritchisong/554notes3.html

Sculpturist Kate MccGwire

London-based artist Kate MccGwire has a unique form of art. Her material of choice? The molted feathers of pigeons. She uses these feathers in great numbers to create vivid pieces of artwork.

Owl Ears and Hearing

 "Because Owls are generally active at night, they have a highly developed auditory (hearing) system. The ears are located at the sides of the head, behind the eyes, and are covered by the feathers of the facial disc. The "Ear Tufts" visible on some species are not ears at all, but simply display feathers.

 Some owl species have asymmetrically set ear openings (i.e. one ear is higher than the other) - in particular the strictly nocturnal species, such as the Barn Owl or the Tengmalm's (Boreal) Owl. These species have a very pronounced facial disc, which acts like a "radar dish", guiding sounds into the ear openings. The shape of the disc can be altered at will, using special facial muscles. Also, an Owl's bill is pointed downward, increasing the surface area over which the soundwaves are collected by the facial disc. In 4 species (Ural, Great Gray, Boreal/Tengmalm's & Saw-whet), the ear asymmetry is actually in the temporal parts of the skull, giving it a "lop-sided" appearance.

An Owl uses these unique, sensitive ears to locate prey by listening for prey movements through ground cover such as leaves, foliage, or even snow. When a noise is heard, the Owl is able to tell its direction because of the minute time difference in which the sound is perceived in the left and right ear - for example, if the sound was to the left of the Owl, the left ear would hear it before the right ear. The Owl then turns it's head so the sound arrives at both ears simultaneously - then it knows the prey is right in front of it. Owls can detect a left/right time difference of about 0.00003 seconds (30 millionths of a second!)

An Owl can also tell if the sound is higher or lower by using the asymmetrical or uneven Ear openings. In a Barn Owl, the left ear left opening is higher than the right - so a sound coming from below the Owl's line of sight will be louder in the right ear."

 From: http://www.owlpages.com/articles.php?section=Owl+Physiology&title=Hearing