Friday 21 April 2023

Another Cambridge System implementation

The Cambridge System seems to be well-liked by Swifts. Perhaps they like the seclusion afforded by having to travel through a tunnel to reach their nesting place. Wherever there is unused roof-space, an attic affords the opportunity to install internal nest boxes accessed via an entrance in the outer leaf, and a tunnel connecting the entrance to the nest box. It requires less disruption of the existing brickwork than installing a Swift brick. We were sent pictures of another project, where an opportunity was grasped during a renovation of an old building. 

Sarah and Dave Richards live on the outskirts of Southport, in a semi-rural location. They fell in love with swifts when hearing their screaming parties during lockdown 2020. They decided to help them by installing Cambridge System internal nest boxes. The Cambridge System was dreamed up by Bill Murrells in 2014. It is essentially the same system as that implemented in the highly successful Fulbourn project.

With the helpful guidance from Tanya and Edmund Hoare of Sedbergh Community Swifts and their builder on board, they created 4 internal nesting spaces and 2 clay cavity liner nest boxes in the gable end of the house.  

A calling system will be installed and fingers will be kept crossed.

The pictures below are essentially self explanatory:

Making an entrance piece

Each nest place has an entrance hole crafted from a high density thermalite block that's been cut to brick size. To cut a 29x66mm entrance hole, a 28mm drill bit was used with a file to finish. The entrance hole is slightly larger on the outside before tapering down to 29x66mm.

Installing the boxes
A 4 inch earthenware pipe runs the breadth of the cavity and the inner wall. Inside are 380x230x210mm plywood boxes located within the loft. 

All boxes have a removable plywood back.  

The plywood boxes are secured to the inner wall with brackets. Within these boxes, we've installed a false floor with 100mm circular cut out so as to avoid the nesting area being raised. All plywood used is 12mm. We intend to fill the edges of the cut outs so as to make them concave. 

Clay cavity liner swift bricks

With limited space in the loft corners, they added two other boxes, based on using a 215x145x200mm clay cavity liner - another Bill Murrells idea. These have the same size entrance hole with a bigger brick surround and no pipe as the box is positioned within the wall, spannng the cavity. 

Sunday 16 April 2023

A proposed Swift Tower Design

I have to admit luke-warm enthusiasm for swift towers because so few can demonstrate success. However, we have enjoyed success with the Trumpington Community Orchard Swift Tower, and at least one other tower, at Tice's Meadow nature reserve in Surrey, of the same design. Both of these towers had 5 pairs in 11 chambers in 2022. 

Proposed Swift tower with 20 chambers (see model)

We have also had worthwhile success with cabinet and triangular gable boxes with a particular style of front with a simple canopy over the entrances. The canopies are made by cutting a batten 3"x 2" in half at 45°:

A 4-chamber cabinet with 2 pairs and a
25-chamber triangle with 9 pairs in 2022

The canopies provide shelter from rain and sun, and also may deter predators. This style of front is easy to make and looks attractive. For this year, after squirrels attacked the original front, we have replaced the Trumpington tower front (see Facebook).

We have now extended the design with a new proposal which combines these ideas in a tower with 20 chambers. There is an online model here. You can spin it around and also look at pre-cooked views under the clapper-board symbol. The carpentry is sufficiently simple for amateur carpenters, though some serious equipment may be needed to erect it.

The Trumpington tower has the lowest boxes at 6.5 metres. This is too high to access with a ladder for basic maintenance (we have tried it!). So suggest  a height of 5.5 metres - this is a good height for the birds and accessible for maintenance.

Thursday 5 May 2022

A New Wildlife Tower

Back in 2015, we visited Nick Watts at Vine House Farm in Lincolnshire, where we saw his wildlife towers, which we thought were a fine inspiration for a tower suitable for Swifts as well. This vision has now been realised.

A view from the south west

This magnificent hexagonal building is 8 metres high. Louvres on 5 sides give access to 50 Swift boxes, hoping to emulate the success of Swift boxes in church belfries. There are also 24 S Bricks embedded in the brickwork.

In total, the tower contains:
74 Swift nest boxes
13 House Martin nest cups
10 bat bricks
4 bat access tiles in the roof
24 bee bricks and
20 small bird boxes

A solar panel charges a battery that powers 2 MP3 players with attraction calls.

A view from the north west

Inside the tower: Louvre Swift boxes and S Bricks

A nice touch

Thursday 13 January 2022

External Wall Insulation

With the drive towards zero carbon, external wall insulation (EWI) on older houses will result in the loss of many Swifts and bats, but it is also an opportunity to provide many more nest places. In particular, the S Brick is an easy to install solution for Swifts and other small cavity-nesting birds. [A solution is also needed for bats!]

External Wall insulation is usually anything between 90mm and 110mm thick. It is thus not thick enough to embed a nest box unless it projects outside the insulation, or it is embedded in the outer leaf.

Older buildings will either have solid walls or they will have a narrow 50mm cavity. As the outer leaf is typically ~100mm thick, there is an available depth of at least 190mm for an S Brick. It just requires the removal of 1 brick and replacing it with an S Brick. The internal floor area would be ~440 sq cm, plenty big enough.

The following images and examples show how it can be done:

Palight S Brick for a rendered wall

Section showing S Brick embedded in outer leaf and EWI

S Brick entrance

Example before render [Credit Conwy County Borough Council]

Four S Bricks embedded in EWI [Credit Conwy County Borough Council]

S Brick entrance embedded in EWI - example from Cambridge

Saturday 2 October 2021

Low budget Swift Tower- Brigsteer Wetlands Reserve

Although Swift Towers can be quite expensive, it doesn't have to be that way if you use a simple design and volunteer labour. This is a good strategy, as Swift towers are known to be difficult to attract occupants, so success with a small project can always be expanded later on.

Robert Pocklington – a National Trust Ranger at Sizergh, South Cumbria obtained some funding through the Trust to make and erect an 8m Swift tower at their Brigsteer Wetland. Rob approached me (Graham Fell) of Kendal Men In Sheds as we have been making swift boxes for a few years and I had developed an inexpensive Swift Micro Caller. The budget was just £300 and I volunteered to do all the necessary work for the calling system and a 20W solar powered panel and controls to power it. I decided to use a 12V small motorbike battery with 9Ah power rating.

8 metre pole
We were lucky in obtaining an 8m telephone pole for free and the site was the edge of a wetland area that Rob had made some 7 years earlier. Each summer swifts were to be seen over the scrape and pond so he was sure a Swift tower would help to increase numbers in the area.

I approached a solar panel company for advice as I had never done this before and we decided to go with their system which was more than adequate for the Micro Caller. So the panel is mounted horizontally on the top of the pole which is not ideal for collecting solar power but it ensures the panel (and its stainless mounting sheet) is well attached to the pole with no risk of coming off. The area is known as the Lyth Valley and is subject to strong winds from Morecambe Bay estuary and localised flooding of the valley. A fellow Shedder I know made the wooden box to house the electronics from a 1930’s oak dining table and he came up with a solution of how to attach the swift boxes to a 9” telephone pole.

6 nest boxes
We made a triangular mock-up that allowed us to make boxes about 370mm long from local larch and we took advice from Ros Taylor of our local Kendal Swift Group and made the upper three boxes with side entry and the lower three boxes with entry up through the floor. There would be room on the pole for more boxes but we felt six to be about right. The boxes were made by the Sizergh NT volunteers.

I assembled all the electrical parts in the box which was well sealed against the weather and then car body underseal covered the whole box for waterproofing. We decided to have the system running all the time as this kept the 12V timer charged and then a separate switch allows the system to be switched on in early May and then off in early August.

Control electronics
Rob, myself and another NT Ranger then took the pole to Brigsteer and in about 5 hours we had attached the boxes, solar panel and got the pole into the hole. Then the wooden control box was attached near the pole about 3 feet off the ground for ease of access and to prevent flood water getting in. This was in September 2021 so we will see whether we have breeding success in 2022.

It was completed within the £300 budget with all labour volunteered. Though not visually appealing, the main objective of keeping within the budget and achieving a practical pole will in time prove to be a success.

Contact details: 

Tuesday 3 August 2021

An Appreciation of Judith Wakelam

Judith releasing a Swift. Photo Nick Upton

Judith's involvement with swifts began thirty years ago when she went to see the late Chris Mead for advice on what to do with a grounded adult swift she had picked up. She described how Chris was sitting in his big chair with a swift, looking for all the world like a brooch, on his sweater. Thereafter, she became an accomplished rehabber, processing up to thirty a season, both grounded adults and chicks which had fallen from the nest. Feeding nestlings every two hours plays havoc with your sleep patterns, but she never complained. She became well known to local vets and wildlife centres, who were happy, and relieved, to pass on to Judith swifts that had been brought to them by members of the public.

In her later years, she gave many talks to local groups and at conferences. In particular, she made valuable contributions to the biennial international swift conferences in Cambridge, Stettin and Tel Aviv. She was a natural communicator, with a puckish sense of humour.

Judith was not just about swifts. She was interested in all aspects of nature and wildlife. Look into the small pond in her tiny back garden teeming with newts and frogs; look at the bundle of hair that she took from Tess, her German Shepherd, to put out on a tree for nest building tits and goldfinches to steal; look at the borders planted with flower species irresistible to bees and butterflies - all witness to her passion for nature. And there is more. She helped her friend Norma with her deer projects, specially muntjac. She went on toad patrol every year, holding up traffic to let the toads get safely across the road, She kept careful records of the wildlife in the area, her favourites being the barn owls in the churchyard and the grey wagtails breeding in a nearby rivulet.

Swifts at All Saints' Worlington. Photo Judith Wakelam
It was Judith who blew the whistle on the destruction of a swift colony near her home, leading to the creation of a vibrant new colony in All Saints' Worlington.

And, as you would expect, she had boxes for her beloved swifts, with cameras installed, so she could enjoy their antics from the comfort of her kitchen. 

Mastery of the Skies. Photo Judith Wakelam

Another wildlife-related passion was photography. It is a measure of her talent that she won the Oxford Museum of Natural History's 'Summer Swifts Competition' in 2014 with her picture 'Mastery of the Skies'.

But perhaps the greatest buzz of all for Judith were her annual safaris to the world's wildlife hotspots: the Serengeti, the Okovango Delta, the cloud forests of Costa Rica and many more. Judith enjoyed companionship so she always took a friend on these trips.

Judith was a very private person, revealing only to her closest friends, details of her background. She rarely spoke about her health until it was clear that things were going seriously wrong.

Judith, you will be sorely missed by the many people whose lives you touched.

Eternal rest grant unto her, O Lord,
 and let perpetual light shine upon her.
 May she rest in peace. 

Jake Allsop

Saturday 3 July 2021

SAW 2021 Events

Sat 3rd -Sun 11th July

Swift Awareness Week begins today!

Search for an event near you here

Sunday 13 June 2021

Cottenham Village Hall

Triangular colony boxes in the apex of a gable have become quite popular. We were presented with an opportunity in a gable which had projecting beams, which could have limited the size of the triangle. However, the shape contained by the beams lead us to a new and attractive shape. which might look good in any gable.

This idea is appropriate. for shallower roof slopes, in this case, 30°.  Normally, a triangle has 1, 2 then 3 ..  chambers on each level. With a shallow roof, it may be better with 2, 4 then  6 ....

However, in this case, we chopped off the corners of the triangle and went for 2, 3, 3 giving 8 nest chambers.

The resulting colony box would make an attractive feature in any gable with a shallow sloping roof, and easy for architects to include as a module in their designs

Computer model

Internal structure

Installation complete with tweeter

Village Hall Pavilion with swift boxes

Sunday 28 March 2021

PVC nest boxes

Some years ago, I visited a friend,  Maurice Wilkinson, who had an array of nestboxes for Swifts and House Martins on his house, with a high occupancy rate. Some of the Swift boxes were made of PVC, the same material that is used for soffits. This inspired the idea for the Model 30, with its PVC roof resulting in John Stimpson upping his production to over 26,000 nestboxes by March 2021

Maurice's PVC swift boxes have now had swifts in them for 5 years, and there is no sign of degradation. One might have expected some damage caused by Swift claws on the entrance hole, but they remain unscathed.

Here is a short video of nestling Swifts in one of Maurice's PVC boxes:

PVC as a material is nice to work with, it screws together to make a robust construction, it has good thermal properties, it is lighter than wood, it will never rot, so what not to like? With a suitable primer, it can be painted. It is more expensive than plywood, but not prohibitively so.

We have recently looked at making nest boxes out of 9mm PVC for the complete structure. As a result, we have built 3 prototypes: A Model 30, a Model 31 and a nest box suitable for embedding in external wall insulation (EWI). 

Our conclusion is that PVC is a promising material.

PVC Model 30

As the Model 30 is intended for exposed situations, built in PVC, it will be even more resilient, especially from water that may run down the back. This prototype was made by Simon Evans. The body is painted with Sandtex 'Mid Stone'.

PVC Model 30 painted with Sandtex 'Mid Stone'

PVC Model 31

The Model 31 is designed to go under broad horizontal eaves. It is intended for well-sheltered locations, so the main advantage of PVC here is its light weight. Here we made a double box:

Computer model

PVC Model 31. The small corner pieces attached to the front enable precise relocation of the front after installation


We were asked for a solution to embed in External Wall Insulation. When EWI is applied, it is between 90mm and 110mm thick with an additional thickness of render on top, but there is not enough depth for a Swift box. There are 2 choices, either penetrate the wall or have the box projecting outside the insulation. We described the former approach here, using a rendered S Brick. As embedding plywood in EWI is probably not a good idea, we developed a solution that does not penetrate the wall, made of PVC:

Section drawing

Appearance after installation

The PVC used here is coated in 'Anthracite Grey'

Monday 25 January 2021

Duchy Big Bird Box survey 2020

There seems to be a gathering momentum for provisioning nest places for cavity-nesting birds in new development, particularly in the south west, where the Duchy has an ambitious policy of providing an average of one nest place per dwelling. What is often lacking is adequate monitoring of these projects, but this report by Dr Thais Martins is very welcome, providing valuable data to support what we advocate.

Although it is early days, the results reported so far are most encouraging with significant numbers of House Sparrows, Starlings, House Martins and the first prospecting Swifts. This is a good example of community engagement in a citizen science project. See The Big Duchy Bird Box Survey

Photo: Hugh Hastings and the Duchy of Cornwall
Swifts often take longer to find new nesting places, but it bodes well for a future with vibrant Swift colonies in all the developments surveyed.

There is much detail in the paper highlighting occupancy rates by different species in different box types  and on different aspects.

As the data builds up over the years, this should provide some guidance as to what works best.

There is now a common understanding that a Swift brick can be considered as a 'Universal' bird box, and that sparrow terraces are not cost effective. The numbers of birds found occupying Swift bricks in Duchy developments confirm the universal nature of Swift bricks.

In this study, of 515  swift bricks, 192 were used by House Sparrows, Starlings and House Martins, but of 12 sparrow nest chambers in 4 sparrow terraces, only 2 were used. Although not significant at the 5% level it does point towards House Sparrows preferring Swift bricks

Download the  PDF

Thursday 3 December 2020

Swift Bricks - the 'universal' nest brick

The SLN Swifts & Planning Group has produced a paper advocating the provision of Swift bricks as a preferred solution for a range of small cavity-nesting species. It comes from a realisation that this will have better outcomes for these species than trying to satisfy all species independently.

The paper makes the points that integral or internal nest boxes are:
  • more aesthetically pleasing
  • maintenance free
  • long lasting
  • less prone to predation
  • less prone to temperature variations
The paper does not address species that prefer open-fronted nest boxes or nest boxes suitable for mounting externally.

Photo: Hugh Hastings and the Duchy of Cornwall
The main thrust of the paper is to counter the current tendency to provision large numbers of sparrow terraces. There is mounting anecdotal evidence that they have very low occupancy rates and that House Sparrows prefer Swift boxes.

A one-size-fits-all policy is not only more effective, it simplifies things for ecologists, planners and builders.

Further, whereas Swift boxes can accommodate House Sparrows, Tree Sparrows, Blue Tits, Great Tits, occasionally House Martins and, with a larger entrance, Starlings, sparrow terraces cannot accommodate Swifts.

You can download the paper here: PDF
There is an extended version of this blogpost on Mark Avery's blog

Tuesday 15 September 2020

Carlton Marshes Nature Reserve

Suffolk Wildlife Trust have built a new visitor centre at Carlton Marshes Nature Reserve. 8 S Bricks have been built in to the timber-frame construction, by making entrances in the wooden cladding.

Steel plates surround the entrances to deter woodpeckers and starlings from attempting to enlarge them. The nest chambers penetrate 50mm into the insulation which is insufficient to cause any heat loss problem.

From their website: "Carlton Marshes lie in the Waveney Valley at the southern tip of the Norfolk Broads and is part of the Suffolk Broads. It comprises a jigsaw of grazing marsh, fens, peat pools, short fen meadow, tall fen (called 'tall litter fen'), dykes, pools and scrub. Mostly man-made, these habitats have developed over hundreds of years of traditional management and now host specialised wildlife."

S Brick dimensions. The opening is enlarged to allow some positioning tolerance

Computer model showing S Brick embedded in insulation

Photo credits below to Steve Aylward, Head of Property & Projects:

S Bricks installed waiting for cladding

Cladding installed with entrances in place

Steel entrance plates installed

Entrances to 8 S Bricks