The 2011 Nestbox Diary

April (part 1)

Go to the last entry on this page .......

An introduction - This is a somewhat belated start to the nest box diary after what has been a quiet start to the year in the boxes monitored using cctv cameras. For various reasons most of the cameras weren't switched on until 12 March.

During the winter a House Sparrow used the House Martin nests as its roost, but moved out during March as Sparrow activity appeared to build in the Swift boxes. Last year a pair attempted to nest in SW-up, only to be ousted when the Swifts arrived. This year they seem to have learnt from that experience and although a male Sparrow has visited that box every day since the cameras were switched on he has not succeeded in attracting a mate that wanted to stay.

Boxes SW-le and SW-ri have needed modifications to their entrances after Starling managed to squeeze in several times, but with the arrival of the Swifts perhaps only days away (the first Swifts have been seen in Northern Ireland) the four boxes dedicated to them are empty and ready. After two successful broods last year, will we see more than two boxes occupied in 2011?

I didn't get to clean out the Great Tit box until the middle of February and the cameras had to wait until 24 February. However, a pair of Great Tits were regulars in the garden and I hoped that despite my late start they would be interested in the box. Things looked promising when the male paid the box a visit on 14 March. Visits by both male and female took place the next day but that was the last time that either approached the box. In fact, while the male continued to make occasional visits to the garden to feed, the female disappeared completely.

I decided to keep the cameras switched on, but over the next couple of weeks the only visitors were queen bumblebees. For a while I wondered if we would have a bee's nest to watch but that too failed to happen.




11 - 15 April -

Then an unfortunate event in the conifers beyond the bottom of the garden brought us an opportunity that I simply hadn't envisaged. Back on 20 March I noted that a female Blackbird was nest building high in the conifers. As usual she was using wet materials from our pond. Then, a couple of weeks later, on 11 April, and  just after her eggs would have hatched, the male went into panic mode as a Magpie raided the nest.


Male Blackbird clears roof of Great Tit box, 12 April



Despite his efforts the brood must have been taken, because the next day the microphone in the Great Tit box picked up the sounds of activity on the next box roof, and from the house I could see the male Blackbird busy clearing it!




Female Blackbird inspects roof of Great Tit box, 12 April



When he left the spot was inspected by his partner.

The next day there was an evening inspection, and then on the 13th the female started to carry bits of straw up to the site.

I was quite concerned about how successful nest building would be as the roof doesn't extend very far out, slopes, and had a row of long nails (with their heads cut off) sticking up along the edge as an anti-cat precaution.




Ledge added to Great Tit box, 14 April


This prompted me to use some old timber to make a horizontal extension to the roof, and once it was in place on the evening of the 14th I removed the nails adjacent to it.





On the 15th there was no activity during the day, but than there were a number of evening visits, and the microphone picked up the unmistakable sounds of s bird 'shuffling' - pressing her breast feathers against the floor as she propels herself forward. That was confirmation that the Blackbirds were serious and it meant that we would get an opportunity to observe their nesting properly for the first time - They have nested here numerous time in the past, but their nests have always been hidden. We would be able to see this one from the house (with the help of a telephoto lens or spotting scope).




Position of Blackbirds' nest on GT box, 15 April



To put the nest site into context, this picture shows the nest box surrounded by Honeysuckle and Ivy to the right and bamboo plants to the left, and beyond are the conifers in which the Blackbirds' original nest was situated.








16 April -


Female Blackbird shaping side of nest, 16 April



On the 16th building got under way in earnest, with many visits to the pond and lots of shuffling,




Blackbird nest under construction - no floor yet, 16 April



resulting in a ring of very soggy plant debris and duckweed, but with the nest box roof still visible inside.





17 April -


Blackbird nest nearing completion, 17 April


Early morning activity (before 8am) by the female resulted in the addition of a layer of fine straw and grass that covered the roof felt.

Once that was done she stayed away for the rest of the day






18 April - the first egg -

Blackbird nest completed, early on 17 April


The early morning of the 18th saw just a few more additions to complete the building task, and in the warm weather we were having the nest was already showing signs of drying out.




The Blackbird's first egg, 18 April



Then, sometime between 10.30 and 11am that morning she laid her first egg. Soon afterwards she left the nest, not returning until 8.25pm to spend the night sitting on the egg.





During the afternoon I took advantage of her absence to set up a cctv camera over the nest. It's a colour camera that does not have night-time capabilities,  so by the time of the Blackbird's arrival in the evening it was already too dark for the camera to provide a useable image. The same was true when she left before 5.30am the next morning.




19 April - The second egg -

The first time I saw her on camera on the 19th was when she appeared for a minute or so at 10.17am. She was back in at 10.24am and for the next ten minutes she turned to face in different directions frequently, and repeatedly poked at the egg as if trying to push it to the back of the nest.


Blackbird's body held high as egg is laid, 19 April



Then she became less restless and settled down facing out form the ledge, and at just before 10.40am she raised her body up in a familiar way.

This position (seen here in the cctv image) was held for about 10 seconds before she had a quick look into the nest cup and settled back down again, having laid her second egg.



Second egg laid by Blackbird, 19 April

Having said that, the bright sunshine through the plant cover produced such a high contrast, mottled image that it was impossible to see the eggs, even when she lifted herself up to move them.

She remained in the nest until 12.09pm and it wasn't until she departed that I was able to confirm that the second egg had indeed been laid.




Sun shade added over camera and Blackbird nest, 19 April


During the afternoon I took advantage of her absence to add a piece of green tarpaulin as a shade to the south side of the nest. Hopefully this will help improve the image on the sunny days to come. It will not hide the nest from early morning sunlight, but should help for most of the day.

The female returned to the nest twice during the afternoon, just before 2pm and again just before 4pm, staying just a few minutes each time, and didn't pay any attention to the shade. At the end of the day she again returned to the nest at 8.25pm.




20 April - Egg #3 laid

Again, she left the nest this morning before 5.30am, and before the camera was able to 'see'!

At 9.15am she returned to the nest and stayed for ten minutes. At just after 10am she was in our Birch tree, clearly disturbed by something, although I could see neither a cat nor Magpie about, returning to the nest at 10.28am.

Third Blackbird egg is laid, 20 April


Her third egg was laid at 10.40am, exactly 24 hours to the minute after the second one. Afterwards she remained on the nest until 12.07pm in an almost perfect repeat of yesterday's behaviour.






Blackbird at her nest, 20 April

Unlike yesterday, she was back on the nest by 12.30pm.

Ten minutes later and she is looking very settled. As I write this she is making a series of high-pitched but quiet 'squeaks' - could this be a call to her mate? She stayed for about 40 minutes.

I'm wondering if I was mistaken about the squeaks - I now suspect that it could have been a Dunnock very close by!



Seeing her returning to sit on the eggs suggests that she may have finished egg laying. She has just returned to the nest at 1.26pm so it does look as though we are now entering the second phase - incubation. If that is so then we now have a wait of perhaps 13 days before the chicks hatch around 3 May.

That early afternoon session finished at 2.21pm and she then made just two short visits during the rest of the afternoon, 2.43pm - 2.46pm and 5.59pm - 6.15pm. She finally returned for the night at 8.27pm.

I'm now having second thoughts about whether or not egg-laying is actually over. On the basis of these timings I suspect that we may see a fourth egg laid tomorrow.

The presence of the shade that I put in place yesterday has certainly made a difference to the view I'm getting from the cctv camera. Those last two images would have been impossible with out it.

Work on this page is still in progress so there are likely to be corrections and additions made over the next day or so, and the large images may not appear until at least tomorrow.





21 April - The summer weather continues with a temperature high of 14C for the second day.

Four eggs now laid by Blackbird, 21 AprilMy doubts yesterday were confirmed when a fourth egg was laid today, some time between 10.15-10.30am.

My recordings were disrupted today as I reorganized the wiring arrangements and added a few bits ready to record the Swifts (and House Martins should they come this year).

However, it was clear that the female spent a lot of the day sitting, with none of the long gaps seen yesterday.

In the early afternoon, when the temperature was at its highest she spent quite a bit of time with her beak open as she coped with what must have been at least a few degrees above the official 24C maximum. If I remember in the morning I'll put a temperature sensor in pFour eggs now laid by Blackbird, 21 Aprillace on the platform while she's away from the nest.

This evening I sent a very pleasant hour or so sitting outside gazing skywards - not a single high-flying bird passed over us, let along a House Martin or Swift, but it won't be long...

One extremely frustrating problem wasted a great deal of the morning. Ever since I started the diaries in 2000 I've used WinTV units (and software) to capture images from the cctv cameras. When I bought my current PC (64bit, with Windows 7) I needed to buy an up-to-date unit.

It worked, but the latest WinTV software which has been produced very much with digital TV users in mind was very disappointing. The device I bought is strictly analogue, and the software really treats it as a second-rate customer, with no facilities for manual control of the image. Instead, this is done automatically, with very annoying sudden changes in brightness every few minutes.

Having worked for several weeks, when I tried to use it this morning it wouldn't display the image being inputted. A check of the lead confirmed that the signal was getting to the WinTV device, but the indicator LEDs remained off, so I did the usual things like plugging it into a different USB port, restarting the computer etc, and when those measures failed I resorted to reinstalling the software and drivers. And the result? - I get error messages telling me that the hardware is incompatible with the system used! If that was so, how come it took weeks to come to that conclusion?

The damned thing works on my laptop so for the time being I'll probably use that to capture the images I need...

After Easter I'll need to go shopping for a device that will work reliably with the PC.




22 April - And then there were five -

Fifth egg laid by Blackbird this morning, 22 April



On another day when the temperature reached at least 24C the Blackbird laid her fifth egg.





This evening I went through the day's recording to establish the timing of that, and also to get an idea of how much time she has spent incubating during the day - she laid the egg at 11.15am.

Her day started when she left the nest at 5.45am and ended on her final return at 8.17pm. In between, she sat on the eggs for sixteen sessions, leaving the nest for an average of just over 11 minutes. The shortest absence was for 3 minutes and the longest, of 26 minutes, was her final trip away before retiring for the night.

The session during which the egg was laid lasted some 159 minutes, between 10.30am and 1.09pm. The remaining sessions averaged 30 minutes, ranging from 56 minutes down to two sessions of 6 minutes before she retired for the night.

I'll check the timings again on the weekend while it is still very warm, and when there will be no egg laying to interfere with the timings. If/when the daytime temperatures drop I'll do it again.


This morning the day started with my first sighting of a House Martin this year, just before 9am. At 10.15am two Swifts flew northwards over us (the breeze was southerly at the time) and then at just after noon I spotted a single Swift that seemed to be feeding to the south of us.

I'm afraid that there is no photographic confirmation of these sightings, and tonight the nest boxes are empty. However, I think that the Sparrow that made repeated visits to SW-up today is fast running out of time!




23 April - And then there were four?!

Blackbird nest after one egg removed by the female, 23 April


More details to follow (along with a clearer picture), but this morning at around 6am the female removed an egg from the nest. All appeared well when she took an earlier short break, but was this egg broken, or could she detect that it wasn't fertile?

She continues to incubate the rest of the eggs.




After reviewing the early morning recordings I can now confirm the sequence that took place this morning.

Balckbird removes one of her eggs, 23 April


When she returned to the nest at just before 6am all five eggs appeared to be intact, and she settled on them as usual. Then, at 6.17am she inspected the eggs, and instead of turning them she picked one up. It appeared intact and she was holding on not to the egg itself by to something that was either attached to it, or had leaked from it and dried.

She left the nest with the egg, and when she returned without it a short time later she settled immediately and incubation continued.


Blackbird male visits nest for the first time, 23 April


At 11.36am the clutch had its first visit from 'dad' when the male spent around a minute perched on the side of the nest.

Previously his only visit was when he cleared the nest box roof before its initial inspection by the female.



Incubatiing Blackbird with beak open to cope with high air temperatures, 23 April



A couple of days ago I mentioned how the female is coping with the high temperatures while on the nest. Well, with the temperature at Farnborough officially 24C at 12.30pm, she is sitting on the eggs with her beak wide open.



Incubatiing Blackbird stands with beak open to cope with high air temperatures, 23 April



By 1pm that temperature had reached 25C for the first time, and with the nest site even hotter, at over 29C in the shade, she was also resorting to standing in the nest cup for some of the time.



Male Blackbird visits female at nest, 23 April



I need to correct something I said earlier in this entry. Having just gone through the day's recordings I find that the male visited the nest four times today, and that the first came at 8.28am while the female was sitting.

On this occasion he remained perched on the edge of the ledge for about half a minute while his partner carried on and turned the eggs.




Blackbird male brings caterpillar to nest (and eats it), 23 April


Then, when he visited again at 11.36am he actually brought a large caterpillar. With the female absent he looked down at the eggs (for the first time) and then ate the caterpillar before leaving.

 The remaining visits took place at 2.45pm and 6.30pm, both while the female was away, and on neither occasion did he bring food. 




The female first left the nest at 5.49am. During the day she had 18 sessions of sitting on the eggs, averaging 35 minutes per session, and she was away from the nest 19 times, with the absences averaging 9.4 minutes. She finally returned to the nest at 8.24pm.






24 April - And then there was ..... just one abandoned egg.

Male Blackbird finds just one egg remaining out of a clutch of five, 24 April



At first glance, it would appear that the male is (at 7.07am) visiting a nest that has been raided. It looks rather scruffy, and has just the one egg left.




male Blackbird returns to inspect depleted clutch, 24 April



And when he returned for a second look at 8.30am it was clear that the egg hadn't been moved, confirming that his partner had not been there since his earlier visit.






The video recording, in a frustratingly limited way, indicates that there had been no raid, and that the eggs had been either removed or eaten by the female.

This was one of those times when I cursed not having available a small cctv camera with night vision capability. When the recording started at 5am the picture was totally black. However, sounds from the nest indicated that the female was present and that the eggs were being moved around a lot.

By 5.15am I could see glimpses of the female's beak that showed she was moving about in the nest a great deal, and at 5.20am she left - I couldn't decide whether or not she had something in her beak, although it would have been too small to be a complete egg.



poor quality images of female Blackbird on nest before abandoning it, 24 April


She returned two minutes later and for the next eighteen minutes she was constantly turning and shuffling in the nest, with much more vigour than I saw when she was nest building - it was almost as if she was scrambling her eggs!



Abandoned Blackbird nest, 24 April




Anyway, she left the nest at 5.30am, leaving just the one egg, and I haven't see her at the nest since, leaving me with the sad conclusion that it has been abandoned.



Male Blackbird inspects abandoned nest, followed by a Blue Tit, 24 April


It is now 4.45pm and there has been no sign of the female either at the nest or simply in the garden.

The nest has had just two visitors since 8.30am, the male Blackbird taking what is possibly his last look at 10.25am, and a Blue Tit five minutes later which was more interested in the insects around the nest.



- Click on the images to see larger versions -

2011 Nestbox Diary Index .......... .........................................................  ..April (part 2)