The sparrows are back. Some have been back for several weeks; others seemed to arrive just a few days ago. They don’t wear flashy garb, but they’re remarkable creatures.
The White-crowned Sparrow has been clocked flying 300 miles in a single night. Most of them breed in the high arctic and fly more than 2000 miles to get here. During migration they can fly for two weeks without regular sleep; they sleep with one brain hemisphere while the other remains awake, with one eye open and the other shut. They have phenomenal endurance. Scientists have put them on experimental treadmills and found that they can run at a pace of about 600 yards per hour indefinitely without tiring.
The Golden-crowned Sparrow also breeds up north in Alaska and far western Canada. An article in Bay Nature by Marissa Ortega Welch points out that this bird has a phenomenal ability to return after a journey of thousands of miles to the same spot it visited the previous year, even to the same bush. There it may meet up with neighbors, not members of its family, whom it met in the past, and they may form flocks that forage together. Both males and females sing in winter.
The Savannah Sparrow, when it migrates, likes to come back to the exact spot where it hatched. They have been known to breed right here in Cesar Chavez Park in March and April. Others are migratory and breed up north in the tundra, or (rare) in coastal marshlands.
The Fox Sparrow has puzzled and divided scientists with the diversity of its appearance. Some authorities consider all of its varieties a single species while others assert four separate species. Comparatively little research appears to have been done about the bird’s capabilities and behavior.
Marissa Welch’s Bay Nature article points out that most migrants spend more time in their wintering territories than up in their breeding grounds. The arctic summer is short. Yet because it’s up there that they establish their families, we humans refer to the breeding grounds as the birds’ “home” and think of their winter stays as “visits.” Really the opposite is true. In terms of duration, the mild regions where they spend the winter are their home, and their northern trips are visits.
Welch also quotes an ornithologist saying, “We know virtually nothing about the social lives of migrant birds in their wintering ground.” That point was also made by scientists studying the Burrowing Owl. Their breeding behavior has been much examined but their preferences and habits in the winter remain a black box. We assume without any real basis that their needs and wants are the same in both modes of their lives. This is a bit like assuming that the lives of single humans without children are identical to the lives of parents with babies and toddlers dependent on them. We would hardly say that about people. Why would we assume it to be the case with birds?