Feathers, Sweaters, and Better Weather: A Short Look at the Big Picture of Bird Migration

Written (and photos) by Gregor Yanega

I invite you to consider bird migration, and how it is simultaneously subtle, regular, and large in scale. Imagine the cold air as it sinks into the furrows of the watershed under the stars while a few puffy clouds scoot across the moon like children late to dinner. Small squadrons of quick, black dots, darker than the night sky, flap from silhouetted barn to field to wood in little flocks, stretching out and clotting together before disappearing up the tree-cloaked slope of the far hillside. There are pulses to the quiet caravans of birds. The more you look, the more they appear, driven sideways like ash or snow – these siskins, finches, and juncos. You hardly hear anything unless you strain for the sound. Single notes quail in the night. Little pips and boops drift down in a soft sonic rain, in all that remains of their passage. Migration is both visible and invisible, the way icebergs are in the arctic: remarkable yet expected, seen, yet underestimated. So much goes on when we are not looking, when it is too cold to stand there much longer, when it is too dark to see.

A hallmark of fall, seasonal migration is like a comfortable sweater or a good watch – it can be counted on. Its reliability and familiarity make the abnormal more acceptable. Whether sailing over oceans of smoke to the next green valley, or across highways, housing developments, and dry lakebeds, migration is increasingly abnormal for birds, but it has always been hard. So, why migrate? Why do these millions of animals fly, sometimes for thousands of miles, each season? It seems almost silly to suggest that it is for the warmer weather and the all-you-can-eat buffet, as though human snowbirds and actual snowbirds were the same. For birds, the act is not for luxury or mere comfort. It is a better shot at survival. And in this way, migration brings into focus the gulf between the near field and the long view, the proximate and ultimate causes operating on different scales. For example, the migration decisions a bird makes on a cold morning might seem to be about right now: Do I feel fat enough to fly far? Do I wait for a clear night to leave? Do I flock with a bunch of other birds like me? Should I land in those trees? Over time, these small, immediate decisions become consolidated into behaviors that are the grist of evolution and specific to each species.

Likewise, humans make decisions that are built up into longer stories that take years to tell. We like to make decisions that we can appreciate in each new slice of now, but we need a way to balance the decisions we make right now (to get a dog, to live in the woods, to thin a stand) with what these decisions will mean for us over time. We can calculate from things we’ve done or learned before, and anticipate what might be, to help us in the long view.

This anticipation of what might be does as much for the short-term and long-term survival of humans as knowing when to migrate, and where to stop, has mattered to populations and species of birds. However, we have more agency than birds do in how we respond to the anticipation of what might be. We can plan to shape our woodlands and yards in ways that balance multiple benefits. We can make immediate choices that support watersheds, migrating and breeding birds, and objectives of fire resilience, harvests, and planting for a new climate. There is a sweet spot between research, legacy, practical considerations, and collaboration that will allow us all to weather the unexpected, and the unwelcome expected, better together. We can plan ways to use lands in times and ways that minimize harm, maximize benefit to forests and birds, and make the places that we live and the job of stewarding the land a more optimistic and enjoyable job in the moment. Forestry for the Birds in the Pacific Northwest is that comfortable sweater you are looking for right now, but it is also there to help make a workable place for humans and birds for years to come.

Photo by Dave Powell, USDA Forest Service (retired), Bugwood.org

When a lot seems to change in a short amount of time, we look to the metaphoric horizon to steady ourselves. Things like the return of green leaves to a winter landscape, the return of flowers, the hum of bees, and animal migration. Yet even migration – this example of timelessness of seasons and the resilience of life in the face of storms and fires and habitat loss – happens later, almost two weeks later for most species, than it did 50 years ago. While it may seem unsettling that even these timeless processes are fluid, it is also encouraging that change, too, is clocklike and reliable, like succession and seasonal renewal. We adjust. Burnscapes heal and forests come back. When the world shifts, we need to shift with it, and make sensible decisions with an eye toward the next harvest, the next copse of trees, the next spring, until we have a plan that makes sense for next year and for the long haul.

This year has been a difficult one with the return of devastating wildfires to the West. Places that haven’t burned in recent memory are burning. The past 20 years have seen more fires and more acres burned than in the previous 100. I think, as hard as this year has been, we are presented with a chance to reconsider our future, and draw on the best blend of science, economics, tradition, and anticipation to think about how silvicultural practices and conservation objectives in a given place can align to lay the groundwork for the next resilient, diverse, and productive forest. Together with the skulking robins, we’ll spend the winter constructing a road map for the space between the near and far field, a patch of shrubs heavy with berries, and a choice among several sweaters.

This preparation is comforting, the constancy of migration, succession, and seasonal renewal is comforting, even if decisions in the short term are hard. Rapid, dramatic changes such as wildfires demand more of our flexibility, and more attentiveness from our present decision-making to ensure that we’ll be better off in the long haul.