Human Impacts

As humans continue to urbanise the planet, we continue to cut into the forests, wetlands and mountain ranges that many migratory birds use as a stopover location during their migration. Unfortunately, birds still seem to stay in the same location despite the human influence as they simply do not have another resting spot. This is the first of many influences that humans have on the migration of birds, as we have continued to encroach on to their territory.

One particular way that humans affect the migration of animals is through our production of electromagnetic noise. Edgar (2014), claims that this noise can mess up the magnetic navigation of many birds and insects, although she does not offer up any proof or evidence of this claim. However, a study conducted by Engels et al. in 2014 showed that when a European Robin was exposed to electromagnetic noise, it became unable to orient itself using it's magnetic compass. While this has not yet been proven for other species of bird, there remains a very real possibility that on an overcast day, a bird navigating by magnetic compass may pass over an urban area and suddenly not be able to orient itself.

The other ways that humans influence the navigation of birds is mainly due to changing the natural environment. Birds that navigate by using landmarks may struggle to find their way if forests are cleared or rivers are diverted or dammed, as those visual cues were specific parts of their navigation. Human structures can also lead to altered wind currents (Zhang, Jiang & Hu, 2004) which could proceed to blow birds off course if they happen to fly over that area.

As humans continue to expand and urbanise the world, we will continue to have a larger and larger impact on migratory birds. Given that more than 4,000 species of birds migrate annually, approximately 40% of all bird species (RSPB, n.d.) it is imperative that humans take the necessary steps to protect these birds.