Virtual Talks: Swift Q & A and other updates

David Campbell’s talk was much enjoyed by well over 300 people and led to so many thoughtful questions that a large number could not be answered in the time available, and are dealt with below.

Please also note that not all the talks will remain permanently on the SOS YouTube channel as guest speakers may update their talks and prefer for older versions to be taken down.


Question Answer(s)
1 We know a nest hole has been blocked up over the winter. Is there anything we can do as the swifts will be back in May and want to access their active nest The situation and type of nest hole in this question is unclear from the question, but doing everything you safely can to clear access for the birds before they arrive will give them the best chance of successfully nesting this year
2 Why do swifts appear to flick alternate wings? This is an illusion usually produced when a Swift is performing aerial manoeurves requiring the wings to beat with unequal force. This, together with the general speed with which Swifts beat their wings, causes the eye to only perceive one wing’s action – but they never beat alternately.
3 Do swifts need to drink, or do they obtain sufficient moisture from their food? Yes, they do need to drink. You will often see them scooping water from lakes and accessible rivers.
4 Where are the main Swift colonies in Kent & sussex ? Brighton and Chichester have some of the biggest numbers of Swifts in Sussex. I’m less certain about Kent but it seems Bromley and Canterbury are examples of towns with good numbers of Swifts.
5 Why can’t we pass a law that every house built has to have a nest brick?! This would be ideal. However, the structure of the planning system means it’s something we currently need to work with on the level of local authorities.
6 If you take baseline further back is there not an even greater decline ? What about declines in insects?

New development opposite me is supposed to be having swift bricks installed. How successful are they?

Shifting baseline syndrome is a genuine issue. The point in time to compare populations against is a subject for endless discussion. For Swifts, should we measure from when they were a part of life in just about every settlement? Or when they nested in trees and cliffs? We have to work with the data we have, which mostly spans the period of declining availability of man-made nest sites. Swift bricks can be very effective. The best chance of success is within or near an existing colony, with the aid of electronic Swift call playback.
7 Do you think Swift bricks/ integrated boxes are an effective way to help swifts? Absolutely. They are the most durable, and aesthetic, solution we can offer Swifts.
8 Do Swifts not appear in Italy or Greece? They do, and both countries also have nesting Alpine Swifts and Pallid Swifts
9 Any problems with putting up a box near boxes for house Martins/ swallows? There shouldn’t be a problem. These species have such different nesting behaviour and do not compete directly for their insect food supply, which can be found across a wide area.
10 How many swift conservation groups are there in sussex? There are groups in Brighton, Chichester, Hastings, Henfield, Horsham, Lewes, Steyning, Winchelsea and now Worthing
11 Greening Steyning have a small swift group. If we want to get our community out listening for the screaming and finding out where they are looking , would we best to focus on the end of June? The end of June would be a good time. Any time in June or July would work and remember evenings are best. Screaming Swifts aren’t proof of breeding but will be your first lead to an area where they might well be nesting. It would be good to set up a line of communication between the group you mention and the SOS, could you drop us an email at
12 Is it easy to retro fit a swift brick? No, but it is possible. See here for advice
13 Can we make additions to buildings to make potential swift nest sites? E.g. in barns/outbuildings/eaves? Are these preferable to swifts than next boxes? If you have the know-how, this kind of work could be a viable alternative but you’d really have to get it right. However, Swift bricks and boxes are known to be successful and will be easier to install.
14 Are there any colonies in Worthing? Yes, there is a colony around where I live in West Worthing and there are a number of other areas in the town with breeding Swifts. We have just started a local Swift group: look up Worthing and Adur Swifts on Facebook.
15 How do you limit sparrows from getting into swift boxes before the swifts arrive You can block the entrance if you like but please be absolutely confident that nothing is nesting in there if you do, and remember to unblock it before Swifts arrive back. House Sparrows need nest sites too, so consider offering them their own boxes and remember a determined Swift will oust nesting House Sparrows.
16 Where is the best place to put a nesting box? On a building at least 4.5 metres high with a clear flight path ahead of it and out of the strong sun.
17 David, I live on a new development, during the final construction phase the developers wanted to install swift nest boxes. The residents were opposed owing to the perceived threat of ‘guano’ down their walls. Have you any thoughts and assurances as to how we may counteract that ? You could show them footage or images of Swift colonies or point out that Swifts live in many settlements but give no evidence of their presence besides their screaming parties in the evenings. If you know a local Swift colony, perhaps you could show them the birds? Many people don’t even realise they have Swifts nesting in their building. Hopefully they’ll take my and many other enthusiasts’ word for it, too.
18 I’ve just contacted a green counsellor in burgess hill to ask she pushes for swift’s to be considered with all the Burgess Hill town development plans and new builds – she will push for discussion I hope! Is there anyone specific she can contact if there is a need….? Great! She’s welcome to drop me an email at to discuss how to move forward.
19 How high up should swift boxes be? At least 4.5 metres off the ground.
20 The survey forms that you mentioned – where is the data submitted? If this different to recording on birdtrack or swift mapper? The forms are designed for use by local Swift groups to collect detailed local information that can inform their work; the forms may be helpful to then transcribe the key information from the surveys (dates, numbers, location, breeding evidence) into BirdTrack, but you don’t need to do it that way if it doesn’t work for you.
21 Thank you for arranging this evening’s talk. Re the 53% decline in Swifts in the UK, are some of the swifts which previously came to the UK, now spending the summer further south on the Continent? You’re welcome. It’s unlikely that the birds have moved to another part of Europe. Unfortunately, the decline will be an actual fall in numbers due to poor breeding success and perhaps increased mortality.
22 Playing swift calls is commonly recommended to encourage swifts to take up a nest box. However, I have read that playing calls is replicating the natural process whereby swifts will call from an occupied nest to ward off others from entering and potentially starting a conflict. Could playing these calls actually discourage swifts from looking into a box? Playing Swift calls is important to draw birds’ attention to a potential nest site. When prospecting birds arrive in an area, they are using the auditory signal of calling birds to home in on colonies and investigate whether it might be worth nesting there in the future. They may ‘bang’ against boxes or attempt to enter them to gauge occupancy. Once you’ve got the attention of a Swift or a pair of Swifts, you’re correct that it’s best to then switch off the recordings so that they can consider the site theirs.
23 How big is a colony? Colonies may comprise just two or three pairs or in some cases several dozen, though these days such large colonies are scarce and tend to be less dense.
24 After at least 40 years, we did not have swifts nesting successfully last year. They returned for about 2 weeks but the nest failed. How likely are they to return this year? We miss them. It’s entirely possible they’ll give it another go this year, or that another pair will take on the site. If they don’t arrive on time, after a ‘grace period’, it might be worth playing Swift calls near the nest site to attract interest from other Swifts
25 Is it only really likely to be worthwhile to put up a swift box if they are already in the area, and when is best to erect them? Your chances of success are far higher if there are already Swifts in the area but there is no harm in putting boxes up if there aren’t currently any Swifts near you. There’s always a chance they could be taken up by Swifts at some point. Boxes can be erected at any time but if you’re thinking about it now, try to get them up before May so that Swifts have a full season to find the opportunity.
26 Do swifts ever nest in rural areas? Yes, you will often find Swift colonies in small villages and hamlets in rural areas.
27 Will having ponds in our gardens help increase the number of air born insects? There are countless insect species which will emerge from even small water bodies, so building a pond in your garden is a fantastic way to boost insect biomass.
28 Can swift nest sites be protected from a developer modernising houses? Swift nests, as in all wild birds, are protected by law when in use. If you are aware of plans to work on a building when Swifts are nesting, and it might affect the birds, please do get in touch with the landowner and/or contractor. If you see a nest in imminent threat and workers ignore your advice, you can contact the police. Unfortunately, nest sites are not protected by law when a breeding attempt is not underway.
29 Although birds of colonies, are there any territorial issues with nest boxes being side by side? Entrances shouldn’t be cheek-by-jowl if it can be avoided, as sometimes Swifts do get confused about which entrance is there nest, which can lead to fights inside boxes. Space out your boxes as much as you have the room for, but as colonial birds they can cope with sharing, say, a normal-sized house with three or four other pairs.
30 What is the evidence like for painting the insides of boxes black? Would a chalk paint be best if on the inside of the box? There is evidence that painting the interior of Swift boxes black boosts success. Chalk paint might shed onto the birds or the nesting material. I’m no painter or handyman but would advise using a non-toxic matt emulsion.
31 What direction should a nest box face? Avoid putting boxes on walls which face southeast, south or southwest, unless they can be well-shaded from the heat of the sun, and only then if there is no other option. Other directions are fine.
32 south facing boxes why no? I have a number up and swift are using them. There is a danger that young will overheat if boxes are facing the worst heat of the day. Some materials may reflect heat better and some situations will give boxes better shade but the general advice is to avoid fitting boxes on south-facing walls.
33 I was keen to try and get some swift boxes up this year in and around my local village – but it sounds as if I’d be better off doing a survey this year first, to see if/where we have a population and build on this next year. Is that about right? Thanks If you have the time and means to install the boxes this year, please do. And if you do, you can always record whether the new boxes are being used or visited and then work out how this might affect your interpretation of your survey results. The most important thing, though, is to provide Swifts with new nesting opportunities as quickly and effectively as possible.
34 How do you ring a swift? Young are either ringed in the nest (with great care to avoid disturbance) or full-grown birds are caught on the wing by ‘flicking’ a mistnet: the net is held at each end and pushed upwards into the path of flying Swifts, while a third person carefully extracts the birds from the net
35 How is the population of swifts doing in Lewes 64 active nests were recorded in Lewes in 2020. Comparing six Swift colonies in Lewes against numbers in 2000, numbers were down by 52% in those 20 years. However, Lewes Swift Supporters is doing excellent work to understand and boost the local population.
36 If I have a swift box, is it OK to also put up boxes for martins/swallows? There won’t be a problem. These species have such different nesting habits and do not compete directly for their food supply, which can be found across a wide area.