Disorderly stands of young cottonwoods and willows now grow in place of straight crop rows, and winter rains create vast stretches of open water, vital to the Pacific Flyway's migrating waterfowl. Some of the largest virgin stands of valley oak grow in the Preserve, which stretches from the Delta to the Sierra foothills between Stockton and Sacramento. A network of trails and waterways for hiking and canoeing have transformed the Preserve's 37,000 protected acres into a paradise for birdwatchers. Tundra swans , American pipits , red-shouldered hawks , and up to 3,000 lesser sandhill cranes are among the nearly 100 species that winter in the Preserve. January Ribbons of green catkins grace white alders this month.
Light winds send the catkins swaying and the pollen flying in gold-green puffs.
The white alder is a common tree that grows along stream banks throughout the state up to 8,000 feet above sea level, so even cross-country skiers can witness this lovely winter flowering. Another winter bloomer, the California hazelnut , grows in moist wooded canyons along the coast and in the Sierra Nevada from Tulare County north. Look for bright red stigmas protruding from tiny female flowers that grow at the tips of year-old twigs, and catkins dangling from the bush's naked outer branches. Though pollination occurs in January when pollen from the catkins alights on the stigmas, fertilization is delayed until May or June when the ovaries beneath the stigmas finally become receptive to sperm cells contained in the pollen. Only then do the hard-shelled nuts start to develop.