Looking out for swifts

Swifts are a joyful icon of summertime with their aerial acrobatics in the sunshine. On Nature’s Calendar you can record your first spring sighting and your last glimpse at the end of summer, here’s more detail on what you need to know for successful recording.

Identification

Swifts are generally seen in the sky as they hunt for insects. From this viewpoint the distinctive features are the dark underside and the long, scythe shaped wings. Their flight is characterised by fast, frantic wingbeats followed by long genteel gliding.

When you’re recording for Nature’s Calendar, it is important to know the difference between swifts, swallows and house martins. Check out our recording page for some photo comparison.

Recording to detect change

All the species you can record on Nature’s Calendar have been chosen to help us study the effects climate change. Swifts are a suitable species as they are found in urban and rural settings and can be easily recognised. We have a lot of records dating back to 1907, it is useful to collect modern data for comparison.

Swifts used to be common.  Sadly they are in decline due to lack of insects, lack of nesting sites and climate change. They are on the Amber list of the Birds of Conservation Concern due to their global decline and the decrease in the breeding (25-50% loss over a 25 year period) in the UK. The number of swift records we receive has been steadily dropping over the last 10 years.

When do swifts arrive in the UK?

From the start of April our recorders regularly check the UK’s skies for the arrival of the first swifts after their 6000 mile flight from the south Sahara. Most are first spotted around the end of April or the beginning of May.

The best time of day to look out for them is early morning or dusk. They hunt for insects high above the ground. You are more likely to see them around their preferred nest sites of rooftops, ventilation shafts or church towers.

Swifts are monogamous meaning they pair for life with their breeding partner. They are also loyal to nest sites which they return to for up to 15 years. Swifts produce one brood of two or three eggs each spring, which they lay two or three days apart. This ensures successful fledging of at least one chick as it spreads out the demand for food and allows for insect fluctuations.

The spring arrival date tends to be quite predictable compared to the late summer departure.

Record first swift seen

When do swifts leave the UK?

The presence of swifts is often most obvious in July and August when the newly fledged young join the adults in swooping flight and screeching calls. The chicks only fly the nest once they are up to the minimum weight for the migration, they and their parents then return to Africa after only a couple of days of flying practice. Their departure date depends on the success of breeding. If there are lots of insects and the chicks have fattened up quickly they leave earlier. They also leave early if their breeding attempt is unsuccessful. If the summer is damp and cool there are fewer insects and it takes longer to feed up the chicks to the ideal weight for fledging and they leave later.

How to record swift last seen

Keep watching the sky from mid-July onwards. Make a note of the date each time you see a swift until you no longer see one. The last date you saw a swift is the date to record with us, they normally leave by the end of September. This data is really valuable to us.

Record last swift seen

Start swift watching

Keep an eye on the summer swifts near you and help us study them by recording the first and last one you see in your area. The more we know about swifts across the UK the more we will be able to help implement effective conservation strategies.

Swift desktop calendar

Download your free swift (last seen) calendar to remind you what to look out for this month.