What could be more exhilarating to bird lovers than to spend an evening being regaled by the many examples of the amazing innate abilities of their avian friends? Using colorful slides to augment his lively presentation at NJ OWL's March meeting, Doctor Charlie Leck, retired professor of Ornithology in the Department of Ecology, Evolution and Natural Resources at Cook College, Rutgers University, went beyond the general knowledge of birds and spotlighted many fascinating facts about the their sense of sight, smell, taste and touch as well as their capacity for communication, navigation and the significance of a bird's color.

"Do birds see color?" Answering his own question with an emphatic "yes", Dr. Leck explained that most birds have color patterns produced by pigments in their feathers while others have structural colors whose prismatic effect is produced by the reflection of light (the blue jay's color is example of this iridescence).

Many birds, as well as insects and butterflies, have ultraviolet colors humans cannot see and many, such as robins and crows, have UV receptors in their eyes. The color of some birds becomes more intense during the spring, but is more subdued in winter, such as with the scarlet tanager. On the flip side some birds have cryptic coloration, which allows them to blend into their backgrounds; the black-bellied plover is an example of this camouflage. A comical (?) example of a bird's use of color is the male bowerbird (from the tropics) that collects blue or pink objects to decorate his "bower", a sort of shelter that the bird builds to impress females during courtship.

A bird's visual acuity is not limited to seeing color. According to Dr. Leck the red-shouldered hawk has 8 to 10 times the density in his retinal eye cells than that found in human eyes. Cormorants and loons have eye lens which are flexible enough to contract in order to adapt to underwater sight while fishing. The osprey has polarized eyes in which oil droplets eliminate the glare on the water enabling this species to spot fish below the water's surface. Black skimmers have cat-like irises that allow them to forage for fish in the bright sunlight. The American woodcock and black-crowned night heron have specialized vision for night hunting and barn owls are able to capture mice in complete darkness. Other nocturnal birds have asymmetrical hearing; that is, one ear is forward on the head and one ear is further back and of a different size.

Dr. Leck also described how many bird species use their sense of smell. For example, turkey vultures, native to the Western Hemisphere, live off carrion, and rely on their large nostrils to find food. In fact, one third of a turkey vulture's brain is given over to the sense of smell. The kiwi, a flightless, nocturnal bird has a great sense of smell guiding him to fruit trees, while honeyguides rely on their sense of smell to zero in on the beeswax in bee hives. The nocturnal storm petrel, forages at sea off coastal Maine and relies on his sense of smell to guide him back to his nesting grounds. In a soil samples test conducted by biologists, the bird chose soil from his own native area. On a different slant, the hooded pitohui, a native bird of Papua, New Guinea, not only smells bad but tastes bad due to the toxins in his body, a defense mechanism making him off limits as a meal for humans and other predators.

According to Dr. Leck, that although birds are thought to have poor taste receptors some actually have gradations of taste; hummingbirds, cedar waxwings and robins will choose a solution with the highest amount of sugar needed for energy, while a thrush will chose lipids or fats. Previously thought to be unimportant, touch is crucial to birds that probe for their food; many have sensitive receptors of touch in their beaks. The male Australian brush turkey is a good example of this; it enables him to monitor the temperature of the site that incubates the eggs laid by the female. Smaller birds, too, use their sense of touch to determine and regulate the temperature of the eggs.

How can we talk about birds and not include their songs and calls? Dr. Leck gave us several insights into a bird's repertoire of songs. For instance, when young and still in the nest, the black-throated warbler learns its species' songs from its parents who are singing close by, while other species are genetically programmed to sing their specie's songs. Crows, ravens and blue jays have about 49 calls that compose a language of their own, which include calls that signal the presence of a certain type of predator, or the location of food. Vocalizations also take place between the young and its parent; a mother penguin parent recognizes its young and vice versa through their individual calls upon the parent's return after feeding. Alarm sounds given by a bird also alert other mammals to danger nearby. Exciting new research (via recordings) has revealed that the calls of the cassowary, a large Australasian, flightless bird of about 150 pounds, can produce sounds at the sub-sonic level which are undetectable by its predators and human ears. Some fascinating facts about the downy woodpecker are that his drilling is not a random act but he actually hears the insects in a hollow tree and the rate of his drilling has been clocked at 22 mph with a deceleration (stopping) rate of 12 G. The cushioning effect inherent in his skull has been used in the design of football helmets.

Wouldn't it be nice on your next overnight trip to put your car on autopilot and sleep? This is exactly what some birds are capable of doing. Dr. Leck explained that some birds have high-density position receptors in their wings, which keep them on course and allow them to sleep on long flights; other species can sleep while flying with half their brains operating, switching sides at will. The albatross circles the world several times in 3 or 4 years, feeding on the run. Some birds like the indigo bunting use the pattern of stars around the North Star to navigate when migrating south to winter while the white-throated sparrow uses the earth's magnetic field to guide his flight. The homing pigeon is spectacular in that he can incorporate the pattern of the stars, smell, a variety of hues and ultrasounds to guide him on a trip of several hundred miles.

We want to thank Dr. Leck again for taking the time to come and enthusiastically share with us from his vast knowledge and reaffirm our belief that birds are pretty amazing.

- Sandy Norman

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