The 2010 Nestbox Diary

May (part 5)

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23 May - We are in for another sunny day with the temperature up into the upper twenties. - As it turned out, Farnborough airfield recorded 26C, while here in our sheltered garden it just about made it to 30C in the shade!

The two Swifts in SW(LE) prepare to leave this morning, 23 May



After last night's event, it was good to see that it was business as usual in SW(LE) this morning.

Here's the pair, preparing to leave at 7.55am.




By that time one of the Swifts (S1) from SW(UP) had already been out (6.55am), returned (7.44am) from its first flight of the morning and swapped places with its partner (S2), which then left at 7.55am. S2 stayed out until 9.29am when it resumed the task of incubation, S1 leaving at 9.45am. During the rest of the day, the pair alternated their incubation duties at the following times:

S1 in 10.56am - S2 out 11.03am

S2 in 12.04pm - S1 out 12.26pm

S1 in 1.23pm  -  S2 out 1.35pm

S2 in 2.18pm  -  S1 out 2.33pm

S1 in 3.15pm  -  S2 out 3.34pm

S2 in 5.08pm  -  S1 out 5.17pm

S1 in 6.42pm  -  S2 out 6.50pm

S2 in 8.59pm

The Swifts in SW(UP) change over as they share incubation duties this evening, 23 May


Although a change-over occurred after this final arrival, the other Swift did not leave the box but remained just inside the exit until around 9.30pm when it rejoined its partner at the nest cup..

This picture shows the pair as the change-over took place, exposing the two eggs for a short time.


Over in SW(LE) it turned into  a day of long duration stays. After the pair left at 7.57am it was 11.03am before 'White Spot' brought in a feather, with his partner arriving less than a minute later. Their visit lasted until the female left at 3.21pm with 'White Spot' heading out three minutes later.

At 3.43pm a Swift entered the box. Definitely not 'White Spot', neither did it behave in a way that suggested that it was his partner. This bird was quite agitated in the way it moved about. Anyway, no other Swift entered before it left again at 4.56pm.

At 5.18pm 'White Spot' brought in another feather. However, it was 5.42pm before its partner arrived, and when it did the interaction between them was quite vigorous for several minutes before they started to settle - they have remained side by side in the box ever since and are now clearly in for the night.


24 May - Egg #1 in SW(LE) - on another cloudless morning and perhaps a hotter day (before things cool again as the week progresses).

The first egg to be laid by the Swifts in SW(LE), 24 May 2010


Great news from SW(LE) this morning as the second pair of Swifts produces its first egg.

I don't have time this morning to investigate when it was laid, but I hope add more details later.




The egg was first seen when the pair headed out for their first flights of the day at 7.26am. White Spot returned with his usual feather at 11.10am, with his partner returning tree minutes later. They remained in the box until 2.33pm.

The next session was much shorter. White Spot arrived with a feather at 2.55pm, his partner entered five minutes later, and they left at 3.34pm.

'White Spot' visits SW(RI) this afternoon, 24 May


At 3.48pm White Spot appeared briefly in SW(RI). Unfortunately I wasn't recording the quad image at that moment (I was using it to note earlier timings!), and just managed to grab this image as it left.




He was back into SW(LE) at 3.53pm, this time with some thin straw. His partner joined him five minutes later. They left again at 4.30pm.

When White Spot appeared next, at 5.36pm he had some long pieces of straw in his beak. This may well correspond to a change in the wind direction. For most of the day there was just a hint of a breeze from the west south-west, but this evening there was a swing round to the East, with a much stronger breeze helping to cool things down. White Spot's partner didn't arrive for another ten minutes, but as usual they left together, at 6.47pm.

At 8.50pm the female returned alone. She left seven minutes later, but just a minute later White Spot arrived and she followed him in, the pair settling down for the night soon afterwards.

In SW(UP) the pair continue to alternate incubation sessions:

S1 out 5.01am

S1 in 5.27am  -  S2 out 6.52am

S2 in 7.24am  -  S2 out 7.40am  (no change over this time?)

S2 in 8.13am  -  S1 out 8.18am

S1 in 9.30am  -  S2 out 9.35am

S2 in 10.33am -  S1 out 11.28am

S1 in 12.02pm -  S2 out 12.14pm

S2 in 12.51pm -  S1 out 1.22pm

S1 in 2.33pm   -  S2 out 2.38pm

S2 in 5.17pm   -  S1 out 5.28pm

S1 in 7.20pm   -  S2 out 7.34pm

and finally, S2 in 8.49pm

I will not be recording timings like this every day, but over the last two days it has helped me to get an idea of the way they behave during incubation. I should point out that today's activities need to be seen against what for us are very warm temperatures.

In the shade of the garden two thermometers have registered just under 31C during the late afternoon, although out in the driveway, below the north-facing boxes, it reached just 29C!

It is time to do a bit of a rethink!

First, Yesterday, George from Oxford explained to me that during the fight I witnessed in SW(LE) it is in fact the bird that was on its back that was winning. By getting underneath its opponent, it is then in a better position to push the one on top out of the exit! This certainly makes a lot of sense -  thank you George.

Next, I have just looked through the recording made of SW(LE) this morning, to establish when the egg was laid. With the pair in constant close contact, with one partly covered just about all the time it took a few viewings to come up with my best guess, which is around 4.40am. However, if this is correct then my assumption that White Spot is the male has to be wrong, as that is the bird that I think laid the egg, which was partially visible for a moment just afterwards.

If this is the case then I have a lot of notes that should be amended. I'll be watching tomorrow morning's recording with interest!


25 May - A bright and breezy (from the east) morning, with hazy skies and the temperature just below 17C at 9.30am.

As we have breakfast there is still one egg in SW(LE) after the pair left for their first flights of the day at 8.06am, so my dilemma over the sex of White Spot remains unresolved.

After leaving the box this morning, the pair remained awy until the late afternoon when White Spot returned, feather in beak, at 4.19pm with its partner following it into the box less than a minute later. The pair didn't leave again today.

This morning I watched the recording that was made yesterday morning between 4 - 5am, and it convinces me even more that it was White Spot that laid the egg, but with neither bird returning to the box during the day the wait for a second egg goes on.

The cooler conditions (19C at noon, as opposed to around 29C at noon yesterday) seem to be having quite an effect on the frequency of change-overs between the pair in SW(UP). Here are the day's timings  -

S1 out 6.40am

S1 in 10.57am  -  S2 out 11.03am

S2 in 11.54am  -  S1 out 12.12pm  (S1 brought in a feather)

S1 in 1.27pm    -  S2 out 1.34pm

S2 in 3.37pm    -  S1 out 3.41pm

S1 in 6.06pm    -  S2 out 6.14pm

S2 in 7.16pm    -  S1 out 7.71pm  (S2 brought in a feather)

S1 in 8.25pm    -   S2 out 8.46pm

And finally, S2 in 9.06pm.


26 May - Egg #2 in SW(LE) - On a bright and breezy day, with the temperature up to 17C at noon.

The second egg is laid by the Swifts in SW(LE), 26 May

And it was at just after noon that I saw the second egg for the first time as I've been doing other things this morning.

When I have chance later today I'll be looking back through the recording, hopefully to establish for definite which bird laid it!

In the meantime, does the fact that the eggs are being left unattended suggest that we can expect another one to be laid?

Yet again, looking back through the recording hasn't really been conclusive, because for most of the morning the best I could see was a small part of one egg, usually for less then a second as one or both birds kept the nest cup covered. However, after its partner left at 11.31am, White Spot moved around quite a bit and it didn't look as though there could be two eggs. Then, when it (she) headed for the exit at 12.07pm the second egg was seen.

White Spot returned at 1.32pm with its partner arriving a minute later. This time they both left at 2.09pm. White Spot was back in on its own at 2.29pm and remained on the eggs until 4.28pm. When the pair returned for the night, it wasn't White Spot that arrived first, this time its partner entered the box at 6.44pm with WS arriving four minutes later.

In SW(UP) the pattern of change-overs was similar to yesterday -

S1 out 8.01am

S1 in 9.28am    -  S2 out 9.34am

S2 in 11.55am   -  S1 out 11.59am

S1 in 2.15pm    -  S2 out 2.28pm

S2 in 3.04pm    -  S1 out 3.10pm

S1 in 5.01pm    -  S2 out 5.06pm

S2 in 7.50pm   -  S1 out 7.54pm

And finally, S2 in 9.07pm



27 May - We had a little bit of rain last night, and this morning started overcast and cool in the morning (around 10C at 9am). It became brighter as the day progressed and the temperature reached 17C briefly during the afternoon.

In SW(UP), incubation continues without incident, while in SW(LE) no additional egg has been laid, although the amount of time the eggs have been left unattended today suggests that egg laying is not finished.

First, the timings for SW(UP) -

S1 out 9.52am

S1 in 11.00am    -  S2 out 11.08am

S2 in 11.35am   -  S1 out 11.40am

S1 in 1.37pm    -  S2 out 1.41pm

S2 in 5.27pm    -  S1 out 5.32pm

and finally, S1 in 9.13pm

In SW(LE)  -

S2 out 9.45am; WS out 11.19am

WS & S2 in 11.34am (WS in first)  - WS out 12.58pm

WS in 1.17pm  - WS out 1.32pm

WS in 1.50pm  -  S2 out 1.54pm; WS out 2.35pm

S2 in 3.01pm   - S2 out 5.08pm

WS in 6.52pm; S2 in 7.59pm

The two Swift pairs tonight, 27 May



For the pair in SW(LE) the day has been far from what had become their usual pattern, but it has been nothing like the incubating behaviour seen in SW(UP) where I haven't been able to see the eggs all day.

Here are the two pairs tonight, with White Spot resting on its partner in SW(LE). Can we still expect to see an additional egg being laid in in that nest tomorrow?

During the day the eggs were left unattended for 1 hr 25min.



28 May - A cloudy, cool morning (nearly 15C at 11am) under largely cloudy skies, but dry so far.



There is no new addition to the clutch in SW(LE) but the Swifts' behaviour still doesn't match that of the pair in SW(UP).

Whereas since the second (and last) egg was laid in SW(UP) there has always been a bird present in that box, this image, captured just before 11am shows that in SW(LE) the eggs are once again being left unattended - for an hour on this occasion.



Today's timings -


WS out 8.04am; S2 out 10.20am

WS in 11.20am  -  WS out 2.52pm

WS in 4.41pm    -  WS out 6.11pm

WS in 7.43pm; S2 in 7.55pm (at last!)



NB. I should have pointed out earlier that in the SW(UP) timings S1 refers to the first bird to leave the box each day. As I am unable to distinguish between the pair, it may not always be the same bird that leaves in the morning.

S1 out 5.24am

S1 in 5.29am    -  S2 out 8.05am

S2 in 8.18am   -  S1 out 8.25am

S1 in 9.25am   -  S2 out 9.29am

S2 in 12.12pm  -  S1 out 12.15pm

S1 in 1.48pm    -  S1 out 2.19pm (no change)

S1 in 4.13pm    -  S2 out 4.18pm

S2 in 6.52pm    -  S1 out 6.54pm  (feather brought in by S2)

S1 in 8.09pm    -  S2 out 8.15pm

S2 in 8.59pm    -  S1 out 9.04pm

and finally, S1 in 9.20pm



I am puzzled by what is happening in SW(LE), with no sign of WS's partner all day. I'm waiting to see that it returns tonight.

Having commented on how the pair in SW(UP) have been keeping their eggs hidden, S1 adjusted its position soon after 6pm and revealed them for the first time in days.

And with neither Swift in SW(LE) at that time it provided the first view of all four eggs.




A sigh of relief could be heard in the household when Swift 2 reappeared in SW(LE) after being away all day.

As I write this at just after 7pm it is S2 that is sitting on the eggs with White Spot half on top of it, and preening the back of its head.

The pair have left the eggs unattended for 4 hours 21 minutes today.




At 8.10pm it looks as though they are going to stay in the box for the night, but in SW(UP) they day isn't quite over.

Here, that pair are in the middle of what will probably be their last change-over of the day.





- I was wrong, there was another swap between the pair around 9pm.

For a while after that it looked as though there could be more departures from both boxes, although by 9.17pm these three birds had returned to their eggs.

Then, the return of S1 to SW(UP) at 9.20pm marked the end of the day's flying activities in both boxes.



At 1.45pm a male Sparrow appeared in SW(LO) but disappeared again when a Swift entered SW(UP) three minutes later.


29 May - An overcast morning with the lowest clouds around 1700ft and periods of drizzle. By 3pm the temperature had reached 15C. At 4.20pm the sun came out for the first, and only time time before it became even gloomier with more drizzle!

The behaviour in SW(LE) continues to puzzle me. Again, it is only White Spot that is taking time to sit on the eggs during the day, leaving long gaps in the incubation.

Here are today's timings -

SW(LE) -

S2 out 8.51am;

WS out 12.26pm

WS in 1.53pm   -   WS out 3.12pm

WS in 6.06pm   -   WS out 7.16pm  (spent a couple of sessions looking out)

S2 in 7.22pm;

WS in 8.23pm


When it finally returned to the nest, S2 settled on the eggs immediately, and when White Spot returned it seemed they were glad to see each other!

They have left the egg unattended for three hours today.




Compare those timings for SW(LE) with the day in SW(UP) where as usual there has been a constant adult presence in the nest -

Here are today's timings:

SW(UP) -

S1 out 5.10am   -  

S1 in 5.19am     -  S2? out 8.01am (lots of movement by pair - not certain about change-over)

S2 in 8.59am     -  S1 out 9.03am

S1 in 11.21am   -  S2 out 11.27am (S1 with feather)

S2 in 1.05pm     -  S1? out 3.48pm (lot of movement by pair - not certain about change-over)

S1 in 5.17pm     -  S2 out 5.30pm

S2 in 6.22pm     -  S1 out 6.30pm

S1 in 8.20pm     -  S2 out 8.23pm

and finally, S2 in 8.56pm



After all that flying it's quite a climb up the side of this nest!





Turning briefly to the Sparrows, while there are numerous youngsters being fed out in the garden at the moment, adults continue to inspect possible sites for further broods.

There hasn't been any activity recorded by my cctv cameras today, with neither Swift or Martin boxes being visited, but I did spot a male Sparrow making several inspection visits to the box across the road that was used earlier in the season by Starlings.

That brood fledged successfully last week, but you can still see the dirty footprints left by their parents!



30 May - After a grey start the day brightened up, although it remained quite cloudy and there was a cool breeze. Despite that the temperature reached 19C in the afternoon.

Well, today it seemed that  in SW(LE) Swift 2 (S2) seems to be realising that he has a role to play, although today's activity record shows that there is still some progress to be made by the pair of their clutch is to be successful -

Here are today's timings:

SW(LE) -

WS out 7.18am; S2 out 10.35am

WS in 11.55am    -   WS out 2.43pm

WS in 4.21pm; S2 in 4.36pm   -  WS out 4.48pm; S2 out 7.43pm

WS in 7.48pm; S2 in 8.58pm

The eggs were left alone for 2 hr 53min today, but at least S2 spent quite a bit of time sitting on them, in fact more than White Spot.

SW(UP) -

S1 out 8.35am  -

S1 in 9.02am   -  S2 out 9.07am

S2 in 9.41am   -  S1 out 9.44am

S1 in 11.45am  -  S2 out 11.50am

S2 in 1.45pm    -  S1 out 1.50pm (S2 with feather)

S1 in 4.07pm    -  S2 out 4.11pm

S2 in 7.29pm    -  S1 out 7.35pm (S2 with feather)

S1 in 9.27pm

As usual, there has been an adult in attendance all day.


31 May - Another dry but cool, mainly cloudy day with a high of around 16C which only came as the sun set!

Here are today's timings -

SW(LE) -

S2 out 8.01am; WS out  10.47am

WS in 1.01pm   -  WS out 1.55pm

WS in 2.29pm   -  WS out 3.01pm    (with feather)

S2 in  3.02pm; WS in 5pm  -  S2 out 5.09pm   (WS with feather)

S2 in 7.25pm    -   WS out 7.28pm

WS in 8.58pm   -   S2 out 9.08pm

and finally, S2 in 9.18pm

While the eggs were again left unattended for a total of 2hr 49min, at least there were a couple of change-overs undertaken today. In addition to the times when both parents left the box, there were also times when White Spot spent time looking out rather than sitting on the eggs.


SW(UP) -

S1 out 7.50am

S1 in 8.28am   -  S2 out 8.33am

S2 in 9.20am   -  S1 out 9.25am

S1 in 11.38am  -  S2 out 12.09pm

S2 in 5.16pm    -  S1 out 5.20pm

S1 in 7.54pm    -  S2 out 7.58pm

S2 in 9.01pm    -  S1 out 9.04pm

and finally S1 in 9.24pm

This pair maintains the incubation of their eggs with no breaks despite S1 being in the box from 11.38am until 5.16pm when S2 next returned.


- Click on the images to see larger versions -

2010 Nestbox Diary Index .......... .................................  .June (part 1)