Duck hunters open their season Saturday (the season runs through Jan. 27) and overall the prospects are pretty good. Mallards are the primary duck in Northern California and, according to the Department of Fish and Game (DFG), their numbers are up considerably.
The Sacramento Valley is the primary wintering ground for the ducks and geese on the West Coast. Clear Lake is not a normal wintering area for the waterfowl although about 1,000 ducks and a few geese do spend the winter here. Many people think ducks and geese spend the entire year in California and while a few birds do spend their life in the state, most spend their summers in the far north and then migrate to California in the fall.
The reason waterfowl nest in the far north is because of the abundance of food. When ducklings hatch during the spring months, they require a lot of protein and the Arctic is home to billions of insects and aquatic invertebrates, which the birds feed on. They also feed on the young grass. The birds use this rich food source to build up fat reserves required to migrate south because the marshes in the north freeze up beginning in September.
Every year thousands of birds make their way down the Western Flyway to the rice fields in the Sacramento Valley. When the waterfowl population reaches its peak in late December, there can be as many as 3 million ducks and 1 million geese in the valley. It is one of the largest concentrations of waterfowl in the world.
The annual winter migration of waterfowl is one of the great spectacles of nature. For example, the snow goose summers in the Arctic and winters in California, Texas and Mexico. The actual flight itself from the cold Arctic to California is a physical challenge second to none. Often the snow goose (and other waterfowl) travels 2,000 miles nonstop.
According to scientists, waterfowl average a speed of about 50 mph during this migration. That means a snow goose is in the air approximately 40 hours. Even more remarkable is that waterfowl rarely glide — their wings are beating constantly.
It is thought the birds actually take short naps during flight. The geese normally fly in V formations to cut down on wind drag and to conserve energy. They constantly talk to each other during the flight to maintain contact and formation. They also change positions in the V formation to give the lead birds a rest. Airline pilots have observed snow geese flying at altitudes of up to 20,000 feet (and you think humans suffer from jet lag).
Unlike snow geese, most of the ducks slowly work their way south, stopping to rest and feeding often. However, the king of ducks in terms of flying long distances is the blue-winged teal. The teal is a small duck and often flies all the way to Hawaii from northern Canada. Another long-distance traveler is the pintail. Pintails have been banded in Alaska and shot in Guatemala, which means they traveled nearly 5,000 miles. Radio-equipped pintails also have been tracked flying nonstop from California to the Arctic nesting areas
Of course, not all the ducks and geese fly nonstop to their wintering grounds. Many stop and rest along the way. Others are forced to land because of bad weather.
How they return to the same areas every winter and how they know to leave their summer range in the far north is one of nature”s greatest mysteries. Biologists think waterfowl have developed an internal clock over eons, one that tells them when to leave the north and migrate south. The biologists believe that clock starts when the birds first arrive in the north in the spring to nest. Even if the weather is nice they will still start their fall migration at approximately the same time.
There are a number of theories on how they actually navigate to their wintering areas. They include navigating by the position of the sun and stars and also by the magnetic forces of the earth. It”s most likely a combination of all three, plus their homing instincts. Older birds who have migrated before normally lead the younger birds to their winter destination.
The mass migration of waterfowl and how they accomplish it is another example of how much we don”t know about nature despite our advanced technology.
