Imagine if the increasing daylight hours after the winter solstice meant that every year you must start preparing for a trek of thousands of miles all the way to the Arctic Circle. As the days grow longer, you eat double portions of food to create fat reserves to keep you sustained. Additionally, you have to sleep as much as possible to keep your energy levels up for the gruelling journey. Then, at the end of February/ beginning of March, you start feeling like something is tugging at you. The days are much longer and warmer too. There is a change in the air. You feel it, and your family and neighbours feel it too. Your whole world feels it. You all know it’s time to go, but have you got enough body fuel saved up to survive?
That’s the gamble you’d have to make. It’s a big risk, because some of you will not make it.
Can you imagine doing this every spring, to then make the same journey back, after a summer spent raising your offspring in faraway lands with no night-time? If you can, then you know what it’s like to be a brent goose, knot, dunlin or any of our migratory shore birds.
The East Atlantic Flyway
Britain’s East Coast lies almost at the exact midpoint of the East Atlantic Flyway, one of the eight global migratory routes connecting the north and south poles. The East Atlantic travellers move between Russia/Northern Europe and Africa, with some, like Arctic terns, flying all the way to Antarctica for the winter. That way, they utilise the almost 24 hour light on both poles.
Millions of migratory birds use our coast to stop over rest, and refuel. Ospreys, cranes, divers as well as thousands of waders and wildfowl spend days or sometimes weeks on the vast flats and tributaries of the Wadden Sea, the Wash and the Essex and Kent coastlines before they continue on their strenuous and dangerous journeys. Additionally, roughly a million birds stop here and spend the entire winter around our large mud flats, saltmarshes and nature reserves. Essex provides the wintering grounds for a quarter of the global population of dark bellied brent geese and for significant numbers of dunlins, black tailed godwits, curlews and many others. Out of the 12,000 black tailed godwits in the UK, 3,000 use the tidal Stour alone! The Blackwater Estuary supports almost 20,000 dunlins and the Colne’s marshlands host nationally important numbers of curlews.
For these reasons, most of our coast is covered by Special Protection Areas (SPAs) for wetland birds, and the East Atlantic Flyway is currently nominated to become part of UNESCO’s World Heritage Sites. This would be a wonderful boost, not only for migrating birds, but also for our coastal communities.
It’s All About the Energy
With all these wonders comes responsibility. Surviving cold winters on the windswept North Sea coastline, just to travel enormous distances in spring, is no mean feat. Especially when the Arctic ground can still be frozen when birds arrive meaning their next meal isn’t waiting for them. Some birds, like the dark bellied brent geese, often have eggs forming in their bodies already while setting off. While coastal birds have marvellous physical adaptations, they also have to work hard to boost their ability to make these adaptations work. It’s all about energy budgeting. Many birds need to put on 50% of their body weight before they begin their journey. Some super athletes like bar tailed godwits double their entire body weight.
Every time birds are flushed out while feeding or roosting, the estimated energy loss resulting from flying around and searching for a safe space or waiting for the perceived danger to end, is 15% (more in roosting birds according to some research).
We’re talking about a single disturbance here. So, after only 6 separate instances, the birds would need to start refuelling all over again or risk not surviving the upcoming journey, or not being fit enough to have offspring that year. This doesn’t even account for the invisible physical damage done by repeated stress (something we can all relate to!). So it’s important to remember the snowball effect of repeated disturbances. This is something that’s frequently forgotten as people don’t understand that a disturbance event they may cause is but one of many to occur to birds during a single day.
Thankfully, just a tiny tweak in our everyday behaviour can significantly increase the birds’ chance of success. All it takes is awareness of your surroundings to avoid flushing events as much as possible.
There are three easy ways to do this:
- Staying on paths and keeping dogs on leads or very close to you
- Avoiding wetland edges and saltmarsh creeks while on water
- Following the coastal code and restrictions while flying drones and aircraft over wetlands and nature reserves
– Lea