Originally written in October 2015.
At WWT Slimbridge, Gloucestershire, on the 11th October 2015 the first Bewick’s swan, Cygnus columbianus, of this autumn reached the reserve. No other recordings of arrivals this early have occurred in more than 50 years, since recording started in 1963, beating the preceding record holding couple ‘Tomato and Ketchup’ which arrived on the 12th October 1980 (WWT, 2015). This early arrival has prompted predictions about a cold and long winter.
Bewick’s swans arrive in Britain in October, having left Siberia in the first few weeks of September. The swans breed in parts of Russia but migrate to areas of Europe to overwinter, including Germany, The Netherlands and Ireland. The swan itself is however sometimes mistaken for a whooper swan, Cygnus cygnus, but can be distinguished by the yellow on its bill which is less than that of the whooper and forms a rounded shape, as well as its flight having quicker wing beats. Around 7,000 Bewick’s swans overwinter in the UK, which contributes to the figure of around 23,000 overwintering birds in Europe (RSPB, n.d.).
So why does the early arrival of one swan species suggest a cold winter? Bewick’s swan migration is influenced by climatic conditions, especially weather factors such as wind direction. It is the combination of this wind direction (north easterly), and cold temperatures which has encouraged swans to hasten their migration this year across Europe, with areas of Eastern Europe and Russia being 5-10oC colder than on average (WWT, 2015). As this swan has arrived earlier than normal in the UK it suggests that weather conditions are harsher than usual, possibly resulting in a longer and colder winter season. It is unclear how climate change may influence this species in the future but the current weather conditions already seem to be affecting migration patterns.
RSPB. (n.d.) Bewick’s Swan [www document].www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/b/bewicksswan/ (Accessed 13/10/2015).
WWT. (2015) Record-breaking Swan Arrival Adds to Cold Winter Rumours [www document]. www.wwt.org.uk/news/all-news/2015/10/wwt-slimbridge-news/record-breaking-swan-arrival-adds-to-cold-winter-rumours/ (Accessed 13/10/2015).