About the cover

CoverThe animal on the cover of C# 3.0 Design Patterns is a greylag goose (Anser anser), probably one of the first domesticated animals. Archaeological evidence suggests that domestic geese lived in ancient Egypt and Rome 3,000 years ago.

Fairly large birds, usually weighing between 5–12 pounds, greylag geese have an average wingspan of 59–66 inches and are generally 29–30 inches in length. Their plumage is grayish-brown, their bellies are white, and their lower breasts are shaded gray. Their bills are large and yellow, and their feet and legs are a pink, flesh-like color. (Younger geese have gray legs and feet that turn pinker as they age.)

They are migratory birds that fly south or west in the winter to escape the harsh weather. During the summer, they live in Scotland, Iceland, Scandinavia, as far east as Russia, Poland, and Germany. In autumn, the geese in Iceland migrate to the British Isles, while the rest of the greylag geese in Europe head to places like the Netherlands, Spain, France, and East Africa.

A social bird, it travels long distances in groups, often in the familiar v-shape pattern. Their groups range from small families to flocks with tens of thousands of geese.

The time at which their breeding season begins depends on their geographic location. In Scotland, breeding starts in late April; in Iceland it starts in early May; and in Europe, it starts earlier. During breeding season, greylag geese live in marshes and fens—places with a lot of vegetation. Nests are built in high places to keep their eggs safe from predators.

A mother can lay as many as 12 eggs, but she usually lays between 4 and 6. She incubates the eggs for approximately 26 days. Once hatched, the goslings wait until they are dry to leave the nest. Young birds feed themselves with their parents’ supervision. Twenty years is their average life expectancy.

Greylag geese thrive on grasses, roots, rhizomes of marsh plants, and small aquatic animals. They also have a taste for some root crops—turnips, potatoes, and carrots—a real concern for farmers in Europe.

Golden eagles, ravens, and hawks are among their predators in the sky; when on the ground, they have to be vigilant for prowling dogs, foxes, and humans. Humans hunt geese for their flavorful meat and their down, or soft feathers. Down is often used to stuff pillows, blankets, and outdoor clothing. Caesar, the Roman emperor, declared greylag geese as sacred in 390 B.C., and he made it illegal to kill and consume them.

Caesar credited them with saving his empire from attack. He believed that when the Gauls tried to invade, the geeses’ loud calls alerted the Romans and saved them from occupation.

The cover image is from Dover Animals Book. The cover font is Adobe ITCGaramond. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont’s TheSans Mono Condensed.