Spring migration is here!
Migratory birds love these environmentally-friendly bird feeders!
Across North America, birds have been arriving in droves. Brightly-colored plumage, cheerful songs, nest-building, and the hustle and bustle of the breeding season are infiltrating backyards across the North American continent. Migration is an exciting time of year, and while birds face many natural AND human-induced hurdles, we CAN take steps to help our birds.
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Why do birds migrate?
Migration is a marvel of nature. What is it? By definition, it is a seasonal movement of organisms from one area or region to another, but the number and diversity of global organisms that migrate are staggering. Mammals, fish, reptiles, amphibians, insects, spiders, and birds are all known to have species that partake in these seasonal movements. In birds, we often think of a north-south migration, a latitudinal migration. However, birds can make migrations of differing varieties. A few other migratory strategies include:
- altitudinal migration (moving up and down mountains)
- longitudinal migration (moving east to west)
- irruptive migration (sporadic movements)
These strategies are not the only types of movements for birds, but they represent the majority of migrations in North American birds. These terms help describe what migration is, but now let's explore why birds make these seasonal movements.
Why do these creatures migrate? Each species may have a specific need, but animals generally migrate due to a shortage of basic needs like food, shelter, or requirements for breeding and nesting. Historically, a common belief was that dangerous winter weather was the cause of migration to occur. While this is not entirely untrue, bad weather alone is not at the root of seasonal movement. Instead, the change in the length of the day can lead to fewer food resources, while worsening weather conditions lead to more significant energy requirements.
These basic tenets of migration explain a majority of the 'cause' of bird migration in North America. For many species, the shortened days of winter remove their most essential food sources from the landscape. For example, arthropods, like insects, become far less available in most habitats. However, a big puzzle piece is missing in this image of bird migration. Why do Neotropic migratory birds spend more time on their winter grounds in Central and South America and only migrate to North America for breeding? Paleontologists and other biology specialists have introduced a theory that these birds originated in the tropics, due to a shortage of nesting space, migrated to North America ONLY to breed. While this theory is not a guarantee, it does seem to offer strong evidence that those of us living in the temperate climates of the US and Canada are enjoying birds that are vacationing in our backyards.
For those familiar with the narrative of the Pacific salmon, this might be a known story. For the uninformed, the Pacific salmon is born in freshwater streams but lives most of its life in saltwater habitats. Are these fish saltwater fish or freshwater fish? Are they fish of our inland lakes and streams or fish of the seas? We can apply this same question to our favorite migratory birds. If they spend most of their lives in the tropics, are they tropical or temperate birds? Birds of the jungles or birds of the northern forests? Answer: Why not both? Migratory birds depend almost equally upon nesting, wintering, and migratory grounds. With this similar dependency, we can still care for these species as if they were our neighbors 24/7/365.
Regardless of the purpose, migration stands as a true wonder of nature. This seasonal movement of living organisms from one region to another is a remarkable phenomenon that encompasses a vast array of species that many of us are familiar with. The sheer number and diversity of these migratory creatures never cease to amaze, showcasing the magnificent power and complexity of the natural world.
How many birds migrate?
In North America, most of our regularly occurring birds are migratory. In fact, 70% of our recurring birds migrate in some capacity every year. This percentage means over 350 species of birds in North America engage in some form of migration. Not all of these species are true long-distance migrants, and some of these species migrate from the Arctic Circle into the lower 48 states. This amazing diversity transits across the continent, but the biodiversity only tells part of the story.
Twenty years ago, scientists would have only been able to provide very rough estimates of the number of birds that make these grand movements. However, recent developments and novel uses of radar technology have allowed scientists to measure the numbers of birds moving across our airspaces. By tapping the same radar systems that we use to predict weather events, scientists could capture moments in migration to measure that approximately three to six billion birds migrate annually. In the fall, greater numbers of birds depart on a southward journey than return north in the spring. This unsavory fact is due to the natural and human-caused threats that birds face during this stressful period of movement.
What hurdles do migratory birds face?
Migration is a serious challenge. However, in addition to the typical problems birds face, such as predators, storms, and exhaustion, humans have created an additional set of hurdles that birds must navigate during these journeys. In a US Fish and Wildlife Service report, the federal agency gathered all the studies with measurements of annual bird mortalities. They listed these threats and their destructive costs. In order of greatest to lowest number of mortalities, these are the ten most significant threats that birds experience:
- Habitat loss
- Cats
- Windows
- Vehicles
- Poison
- Electrical line collisions
- Communication tower collisions
- Electrocutions
- Oil pits
- Wind turbines
These combined threats (without habitat loss included) likely account for the loss of over three billion bird deaths yearly. Compared with the number of birds that migrate annually, it may seem like the math does not add up. Remember, these numbers also include impacts on resident species that do not migrate. Unfortunately, the stark reality is these losses still have an exponential effect on losses in migratory birds. These anthropogenic threats are why migratory birds have seen a 30% population decline since the 1970s.
While these numbers can be overwhelming, we can take simple actions to fix these problems at home and across industries.
How do we help migratory birds?
Bird conservation groups have created a list of seven basic steps anyone can take to help birds. These actions may take some time and effort for each of us to accomplish, but they are not impossible to achieve:
- Keep cats indoors
- Protect windows
- Remove plastics
- Plant native plants
- Avoid pesticides
- Protect winter habitat
- Shut off lights
From this list, four actions can be taken today by anyone reading this list. Keeping cats indoors is as simple as not letting invasive pets roam free. It may seem like a difficult decision, but it keeps cats AND birds safe. Moving to the mechanical removal of pests, rodents, and plants is another step you can take today. Cutting poisons out of our daily uses keeps birds from accidentally ingesting a prey item packed with these toxins. Shutting off our lights at nighttime can prevent migrating birds from becoming disoriented or colliding with reflective glass. A final change you can make today to help birds is protecting winter habitat by switching from regular to bird friendly coffee. The remaining three actions are still easily achieved but may require an extra day (or a few) to complete the action. Using protective stickers and window coatings reduces window collisions, but additional time may be needed to order and apply the decals and make your windows bird friendly. Removing plastics from our daily use is difficult, but we can all take small steps to cut back, piece by piece. And finally, planting native plants may require an entire growing season (or two) to create a space that birds can use will eventually cut your water bill while also creating an at-home bird sanctuary.
There is on final action you can take, and Birds Choice can help every step of the way. Provide birds with a supplemental food source by hanging a bird feeder. Migratory birds of all varieties will appreciate the boost of fresh water and supplemental feed that Birds Choice can ship straight to your door. You can act TODAY by visiting the Birds Choice store and creating a backyard buffet!
As we witness the influx of birds across North America, our backyards become adorned with vibrant feathers, joyful melodies, and the diligent activities of nest-building during the breeding season. Migration brings excitement to this time of year, despite the numerous challenges that birds encounter, whether they are natural or brought about by human activities. However, let us remember that we hold the power to make a difference and support our feathered friends by taking proactive measures. Together, we can create a safe haven for these magnificent creatures and ensure their continued presence in our lives.
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