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Who needs Scientists?

"Apus apus flock flying" by Keta is licensed under CC BY-SA 2.5. To view a copy of this license, visit
"Apus apus flock flying" by Keta is licensed under CC BY-SA 2.5.

Michelle Reeve is GBW Manager and the Editor of the BTO magazine Bird Table. Back on the 10 April this year I wrote to Michelle about an article written by a BTO research ecologist in the Spring 2023 issue of the magazine:

“Hi Michelle

I read the article on p. 30 of the latest Bird Table by Joe Cooper with interest – and then surprise. It is entitled “A bird in the garden is worth two in the field”. It talks of ‘developers having little encouragement to create spaces for human-nature interaction.’ And yet there is no mention at all of providing integral bird bricks into new housing. Why not? This alone would be the single most important factor to increase our catastrophically declined urban birds, the Swifts, Starlings and House Sparrows (and Tree Sparrows further north), and yet it is not even mentioned. Why is the BTO once again missing a great opportunity? No amount of application of “your datasets” will give you the right answer. Whilst I commend the promotion of ponds and of proper planting which is sadly lacking in most developments, the fact is that many home owners do provide food and water for the birds and over time they also plant bushes and trees, but to ignore the fact that these species will never have anywhere to nest in the newer properties built over the past 25 years or so as they have much more insulation and are built to enhanced air tightness standards is to completely miss a huge opportunity.

I’m sure you are aware of the e-petition doing the rounds at the moment that has so far around 105,000 signatures asking for the Government to mandate an integral Swift brick be built into all new properties. Imagine where we would be now if your scientists had done the right science years back and been a part of the ‘Swift community’ rather than apparently fighting against the tide. Imagine if the BTO had been stating clearly for many years what the real cause of the decline was rather than the headline on the subject on your website suggesting that changes in juvenile survival are the most likely driver of the decline. That in many people's opinion is incorrect and based on very flimsy data and is hugely damaging to our Swift population which continues to be in freefall. To put that on your website without making very clear that the paper referred to did not look at the issue of loss of nest sites at all is a misrepresentation which I believe damages the great reputation of the BTO.

My friend Paul Stancliffe (ex-BTO Media Manager) wrote an article on Swifts in Bird Table Issue 109 p.23 and whilst it had much of the right information in it, he lists only two factors under the heading Drivers of Decline: 1) poor weather during northward migration and 2) the loss of insects. I don’t believe there is any scientific evidence at all that either of these factors have affected the Swift population in the UK. He then discusses, under the heading How we can help, the loss of nesting space being thought to be another driver of the decline in our Swift breeding population. To pass off the first two factors as proven scientific fact (which they are not) whilst suggesting that people might want to help by putting up a Swift box on their house on the off-chance that a Swift might occupy it, shows the complete disconnect that the BTO has with what is happening on the ground. It completely ignores the huge wealth of citizen science that shows that once Swifts start to use boxes and recognise them as nesting sites then it can quickly reach a situation where a new box is occupied in the year of installation. Why have your scientists not talked to the many citizen scientists around the country that have this information and studied what it shows? What other possible explanation is there except that it is loss of nest sites that is the primary cause of the decline? Here in Hampshire I know of no Swift colonies where numbers are declining – except of course where Council-initiated re-roofing projects on Council properties have and continue to wipe out large swathes of our breeding Swifts and other co-domestic urban birds in just a matter of months leaving them as biodiversity deserts – unless of course Swift boxes are installed at the same time in mitigation. You can read about what happened in the Highcliffe area of Winchester here.

It is a fact that repairs to houses have always taken place. So it is fair to ask what has changed so that urban bird populations have collapsed in the last 25 years? What Paul didn’t explain in his article was that when repairs to eaves have been carried out during that period it has been done with uPVC rather than timber and so never shrinks or rots in the same way that timber does. And it is often sealed to the brickwork with mastic. Once that is done there will never be any opportunity for Swifts to nest in that house ever again. When you combine that with the way new houses have been constructed in that same period with much more roof insulation and with the introduction of air-testing of houses in order to prove reduced heat loss then it really isn’t hard to understand. That has meant that for the first time since man started living in houses there are no ‘newer’ properties falling into a state of disrepair where our urban birds could find new places to nest. I find it baffling that scientists have not realised the problem. They should have done 15+ years ago but seem to have been fixated on trying to prove that insect loss was the cause of the problem.

Please pass my email on to Joe as I would like his comment.

And I’m also copying this to Juliet Vickery and to Beccy Speight RSPB as the change needs to be led from the top of both your great organisations.

Best wishes

Tim Norriss

Hampshire Swifts”

On the same day I also emailed Juliet Vickery and Beccy Speight asking if I could do a presentation to the scientists of both their organisations together on the decline of Swifts as I wanted to explain in detail the changes that have occurred within the construction industry that have, without any shadow of doubt, been the major cause of the decline of our urban birds.

And their response? Silence! No reply from Michelle Reeve. No reply from Joe Cooper. No reply from Juliet Vickery. No reply from Beccy Speight. Not even the courtesy of an acknowledgement.

"Common Swift (Apus apus)" by sussexbirder is licensed under CC BY 2.0. To view a copy of this license, visit
"Common Swift (Apus apus)" by sussexbirder is licensed under CC BY 2.0.

The refusal of Paul and the BTO to acknowledge the changes in the construction industry that have caused the problem while happily touting factors for which there is no evidence is odd. They have also claimed to me that putting up boxes simply encourages birds to move from their natural nest sites to the boxes and that the population doesn’t increase overall. They say this without a shred of evidence, and it isn’t supported by the facts.

It was around 1994 that Chris Mead of the BTO recognised there was a problem with Swifts rapidly declining in numbers. And here we are close on 30 years later and the scientists have been studiously looking the wrong way for all that time. As far as I am aware they have not even looked at the blindingly obvious cause which is the issue of plastic fascias and soffits. When I asked a senior BTO scientist last year what he thought was the major cause of the decline of Swifts he replied that he thought it was loss of insects. When the paper on the Demography of Common Swifts was published later in the year it stated that they could find no correlation between the decline in aphid biomass and the Swift’s population decline.

While scientists continue to study things like Discerning the status of a rapidly declining naturalised bird: the Golden Pheasant in Britain, William J. Smith, Michał T. Jezierski, Dawn E. Balmer 2023, our native urban bird species like Common Swift and Starling continue to freefall as they have for decades because scientists have not studied the changes in the construction industry. They continue to claim that the reasons for the decline are not clear. That’s hardly surprising if they fail to study the obvious cause.

How many more decades do we have to wait for scientists to wake up and do the right science and show that it is changed construction methods and specifically the use of plastic fascias and soffits to replace/overclad the original timber that is overwhelmingly the major cause of the problem?

So, in answer to the original question – yes of course we need scientists but we need ones that aren’t prejudiced by unconscious biases. We need ones with common sense who are prepared to work with the many citizen scientists throughout the UK, many of these volunteering for the approx. 127 Swift groups around the country and who together have an amazing depth of knowledge of the birds for whom we have a shared passion. And don’t forget the Starlings – it is clear from the BTO website, which makes no mention of loss of nest sites as even being a potential cause of the huge decline, how scientists have completely missed the changes in the construction industry that have taken place. This has had a huge effect on Starlings in urban areas.

C’mon guys & gals you need to step up and concentrate your efforts on doing the right science that will help to save our rapidly declining co-dependent urban bird species rather than inconsequential stuff on introduced non-native species that are about to go extinct here.

Beccy Speight and Juliet Vickery please note.

Starling – Photo: Tim Norriss. The breeding population has decreased by 53% (1995-2020). This decline is not dissimilar to that of Common Swift.
Starling – Photo: Tim Norriss. The breeding population has decreased by 53% (1995-2020). This decline is not dissimilar to that of Common Swift.

Tim Norriss

Hampshire Swifts

BTO and RSPB member


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