The sight and sound of swifts in the sky means summer has arrived! by Catherine Day

  • The sight and sound of swifts in the sky means summer has arrived!

    Swifts are here for only three months of the year, from early May to late July, making them the last of our summer migrant bird species to arrive, and the first to leave. They come here to breed after spending nine months on migration in central and southern Africa.

    Swifts score top marks in the bird world for many of their other characteristics:
    • They are the world’s most aerial birds: they spend all their lives in the air, touching down only to breed at their nest sites high up in buildings.
    • They are the world’s fastest bird in level flight – in other words, in powered forward flight – with a top speed so far recorded of 69.57 miles per hour. (This is in contrast to other famously fast birds such as the peregrine, which achieves its astonishing speeds aided by gravity in a downward ‘stoop’ or dive). 
    • Swifts have the longest wing-to-body-length ratio of any bird. This gives them their incredible aerodynamic performance.
    • Swifts eat, drink and sleep on the wing, and can even mate in the air.
    • Swiftlets do ‘wing press-ups’ in the nest to strengthen their wing muscles before they fledge. When they take off for the first time, they will not touch down again for at least two years.
    • Swifts are the UK’s most nest-site faithful bird. They return to the same nesting place year after year for life.
    • Swifts are the most building-dependent bird in the UK: they rely on our buildings for nesting places.

    How to tell a swift from a swallow, house martin, or sand martin

    Swifts are unrelated to swallows or martins (hirundines). They are distantly related to hummingbirds.
    Swifts are not perching birds (passerines), so you will never see a swift perched on a telephone wire, or a tree, or anywhere else!
    Swift are all dark brown (apart from a small pale patch under their chins), whereas swallows and martins have large white or buff areas of plumage. NB: because you often see swifts silhouetted against a bright sky, they will often appear all black.
    Swift have very much longer, narrow wings that are swept back to form a characteristic crescent scythe or sickle shape.
    Swifts do not build visible mud nests. They make minimalist little saucer-shaped nests of feathers completely hidden away, high up in gaps under roof tiles and eaves.
    Swifts do not twitter like swallows and martins. They have a high-pitched, excited ‘scream’ as they glide and swoop high in the sky, hunting flying insects and tiny floating spiders, or when they gather in groups for thrilling, roof-skimming aerobatic displays, especially in the evening or early morning during warm, sunny, summer weather.

    Swifts are now Amber Listed as a Bird of Conservation Concern in the UK

    The species of swift we have in the UK is the Common Swift (Apus apus). However, now, sadly, it is not so common as we have lost over half our swifts in just the last 20 years, (in fact, their population declined by 57% between 1995 and 2016). A very big factor is loss of nest sites. 
    Renovation and re-roofing of older houses and the demolition or conversion of old buildings mean that traditional nest sites are destroyed. Also, modern building materials, methods and regulations used in new developments mean that there are no crannies, openings or traditional open eaves in new buildings for swifts to make their homes in. Swifts are being made homeless!

    How you can help swifts 

    • Protect existing swift nest places.
    • Put up swift nest boxes at home, school, work, or on community buildings.
    • Incorporate a few swift nest bricks when doing building work.
    • Buy a swift nesting box.
    There are now many types of swift nest boxes and nest bricks available in a range of different materials to suit all budgets, and to suit all styles of building! 
    • Make your own:
    There are lots of DIY swifts nest-box patterns and ideas available on the websites below.

    Where are our Marlow swifts at the moment?

    They will be in the later stages of their 7,000-mile journey home from Central Africa. Our UK swifts mostly take the ‘western route’ from Africa over the Strait of Gibraltar and up through Spain and France. It looks as if quite a few are arriving early this year, with a scattering of sightings of one or two from various parts of the UK at the weekend (25th/26th April).
    Excitingly, we spotted three over Marlow town centre on Saturday (25th April - see photo) and again on Sunday (26th April). Summer has definitely arrived! However, apart from these very ‘early birds’, the majority of our Marlow swifts will arrive home during May. Keep your ears open, as you are likely to hear them first, and then look up to see if you can spot them high in the sky! Visit the website xeno-canto below to hear a selection of swift calls.

    Find out more about swifts:

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