It seems that with each passing year, we are treated to different species of birds during migration. While we may not all personally get a glimpse of a wayward bird, we often will hear about it locally or even nationally when a non-resident species wander into unfamiliar territory. This year, here in the Ottawa area, local birders in Pakenham, Ontario were treated with the sight of a Bullocks Oriole, often only seen in western North America.
While this phenomenon happens both in the spring and winter migration periods, it is often more pronounced in the fall. Many of us with automatically think these happenings to be harmful to birds, but for the most part, the opposite is true. These rare sightings give way to more detailed ornithological study, raise awareness of bird diversity and can actually strengthen the genetics of the species.
Here are a few reasons that are believed to be the main culprits of leading migrating birds so far off their course.
Believed to be one of the biggest factors contributing to vagrant birds is the weather. When the weather conditions are poor or unseasonal, migrating birds easily are pushed off their path by the wind or can often get lost attempting to avoid thick and heavy cloud cover or storm systems.
When you think of food sources as fuel stations, it is not hard to imagine how much these can influence a bird’s flight pattern. As birds follow food sources or leave familiar habitat in search of reliable ones, they can easily become disoriented and end up where they don’t belong.
Much the same as food sources, loss of habitat is another leading factor. Birds are very habitual creatures, often returning to the same habitat year after year. Factors such as natural disasters and habitat destruction can severely alter a bird’s habitat from one year to the next. When birds change locations in search of better habitat, they can often get lost as they search for the geographical clues that have safely guided them in years past.
Inexperience is also a leading contributor to vagrant birds. More often than not, birds spotted far outside their typical range are of juvenile age and simply did not have the experience to guide them through their migration. This, however, usually is combined with one of the above factors as well, as bird do innately know where and when to migrate.