Saturday 9th May 2020 is World Migratory Bird Day. There seems to be a day for everything now, but these birds deserve recognition for their incredible annual journeys.
There are thousands of species of bird that migrate with changing seasons around the world. In the UK this sees many species of birds arriving here to begin breeding in the spring. Most of these birds have travelled North from wintering grounds in the Southern Hemisphere. Many travel from Africa, but some travel even further.
If you are in your garden or a local green space during the lockdown, you can see several species that have made the long journey back from wintering in Africa. Chiffchaffs and other warblers are some of the earliest arrivals, making landfall on the South Coast around March and April (though some Chiffchaffs are staying all year round with the warming climate). These are soon joined by other small birds such as whitethroats and flycatchers. They have travelled from the Mediterranean and Western Africa where they’ve spent the winter months, and have returned as our insect population wakes from their winter hibernation. They time this arrival in order to reproduce themselves, so their newborn chicks have enough food to eat. This also lets them avoid competition and predation from animals that stay resident in the tropics year-round, as there are far fewer resident species in the Northern Hemisphere.
Late spring sees the arrival of some of the great migratory species. The swallows are some of the first to arrive in April, having spent six weeks flying up from as far away as Namibia and South Africa. They set about building nests in order to hatch a first brood of eggs in early July. This gives them the chance to raise a second, and sometimes even a third brood before the autumn migration south. By raising several broods they increase the chance that some of their chicks will survive through to the following spring to have chicks themselves.
Swifts are another popular summer migrant to the UK and like swallows can travel from as far as South Africa. However, even if they only travel up from and back to Western Africa, their time on the wing is arguably more impressive than that of the swallow. Whilst swallows roost en route and when they arrive at their destination, the swifts never land for the entire round trip to and from Africa! A healthy swift will not land until they are ready to lay eggs. They will eat, drink, mate and even sleep on the wing.
Other birds migrate in order to follow these birds. Some to hunt them and some for more nefarious reasons. The common cuckoo, for example, migrates north following the small warblers and flycatchers. They stop off on the way to rest and feed, and arrive during the nesting period for these little birds. They will then lay their eggs in one of several species of small birds nest (some, such as the dunnock are non-migratory residents). Adult cuckoos play no part in rearing their chicks, so once they are satisfied their chick is safe, they head south earlier than any other migrants, most having left by June.
The hobby migrates up from Africa following their prey – the swifts and martins. These small falcons look like oversized swifts in flight. They arrive shortly after swifts do and breed in Europe and the UK while their prey are here. When their prey head back south again the hobby’s follow.
These long migrations are all impressive, but none compare to that of the Arctic tern. These small birds – about as long as a pigeon, but far more streamlined – travel from the Antarctic where they spend the European winter all the way up to the Arctic to nest during our summer. Some birds don’t head all the way up to the Arctic and nest in Scotland and Ireland. Those birds that nest in the Arctic circle hold the world record for the longest animal migration on the planet – and they fly it every year!
Unfortunately, as with most elements of the natural world, these birds are threatened by human activity. Industrial farming and loss of important insect habitats, such as wetlands, has resulted in a devastating drop in insect numbers. This means many birds starve on their journeys. They even face a huge direct onslaught by humans in many Mediterranean countries. Cyprus, Egypt, Lebanon and Syria account for a large number of migratory bird deaths, but the worst offender is Malta where there is uncontrolled shooting of birds during the annual migrations. Even if you don’t respect the incredible journeys these birds make, or appreciate their aesthetic presence in our environment, these birds need to be preserved and protected for their importance to the environmental health of the planet.
So we hope you agree World Migratory Bird Day is a day worth celebrating!
Lee Ismail, Curator of Natural Sciences