Monday 22 December 2014

Cherwell Swifts Conservation Project (CSCP) Report 2014

We are happy to host this report of the activities of the Cherwell Swifts Conservation Project. CSCP is a good example of a number of such groups in the country who hope to establish a Swift Local Network in 2015 with a view to sharing experiences and ideas.

by Chris Mason

The worldwide network of Swift enthusiasts grows. So too does the range and extent of our own activities. This year we attended the International Swift Conference in Cambridge which was attended by over 150 delegates from 24 countries and we took part in a survey organised by the RSPB studying Swift populations. We further strengthened our link with the Cherwell District Council; we have been involved in discussions to set up a nationwide network of local groups which, like CSCP, are trying to help conserve Swifts (similar to CSCP) and established an important link with Oxford University Estates Services.

Our priorities remain: 
1. Finding and looking after nest sites.

Survey map. Click to enlarge
The RSPB is trialling ways to improve estimates of the UK Swift population. We took part in surveys organised by the Society. George Candelin, on a short assignment with the RSPB, spent long hours surveying Swifts in Bicester, Bloxham and Bodicote, and with a lot of help from Alison Urwick and David Yates in Bloxham and Reg Tipping in Bodicote, we now know pretty well which buildings are being used in these two villages, and even how many nests there are in each building. The results show that there were more than 40 active nests in each village this year, making them two of the best places to watch Swifts around here; also in Bicester George recorded nearly 20 Swifts nests just on one estate of 1950s council-built properties (Kings Avenue). There is a map showing the latest information we have about Cherwell Swift numbers by parish at the end of this report.

2. Creating new sites 
The Cherwell District Council is building 250 new affordable homes in Banbury and Bicester. The Build! Project enables future residents to get a discount on their rent or purchase price in return for undertaking some of the work themselves. We have been in discussion with the Council’s planning department and expect that nest places for Swifts (boxes or bricks) will be included at 8 of these sites. Swifts nests are also to be included in several new private developments in the District where the Council has made the inclusion of Swift bricks/boxes a condition of the development. Data from the CSCP about local Swift nest sites have been instrumental in these decisions. Nest boxes have been put up, and in some cases new nest places created under eaves, in Bicester, Epwell, Bodicote, Lower Heyford, Souldern, Swerford and Adderbury. We were particularly delighted to receive an invitation from Broughton Castle. Swifts have nested there for as long as anyone can remember, and we were asked if we would like to take advantage of scaffolding at the castle to create some new nest places under the eaves - which Reg Tipping and Bill Cupit did. 

Reg Tipping and Bill Cupit at work at Broughton Castle (left) 
and Bill installing a made-to-measure box in Bodicote (right)

Making the concrete base for the tower
In November work on the installation of a Swift tower at the Banbury Ornithological Society’s wetland reserve in Bicester was finished. The tower has a box with 20 nest places on a galvanised steel pole, and we hope that as Swifts nest nearby in Bicester and often feed at the reserve they will eventually find and use these new nest places. We are grateful to the HDH Wills Trust and the Trust for Oxfordshire’s Environment (TOE2) for funding this project. 

Fitting the nest box on to the pole and the completed tower    

3. Generating Interest 

Swift Stories: The film was premiered at Kirtlington Village Hall in February and later also shown in full at Broughton Castle. On both occasions it attracted full houses (about 100 at each event) and an enthusiastic reception. Since then I have shown extracts of the film in Charlbury, Kidlington, Abingdon, South Newington, Bloxham and at the Cambridge conference, and have more commitments for 2015.  Copies of the film are available on request. The complete film lasts 110 minutes, but extracts lasting about 45 minutes are available, as is a 17-minute version suitable for use in schools. For more information please contact me or visit

We ran stalls at Village Festivals in Bloxham and Bodicote. These generated plenty of local interest, tied in well with efforts to find the local Swifts nest sites and resulted in several requests for nest boxes. We also had a stall at the market in Bicester, but shoppers obviously had other priorities that day.
Making Swift kites at the Bloxfest with David Yates    

Setting up at Bodfest with Reg Tipping    

Evening Swift-watching walks were organised in Leafield, Fritwell, Kidlington and Kirtlington. Oxford University We made a link with Estates Services in Oxford University. A lunchtime meeting took place and two walks were organised, beginning in Wellington Square and finishing at the Museum of Natural History to see the tower and watch nesting Swifts on the webcam. The aim is to encourage interest in Swifts amongst University staff and Swift-friendly building work at the University. On the second walk we were delighted to spot a Swift’s nest in Wellington Square (the second one we have found) where the great David Lack watched them 70 years ago. We were equally excited to be told that Swifts have been seen going into one of the nest boxes we put up in the square a couple of years ago.

My thanks to all who have checked on nest sites, sent in records, raised alerts about building work and made space for Swifts in their homes; to those who have organised walks and meetings and helped at fetes and other events; to TVERC for checking the records so carefully and submitting them to the Council, and to all at the Cherwell DC who have made such good use of the data; to BOS members who have helped to get the tower erected; to the ever-willing team of nest box installers and of course to Andy Russell for the wonderful film and setting up the website. 

Tuesday 16 December 2014

Premier Inn Cambridge

We previously reported on a press release by Whitbread, publicising their intentions to install Swift boxes in new Premier Inn Hotels.  One of the first Premier Inns to adopt this idea is the new hotel in Newmarket Road, Cambridge.

Front view of the hotel
All of the Swift boxes are on the back
Although, in an ideal world, it is best to plan nest boxes at the design stage, by good fortune, the geometry of the eaves of this building lent itself to adding nest boxes unobtrusively after the building was erected.

The building has broad eaves, with a channel along the top of the wall of an ideal size to accommodate Swift boxes. As there were no right angles, something custom designed was required, so Filcris undertook the building of treble boxes, tailored to fit the shape of the channel.

It was also important that the colour of the boxes matched the grey of the building, so Filcris chose a recycled material that could be painted the required colour.

As a result, the hotel now has 24 homes for Swifts (8 treble boxes) in groups of 12, 6 and 6.

It is planned to install an attraction call system by next May.

The following pictures are self explanatory:

12 boxes
6 boxes
6 boxes
Design model
Design model, internal structure

Monday 1 December 2014

Elizabeth Way Bridge, Cambridge

The Friends of Midsummer Common (FoMC) in Cambridge have noticed a significant decline in the numbers of Swifts in their part of Cambridge, so we searched for a suitable place for Swift boxes. It did not take long to realise that Elizabeth Way Bridge provided a good opportunity.

Elizabeth Way Bridge supports one of the main arterial roads into Cambridge across the river Cam. It forms part of the boundary of Midsummer Common. At the top of the wall under the very wide eaves runs a channel which looks as if it was designed to take Swift nest-boxes. The channel has a circular section so we thought the ideal design would be a recycled water-pipe nest box.

6 double pipe boxes installed
After consulting both Cambridge City Council and Cambridge County Council (who have responsibiity for the bridge) we were given permission to install the boxes.

We came up with the idea of a pipe box a few years ago when we installed a small number, 3 of which now have breeding Swifts and at least 4 have breeding House Sparrows. We documented the idea here.

A view across the river Cam
For the bridge, we decided to make 6 double boxes. We used 2 2-metre pieces of recycled water pipe cut into pieces 66cm long with some simple internal carpentry to make 2 boxes out of each piece. The finished boxes were painted with Sandtex, colour 'Mid Stone'.

The boxes are secured with small wedges, glued in place with silicon glue - brand name "Sticks like Sh*t" (and it does!)

Power is available within the bridge to drive an attraction call system.

The following pictures show how the boxes were constructed.

Components of a double pipe box, before painting
6 sets of components, painted and ready for assembly.

This project was a combined effort by Action for Swifts and Friends of Midsummer Common. Pictured (left) are Bruce Martin, Barry and Susan Stobbs .

Bob Tonks and Dick Newell installed the boxes.

Sunday 16 November 2014

How to help House Sparrows

House Sparrows are said to be in trouble in the UK. They are a red-listed species, apparently in a  worse predicament than Swifts which are only amber-listed, even though, according to official estimates, there is only 1 pair of Swifts for every 60 pairs of House Sparrows.

Although the rate of decline of House Sparrow numbers has reduced since 1994, the start of BBS, prior to that, between 1976 and 1994, there had been an enormous drop of about 70% detected by the Common Bird Census (see BTO webpage)The causes of the decline in House Sparrows are stated to be a decrease in survival and a decrease in productivity.

There is little data on the population level of Swifts prior to 1994, apart from the Atlases of 1968-72 and 1988-91, which show a contraction. It could also be the case that environmental factors affecting food availability are a contributory factor in the decline of Swifts.

A House Sparrow in an internal Swift box in Fulbourn
House Sparrows also largely depend upon cavities in human dwellings, but loss of nest sites has not been cited as a contributory cause of any decline. This is surprising, since modern building standards, renovation practices and insulation policies would affect House Sparrows at least as much as Swifts. 

This may be more damaging for House Sparrows, as they prefer to nest in close association with their congeners, whereas Swifts will nest either alone or in close association with each other, depending upon the distribution of cavities.

Many more House Sparrows than Swifts occupy these
Zeist boxes at Edgecombe flats, Cambridge
It is therefore good news for sparrows that they will happily occupy Swift boxes. It seems that a horizontally extending cavity, with an entrance near the floor, is perfectly acceptable to sparrows. 

Sparrow terraces, comprising 3 adjacent tit-like nest boxes are commonly erected for House Sparrows, but occupancy rates are low. They host more Great Tits and Blue Tits than House Sparrows.

Swift nest on top of House Sparrow nest at Ely Maltings
Should Swifts wish to take over a Swift nest box occupied by House Sparrows, then they will usually evict the sparrows, and then nest on top of the 'haystack' built by the sparrows. 

There can be a risk that Swifts get themselves entangled, especially if string or twine is brought into the nest, so removing this at the end of the season might be a good idea.

Therefore, if you wish to help House Sparrows, erect plenty of Swift boxes!

Saturday 25 October 2014

Worlington celebrates Suffolk Wildlife Trust accolade

Worlington has won the Suffolk Wildlife Trust Award for Conservation for 2014.

In 2012 we reported on the success of nest boxes in All Saints church, now increased to 20 occupied nest boxes in 2014. Originally, back in 2009, Judith Wakelam raised the alarm when a cottage with breeding swifts was scheduled to be knocked down.

Swift boxes were installed by Action for Swifts as mitigation for the loss of these nest sites. Don McBean, who lives right next to the church organised an attraction call player and, eventually, cameras in the boxes after Swifts took up residence. A Swift Fest event in July 2013 attracted 200 people to observe a truly great spectacle.

Ironically, the conservation award was judged in Worlington in August 2014 after all of the Swifts had departed, but despite this, Judith's vivid description of the spectacle that they had missed was enough.

The following appeared in the Newmarket Journal:

Swift project helps village scoop conservation award
Villagers in Worlington have been celebrating after the village picked up a major conservation award.
Worlington, Forest Heath's Village of the Year, lost out on the county title to Whatfield but on Saturday it was awarded the Suffolk Wildlife Trust Award for conservation, recognising projects in the village, including one aimed at encouraging swifts run by Judith Wakelam and featured in the journal earlier this year. Other initiatives included not cutting areas of the churchyard in the growing season and planting hedge plants. Pictured above are, from left, Gill Jones, Val McClure and Judith Wakelam with their winners' certificates.

Monday 8 September 2014

Experiences with small Swift boxes

Since 2006, in my local church belfry in Landbeach, we have had 4 cabinets, each containing 4 large boxes, and the swifts have ignored them, though 3 swarms of bees have not. As soon as we added small boxes in 2013, behind the top louvres, we had success.

[UPDATE JULY 2017: We think we have 6 occupied boxes this year, 3 raised chicks]
[UPDATE JUNE 2018: On 8th June we found 8 boxes with eggs or adults and 1 well-feathered nest]

by Dick

All Saints, Landbeach
We have been getting a gratifyingly high success rate with small Swift boxes. e.g. not only 4 out of 8 small boxes in Landbeach church, but also 7 out of 12 air brick liners occupied in St Neots, and 6 out of 18 small boxes in Worlington church. These boxes have a floor area of 175mm-200mm x 200mm and at least 100mm internal headroom. 

In the two churches we played attraction calls using the Cheng Sheng player-amplifier. In St Neots, no calls were played, but the boxes were installed as mitigation for lost nest sites. 

In all three cases, the entrances are set back from the 'outside world': behind louvres in the churches and behind a thick barge board in St NeotsAll occupations were achieved within a year or 2 of installation. 

Further evidence of the acceptability of small boxes is at St Mary's Ely: the success rate of the smallest boxes with floor area 100mm x 300mm marginally exceeds the larger boxes. Also the successful Losser box in Holland has a floor area of only 160mm x 165mm. The Ibstock swift brick, with an internal width of 100mm is accepted by Swifts.

So, it is established that boxes with a small floor area are accepted by Swifts. Could they even be preferred? We are now trying to establish where the limits are with headroom, before occupancy rates drop off to an unacceptable level. There are many examples of Swifts nesting successfully with low headroom under tiles, and we know of one occupied box in Cambridge with internal headroom 75mm, floor area ~120mm x 375mm. These birds raised 2 chicks.

We are now in the process of reengineering the Landbeach church cabinets. The louvres are close together (80-90mm), so, originally, to give what we thought was adequate headroom, the entrances were behind every other louvre gap. The original four cabinets had 4 boxes each with floor area 200mm x ~400mm and internal height ~180mm.

Two of these cabinets will have each box further divided into 4 smaller boxes - each one half the height and half the floor area. There will be 2 entrances within each louvre gap (see cabinet on the right below). In the other two cabinets, each original box is divided into 2 with half the floor area, but staggered in such a way that there is at least 1 entrance in each louvre gap. So, to make this work, there are some boxes at the top and bottom of these 2 cabinets with smaller headroom (see cabinet on the left below)

Part of the incentive for doing this is to make the boxes less attractive to bees, a problem peculiar to this belfry. Bees should not survive a winter in a box this small. But the main incentive is in the nature of an experiment (somebody has to try it), which ultimately may mean modifying one of these 2 configurations to the other in the future, depending on the results.

If small boxes are at least as effective as large boxes, then they should be preferred - they are less obtrusive and easier to install.

Front arrangement of entrances

Hinged inspection doors

(Dead) Swift on concave in box with headroom ~130mm

Swift in box with low headroom of ~85mm

Tuesday 2 September 2014

A Remarkable Escape

We often wonder at how a young Swift, never having flown before, manages to emerge from a dark nesting place, launch itself into the outside world, then navigate itself to Africa.

Judith with one of her rescued Swifts
Judith Wakelam is an experienced Swift rehabber who so far this year (2014) had taken in 24 Swifts and subsequently successfully released all of them into the wild. Her normal method of release is to take them to Newmarket Heath, a large open space with short grass, so should a released Swift come to ground, there is a high chance of retrieving it. This cautious approach has led to nearly a hundred successful releases in previous years. On her own, Judith's efforts are equivalent to the production of a substantial Swift colony.

Then came Swift number 25, weighing in at 22 grams which Judith managed to fatten up to 33gm: quite light for a Swift, but it was a small bird. Judith realised that it was near ready for release as it was as fat as larger Swifts that are ready to go. 

The bird was in a box in the study. The walls of the box were about 31cm high with a base 51cm x 42cm. The back door was open and as Judith was putting some items away in a hall cupboard she was overtaken by a bird which came out of the study, through the short hallway, into the kitchen out of the open back door, then up and away!  From where the box was situated to the back door, is approximately 17 metres as the swift flies. 

Judith's reaction was : "I was so shocked that for a few moments I couldn’t believe what I had seen.  I rushed to look in the box to confirm what I thought I had seen and yes I had been overtaken by an escaping swift!"

This anecdote illustrates that young Swifts are nowhere near as feeble and vulnerable as we, who anthropomorphise, might think.

Swift 25 on 21st August
Swift 25 on 25th August, 5 days before it escaped

Thursday 14 August 2014

Cambridge Swift Tower - 2014 update

The breaking news is that, in the 4th summer of playing attraction calls, the Swifts have finally found the nest-boxes.

[Update 2018: We now have 4 pairs in the tower, 2 in the back, 1 in the front and 1 in the side nearer the river. That is up from 3 pairs in 2017]

The tower was built in 2011 and we started playing calls with a customised bird scarer. Swifts showed some interest, but none were seen going very close to the nest-boxes.

We continued in 2012 with the same result and the bird scarer had become unreliable. We suspect the 5 watt solar panel was not quite up to the task, so we installed our own 'Box of Swifts' with a 1.5 inch car tweeter. The result was the same.

So, in 2013, after we had stumbled across the Cheng Sheng player amplifier, we installed a 20 watt solar panel to charge the battery which drove the player-amp and 2 tweeters. This resulted in Swifts actually making contact with the tower, clinging to the boxes, but still not finding any entrances. As a result of this, we made some more entrances where we thought the birds were trying to get in.

Solar panel facing south at 30°
In 2014, things seemed much the same, with Swifts regularly seen near the tower, but none making an entrance. At one point the battery went flat, so we resited the solar panel so that it was never in the shade and pointing in the optimal direction (south sloping 30°).

We seemed to be making little progress, so, in mid June, I popped an email to Brian Cahalane, an attraction call playing afficionado, to ask what would he do? His reply was to start playing calls at dawn and finish at dusk.

So the timer was reset to go from 5am to 12 noon and from 5pm to 10pm - this gave 12 hours of playing, we are not confident how much longer the solar panel and battery could go in a day. We had not previously played at the ends of the day for fear of disturbing local residents.

On 26th June, Bob Tonks was cycling past the tower, and he saw a Swift exiting one of the boxes (so thank you Brian and Bob). Since then we have seen Swifts entering or leaving 15 different boxes, 12 on the front and 3 on the back. Most observation has been done on the front. We saw no Swifts entering the new entrances that we had made on the back.

The only entrance in the top half of the back;
visited by swifts in 2014
We don't think there are 15 potential pairs for next year, as this was probably a small number of birds exploring their options.

One or 2 observations:

Although there are entrances at all levels on the front of the tower, Swifts only entered boxes in the top half. On the back, there is only 1 entrance in the top half, and Swifts used it. So, should we add more entrances in the top half on the back?

3 entrances with white canopies
were visited by swifts in 2014
Another thing, on the front, the paint had peeled away from the canopies above 3 entrances, turning them white. Swifts were seen entering these 3 boxes. The statistical probability of randomly choosing 3 specific boxes turns out to be about 2% - so should we paint a few more canopies white, especially in the lower half?

For the whole of July, if one loitered near the tower one would see anything between 3 and 10 Swifts in the near vicinity with some impressive screaming displays past the face of the tower. If this is a taste of what is to come, then it should be an impressive spectacle on summer evenings in the future.

Monday 11 August 2014

Erich Kaiser's swift colony

[This may be a temporary post, as the video may disappear at any time.]
This is an inspiring video showing how Erich's Swifts trust him at close proximity, provided he does not disturb them in their space.

Sunday 10 August 2014

Band of volunteers work tirelessly to keep childhood memories alive

[It is nice when the press puts out a positive story, especially when they get their facts right. So we unashamedly reproduce this piece that appeared in the Newmarket Journal.]

With suitable nesting locations rapidly dwindling it is no wonder that our country's swift population is in decline. Recognising this problem, volunteers at Worlington are working to re-establish the area's swift population, bringing back the once familiar sight of swifts circling around the village's church.

Click to enlarge

Pictures by Geoffrey Pieter and Judith Wakelam;

For many they will always evoke memories of childhood as they wheel, tirelessly, high in the summer skies and although the swift's stay on these shores is short the tiny birds have, for decades, been a much-loved feature of the countryside.

But now they are in need of help as numbers are declining, not least as modern buildings have fewer holes for them to nest in.

Among a group of dedicated volunteers at the forefront of the campaign to help re-establish swifts is Worlington resident Judith Wakelam.

Her interest in the tiny globe-trotting birds was first sparked more than a decade ago when she picked one up that had fallen from a nest and set about trying to find out how to care for it.

Chris Mead ©BBC
"No one could really give me any advice until I reached the British Trust for Ornithology and with the help of member, Chris Mead, I managed to rear the bird," said Judith.

Since then she has become something of an expert and the results of her hard work are evident to anyone glancing up at the sky around the tower of the village's All Saints Church which is currently full of swifts.

The tower is now home to 38 special swift nest boxes, the first of which were installed in 2009, with the first pair of swifts nesting the following year. Now there are around 20 pairs rearing young in the church.

And at her bungalow in Church Lane, Judith has not only had a special nest box installed which she constantly monitors with the help of a television camera, she also has three young swifts. the Ely Three as she calls them, which came to her via builders replacing a roof in the city, and which she has hand reared and will release on Newmarket Heath within the next few days.

Fed on wax worms and black crickets, the tiny birds appear clumsy but once they are freed they can fly, balancing on the air at up to 10,000 feet and unlikely to ever land again feeding, drinking, preening and even mating on the wing.

"They are truly remarkable birds." said Judith. "They are prompted to leave their nest by hunger as their parents will already have begun their migration so they are completely on their own.

The birds will fly to Africa in August and return to Britain to nest in April, a round trip of some 22,000 kilometres and they will return to same nesting site, which is why Judith wants to encourage churches, households and schools to install nesting boxes.

"If everyone put up just one nest box it would really help," said Judith, who is a member of Action for Swifts, an organisation which offers advice on rescue and conservation of the birds.

And as a volunteer, Judith takes calls from all over the country and beyond from people who have come across the birds and want to help them.

Hers is truly a labour of love and she is heartened that her efforts are bearing fruit. An elderly village resident came up to me recently and said I want to thank you for what you have done to get the swifts back in the church tower," said Judith. "He told me he had not seen as many birds since around 1951 when the church roof had had to be replaced and the nesting holes were blocked up."

As for the swifts, to Judith they have become part of her family. "The fact that these tiny things will leave here totally alone and fly half way round the world and back again is amazing," she said.

"And when I release one it is a moment for a few tears, one of those sad but happy moments which leaves me looking forward to welcoming them back next year." For more information on how you could provide a nesting box for swifts, contact Judith on 01638 715971 or go to

Thursday 24 July 2014

Is 2014 really a good year?

There seems to be a general impression that this is a good year for Swifts in the UK, however, the Reporting Rate recorded by BirdTrack across the UK shows 2014 to be lower than 2013 and 2012, indeed, it seems to be the lowest ever! [Reporting Rate is the percentage of BirdTrack lists that record at least 1 Swift].

Written by Dick

BirdTrack Reporting Rate for Swifts, 2006-2008
(click on graphs to see them larger)

BirdTrack Reporting Rate for Swifts, 2012-2014
(click on graphs to see them larger)
Athough not designed for this purpose, an advantage of BirdTrack for an early indication of trends is that the data is available up to 2 years ahead of BBS. In fact it is available in near realtime!

The graphs, left, include the Reporting Rates for 2006 and for 2014.

The BirdTrack Reporting Rate for 2006 through June to mid-July (the peak season) averages 47.2%. In 2014, the reporting rate for this period averages 37.6%.

This is a decline in reporting rate of 20% in 8 years. Given that changes in BirdTrack Reporting Rate underestimate changes in abundance, this is quite a drop.

[Older graphs than this on the BTO website were calculated incorrectly - so we cannot go back further than 2006]

There could be a number of explanations for the apparent contradiction between numbers at colonies and numbers recorded by BirdTrack:

With the fine weather, it could mean that Swifts are finding plenty of food near their colonies, giving colony watchers an impression of abundance, but, as Swifts do not need to forage further afield, maybe they are seen less frequently by BirdTrack listers.

It could just be that they fly higher in good weather, so are again less likely to be seen.

Alternatively, it could be that those birds that still have their nesting places intact have had a good year, but there may be fewer intact nesting places, so birds recorded away from colonies may appear scarcer.

Another explanation is that birds from destroyed colonies are prospecting those colonies that still exist. This ties in with anecdotes from Poland, where survey data indicates increasing Swift numbers at a time when large numbers of colonies are being lost - the birds may be in the air, and visible, rather than sitting on their nests.

Whatever the explanation, it is a situation that needs watching.

Friday 18 July 2014

Swifts do prefer boxes with concaves

There is little in the way of statistics that support what Swifts might prefer in their breeding location, so I was pleased to get this result.

by Dick
Feathers added by a pair of Swifts to a concave
Photo Judith Wakelam
Some years ago, we put 24 nest boxes in St Mary's Ely, with a concave in every other box. So 12 boxes with and 12 without a concave. When we examined the boxes a couple of years later, 10 were occupied, 7 with a concave and 3 without. So, it appeared that Swifts prefer a box with a concave. However, the probability of this being a chance result was 10.7%

This year we put 18 new nest boxes in Worlington church, again with a concave in every other box. So 9 with and 9 without a concave. We have checked the boxes and 6 boxes were occupied, 5 with a concave and just 1 without. The probability of this result by chance is lower at 6.6%.

Neither of these experiments passed the statisticians test for 'confidence' of 5%, but together, they do.

The probability of both of these results occurring by chance is 10.7% x 6.6% = 0.7% 4.18% (I used Fisher's Method to combine the results)

So now we can be sure that Swifts do prefer boxes with concaves.

2 chicks on a concave. Photo Rob Mungovan

Not only that, but 2 of the Worlington boxes contained chicks, (as did 2 first time occupants in Landbeach church) supporting the assertion that breeding in the first year of occupancy is more likely in a nest-box with a concave.

So, on our next visits to St Mary's and Worlington we will insert a concave in all unoccupied nestboxes.

We need more experiments like this e.g.:
Dark interior versus light interior
Oval entrance versus rectangular entrance
Rough exterior versus smooth exterior
Large box versus small box

[For the technically minded, for the statistics I used the Excel HYPGEOM.DIST() function.]

Postscript 2016: Since the above, George Candelin sent me the results after putting 12 concaves into 52 boxes in the Oxford Museum Tower. After the first season 6 boxes were occupied, 3 with concaves and 3 without. The probability of this result occurring by chance, assuming that Swifts have no preference is  12.73%. Combining this with the 2 results above (10.7% and 6.6%) using Fisher's Method gives a significance level of 2.92%

Thursday 10 July 2014

Neat internal nest boxes in Nijmegen

We thought it worth reblogging 3 pictures from Jochem K├╝hnen's website, as they show just how unobtrusive, simple and effective built in nest-boxes can be.  Swifts are already occupying these nest-boxes.

Facade with virtually invisible entrances
Jochem says:
"I suggested several suitable nest bricks to the architects, and they went for this one. They placed 40 in the project in total, 10 in the facade where a Swift went in last week. I'm very happy with this development, this is a very busy square in the middle of the city centre, so a nice place to show people Swifts. Who knows, one day I'll go and stand there with a table with info to show passers by!"

The entrances were made by simply cutting a piece out of a brick and then positioning the Schwegler nest-box behind it

Entrance close-up
Schwegler internal nestbox