Think of the fall bird migration as the second half of migratory birds’ annual journey. Birds fly north in spring and south in fall. This journey mirrors that of “snowbird” retirees who live in Michigan or Maine in summer, then, come fall, head to Arizona or Mexico.
But while these human snowbirds are inspired almost exclusively by the weather, the reasons for the fall migration of birds are much more complex and layered. You can help our feathered friends on their seasonal journey by creating a bird garden that will help them rest and refuel.
Why do birds fly south in fall? Nobody is certain of all of their motivations, including, perhaps, the birds themselves. Migration has its roots deep in the history of the planet and the whys and wherefores are well worth exploring.
What Is Fall Bird Migration?
At its most simple, fall bird migration refers to the time in autumn when migratory birds head south for the winter. However, this does not always occur in the months that we humans refer to as fall – September, October, and November. The timing varies among species as well as the reasons for migration and the distance to be traveled.
Some birds head south to spend the winter in warmer regions. Others migrate to southern climes because their food sources – insects and/or seeds or fruits - diminish toward the end of summer in northern areas. You can watch the seasonal bird migration up close with one of the top binocular picks from the Cornell Lab of Ornithology, the Nikon ProStaff P7. Find these waterproof compact binocs on Amazon.
When Is Fall Bird Migration?
When do birds migrate in fall? If you think of fall bird migration as wild geese heading south in September or October, you are not alone. The classic flying Vs of noisy geese have been the poster children of fall migration for decades. But there are hundreds of species of migratory birds – more than half of the breeding birds on the continent migrate! – and each species has its own migratory triggers. These can range from changes in day length, genetic predisposition, and changes in food supply.
Take Rufus hummingbirds as an example. They mate in the Pacific Northwest and overwinter in Mexico. These birds often are the first to leave the northern mating grounds. Males of this species are not active fathers and take no responsibility for raising their young. That means that they are free to leave when the breeding is done. They take advantage of this and often head south in mid-June. Females wait until the young birds fledge, often getting to southern states – like Arizona - by early July. They are followed some weeks after by the juvenile birds. After a few months of feasting on summer wildflowers, they continue south to their wintering grounds in Mexico. You can support migrating hummingbirds by supplying supplemental food and water in your garden.
Why Do Birds Migrate in Fall?
Scientists have investigated why different species of birds migrate in the fall. In general, they concluded that birds migrate from locations with low or decreasing resources to regions with high or increasing resources. You can help them as they prepare for their journey by continuing your late summer bird feeding and not deadheading your native plants.
Weather is, of course, a factor in the resource question, especially for those with breeding grounds in the far north. The birds themselves may want to avoid cold, snowy weather, but, more significantly, the wildflowers and insects they rely on for food start disappearing as winter approaches. The birds would die off quickly if they had no food.
But that’s only part of it. The patterns of long-distant migration evolved over thousands of years, and it is thought that birds are born with this knowledge embedded in their genetics. The original reasons could have included day length, weather, and many other factors.
How Do Birds Know Where to Go?
Fall bird migration refers to long-distance migration, trips north and then south that cover thousands of miles a year. Birds rarely take “the road less traveled by,” but tend to travel the same course year after year. But it’s not the force of repetition. Birds in their very first year, traveling alone, will take the same route that their parents took, finding their parents’ winter home despite never having seen it before.
How do they know where to go? Scientists don’t have all the answers. But they do tell us that the migrating birds don’t just rely on sight, looking for landmarks they flew over before. They apparently obtain data from the stars, the position of the setting sun, and even the earth’s magnetic field. However, since species follow the same pathways , they do get to used the same stopover locations that provide essential food supplies.
Fall Migrating Birds
There are about 650 species of breeding birds in North America. More than 350 of them migratory, so a complete list is beyond this article. This includes birds of prey to tiny songbirds.
Some common migrating birds are the bald eagle, swallow, white pelican, mourning dove, thrush, hummingbird, sandhill crane, great blue heron, goose, trumpeter swan, warbler, and Arctic tern (famed for their incredible migration route from the Arctic Circle to Antarctica and back.) Learn how to identify birds with some tips from the Audubon Society.
How to Help Migrating Birds in Your Garden
If you want to assist our migrating birds, you can! The first step is to create a garden that attracts birds. There are a number of small actions that you can take that could have a major impact on fall migrating birds.
- Plant native! We’ve mentioned many times how native plants are tough, drought resistant, and easy care, but here’s yet another reason to go native with fruit trees, grasses, shrubs, and flowers that attract birds. These are the plants the birds have come to rely on in your area and they are far more bird-friendly than sterile hybrids. Shop native plants in the Gardening Know How Shop.
- Off with the lights! Turn off your exterior lights during migration season, or at least dim them. This includes rooftop lights and flood lights. Reduce indoor light with shutters or blinds.
- Prevent birds from hitting your window. Use decals, netting, screens or paint to make sure that your windows can be seen by passing birds. A simple product like BirdTape will protect birds, but won't obstruct your view. You can find BirdTape on Amazon.
- Create natural foraging opportunities for migrating birds. Leave leaf litter and fallen branches on the ground. This gives them cover from predators and encourages insect populations that are the bread and butter of the avian world.
I hope you learned a little bit more about why birds migrate and how you can help them on their journey. It is up to all of us to protect and respect these wild animals.
