BIRDS CALENDARS

Audubon Fantasy

John James Audubon was an ornithologist, naturalist, and artist who painted, catalogued, and described the birds of North America.

Bird Migration Map - the Americas: sixty-seven full illustrations, printed at a scale of 1 inch to every 315 miles.

The Mystery of Migration -

Bulging with fat for fuel, congregations of blackpool warblers wing south over the Atlantic each autumn from the coasts of New England and eastern Canada. some pause at Bermuda or other islands, but most fly nonstop to South America – a journey of nearly 2,5000 miles at a maximum altitude of 21,000 feet. The black poll warbler is smaller than a sparrow.

The arctic tern, a much larger bird, migrates from near the top of the owrld to the bottom – Antarctica. counting the eturn flight in spring, it may travel 25,000 miles, the earth's circumference.

Scientists don't know exactly how the migrating birds find their way over long distances, but they are discovering that birds tune in to an astonishing variety of sensory cues that may be used for navigation.

Observers have long theorized that migrants use mountain rangess, rivers, and coastlines for guidance. Scientific research suggests that some birds may also set their courses by the sun, bu the patterns of stars, even by the lines of force in earth's magnetic field, perhaps in combination with gravity.

Some birds respond to ltraviolet and polarized light and can hear low-frequency sound that travels thousands of miles. Thus upland sandpipers flying high above the Mississippi conceivably could hear surf from both the Atlantic and Pacific Coasts.

How the migrants process these cues is a mystery. But the increadible facts remain: The birds know where they are, and they know where they are going.

• more map posters

Passerines are the perching birds, characterized by having four toes, three directed forward and one backward, joining the foot at the same level.

The “tropics” is the region circling the planet Earth that is centered on the equator and limited by the the lines of latitude called the Tropic of Cancer (23°27'N) and the Tropic of Capricorn (23°27'S). The tropics experience little seasonal change and climate is characterized by high temperatures, humidity, and rainfall, though the Andes Mountains and the Sahara Desert both lay in the tropic zone and have the extremes of cold, hot and dry.

[birds listed in this poster]