
The short answer: absolutely. Birds get lost all the time. Their built-in GPS may still be a mystery to us, but it isn’t infallible.
Long distance migrants like waders and wheatears feature highly on the list of vagrants (birds that do not “belong“ in a given place). Strong winds, storms, and reasons we don’t even understand can change the bird’s measurement of longitude and drive the migrating individual to a more easterly or westerly location than usual. A small change in course at the journey’s outset can result in a large displacement after thousands of kilometres. Considering this planet is blue, one can imagine the untold numbers of birds that end up in the drink. From that perspective, vagrants are the lucky ones.
Sometimes a bird errs with the latitude and flies the wrong way, south instead of north. This so-called reverse migration is rare, but common enough to give Australians and Southern African birders several vagrants each year. We know it’s reverse migration and not “over-shooting” because these reversos end up deeper south while they should be up north at that time of year. Over-shooting happens in autumn when southbound migrants keep on flying and end up at higher latitudes south. I am not purposefully Euro-centric or north-centric – just think where over-shooters end up in the south-north scenario: in the Sahara or in the Southern Ocean. Dead.
Some bird families are adventurous. They wander on purpose. The rails in particular have flown to every possible island on the planet despite being rather poor fliers. Adventurous birds discover new lands to inhabit, but not every vagrant starts a new population. Or do they? Yellow-browed Warbler was a vagrant a few decades ago but seems to turn up in Western Europe every year now with new breeding populations further and further west. Are we witnessing the colonisation of Europe by this little leaf warbler? If that happens, I can take my own picture instead of stealing one from Kai…
As I am always concerned about the quality of the photos on this site, I hope the leaf warblers will keep avoiding Europe.