The Common Swift and Nest Boxes – 2025 update
Last year we wrote about the extraordinary lives of Swifts and our attempts to attract them to nest under the eves of our house: https://woodcockwood.com/part-2-nest-boxes-and-the-attraction-of-swifts/. And there’s no doubting the danger that this interest in Swifts can quickly grow into passion verging on obsession, and so beware!
The Importance of the Swift Caller and Its Position
Swifts are communal nesters. Young Swifts looking for a place to nest are drawn to existing small colonies, and an essential component of attracting Swifts to a new site is a swift caller that mimics the defensive nesting call of the adult Swift.
For the last two years our caller was a large tannoy speaker on a window sill close to, and adjacent to the boxes. This seemed to be effective in attracting Swifts to the area close to the boxes, but not directly to the box itself.
We frequently saw the Swifts flying at great speed past the boxes, but we didn’t once witness a Swift go to a box. We often wondered, at that speed, would they even notice the box entrance.
Early this year we put up a fourth box, this one containing a camera and small speaker so that the swift call also comes from inside the box. And this year we finally had Swifts showing real interest in the box.
Camera and speaker in place in new box. Cables run internally, but are concealed when lid is in place to ensure the Swifts can’t nibble and interfere with them. They may have small beaks, but they are powerful – see video.
Partial Success in 2025
A pair of Swifts and at least two different individual Swifts entered the box over a period of two weeks. The only box we saw them entering was the new box with the caller, even though the entrance to box number 1 was only a few centimetres from that of the new box.
Comparison of Observations – 2024 and 2025
Overall it seemed that in our part of Hastings and St Leonards we saw fewer Swifts this year than in 2024 – we saw them less frequently, and the size of the groups was smaller.
The largest group we saw this year was five birds, and that number was infrequent. In 2024 we once saw a group that we estimated to number about 30 birds, and on another occasion we saw a group of around 20.
During May and July, in both years, the normal view was of groups of two or three flying high, and obviously feeding.
The most intensive period of activity around our house and close to the boxes was mid June.
On the 17th June 2024 we first observed a small group of birds calling loudly and flying at roof level past the boxes, between our house and the house next door. This began around 9.00 am and continued until past 11.00, and was repeated in the evening from 5.00 pm until dusk. We saw a similar pattern on the 26th June.
Although in 2025 we saw less overall Swift activity, it was the year that Swifts explored the box.
On the 16th June a group of four Swifts were flying low past the box, and we saw one approaching the box and partially entering.
This behaviour continued during the 17th, and on the 18th it went into the box. It spent the day in and out, shuffling around and settling on the nest pad, finally leaving at dusk.
On the 19th at 7.30 am, one Swift arrived, and was soon followed by a second.
On the 20th they were both in the box by 6.40 am. They were in and out briefly during the first part of the morning, and spent the rest of the day away, presumably feeding. They returned at 7.30 pm and left at 10.30 pm when it was totally dark.
They continued this type of behaviour until the 23rd, when both Swifts returned to the box at 9.00 pm and stayed throughout the night. They left at 8.15 am, reappeared briefly at 9.00 pm that night, and that was the last we saw of the pair.
On the 26th, the 29th of June, and the 2nd of July we saw a number of short appearances of individual Swifts in the box. Each stay was short. The birds didn’t settle long on the nest pad, as the pair had done.
It was interesting that we didn’t see them clinging to the entrance of the box. They entered quickly and departed.
From then on, we had few close views of Swifts.
How We Interprete the 2025 Observations
There is an expected pattern to Swift behaviour, as we see it in the UK. The established breeders will arrive late April. They are nest site faithful, and a pair will return to the nest site that they used in the previous year. Young will be reared and they will begin to depart for southern Africa in August.
Younger birds will arrive towards the end of May. Those in their second and third years will be looking for vacant sites in existing colonies. The older the bird, the stronger the urge to find a nest.
A bird will find a suitable place, encourage a mate to join, and they will adopt this site, guard it against intruders, and perhaps begin to build a nest. The following year they will arrive early, and breed for the first time.
In reality, of course, life is a lot more complicated than that, and there is often considerable variation in these behaviour patterns.
For instance, Jonathon Pomroy has studied Swifts over many years, and his detailed observations offer a fascinating insight into life in Swift colonies. https://jonathanpomroy.wordpress.com/.
Jonathan describes how first year breeding pairs often breed late and their young can fledge well into September, when we would expect all of the UK’s Swifts to have long departed south. He talks of the consequences to the colony when one of an established pair fails to return. The other may succeed in attracting a new mate, or may well go off to join a partner in another colony. Colonies expand and contract in size accordingly.
It is complicated, and we offer our observation as a small contribution to the overall understanding of Swift dynamics.
Our Pair Of Swifts
The Swifts that entered the box on the 19th were clearly an established pair. They always entered and left the box together. Their behaviour in the box seemed intimate – shot taken from video: https://youtu.be/TWgxndwJ-48.
Whether the first swift to enter the box was a male or female is not clear. It seems either could have been the one to explore it first.
After several days we were convinced the pair had adopted the box, and that they would occupy it until the end of July, when they would prepare for their migration south. A final stage in their adoption process might have been that they would construct a nest in readiness for breeding in 2026. Their sudden departure was a surprise.
Whether “our” box was the first box that they tried we obviously don’t know. Nor do we know if they will return in early May next year to nest. We now have to wait 10 months to find out!
From differences in behaviour, we believe there were at least two single birds that made brief visits to the box following their departure. We had five short sightings in all.
These birds were definitely unmated birds that seemed to be trying out boxes. What might have happened is that one of these birds could have decided to stay. It would then have spent time trying to encourage a mate to also enter the box. According to Jonathan, this process can be quick, or can take up to a month.
How a single bird behaves to encourage a mate is unclear to us.
May 2026 now seems a long time to wait!
See the following for a wider description of Swift behaviour, and our 2023/4 experience of attracting them to nest:
Local Swift Conservation Groups
The are many dedicated Swift groups across the UK. Our local group has more than 600 members, and does an enormous amount to promote awareness and effective conservation measures: https://e-voice.org.uk/hastingsandrotherswifts/