A new study found that Eurasian blackcap (Sylvia atricapilla) birds are shifting their migratory destinations from sunny Spain to cold UK. According to the researchers, the change in patterns are influenced by availability of food and alterations in environmental temperatures.
Swift changes in the global environment are being caused by various human activities. As more and more areas become urbanized, evolutionary alterations and intense human-induced habitat changes are triggered. However, proof and comprehensive knowledge regarding the mechanisms entailed in this phenomenon are minimal. In this new study, the researchers studied the possible factors involved in the modern evolution of behavioral migration among blackcap birds.
The researchers from the British Trust for Ornithology (BTO) performed the study by initiating an online survey involving more than 14,000 garden-owners, who volunteered to give food to birds and provide data regarding the visits of the avian species in their gardens. The experiment, which looked into the presence and absence of the birds, was performed over 12 winters (1999/2000-2010/2011).
The findings of the study, published in the journal Global Change Biology, showed that the availability of food is an essential factor in the migratory behavior and seasonal distributions of the birds. According to the data collated by the authors, gardens that provided food for most of the winter season were more frequented by the blackcaps. With this, it can be said that food supply is an important driver for bird migration in the UK. More specifically, fat and sunflower hearts provision became rampant in the entire course of the study.
"This is the first time that we've shown that feeding birds actually influences the distribution of a bird species across a whole country," Dr. Kate Plummer, the study lead author told the BBC.
The study also found that feeding is not the only factor that influenced bird migration. As per previous studies, the authors also discovered that the south and west parts of the region were more occupied compared to other sites. As the said locations are relatively warmer during the winter, the researchers noted that climate is also a key driver in the bird migration shift.
In the end, the authors concluded that food supplementation and winter temperatures have equal impacts in the migration and distribution of blackcap birds in Britain during the winter season.
Blackcaps breed in Austria and southern Germany, and were rarely seen in Britain prior to the 1950s. However, their populations have rose swiftly in the past 60 years.
The biological diversity around the world are imperiled by the environmental alterations caused by humans, the study said. This research was able to demonstrate new and timely proof that humans have vital roles in influencing the directions of evolution.
Photo: Ron Knight | Flickr