Apus apus (Common swift) - Diary 2021

My notes on the activity of swifts at my house in 2021...

See the main page for notes, photos, and diaries for other years.

You can view live video here from some of the nestboxes (not guaranteed always online, but I try to keep it running).
Now offline for 2021 season as the birds have left.
Here is a page with some explanation of how I do the video.

2021 Swift diary...

The numbered nestboxes can be seen on this photo, and the entrances to the internal boxes on the gable end in this photo.

Activity in inspected boxes 2021 (prediction in red italic; '≤' 'less-than-or-equal' or '≥' 'greater-than-or-equal' date could be earlier/later). See all years here.
2021#1May-7May-11≤Jun-17Jun-19Jun-21Jul-14Aug-26Aug-26-Pair overnight May-19, but only settled Jun-10. One egg didn't hatch.
2021#4May-9May-12Jun-5xEgg 1 broken Jun-6.
2021#4a≤Jun-10≤Jun-10Jun-17Jun-19-Jul-7Aug-17Aug-18-Re-lay by same or different birds, first settled Jun-10.
2021#g1??Jun-1/2Jun-4?≤Jun-23Aug-1/2Aug-4/5xSmall chick dead Jul-4.
2021#sb2≤May-8≤May-23May-31Jun-2-≤Jun-25Aug-1/2--1 broken egg removed Jun-2.
2021#sb4≤Jun-15≤Jun-15Jun-28/29?-Jul-21Aug-27/30--1 egg broken Jul-18.

Predicted dates above based on the average for previous nests with camera: last egg to hatching 19 days; hatching to first fledging 42 days.

2021-Sep-5 The final young swift of the season, from nestbox #sb1, fledged at 09:42 today. An adult swift had returned to the nest around 20 minutes earlier, and left a few minutes after the fledgeling. The outside camera captured them leaving - I think the fledgeling was the first to leave, as it spent some minutes looking out of the hole first, and maybe had the typical 'flappy' flight, but that was more difficult to say. The adult swift returned briefly around 40 minutes later, but didn't come back at night.

2021-Sep-1 I think just a single adult swift is visiting nestbox #sb1, presumably feeding the single chick. It made several typical short 'feeding visits' today, and has been coming in for the night. I've got a camera watching the nestbox from the outside, and it seems to be detecting in/out activity reliably.

2021-Aug-30 The single swift chick in 'starling' nestbox #sb4 has fledged, sometime in the last 3 days, which just leaves the single chick in #sb1 which is predicted to have another 9 days before fledging.

2021-Aug-27 The single adult swift in nestbox #1 left at 06:19. We'll see whether it returns tonight, even though the young have now gone. [Later: no adult swifts returned after this morning.]

The single swift chick in 'starling' nestbox #sb3 has fledged - nest empty by this afternoon. I hadn't looked for a few days, and I'd predicted it would fledge 'tomorrow or earlier', but didn't have an accurate time for when the egg hatched.

2021-Aug-26 The two swift chicks in camera nest #1 are still there (my predicted fledging day was yesterday). Last night, there was only one adult swift present for the first time. The adult left at 07:42 and didn't return during the day until 19:40. then going out again briefly from 19:55 to 20:06. Will the young ones go at the usual 'favourite' time just as it gets dark? I've got two outside cameras watching - one aimed at the nestbox, and one aimed away in the direction of flight, so I'm hoping to capture video when the chicks eventually fledge.

Later: The two young swifts fledged from #1 in quick succession at 20:26 and 20:28, leaving just the single adult spending the night. The outside cameras recorded video of the young ones leaving, despite it being nearly dark.

So just 3 swift chicks left in the colony for this year - a single chick in each of 3 'starling' boxes.

2021-Aug-24 The second and last swift chick in nestbox #g5 has fledged. The two in #g5 were very close to the same age as those in camera nest #1, which are still there. I'll be watching #1 closely this evening, and with the outside camera, though predicted fledging date is tomorrow.

2021-Aug-23 One of the two swift chicks in nestbox #g5 has fledged. I hadn't checked for a few days, as it's still 2 days until the day I predicted fledging. The remaining 6 chicks in the colony are developing as expected.

2021-Aug-18 The second and last swift chick in camera-nest #4a fledged at 20:43 - like its sibling yesterday leaving just as it got dark. The (by now) single adult swift at the nest had returned for the night at 20:17 - I'm used to typical swift behaviour by now, but it still seems strange that the adult birds return to the nest for the night, but then the fledgling follows its own instinct and leaves. Also how little variation there is from 42 days from hatching to fledging.

2021-Aug-17 The two swift chicks in camera-nest #4a are predicted to fledge tomorrow. I think there has only been a single parent bird visiting and staying overnight for the last two days - not a problem at this stage, when the chicks don't eat much, and lose weight to reach their 'flying-weight'.

Later: One of the two swift chicks in #4a fledged at 20:48, and was recorded by the outside camera. By that time, it was dark, but probably the most common time for young ones to leave.

2021-Aug-10 The second and last swift chick in nest #g2 has fledged.

2021-Aug-9 The first of the two swift chicks in nest #g2 has fledged. All other chicks are 'as expected' for their age - that's the remaining one in #g2; two in #g5; two each in the camera nests #1 and #4a; and one in each of three 'starling' boxes #sb1 #sb3 and #sb4.

Swift chicks in gable nestbox #g5
Here are the two swift chicks in gable nestbox #g5 on 9th August 2021, at 26 days old. As mentioned with the last photo of these, 6 days ago, they're no longer 'downy', and looking like the finished article, though it will be around another 16 days before they're ready to fledge.

These chicks happen to be exactly the same age as the two in camera-nest #1, so these occasional photos give a clearer idea of the appearance than the lower-resolution video from #1.

2021-Aug-5 The second and last swift chick has left nest #g1, and both chicks have left nest #g4.

2021-Aug-4 The third and last swift chick left nest #5 at 08:02.

2021-Aug-3 The second swift chick in nest #g1 is still there, as is the third chick in #5.

Swift chicks in gable nestbox #g5
Here are the two swift chicks in gable nestbox #g5 on 3rd August 2021, at 20 days old. In terms of nest recording with the British Trust for Ornithology, I describe these chicks as "DO" (downy), and "FM" (feathers medium). Their eyes were open several days ago, so they're not "EY" (eyes just open). I'm thinking that I should put all my photos of swift chicks at various stages in one place for easy comparison - I don't think I've had one close to the 20-day mark before, not long before they lose the 'downy chick' appearance, and start looking like the finished article, even though they don't fledge until around 42 days from hatching.

2021-Aug-2 Checking in the afternoon: The second and last swift chick has fledged from nest #2; the final two of three have fledged from #3; one of three has fledged from #5; the single chick has fledged from #sb2; and one of two has fledged from #g1. Counting up from the 15 inspected nests: 14 chicks have fledged, and 15 still to go.

I have the outside camera watching the outside of nestboxes #3, #4, and #5. At 21:14, after dark, I could see that a swift was on the point of leaving #5, so I went outside to watch - it left with the typical fluttering flight of a fledgling, not losing much height. Adults most often drop much lower, gaining speed, and missing garden-obstacles by the minimum amount possible. I assume this was the second of the three chicks fledging [later: still one chick left the next day, so this was definitely the second].

2021-Aug-1 One of two swift chicks has fledged from nest #2; one of three has fledged from #3; and all three have fledged from #g6. All others expected to fledge soon are still present.

2021-Jul-30 With quite a lot of swift chicks due to fledge over the next few days, I checked all their nestboxes - all the chicks were still present.

2021-Jul-27 Today in #sb1, although there was an adult swift in the way as usual, there is some eggshell/membrane visible, so I can say that the single egg has hatched - that's the last hatching in all the swift nests here this season.

2021-Jul-26 All 3 swift chicks in nest #g3 have fledged - the first of the inspected nests to fledge. I check #sb1 each day, as the single egg is due to hatch - so far there's always an adult swift in the way, and no signs of egg-shell yet.

2021-Jul-23 As of this afternoon, the three swift chicks in #g3, predicted to fledge yesterday, were still there. Of the non-inspectable nests, chicks are audible in soffit-space #w2r, but I think the chicks from #w1r have fledged - no longer droppings on the window ledge. Yesterday, there was an adult swift in the house - it could have entered through a window, but quite likely to be from nest #w1r, where I intended to block access from the nest to the loft space, but haven't got round to it. If a swift enters the loft space, I could imagine it having difficulty finding the way back from the nest - as last year, they probably exit towards the light via the loft-hatch, open because of my frequent inspections of the gable-end boxes. This bird was on an upstairs window ledge, and remained motionless while I picked it up - it remained a while on the open palm of my hand, before flying off from an open window.

2021-Jul-21 Finally able to see into nest #sb1 without an adult swift in the way - as suspected, there is just one egg. In #g5, I was able to see the second chick for the first time - both are similar size (one hatched 7 days ago). The single good egg in #sb4 has hatched, pretty much at the time expected - with no adult swifts present, I was able to take a photo.

Swift chick in 'Starling' nestbox #sb4
Here is the swift chick in 'starling' box #sb4 on 21st July 2021, at less than one day old. A piece of its eggshell/membrane is visible at the bottom. The remaining egg has a hole in it (not visible in the photo), so definitely isn't going to hatch.

Since there is now an accurate count of eggs/chicks in the 15 inspectable nests, I can now add them up: there are 29 chicks developing, and one egg yet to hatch. The two non-inspectable nests, #w1r and #w2r, inside the soffit, both have young swifts - droppings below the nest.

2021-Jul-20 In #sb4, finding no adult swifts present, I checked both eggs as due to hatch around today: the 'good' egg felt heavy compared with the one that has a hole in it (spotted two days ago).

2021-Jul-18 It's just one swift chick in #sb3 - no signs that there was ever more than one egg, but of course can't be certain. In #sb4, one of the two eggs is broken - it could have been broken a while ago, as I might not have noticed yesterday, depending which way up the egg was.

2021-Jul-17 Still no luck counting eggs in #sb1 - both adult swifts in the way. The single chick in #sb2 is looking good. In #sb3, I was surprised to see a tiny chick poking out below an adult swift - I wasn't expecting hatching yet, but perhaps I should have been, as I don't know accurately when the egg(s) were laid, or whether there was more than one. In #sb4, finally able to confirm that the clutch is 2 eggs.

2021-Jul-16 The third egg in nestbox #1 still hasn't hatched. I think the parent swifts have got the idea of feeding the two chicks. I wasn't convinced to start with - they sometimes arrived with nesting material, when I think that food might have been more appropriate, but I don't suppose the chicks need much food when they're so small. The chicks have been left unattended a bit more than I'm used to - nearly 2 hours this afternoon, but it was a hot day - at least it means that I can see them on camera without an adult in the way. After that, I recorded 4 'change-overs' of the adults, with feeding, each about an hour apart.

2021-Jul-15 A second egg has hatched in nestbox #1, with the second chick spotted on camera at 06:13 this morning. So just one egg still left.

2021-Jul-14 The eggs in #g5 appear to have hatched on schedule - I didn't see the chick(s) due to an adult in the way, but I could see some egg-shell fragments in the box that weren't there yesterday.

I didn't notice until evening, when I was surprised to see a chick on video, but at 14:46 one of eggs in nestbox #1 started to hatch. There was only one adult swift present last night and today, so there were periods when it left the nest, and I had a good view. The chick took about an hour to free itself from the egg. At dusk, both the adult swifts returned for the night, so assuming it's been the same one doing most of the work incubating the eggs, hopefully having a chick to feed will persuade the other one to put in more effort! I wonder if the remaining two eggs will hatch - it's already 4 days since I expected hatching - is the delay just natural variation, or due to the inconsistent incubation of this clutch?

2021-Jul-10 I got a view into 'starling' box #sb1 without an adult swift sitting - just the one egg. As this was laid 3 days ago, and eggs are laid in the morning 2 or 3 days apart, then maybe it's going to stay at one. I've stopped trying to see whether there's more than one egg in #sb3 or #sb4, as there's always an adult swift in the way - and when it's at the bottom of a 'starling' box, with nowhere to move sideways, there's no chance of it moving out of the way.

2021-Jul-8 The second of the two eggs in camera nestbox #4 has hatched.

Two days ago, a swift in camera nestbox #1 removed one of the eggs from the nest. The 'intentions' of a swift are unknown, but it was apparently incubating all 3 eggs, when it picked one up from under itself, and 'threw' it towards the far end of the box. This looked like a random act - I feel that the egg could have been any of the three. I decided to replace it. As a rule, nothing ever seems to disturb a swift, but maybe I exceeded some threshold, as the adult swift left and only one at once was seen for the two days since. But this morning, a second swift entered for a while, so we seem to be back 'on track'. I feel it will be a miracle if these 3 eggs come to anything - they've been out of the nest many times, and left not incubated for periods of time. Just another two days until hatching is likely. [Later: one of the eggs hatched on 2021-Jul-14, 4 days 'late', and another the next day.]

2021-Jul-7 The first of the two eggs in camera nestbox #4 has hatched.

Swifts have been entering 'starling' box #sb1 since 26th June 2021 (or before), and today there was a first egg. This means that all 4 starling boxes are now in use by swifts (3 of them for the first time). By this stage of the season, it's unlikely that starlings will be showing much interest in the boxes - they finished their broods a while ago, but if swifts return at the start of the season, there is likely to be competition with nesting starlings. This new nest means that there are now 15 with eggs/young where I know what's going on; 2 more in the soffit that I think have young (#w1r and #w2r); and the two brick-sized boxes where there have been eggs but which don't look likely to succeed this year.

2021-Jul-4 By today, the small swift chick (of 3) in nest #g1 was dead, and not looking any larger than when I saw it alive 5 days ago. I can't say whether it might be that it was displaced out of the nest again; or it wasn't fed enough in competition with the two larger chicks; or whether there was something wrong with it that resulted in it being small.

2021-Jul-2 A warm day, so swifts away from the nests more. First sighting of a single egg in #sb3, but can't say much about when it was laid, or if there might be more to come. A check in the two 'brick-sized' boxes: 2 eggs in #b1 (I replaced one of them in the nest yet again); in #b2, the two eggs (which were often out of the nest) are now gone, but an adult swift was present.

Swift chick in 'Starling' nestbox #sb2
Here is the single swift chick in 'starling' box #sb2 on 2nd July 2021, estimated to be around 9 days old.

2021-Jul-1 Today was the day to expect a second swift egg in 'starling' box #sb4, but an adult swift was on the nest, so I couldn't see. My guess is that there is a second egg. And in 'starling' box #sb3, an adult swift was on the nest again - although I've not spotted egg(s) here yet, to find an adult on the nest in the middle of the afternoon (several times now) suggests that eggs are probably present.

2021-Jun-29 Yet another new swift nest with an egg - in 'starling' box #sb4, where I first noticed swifts going in and out on 15th June 2021. No eggs yet in #sb1, and a swift was sitting in #sb3 so I couldn't see whether any eggs yet.

In the gable-end swift boxes, the clutch of eggs in #g5 is evidently complete at 2 (2nd one laid 4 days ago). In #g1, I'd so far only been able to see 2 chicks from the 3 eggs, hatched at least 6 days ago. Today, as well as the two well-grown chicks, there was a tiny one out of the nest - it was very much alive, and I replaced it in the nest (later: found nest unattended, so took photo).

Gable internal swift box #g1 with chicks
Here are the three swift chicks in box #g1 on 29th June 2021. Two of them are 6 days old (possibly 7), while the other (which I replaced in the nest earlier today) has clearly hatched more recently (I estimate around 3 days younger).

At upper left (and slightly out of focus) you can see the back end of a 'flatfly' swift parasite Crataerina pallida. Two legs and part of the body are visible, with the front end of it behind the swift chick.

[Later: By 4th July 2021, the small chick was dead, not looking any larger than in this photo.]

2021-Jun-28 Checking swift nestbox #g2 today (as eggs predicted to hatch tomorrow), an adult swift was on the nest, but a very young chick out of the nest. At first, it wasn't moving, and I assumed it was dead, but then it moved. I replaced it in the nest, without the adult swift apparently being bothered. It appears that even freshly hatched swifts have working claws, as there was some resistance to being picked up as it clung to the wood of the nestbox. I can't say whether or not the other egg has hatched - I certainly wasn't going to disturb the adult even more to try to see.

I don't often say much about 'brick-size' nestboxes #b1 and #b2 - I don't often look as it needs the big ladder, and one can only look through the entrances, but in the last week, I've replaced swift-eggs in the nest-concave in both of these - quite easy to do with a spoon through the entrance. I've also found that I can look inside from an upstairs window using a mirror. Today, there was an adult swift on the nest in #b1, and eggs out of the nest again in #b2.

2021-Jun-26 Swifts are already in 3 out of 4 'starling' boxes (with a chick in one of them, but no eggs so far in the others), but I hadn't imagined swifts taking an interest in the remaining 'starling' box (#sb1) - only 3 metres up, and close to trees. Starlings had a 2nd brood in this one, with a chick fledging about a week ago (3 others dead in the nest). But last night, I could clearly hear a pair of swifts in there - initially their fairly quiet 'twittering' noise, then some 'duetting'. I still haven't actually seen them go in or out (later: I've now seen a swift leaving the box).

Gable internal swift box #g6 with chicks
Here are the three swift chicks in box #g6 on 26th June 2021, estimated to be 5 days old. These look fairly equal in size, though the one at back left might be smaller. With egg-laying spread over 4 days, and hatching sometimes spread out (though not usually by as much), it's not unusual for very young chicks to differ in size.

I think these are the youngest swift chicks I've taken a proper photograph of so far (though I have lots of saved video from over the years) - probably because it's more likely that there will be an adult swift in attendance when the chicks are young.

2021-Jun-25 I finally managed to see the single swift chick in 'starling' box #sb2, which probably hatched a few days ago. A second egg has been laid in #g5.

2021-Jun-23 A warmer day, so more chance of adult swifts not covering eggs or chicks. The main news is that there is an egg in gable nestbox #g5 (I saw a swift looking out of this one 8 days ago). There is no significant addition of nest material to the provided 'concave'. It's the first time that this box has been used since installation in 2016, and means that all 6 of the gable nestboxes are now in use.

In #g1, there are two newly hatched chicks, and a single egg, which is the first indication that there was a 3rd egg. There are 2 eggs in #g2 and #g4, which means just two eggs in these clutches.

First look in #3 and #5 for some time, as hatching expected. 3 swift chicks in #3, and 2 chicks plus one egg in #5.

There are still no swift eggs in 'starling' boxes #sb3 and #sb4. The single swift egg in 'starling' box #sb2 should have hatched, but I've yet to catch a moment when there's not an adult swift blocking the view.

2021-Jun-22 Today, I spotted that at least two of the three eggs in #g6 have hatched, but an adult swift was blocking the view. There appeared to be pieces of egg-shell in #g1 and #g6 yesterday, but I've not yet been able to get a proper view without a swift in the way.

By yesterday evening, it was evident that the eggs in #1 were never going to stay in the nest - I think I'd replaced an egg 5 times, and still there was one out of the nest. The nest is very insubstantial, and an egg seemed to be displaced almost every time a swift attempted to turn round. Perhaps as a result of the disturbance, only one swift stayed in the box last night. I decided to make a wooden 'barrier' to stop eggs rolling in the direction of the entrance (the sides and end of the nestbox restrict movement in other directions). Once the single swift left this morning, I fitted the barrier to the box. No swifts returned at all until early evening, when I was relieved that both birds returned. I feel confident that the eggs won't be displaced now, unless the swifts remove them intentionally.

Camera swift box #1 wooden barrier to keep eggs in place
Added wooden barrier across the nestbox in front of the nest. The piece of wood is 125mm long and 20mm tall. This is the next day, after the swifts had been back.

2021-Jun-20 The two eggs in #1 are still in the nest, so at least the swifts havce managed not to displace them during the night. I can see fragment of eggshell in box #2, so maybe an egg has hatched there (predicted for tomorrow). An adult swift was (as usual) in the way, so I couldn't see the nest contents. Later: the adult swift moved out of the way - it's one chick and one egg in #2 (I can easily look in this nestbox from an upstairs window).

Gable internal swift box #g3 with chicks
Here are the three swift chicks in box #g3 on 20th June 2021, estimated to be 10 days old. The one in front (head to the right, body to the left) is largely blocking the view of the other two.

2021-Jun-19 A second egg in nest #4a this morning, also a second egg in #1. I've now replaced the first egg in #1 in the nest three times. As reported two days ago, I don't know how come it wasn't in the nest the first time, as it was out of the nest when I first spotted it. During each of the last two nights, it was shown on camera being pushed out of the nest accidentally while the swifts were moving around. Will they be any better at keeping two eggs in the nest?

2021-Jun-17 A first egg in camera nestbox #4 spotted this morning. I'm calling this nest #4a, as it might not be the same swifts which laid then destroyed an egg here earlier in the season.

A bit later in the morning, the swifts in #1 knocked an egg into the view of the camera. I don't know how long it's been there, out of view, but I placed it in the nest area, for them to do as they please with.

All as expected in other nests (I didn't look in #2, #3, #5). A swift was sitting tight in 'starling' box #sb3, so there could be egg(s) there (later: no eggs yet). No signs of swift activity in #g5 or #sb4 (other than having seen swifts go in and out).

2021-Jun-15 Still waiting hopefully for eggs in the two camera nests #1 and #4. The swifts in #1 have quickly made a decent-looking nest, apparently from pieces of dead grass (which they would have gathered in the air) - there was nothing in this box at the start of the season. #4 already had a nest from last year, and it has a 'concave' too.

I've seen swifts going in and out of yet another 'starling' box - this one doesn't have a code-name yet - I'd better call it #sb4. It's the box higher up to wall above #sb2 (which swifts regularly use). There's a description of how it came to be in that position here - to summarise, the lower box (now called #sb2) was originally in the higher position when swifts prospected it in 2017. Before the 2018 season, I moved it lower down for starlings to use, and just in time for the swifts installed a new 'starling' box in the old position. The swifts initially moved in, but as soon as the starlings left the lower box, the swifts went there instead. In recent seasons, I remove #sb2 over winter, and only replace it in time for arrival of swifts (so starlings don't use it), but I think with other starling boxes, I'll just let the swifts and starlings fight it out if need be. So long as starlings only have one brood (which seems the most usual), then they leave just about the time that swifts arrive and move in.

I saw a swift looking out of gable-end entrance #g5 (so far unused), so maybe all 6 gable-end boxes are now in use.

2021-Jun-10 Pairs of swifts remained overnight in #1 and #4, so perhaps some consistency now. The first egg hatched on the predicted day in nest #g3.

2021-Jun-9 Last night, one of the pairs of swifts in both camera nests (#1 and #4) left in the late evening, and both returned at 04:05 this morning. I've not seen behaviour like this before. And (obviously, from camera view) no eggs in either nest yet. It's 4 days since an egg was laid in #4 (and destroyed by one of the swifts), so with eggs usually laid at 2 or 3 day intervals, one guesses that they'll make a fresh start eventually (of course can't even guarantee that it's the same birds).

I wasn't entirely surprised to see a swift looking out of 'starling' box #sb3 - it flew off, but I think there were still calls from another one inside. I don't think that this box has been used by swifts before, but with the competition for nesting spaces, it seemed logical that they'd try other starling boxes, seeing as they already regularly use #sb2. I got the ladder and looked inside #sb3 - just a starling nest from earlier in 2021, with nothing significant added by swifts so far. I also checked inside #sb1, where starlings still have a 2nb brood in progress: 4 downy chicks present. There's still another starling box, higher up the wall above #sb2 (so far without a name) - user by starlings earlier in 2021, and not easy to check, so I won't bother unless I see swifts using it. I saw a swift enter 'brick-size' #b1, right next to #b2 which is definitely already in use by swifts.

2021-Jun-8 A new nestbox in use: 1 egg in gable-end #g2 today - the first time this one has been used since installation in 2016, so just #g5 remaining unused out of the 6 gable-end entrances. There have never been swifts in #g2 when I've looked (usually in the middle of the day, so they're likely to be out), and there's no significant nest-material added to the provided 'concave'.

There were swifts sitting on eggs in the other 4 occupied gable-end boxes, and I decided against disturbing them to check for a third egg in each of #g1 and #g4. I'm able to take quick look without disturbing them, so at least I know that there are no eggs displaced out of the nests.

2021-Jun-7 Once again, the second swift in #4 left for the night, departing at 21:47 (fairly dark), and returning at 06:01 (one assumes the same bird). Suspiciously similar behaviour as was happening for about a week towards the end of May, but it's not visiting nest #1 this time, as the pair there were present the whole time.

I have to say: if this was my first year with swifts, I'd be wishing that the birds in camera nests #1 and #4 would 'get on with it' and produce clutches of eggs. But it's 10 years since a swift first visited one of the boxes, and the 8th year with cameras - I've seen all that, so this is far more interesting!

2021-Jun-6 Only one swift spent last night in box #4, but at 05:34 a second one arrived, and at 05:52 one of them again picked up the egg, and threw it - seemingly with some force. Given that one of them definitely doesn't want this egg (usual theory would be that it's not one of the 'parents'), I had a vague plan to try transferring it to nest #2, where the clutch is complete at two eggs, but on retrieving the egg from #4, I found that it was broken.

A third egg today in #5, and a second in #g4.

2021-Jun-5 Finally a first swift egg in camera box #4 laid this morning. In the evening, I spotted that the egg was no longer in the nest-concave, so I replaced it. On searching through saved videos, I found that the egg had been intentionally removed by one of a pair of swifts present at 15:39 - picked up in the beak and 'thrown'. Apart from an hour or two this morning, I think there have been two swifts in #4 for the rest of the day - it seems strange that they wouldn't be out feeding, and at times their behaviour appeared quite aggressive towards each other. So who knows what's going on!

The cameras recorded fights with intruding swifts in both #1 and #4. The colony is quite 'full' (as it has been for several years), so prospecting birds struggle to find a space. Gable-end boxes #2 and #5 still remain unused though, and there are at least two more holes in the soffit, one of which (#w2l) was occupied for a while in 2013 and 2014, but not since, as far as I know.

2021-Jun-4 A third swift egg in box #3 today; also a second in #5; and a second in #g1.

2021-Jun-3 First swift egg in gable-end box #g4 today. While checking that, I think there were birds in #g5 which, along with #g2, hasn't been used since the gable-end boxes were installed for the 2016 season.

2021-Jun-2 After a couple of days with no swift activity in camera nestbox #1, apart from some noise from swifts 'banging' the entrance, a swift entered at 06:27 this morning, and was joined by a second at 06:42. They stayed for a long time, the first one leaving at 13:17 and the second at 14:35. This looks more like a 'proper' pair, compared the the erratic earlier behaviour of swifts in this box.

On inspecting nests: A second egg in #2; a second egg in #3 (one egg replaced in nest-cup); a first egg in #5; a first egg in #g1; a third egg in #g6; and a second egg in #sb2 (but one of the two eggs broken and not in nest - I removed it).

2021-May-31 Four new swift eggs today, which weren't there yesterday - in nests #2, #3, #g6, and #sb2. No activity at all last night or today in #1, so it looks as though that camera-nest is now vacant. There are now swifts 'prospecting' for nest-spaces, so hopefully they'll discover it, instead of 'banging' on the entrance of occupied nests.

2021-May-30 Last night, a pair of swifts stayed in camera nest #4 all night, and there were no swifts in #1, so what you might call 'normal', with no nest-swapping. Several times during the day, a swift turned up in #1 with nesting material, but soon left again taking the material with it - as though maybe it had entered the 'wrong' nestbox. On at least one of these occasions, there was a pair of swifts in #4, so it's not one of that pair.

On inspecting the nests, I observed a pair of swifts in #5 - the first time this season for a second bird, but it could have been present without me noticing. And a first egg in #g6, which wasn't in the nest cup - I replaced it - if the swifts really want to discard it, then they can remove it again.

2021-May-29 Again last night, there was only one swift in each of the camera nests #1 and #4, but saved video suggests that the bird in #1 spent several hours in #4 during the early evening, moving over to #1 at 21:25 and returning to #4 at 04:02. During the day so far on video, there has occasionally been a pair of swifts in both nests, and also brief visits by a single bird, but never birds in both nests at the same time. Nesting material has been added to both nests.

2021-May-28 Last night, there was only one swift in each of the camera nests #1 and #4, but at 04:09 a second one entered #4 - close to the usual time. Perhaps it visits other nests, as well as these two...

2021-May-27 And again this morning: 2nd of pair of swifts in nestbox #1 leaves at 04:18:24 and apparently joins the single swift in #4 19 seconds later.

No more eggs in inspectable nests. A swift was sitting (presumably on 3 eggs) in #g3, and I didn't want to disturb it.

2021-May-26 Still no end to the saga of 3 swifts and 2 nests. For 4 mornings now, soon after 4am, one of the pair overnight in nest #1 leaves and joins the single swift in nest #4 for a few hours. Sometimes it also spends time in #4 in the evening, before returning to #1 for the night. I feel that by now, the timings on video rule out coincidence. If either nest wasn't on camera, then I wouldn't notice, so with lots of the nests not having a camera, maybe this kind of thing happens regularly?

2021-May-24 More evidence that maybe the same swift is visiting two nests: 2nd swift of pair in #1 left at 04:31:58, and 2nd one joined a single swift in #4 at 04:32:30 (so the same as yesterday morning, when arrival in #4 was at 04:27). All three swifts then stayed where they were until leaving at around 07:40. In the evening, once again the same pattern as yesterday evening: a single swift in #1, and a pair in #4. One of the pair leaves at 21:02:48, and at 21:03:28 a second swift enters #1 and stays. In the half-hour before this, an unwelcome swift had been fought off from both #1 and #4 (not necessarily the same one).

There are now 3 swift eggs in nestbox #g3, but none in any of the other inspectable boxes.

This morning, I thought I heard the characteristic 'thump' of a swift entering soffit space #w2r (audible in the nearby upstairs room). At 17:45, a swift entered nestbox #5 - the first sighted activity here this season, but of course easily missed, so could have been earlier.

2021-May-23 At 04:27 a second swift joined the one in nestbox #4 - that's the third time this season that a second swift has appeared here, the first occasion being 11 days ago, but previous ones haven't stayed for long. Just two swifts in nestbox #1 last night, as opposed to three the night before.

Just a thought, but today's saved video can't rule out the 2nd swift in the two camera nests being the same bird. This morning, the 2nd swift which spent the night in #1 left, and a few seconds later a 2nd swift entered #4 (as above). This evening, the opposite - a 2nd swift left #4, followed within a minute or so by a 2nd one entering #1. Of course this is no proof that it's actually the same bird.

At 07:26, I saw a pair of swifts leaving 'starling' box #sb2, which is the first evidence of a second swift there this season.

2021-May-22 The three swifts overnight in nestbox #1 left a few minutes apart this morning - will there be any new and unexpected behaviour today? There were no new eggs in inspectable boxes - I couldn't see in nestbox #g3 because a swift was on the nest. I saw a swift enter 'brick-size' nestbox #b2 - the first activity sighted there this season.

2021-May-21 Strong winds and rain most of the day, so the swifts aren't doing much. At 18:18 a third swift joined two which were already in nestbox #1, and there are still 3 about 20 minutes later. No signs of aggression between them. This isn't something I've seen before - apart from when it's parents and their young, more than two swifts usually results in a fight until one of them leaves.

2021-May-19 At 06:04 a second swift joined the one that had been in nestbox #1 overnight, and they're both still there two hours later.

At 08:37 two swifts entered nestbox #4 one after the other. The pair were still there in #1, but left shortly afterwards. To contrast the behaviour of the single swifts that have been using #1 and #4 up to now: for some days the one in #4 has been in and out lots of times, sometimes every few minutes - I suspect trying to get a second one to follow it into the nestbox. It has also brought in quite a number of feathers. The one in #1 has tended to go out for the whole day, and has hardly brought any material in at all. By nightfall, there was a pair of swifts in #1, but still just the single one in #4.

Around mid-day, I checked all accessible swift nestboxes - that's #2, #3, #5, #sb2, and all six of gable-end #g1-#g6 (of course no need with #1 and #4 which have cameras). There was a single egg in #g3, but none anywhere else. I didn't even encounter any swifts - although they don't tend to be disturbed, that's the idea with inspecting in the middle of the day - chances are that they won't be at the nest.

2021-May-16 At 07:24 two swifts entered camera nestbox #4 one after the other - the first time I've seen two in there since a second one first appeared 4 days ago. By nightfall, there was still only one swift in each of the two camera nestboxes #1 & #4.

At 19:30, a swift entered soffit nest-space #w1r, followed (after it made 2 or 3 'approach-runs') by a second one. Probably not the first time, as at least one of a circling pair entered 4 days ago.

2021-May-14 Not much to say about the swifts. Quite poor weather, and I've not been watching enough to see whether any swifts have enetered other nest-spaces. The two camera-nests still only seem to have one regular swift each. The starling broods seem to have fledged from their own nest-boxes, and after a day or two of trying to chase swifts away, the starlings and their young have disappeared from the garden. It must be an instinct for starlings to try to keep swifts away - both species could use similar nest-spaces - but it seems a futile exercise, as the swifts out-manoeuvre the starlings in flight, and the starlings give up when it starts going dark, even though swifts still fly in quite dark conditions.

2021-May-12 This morning, a swift entered soffit nest-space #w1r, one of a pair that were making repeated 'approach-runs'. At 13:42 two swifts entered camera nestbox #4 one after the other. I saw them while watching outside in the garden, but the saved video confirms that this was the first time there had been two this season. They typically acted a bit 'suspicious' of each other, but soon settled down. By nightfall, there was still only one swift in each of the camera nestboxes #1 & #4, despite both having had a pair in for a while.

2021-May-11 This morning, I saw a swift enter nestbox #2, and at 08:55 a second swift joined the first in camera nestbox #1 (the first swift had been out this morning, but had returned shortly before). At 09:54 a pair of swifts entered gable-end entrance #g6 one after the other, and I saw a swift leaving #g3. The pair of swifts in #1 this morning acted like a pair, and stayed for nearly an hour before leaving together, but there was still only one swift present a nighttime.

2021-May-9 At 20:34, a swift entered camera nestbox #4 for the first time this season.

2021-May-8 In the afternoon, I saw a swift looking out of 'starling' box #sb2, after thinking I'd heard a swift-call coming from somewhere near there. The swifts didn't succeed in raising young in this box last year - perhaps there was interference by starlings - but I'm interested to see the swifts take their chances, after all they choose to use this box, even though it seem inappropriate.

Later in the afternoon, I saw a swift enter nestbox #3.

2021-May-7 A first swift arrived in camera nestbox #1 at 14:40 and stayed until 15:24, returning for the night at 19:19. I haven't yet seen any enter other nestspaces, but I could easily have failed to notice.

2021-May-4 I've just put the two nest-cameras online. No swifts yet in those boxes (#1 and #4), and none in any other boxes yet as far as I know. I saw some swifts flying in the area a few days ago.

2021-Apr-26 The swift nestboxes are ready to go for another season. I've cleaned them out if needed (not that it's ever really needed) - some nests had been reduced to debris by various insect-life, while others were relatively untouched.

For three years now, swifts have nested in a 'starling box' (#sb2) despite it seeming inappropriate for swifts. This year, that particular box was taken down over winter, so I've just put it back in position. Starlings already have young in 3 other starling-boxes.

The two video cameras are not yet online for the 2021 season (link to live video above).

This is nestbox #1 in which swifts raised young for the first time in 2012.

In 2013 (with a camera in the box for the first time) they raised 3 chicks; 2 in 2014; 3 in 2015; 2 in 2016; 1 in 2017; 2 in 2018; 3 in 2019; and 1 in 2020.

The dates of arrival of the first swift in this box were: 2013 May 6th evening; 2014 May 5th evening; 2015 May 5th evening; 2016 May 4th afternoon; 2017 May 6th midday; 2018 May 7th afternoon; 2019 May 7th afternoon; 2020 May 9th morning; 2021 May 7th afternoon.

This is nestbox #4 in which swifts raised young for the first time in 2014 (with a camera in the box).

2 chicks were raised in 2014; 3 in 2015; 2 in 2016; 3 in 2017; 2 in 2018; 1 in 2019; and 3 in 2020.

The dates of arrival of the first swift in this box were: 2014 May 7th evening; 2015 May 4th evening; 2016 May 5th evening; 2017 May 5th evening; 2018 May 18th morning; 2019 May 15th afternoon; 2020 May 4th afternoon; 2021 May 9th evening.

[ Clarke Brunt's Home Page | Animals | Swifts index ]

Author: Clarke Brunt (clarke.brunt@viridis.net)
Last modified: 5th September 2021