These hardy travellers arrive from the end of March, a few weeks after the first sand martins have appeared above our river Ouse.

Swallows are joined, in turn, by the handsome black and white-rumped house martins, a familiar sight around housing estates, where their intricate mud nests are a constant source of interest for householders.

Last to come, slipping in unseen towards the end of April are the larger swifts. These aerial masters, with thin, sickle-shaped wings power over wetlands scooping up clouds of small insects until the weather warms sufficiently for them to think about nesting. Only then will they appear in the skies above our homes. By early summer, parties of swifts scream around the rooftops, a quintessential part of the English summer soundscape.

A remarkable journey

Swifts are incredible birds. What we might think of as ‘our’ swifts actually spend nine months of the year touring Africa, so really they are our guests for just a short part of the year. Crossing Europe rapidly, they head south over the mighty wastes of the Sahara into West Africa, before turning into the rising sun, winging their way to the southeast coast of Mozambique. By the turn of the year, they continue their odyssey, travelling back into West Africa. They make their way north in spring, arriving back here by May.

Fewer and fewer swifts return each year

The arrival of swifts and swallows each year is warmly anticipated but it is with some anxiety as populations of these fantastic birds are declining rapidly. House martins and swifts both are birds of conservation concern throughout Britain and Europe.

Traditionally, house martins built their cup-shaped mud nests on vertical rock faces, including sea cliffs. Yorkshire Wildlife Trust’s Flamborough Cliffs for example hosts a few pairs each year. Swifts would have used large cavities and holes in old trees.

Our buildings offer these birds great alternative places to build nests which has brought them into close contact with people. Unfortunately, many new buildings have no eaves under which house martins can build their nests and changes to roof tiles and facias means that swifts can no longer access holes in which to nest.

House martins and swifts catch tiny insects on the wing but over the last few decades, there has been a collapse in the number of insects thought to be linked to the amount of chemicals being used across our countryside and even our gardens. Fewer insects make it harder for adults to regain good condition for breeding following their arduous migration and to feed growing young. The loss of nesting sites and food are the reasons these once familiar birds are disappearing from our skies.

How you can help

But it is not too late. The Wildlife Trusts and Royal Horticultural Society have launched their annual Wild About Gardens campaign, ‘Act Swiftly!’ which this year is focussing on helping these much-loved birds. There are many simple things you can do.

• Refrain from using chemicals, especially pesticides in your garden. This will reduce the amount of insect-killing pollution in the environment and will be better for you, too.
   
• Plant some insect-attracting flowers, or even better, build a pond. A muddy edge around the pond is a source of nest building material for both house martins and swallows.
   
• Install nest boxes for house martins, swallows and swifts. In areas where they still occur, they can rapidly move in to your new ‘des res’.
   
• Support a local swift action group. In York, a volunteer led group York Swifts is working to raise awareness of the plight of these birds and taking direct action to help them. Last year, it built and installed 20 new swift nest boxes around York and is currently building lots more to put up this spring. Find more on Twitter.

If we all act swiftly, we can improve the fortunes of these lovely birds and continue to welcome them back to our skies every spring. Find out more about how to help these wonderful birds,