Cold weather, shorter daylength and stormy dilemmas. How do coastal birds survive during the most challenging time of the year?
Read Ranger Eloise’s account of the seasonal problems and solutions of birds’ day-to-day lives throughout the winter.
The winter needs no introduction in the UK. The darkness creeps in at 4pm, boxes of scarves and woolly hats are pulled out from storage, and the weather usually takes a turn for the worst.
We’ve certainly had a mixed bag of weather conditions so far this year.
From a mild and sunny start, to snow and freezing temperatures, and finishing November with Storm Bert.
But despite our opinions about the winter, hundreds of thousands of birds choose to migrate to our coastline to escape the Arctic cold. The Solent offers a bountiful supply of food all year round, so the benefits outweigh the risks for these far-travelled birds.
Coastal birds still must consider the colder temperatures, stormy weather and shorter daylight hours when foraging for food. So what challenges do our overwintering birds face and what adaptations have they made to deal with them?
Darker days
The first dramatic change we see during the winter is in daylight hours.
As we move into our winter months, the day length shortens by almost nine hours compared to summer months – and shorter days mean less time looking for food in daylight.
Most wading species rely on the tide cycle rather than the day/night cycle, so they will also feed at night depending on how successful their foraging day has been. That is, if they haven’t eaten enough during daylight hours, they’ll continue looking for food when it starts getting dark.
Some of our coastal birds are more successful at night-time feeding than others. For example waders that rely on senses like hearing, smell, and touch, rather than just sight, have a clear edge when it comes to finding food in the dark. Birds with sensitive long bills, like the curlews, are at an advantage for night-time feeding because they can hunt by picking up vibrations in the mud.
A long-billed curlew feeding at night.
Others are specially adapted for seeing in low light.
Grey plovers, for example, have larger eyes in relation to their heads compared with other wading birds, and this is thought to aid low light vision.
But not all wading birds are successful at night. Research has shown that knots at night eat as little as a quarter of the amount compared with the same period of feeding during daylight.
A grey plover with its large eyes
Chillier temperatures
The next most obvious change to winter is the drop in temperature.
Colder days mean more energy is needed to keep warm, and many of our coastal birds will feel the full brunt of nature out on the open coast and seas. So, how exactly do they survive?
Just like humans, birds shiver to keep warm. They fluff up an insulating layer of feathers, which traps pockets of air, to retain body heat.
Sanderlings puff up their feathers to keep warm.
Birds also use a clever circulation system to stop their legs and feet getting too cold. The arteries that carry warm blood from their heart pass right next to the veins carrying cooler blood from their legs, heating them up. ⠀⠀ ⠀⠀
You might notice birds often stand on one leg and tuck their heads into their plumage while resting, and this again is another tactic to reduce heat loss. The beak tucked away allows the bird to breath in warm air trapped in its feathers, almost like breathing into a blanket.
A resting redshank stands on one leg and tucks its bill into its cosy feathers to keep warm.
Storm damage
What effect do storms have on migratory birds? In November 2024, Storm Bert left a trail of destruction with heavy rains and strong winds in along the Solent coastline. For any migratory bird flying from the Arctic circle, and especially for young ones, storms like these can throw their navigation completely off course.
Migratory birds typically rely on a tailwind when travelling down to the UK for the winter, as it’s more energy-efficient and can help them reach higher altitudes.
For small species, such as dunlins weighing only around 50g, flying into a headwind would be disastrous. They may end up on the wrong route completely.
A dunlin, weighing only around 50g migrates, extraordinary distances to get to our coastline.
Quite often in these conditions, birds’ migration routes will be completely changed, which is why sometimes we get some unusual species in the UK.
Some birds will delay their migrations completely if the weather is particularly bad.
Once they’ve migrated for the winter, the storms provide additional challenges by pushing the tide higher up the beach for longer periods of time, reducing the amount of foraging available to feed in a day.
Whether they feed at day or night, in storms or bright blue sky, it is important we give our coastal birds the space they need to feed and rest without being disturbed. That way, we can give them the best chance to thrive this winter.
