Year of the Bird

Tim Iverson

(6/2018) Summer is now squarely upon us. The ephemeral spring flowers have given way to lush greens and warm temperatures. Insects, seeds, fruits, and other veritable menu items are now on tap for our seasonal avian residents. Birds are finishing their migratory routes and settling into their summer nesting places.

The term migration is an umbrella term that describes several different variations on the bi-annual movement birds make. It’s important to note that some birds stay put all year long. Cardinals, for instance, don’t migrate and are year long residents finding suitable food and shelter no matter the weather. Some birds migrate very short distances. Short as in from the top of a mountain to the bottom of the same mountain. This type of migration is called altitudinal migration. Some of these species may spend their entire lives within a 20 miles radius. Medium distance migrants may travel the distance of a few states. Most impressive though are the long distance migrants. These are the birds that will travel thousands of miles crossing hemispheres to find residence in new quadrants of the globe for a few months at a time.

Short distance migration is primarily driven by the lack of resources available during the winter months. Simply put, they’ll move to where survival is easiest. Long distance migration is less understood and not as easy to justify. There’s simply no need to travel thousands of miles for beetles and berries when there are other ones considerably closer. Research suggests these routes developed as a result of better breeding habitats. While tropical zones provide abundant food during the winter months, temperate zones are more habitable during breeding seasons. Longer daylight hours and ample food allow these migrants to produce twice as many offspring compared to their non-migrant cousins. Of course, during the tough winter months it’s time to head back to the tropics.

The switch that flips indicating when a bird should head south is initiated by a few factors. Shortening daylight hours, cooler temperatures, dwindling food supplies, and genetic factors are all cues that tell a bird when it’s time to go. Migratory birds can cover thousands of miles during a single trip. They seem to intuitively know the way to go. Even first year birds who have never made the trip before can manage on their own. Biologists have wondered how that can be, and the best research indicates that they utilize landmarks, the sun and stars, and the Earth’s magnetic field. Many young birds are believed to develop a site attachment during the first migration and will continue to return to those sites year after year. Some birds, barn swallows included, may even use the very same nests time and time again.

Migrants often get bottlenecked in what bird enthusiasts call migrant traps. These are areas that migrating birds concentrate into in very large numbers. These traps are often last pit stops, like islands or peninsulas, before long barren stretches of distance must be covered without readily available resources. Bird watchers can see many birds of different species in a short time span, which makes them exceptionally popular for people as well as birds. In some instances these traps might provide an important food sources for migrating species. The Red Knot is a long distance migrant that travels 9,000 miles from the coasts of South America in winter to breed in the Canadian arctic. While making this journey they make a pit stop in Delaware Bay. On some days it’s estimated that nearly 90% of the entire subspecies can be found there during these mass migrations. This trap is a midway pit stop on their long journey and provides an essential food source to power them through. They arrive in the spring when Horseshoe Crabs lay their green eggs in sand. The Red Knot devours as much as he can and continues his way onward.

Birders, or bird enthusiasts, often refer to a "big year." A "big year" is a personal challenge to see how many different species they can spy in a single year. 2018 is a big year for birds too. This year marks 100 years since the Migratory Bird Treaty Act (MBTA) became law, which makes 2018 The Year of the Bird.

The MBTA is one of the very first conservation laws enacted by the United States, making us a model and a forerunner in the conservation movement for the rest of the world. The law originally was a response to the near extinction of several bird species that had been hunted for their feathers or sport. It grew out of an international treaty signed with Canada, and after being codified has since attracted other nations to join such as Mexico, Russia, and Japan.

The US FIsh and Wildlife Service, under the US Department of the Interior, is primarily responsible for enforcing the law. They describe the law as, "unlawful to pursue, hunt, take, capture, kill, possess, sell, purchase, barter, import, export, or transport any migratory bird, or any part, nest, or egg or any such bird, unless authorized under a permit issued by the Secretary of the Interior. Some regulatory exceptions apply. Take is defined in regulations as: ‘pursue, hunt, shoot, wound, kill, trap, capture, or collect, or attempt to pursue, hunt, shoot, wound, kill, trap, capture, or collect.’ "

The Migratory Bird Treaty Act is credited with saving Snow Egrets, Sandhill Cranes, and Wood Ducks from extinction. It covers more than 1,000 species in North America, which is nearly all bird species in the US. Recently, the US Department of the Interior, which is ultimately responsible for enforcing this law, has changed its interpretation of the law. The law is a century old, but new threats have emerged since its inception. Oil spills, power transmission lines, wind turbines, and cell phone towers weren’t able to be considered when the law was adopted. When birds die as a result from an encounter with one of these modern day hazards these deaths are considered "incidental takes."

The BP oil spill in 2010 resulted in over a hundred thousand bird deaths. Wind turbines that are placed in migratory routes account for as many as 100,000 deaths annually. Power lines account for upwards of 50,000 bird deaths per year. The MBTA provides incentive and legal repercussions for companies to mitigate these instances. The current administration is changing its understanding of policy and enforcement of the treaty. The MBTA will no longer consider these or penalize incidental bird deaths. In effect, what this means is that unless a person or company intentionally means to kill birds they can not be held accountable for their actions.

Migration can be dangerous business. It is physically taxing and may be too much for older or injured birds to handle. It increases exposure to predators. Man made structures like wind turbines, communication towers, and the electrical grid present additional problems. Climate change is already eroding shorelines, altering food availability, and distorting weather patterns creating problems throughout the entire migratory cycle. The Migratory Bird Treaty Act ushered in a century or pragmatic conservation. The phenomenon or migration is as arduous as it is inspiring. The somewhat nomadic lifestyle of birds was shaped thousands of years ago and has also helped to ensure the survival of our modern day dinosaurs. Here’s hoping the prevailing winds provide smooth sailing for many more to come.