Swifts diary

The colony of swifts that nests in the Museum tower has been the subject of a research study since May 1947. It is one of the longest continuous studies of a single bird species in the world, and has contributed much to our knowledge of the swift.


6 May 2024

They're back! The first swift was seen flying past the tower on 30th April and the next day several were back for May Day morning with the warm southerly breeze. Our first survey on 6th May revealed that these first arrivals weren't wasting time, with several nestboxes showing signs of occupancy. One adult pair was on the nest and another single adult had obligingly occupied one of our boxes with a camera that streams live to our website.

13 May 2024

The warm weather of the last week has seen swifts returning in larger numbers and screaming parties of up to 14 birds have been whizzing past the tower and filling the skies overhead with their cries. More boxes are showing signs that they have been visited and another pair and another two single birds were observed on their nests. Last week's pair have been busy and we have our first egg!

20 May 2024

As the weather warms, more swifts are arriving. We now have 31 nestboxes showing signs of activity inside while screaming parties of up to 14 birds at a time whizz excitedly past the tower outside. This morning's cool weather saw 17 adult pairs snuggled together on the nest as well as 6 lone adults, some of whom sat hunched with feathers fluffed; likely incubating their first eggs. There are certainly more than 5 eggs already but there are adult birds sitting on the nests, meaning it is hard to tell exactly how many. We need to be as quiet and careful as possible not to disturb them as we lift the blinds to peek into the nest boxes. At least the birds on our webcam have been generous enough to produce a couple of eggs! As the weather warms, we should have more arrivals occupying more boxes, and perhaps even our first chicks next week!

27 May 2024

Today's survey revealed 35 nests showing signs of occupation and 29 eggs. With some birds sitting tight there are undoubtedly other eggs that are not visible. The wet weather has meant that the start to the season has been slow and some nestboxes that have been occupied for several years remain empty. We can only hope that the tenants are yet to arrive and will be with us in the next two crucial weeks.

One box revealed how ferociously territorial swifts can be over their nest sites. Lifting the blind to look inside we were met with the sight of three dead adults. A pair had obviously taken up residence and been visited by an intruder hoping to nest there itself. The ensuing fight had left at least one dead bird blocking the entrance hole. Unable to leave, or mortally wounded, another bird had perished next to it whilst a third, trapped by the others, was found recently dead at the back of the box. None of the birds were ringed meaning these were most probably first-time breeders staking a claim to their first nest site. These sites are so cherished that the same adults will occupy them faithfully year after year and will fight, sometimes to the death, to claim and defend them.

3 June 2024

This morning we were greeted at the Museum by large screaming parties of over 20 birds. Inside the tower, our survey revealed that we now have 38 active nests, around 60 eggs and our first 3 chicks! There is still time for more birds to arrive over the next week or so and we hope that with the warmer weather and change in wind direction we will see more nesting activity, and hopefully some more chicks, although we still have a way to go to reach last year’s high of 57 nesting attempts.

10 June 2024

A brisk, cold north wind was blowing today and the swifts were sitting tight over eggs and young with very little activity outside the tower. With the adults hunkered down on their nests, counting eggs and young proved difficult with some young only making themselves known by their whickering calls but we now have 42 active nests and over 31 chicks. Some of these had only hatched within hours but last week's hatchlings are already in pin, showing the very beginnings of their first coat of downy feathers. As well as the young we also have over 26 eggs still to hatch. We must hope that the weather improves over the next week or so, so that their insect food becomes more readily available.

17 June 2024

After a cold and windy week, the swifts are doing pretty well and we now have 53 young ranging from tiny and very recently hatched, naked, blind chicks to those that hatched last week and now have their eyes open and are covered in downy feathers and growing fast. Looking at them it is hard to believe that only a week ago they were as small as some of their neighbours and good to see that their parents are obviously managing to catch enough insects to feed them during such disappointing weather. There are also over 15 eggs still to hatch.


The average numbers of young swifts ringed each year over the last 50 years are:


1963–72: 36.7


1973–82: 70.4


1983–92: 100.0


1993–2002: 99.2


2003–12: 81.1