Winter is a difficult time for Solent’s ducks, geese and wading birds, but how do they fair during summer?
Most of ‘our’ birds began journeying back to their summer breeding grounds weeks ago, some travelling thousands of miles to destinations such as Northern Russia. Having reached them, they now have a whole host of new challenges to face.
Let’s focus on our beloved dark-bellied brent goose, this fabulous bird travels over 3000 miles to reach its breeding grounds in Siberia. After several stops en-route to feed and rest, it reaches the Artic just as the snow and ice are starting to melt. The first challenge for the geese is to find a suitable place to nest – this needs to be the boggy Arctic tundra. Once settled, the severe climate only allows them about two months of good weather in which to raise a family…the clock is ticking.
Next comes the threat of predation, and Siberia has its fair share of hunters. Arctic foxes and snowy owls prey on young brent geese, however their main source of food are small mammals such as hares, lemmings and voles. The abundance of these mammals, in particular lemmings, can be the difference in the numbers of young geese that are taken by the two wily hunters. If the breeding season of the lemmings has been unsuccessful, the owls and foxes turn their attentions to brent goose chicks as an easy source of food which can have a huge impact on their numbers.
Recent research has shown that the breeding success of dark-bellied brent geese follows a three-year cycle of ‘good’, ‘poor’ and ‘variable’, and predator pressure influenced by the numbers of lemmings can mean the difference between ‘good’ and ‘poor’.
Weather also plays an important role on the mortality rate of the birds and hypothermia can be common amongst the chicks if the temperature is just a few degrees lower than normal. Sadly, changing weather patterns caused by climate change is meaning this challenge is increasing for our feathered friends.
Rapidly changing climate can also lead to changing ecosystems. This in turn can create a mismatch in timing between insects and birds which causes an adverse effect on our insect eating birds such as sanderling.
However not all challenges have reached these summer destinations. Due to many locations being remote and inhospitable there are very few human disturbance issues for these birds compared to pressures faced over the winter months in the Solent. This small mercy is very welcome for our feathered friends as they already have so much to contend with.