For most plants and animals, just listing the family, genus or species is enough to let biologists know what the other levels should be. The most common way to list the taxonomic name of an organism is to list the genus and species; this is known as binomial nomenclature, meaning a two-name system.
The grey jay is a relatively large songbird, though smaller than other jays. A typical adult grey jay is between 25 to 33 cm (9.8 to 13.0 in) long. Its wingspan is around 45 cm (18 in). It weighs about 65 to 70 g (2.3 to 2.5 oz). Adults have medium grey back feathers with a lighter grey underside.
this species was first discovered on Hudson Bay. The red squirrel is a small arboreal squirrel, smaller than the gray. squirrel or the fox squirrel, and weighing an average of only 11 ounces (300 grams). The red squirrel's head and body are. about 7 to 8 inches (18-20 cm) long and its tail is about 4 to 6 inches (10-15 cm) long. The red squirrel is not actually red, but rather reddish-orange in color. This species of squirrel molts its fur coat twice each year.