Threats to Migrating Birds

Clearcutting habitat loss with tree stumps among the forest

Tero Laakso / Flickr / CC BY 2.0

Migration is a hazardous journey, but those hazards are often overlooked in the large-scale spectacle of millions of birds that successfully travel between their breeding and wintering grounds each year. Birders who understand the threats migrating birds face, however, can help those birds be better equipped for a successful flight. Whether their migration is just a few hundred miles or as far as a few thousand, every bird deserves the chance to reach its destination safely.

Migration Threats

Different birds face different threats along their journeys, but all birds have to endure some risks as they migrate. The most common and most deadly threats to migratory birds include the following:

  • Exhaustion: Birds may fly hundreds of miles during migration, often covering large distances without rest. Exhaustion can make birds less wary of potential threats, and tired birds are more apt to collide with obstacles or falter in flight. This is especially true if their flight path passes through storms or unfavorable wind patterns, or if birds are migrating later in the season and must cover more ground each day to reach their destination.
  • Starvation: Inadequate food supplies cause starvation among migrating birds every year. This may be caused by habitat destruction that effectively strands migrating birds without food along their route, or it can be due to greater feeding competition among large flocks of migratory birds.
  • Collisions: Tens of thousands of migrating birds collide with obstacles in mid-flight during both spring and fall migrations, and the majority of these collisions cause fatal injuries. Even if the birds are not killed on impact, stunned birds are more susceptible to predators. The most common dangerous obstacles include tall glass buildings, electrical wires and poles, wind turbines, and similar structures.
  • Predators: Predators kill hundreds of thousands of birds each year, and during migration, migrating birds may be unaware of local predators at stopovers during their journey. Outdoor cats and feral cats are the most common predators that threaten migrating birds, but even wild predators can be a deadly hazard.
  • Disease: When migrating birds gather in large flocks, a disease outbreak can be devastating. This can be even more detrimental when surviving birds carry the illness to either breeding grounds or densely populated winter ranges. In those large flocks, more birds may become infected and the overall population can be decimated.
  • Pollution: Pollution such as lead poisoning or oil spills is not only harmful to locally affected birds but migratory birds as well. Polluted habitats provide less food, and birds that ingest toxins during migration may continue to suffer from the poisonous effects long after leaving the area. Furthermore, heavy pollution will reduce suitable habitat, making it more difficult for birds to complete their migration successfully.
  • Natural Disasters: Hurricanes, blizzards, wildfires, floods, and other natural disasters can destroy crucial stopover and rest sites as well as destroy food sources birds need to refuel along their journeys. Birds that are caught in these disasters can suffer other effects that cause injury, debilitation, or death, such as singed feathers in a wildfire or freezing in an early or late blizzard.
  • Hunting: Many hunting seasons coincide with migration periods, making this perilous time even more threatening for birds. Illegal hunting and poaching are also a threat at this time. Even legitimate, experienced hunters may make mistakes and inadvertently shoot protected birds that they have misidentified in flight.
  • Inexperience: A bird's inexperience with migration can be a great threat to its success and survival. Many juvenile birds make these long journeys without guidance from adults. They may not be able to complete the trip if they are unsuccessful in finding adequate food or if they stray too far from the typical migration route. While birders may enjoy the vagrant sightings of inexperienced juveniles during migration, straying far off course is likely a death sentence for the bird.
  • Ignorance: Many people don't realize how perilous migration can be for birds, and instead chalk this seasonal behavior up as "just something birds do." A more informed public can better appreciate the threats to migratory birds. The more awareness there is of those threats, the more likely it is that sufficient steps will be taken to help birds survive.

How You Can Help

The first step in helping birds migrate successfully is to understand the threats they face along the way. Birders who want to help migrating birds can also take a variety of simple actions to minimize those threats.

  • Create bird-friendly landscaping and preserve natural habitats for birds to rest and refuel during migration. This includes choosing native plants and providing water to birds as well as offering good food both naturally and through supplemental feeders.
  • Feed birds year-round by offering nutritious foods such as suet, black-oil sunflower seeds, fruit, nuts, and nectar. These foods provide high amounts of fat and sugar to give birds plenty of energy during migration.
  • Keep bird feeders and birdbaths clean and fresh to avoid spreading diseases that could infect migrating birds and thus spread to migratory flocks.
  • Use several methods to prevent bird-window collisions at home, and support "lights out" campaigns in local cities where office buildings can be a hazard to migrating birds. In large cities, volunteers are always welcome to patrol collision zones to collect stunned birds so they can be effectively rehabilitated.
  • Minimize or eliminate pesticide use and dispose of oil, lead, and other toxic materials safely and responsibly so there is no environmental contamination that can affect birds. If a spill occurs, participate in cleanup efforts can help protect both local and migratory birds.
  • Take steps to discourage feral cats and always keep pet cats indoors so they do not threaten birds. Dogs should always be closely supervised and leashed when near popular bird habitats as well.
  • Support strong enforcement of local hunting laws and measures to prevent poaching or illegal hunting activities.
  • Share your love of birds with friends and family members to introduce them to this rewarding hobby. This helps raise awareness of birds in every season and encourages more people to enjoy migration and protect migrating birds.

Migration is a natural part of many birds' lives, but it is fraught with danger. By understanding the threats migrating birds face, every birder can help their feathered friends complete these seasonal journeys safely.