Now that spring is in the air, the UK is starting to see its summer visitors arrive. Ospreys are back in their nests, warblers sing their song to reestablish their territories, and puffins have reached their roosts in the British Isles.
Several centuries ago, people believed that swallows spent the winter sleeping at the bottom of ponds and lakes, or even on the Moon, but of course that was complete nonsense.
We now know that animals migrate to increase their survival and that of their young. It also helps in their quest to find food, mate or avoid predators.
Although we tend to think of migration as birds flying from one country to another, there are actually many animals that migrate. Wildebeest, for example, make a circular migration, roaming the African plains in large numbers during the dry season in search of fresh grass. And humpback whales migrate to warmer waters to raise their young.
However, it is the birds that break records when it comes to travel.
The hummingbird has the longest non-stop migration on record, with one individual spending almost ten days traveling from Alaska to New Zealand without a break, it’s a whopping journey of around 12,200 km (7,580 miles).
But the arctic tern is the true champion, making a 35,000 km (22,000 mile) round trip from the Arctic to Antarctica and back each year. This huge migration means that it lives in a constant summer, experiencing more daylight than any other animal, as it stops in countries like Mauritania, Ghana and South Africa, during its global journey.
How the birds find their way
Migration is an expensive business: birds need to carry enough fat reserves to power their flight and sustain themselves for the duration of their journey. Getting lost could have disastrous consequences, which is why birds have developed incredible navigation skills to fly the shortest and safest routes.
Some species have an innate and inherited ability to migrate, allowing them to move to areas independently to enhance their survival.
The cuckoo, for example, is not raised by its parents as mother cuckoos lay their eggs in nests belonging to birds of an entirely different species. However, a young cuckoo is capable of traveling alone, from Europe to Africa, and back, using a legacy “internal GPS”.
But some species, such as the Caspian tern, which makes a long-distance migration from its breeding home in northern Europe to its wintering grounds in Africa, have very little hereditary basis for their migratory habits. In most cases, they are taught by their parents, also known as “cultural heritage” or social learning.
A recent study, for example, found that young Caspians appear to learn their migratory route from their father, who has primary responsibility for migrating with their young. Along the journey, he also shows them suitable stopover places to refuel with fish and crustaceans.
But, whether genetically or socially inherited, birds use a variety of natural cues, such as the shape of coastlines or the position of the Sun or stars, or olfactory cues such as the scent of their nest, to help them navigate. the environment. balloon.
Read more: Birds use massive magnetic maps to migrate, and some could cover the entire world
Some birds, like carrier pigeons, even use a magnetic map to align with Earth’s magnetic field as they travel.
UK summer visitors
Our understanding of bird migration has increased dramatically since the development of biologgers, small data-logging devices that are attached to birds. These allow us to track an individual’s location, speed, stopover sites and timing of their migration.
One such study is the cuckoo tracking project. This has revealed that several cuckoos left central Africa in early 2022, each traveling separately for hundreds of kilometers before stopping for a couple of weeks in countries such as the Ivory Coast and Morocco. They then continued on to the next leg of their journey, and the northernmost bird had reached France around April 10. These migratory cuckoos are expected to return to their UK breeding grounds very soon.
And they are not alone. Many birds make long-distance migrations to the UK for the summer breeding season. For example, the wheatear also winters in Central Africa, but returns to the UK much earlier, from late February to mid-August, while the hobbyist, a predator of dragonflies, winters in South Africa and is in the UK. Kingdom from the end of April to October. .
This allows them to take advantage of the longer hours of daylight and the abundance of food, such as insects, during the summer months in the UK.
Read more: Garden bird feeders are increasing blue tit numbers, but leaving other species hungry
If you want to help birds during their breeding season, and at the same time help other more permanent resident birds, such as chickadees and sparrows, here are some ideas.
Feeding the birds nuts, seeds, and household scraps such as cakes, fruit, or cheese will help provide easily accessible food.
But some species, like house martins and swallows, rely on insects. So you can improve the biodiversity in your garden by creating a wildflower meadow or by taking part in No Mow May, an initiative by UK conservation charity Plantlife, which asks everyone to “lock up your lawnmowers” and let the grass grow. vegetation during the month of May. It will also be very beneficial.
Don’t forget that birds need water too, for drinking and bathing, so a small birdbath or wildlife pond is ideal. You can also put up nest boxes to provide even more resources for our returning birds, an excellent substitute for the lack of natural nesting sites to raise young, especially in urban areas.
Waking up to the song of birds, courtesy of our summer visitors, including willows and nightingales, fills many of us with joy. Let’s not forget the epic journey they have made to reach our shores, and let’s do everything we can to ensure a successful breeding season.