The cheerful-voiced Chestnut-collared Longspur shares its northern prairie breeding range with grazing cattle. Although heavy grazing can have adverse effects, breeding densities of longspurs jump by two, three, or even 10 times when ranchers graze their cattle responsibly on native…

The ability to fly seems to define birds. But there are more than 50 species of flightless birds throughout the world — from the Ostrich and Kiwi to flightless rails, ducks, and this Humboldt Penguin. Why did they evolve the inability to fly? Many dwelt on islands. Others evolved until…

Picture this Gadwall duckling swimming slowly across a pond, skimming the water’s surface with its broad, spatulate bill. This behavior is called dabbling. Along with the pond water, multitudes of tiny particles pass through the duck’s bill. Somehow it sorts out and swallows the edible…

When young Bald Eagles fledge, the event is the culmination of nearly a year’s work by the parents. Let’s recap how it might have gone: male and female build a nest over the winter. By March, they have two eggs. The female incubates the eggs for about a month, with the male taking an…

By late summer, the male Mallard’s need for fancy feathers to attract the females has passed. These birds have molted, and their bright feathers are replaced with mottled brown ones. Subdued colors help camouflage the male ducks, protecting them from predators. Come fall, the male Mallards…

By August, many birds have just completed the intense rigors of nesting and raising young and now undergo a complete molt. Molt is a cyclic process of feather growth. As new feathers grow in, they push the old ones out. Why molt? Because feathers wear out. Songbirds that migrate long…

Crested Auklets are small seabirds that nest on remote cliffs in the Northern Pacific and the Bering Sea. But it’s their smell that really sets these birds apart. They smell like tangerines! Experiments show that females go for males that emit the strongest scents. This episode brought to…

On a hot summer’s day, watch a bird such as a crow — or this Bald Eagle — very carefully. You’ll never see them sweat, because birds don’t have sweat glands. So how do they keep cool? One way is panting. As the bird breathes rapidly, heat is carried out of its body through the lungs and…

Bar-headed Geese, champions of high-altitude migration, leave their nesting grounds in Tibet and scale the Himalayan range on their way to wintering grounds in the lowlands of India. How do they do it? These geese have a breathing structure that extracts oxygen from thin air, even at 30…

Savannah Sparrows are abundant in open habitats throughout North America. In spring, they migrate north from the Southern US and Mexico to open agricultural fields, meadows, coastal grasslands, salt marshes, and even tundra to breed and raise young. They nest on the ground and walk, run…