Agent-Based Modelling of Trans-Atlantic Bird Flights

Abstract

Many North American bird species migrate towards South America to spend the colder seasons. Occasionally, some of the birds that were meant to migrate south arrive in Europe, far outside of their normal habitat. It is hypothesized that strong, eastward winds allow these vagrant birds to reach the other side of the Atlantic oceans. This paper presents a model for simulating migratory bird flights that takes wind speeds into account to gain some insight in the influence of wind circumstances on these bird flights. Simulations were run with birds starting on the eastern coast of North America between 30◦and 70◦latitude in the autumnal months of 2016 to 2020 using two different strategies for orientation. Results show that strong eastern winds allow birds to reach Europe from North America. Factors that distinguished birds that reached Europe from other birds in this model are a high wind speed and a starting position between 45 and 56 . While high eastward wind speeds make it possible for Nearctic birds to reach Europe, they might not sufficiently explain the phenomenon of vagrants: when birds navigate towards a goal, the wind speed and direction has a much smaller influence on the trajectory. Other orientation strategies or malfunctioning of the navigation apparatus of birds might provide more explanation.