Vagrant Birds

Why Birds Go Out of Range

Ivory Gull
The Arctic-dwelling ivory gull is a rare but regular vagrant much further south than expected.

Ed Schneider/Flickr/Used With Permission

Spotting vagrant birds is always exciting for any birder, but what exactly is a vagrant bird, how does it arrive in unexpected locations, and what are the best tips for seeing one?

About Vagrant Birds

A bird is considered vagrant if it strays far outside its expected breeding, wintering, or migrating range. The key factor in defining vagrant is the distance: A bird that is just barely outside its normal range is not usually considered vagrant, but a bird found hundreds of miles from its familiar territory is a vagrant. Many times, vagrant birds may be from other continents or so far from their expected range that they have never been seen in an area previously.

Also called accidental birds, these unusual visitors can cause great excitement in the birding world. Birders are often willing to travel great distances themselves to see such rare avian guests and add new species to their life lists, especially if the birds are so far out of range that it might be impossible to see them in their typical locations.

How Birds Get Lost

Exactly how vagrant birds appear so far from their regular ranges is somewhat of a mystery, but there are several possible explanations.

  • Weather: Storms and unexpected, turbulent air currents can force flying birds far from a regular route. The exhausted birds then come to rest in a completely foreign territory, well away from their regular range, but anxious to find the first food, water, and shelter available. Because they are so disoriented, they may remain in the unusual location for several days, giving birders plenty of viewing opportunities.
  • Inexperience: Juvenile birds making their first migration without the guidance of adult birds may overshoot or undershoot their destination, instead stopping in areas where they aren't normally seen. These youngsters may not stay in the area for long, but will quickly move on as they continue their migration.
  • Genetic Abnormalities: Birds sense the Earth's magnetic field to help guide them on migration, but some birds may have impairments that misdirect them to distant locations instead of familiar destinations. These birds may end up being vagrant in the same general location for several years, as their annual migrations continue to be misdirected.
  • Wanderers: It is believed that some individual birds wander more than others, just as some humans long to travel. The causes are unknown but may be linked to food sources, types of habitat, or just individual preference. These "wandering" birds may end up far from their typical ranges, but their appearances and how long they stay are random.
  • Hitchhiking: Birds will occasionally "hitchhike" on ships and end up traveling from one continent to another. While this type of human-assisted travel does not qualify a bird as an acceptable life list addition for many official birding organizations, seeing a rare transoceanic visitor can be a thrill for birders.
  • Pets: Tropical birds are vulnerable to poaching and may end up in pet stores far from their native habitats, and if those pets are released or escape they can be considered vagrants. This is another type of vagrancy that is not usually acceptable for an organization's official counts or lists, but can make for a very unusual sighting.

Finding Vagrant Birds

Birders are often excited to learn of vagrant sightings because of the rare opportunity to see an unfamiliar species. Staying connected to local and regional birding hotlines, listservs, social media accounts, and notification lists is the best way to hear about unusual sightings. Birding organizations such as Audubon chapters or local bird groups may have members-only message boards, text alerts, and calling trees to send out rare bird alerts.

When a vagrant is initially spotted, the first thing to do is identify the bird carefully. Hybrid birds, juveniles, and molting birds with indistinct plumages may be mistaken for vagrant species, and many organizations require expert identification and verification before they will announce a rare bird.

It is also important to treat a vagrant bird with care and observe it cautiously. These birds already tend to be nervous so far from familiar territory, and undue stress can cause health difficulties and make the bird more susceptible to predators. No matter how rare a bird may be, birders should always follow proper birding ethics to ensure the bird's safety.

Seeing a vagrant bird can be a unique and exciting experience for any birder. By understanding what makes a bird vagrant, birders can even better appreciate the resiliency and endurance of their unusual feathered friends.