Interview: Lynda Huxley on Swift Conservation and Nest Boxes

Interview: Lynda Huxley on Swift Conservation and Nest Boxes

Swift header image (with Quickcrop logo)

Regular readers may remember an exploratory email I published a few weeks ago about conservation grade nest boxes for Irish birds. I had compiled a little survey to see what kind of interest there was in a number of nest box options made by the experts, Schwegler. 

The reason for our move to conservation grade nest boxes was the realisation that many of the domestic products sold in garden centres (including us) may not be ideal for some of our garden birds. The issues may include short product lifespan, insufficient insulation (from both cold and heat) and bright colours which may alert predators to the location of the box. 

a Schwegler 'woodcrete' nest box

The German-manufactured Schwegler products are made from 'Woodcrete': a long-lasting mix of clay, wood fibre and concrete. Apart from the fact that these purpose built nest boxes will last over 25 years, the material also provides a breathable, temperature-regulated home for many of our favourite bird species. 

I am delighted to report that after a lot of interest from readers, we are now stocking a comprehensive range of Schwegler products. As I said in my previous mail about the nest boxes, they may not look particularly attractive to us (not being designed like mini pastel-coloured 1920's bathing huts) but they are very attractive to - and provide the perfect environment for - a wide range of wild bird species. 

tits availing of a Schwegler nest box

We will be further expanding our options in high grade nest boxes and bird conservation products; a journey both myself and Niall are particularly interested in. We very much look forward to providing species-specific solutions that give the best occupancy rates and offer ideal conditions for successful breeding. 

As with any new departure for us, we are keen to learn as much as we can about the subject. Our first really in-depth bit of research involves the swift, a truly remarkable migratory bird that calls Ireland its home. As you will see, I also encountered the equally remarkable Lynda Huxley who has shared her passion for the swift with us and has been a mine of valuable information. 

Here follows an interview with Lynda where she gives us some fascinating insights into the species that she (and the Swift Conservation Ireland volunteers) are doing so much to support. I hope you find it as interesting as I did. 

As regards placing a nest box for any bird species, the very latest they should go up is March - but the further in advance of spring you can get them up, the better. The proverb 'The best time to plant a tree is 20 years ago, the second best time is now' also applies to nest boxes: the sooner you can get them in place, the better. 

Swifts flying over rooftops

Moving swiftly on...
There is nothing better (when beginning a new project) than dealing with an expert that you have full confidence in. Right now, I am thanking my lucky stars that I picked up the phone to Lynda Huxley of Swift Conservation Ireland when I started researching bird nesting boxes. 

We have a lot more to learn (every day is a school day) about supporting our native bird populations, so talking to someone with such deep knowledge has been both helpful and absolutely fascinating. 

It will come as no surprise to learn that Lynda specialises in swift conservation. The swift is a very interesting bird that is sadly on the 'red list' of conservation concern in both Ireland and the UK. After a couple of enlightening phone calls, I asked Lynda if she would do an interview with me so I could share the story of the swift with you. 

If you read on you will learn about a lightning fast bird that flies at over 100 kph, and completes an annual 6,800 mile round trip to Africa where it never touches the ground. You will also learn about the reasons for their dramatic population decline and (unusually these days) about how this can and is being reversed by skilled conservationists like Lynda. 

Lynda Huxley

Note: I am presenting our interview in the same Q&A format that we used on our phone call but - as I didn't record it - Lynda's answers are from my notes and unreliable recollection; they are not therefore her own words. You can take it that the information is Lynda's but, if the sentence gets a bit mangled, that is me. 

Q: There are many wild things that are suffering population decline in Ireland, can I ask why you have concentrated your efforts on the swift?

A: I am not a trained professional ecologist, but have been a very keen amateur conservationist all my adult life. I am also married to a professional ecologist (Chris Huxley), so have had plenty of exposure to field work and professional practice. 

My particular interest in swifts began while working at ATU Mayo campus in Castlebar, where there is an established colony of birds. I began recording numbers and monitoring nest sites on campus in the summer months, and noticed a marked decline in bird numbers returning each year.

A bird in the hand is worth two in the bush

Why are swift numbers declining, is it loss of habitat and the effects of climate change?

The climate change part is difficult to pin down as - while it will be having some effect - it is not the main reason for the decline. We have lost around 40% of our swifts since the 1990s, which coincides with the Celtic Tiger years and the associated building and renovation boom. 

Swifts nest in cavities in walls, or in spaces in the eaves of old buildings which they access through small gaps in the stone work. So when the buildings are renovated or demolished and the nest sites are lost, the number of breeding birds declines. 

Contemporary architecture with smooth, rendered surfaces and no nooks and crannies means that new builds are not swift-friendly unless measures are taken to accommodate them. 

Swifts nesting in an old wall

I know we have some protection for wild birds written into law like the ban on cutting hedges between March and August. Are there any protections in place for the swift? 

Yes and no, but in a practical sense no. Nest sites are protected by law, but only if the birds are in residence during the breeding season. Unfortunately this is ineffective for swifts because the breeding pairs, who mate for life, return to the same nest every year. If the nest site is no longer there - or is inaccessible for any reason - the pair will be homeless and won't breed for that season, and may not in subsequent years either. 

Given that swifts have an average lifespan of 10 years and start breeding at 2-3 years old, this percentage loss of breeding time is very significant. This is especially true for older birds who may not be able to find a replacement nest site before they die of old age. 

Swift migration map

I know that you have had some big successes with new nest sites in Co. Mayo but before we look at that, I'd like to learn more about the swift itself, can you tell me a little about this interesting bird? 

The common swift that we see in Ireland is an extraordinary bird in that - unless a pair is nesting and breeding - they never land. They eat, drink, preen, mate and even sleep while flying. It is thought that swifts have the ability to switch off half their brain while keeping the other side active, which is what allows them to sleep and fly at the same time.

Breeding and rearing of chicks happens here in Ireland in our summer months, with birds visiting between May and September - which I believe makes Ireland their home. When the weather cools, swifts migrate to southern Africa, where they feed in the skies of countries like Tanzania, Mozambique or Namibia. 

The birds don't breed in Africa and are feeding only to spend a full 8 months, 24 hrs a day in flight. I am lucky enough to have been to Namibia and seen 1000s of swifts feeding on termite hatchings (where a new generation of winged termites depart their old colony). It was completely mesmerising to watch. 

a fledgling swift

Interestingly, while swift pairs mate for life, they don't migrate together - so they get an 8 month break from each other when in Africa. We know this from monitoring the nest boxes at ATU Campus (which are live-streamed and recorded 24/7 during the breeding season), as the partners usually return a week or more apart. 

Once the chicks have left the nest, the adult birds tend to remain for a few days to a couple of weeks; going out to feed on airborne insects such as midges and returning to the nest site each night to sleep. When they leave on their migratory flight, they do so at different times, often a week or more apart. 

A swift flying, and possibly sleeping

They must be pretty fit birds if they spend 24 hrs a day exercising? 

They are! Swifts are very strong birds with large pectoral muscles developed for prolonged flight. It is also very interesting to see the behaviour of fledglings in the nest box (seen using nest box cameras) as they literally complete exercise routines to strengthen their muscles before their first flight. 

The first time a young swift leaves the nest is the last time, as once they leave they are no longer fed by their parents. A young swift also needs to be prepared for constant flight immediately because, due to their short legs, a grounded bird finds it very difficult (usually impossible) to take off again. 

Swifts have evolved to have short legs to make them more aerodynamic; a bit like an aircraft with it's landing gear up. This contributes to their flying speed and skills, making them more streamlined. 

Young swifts in a nest box

Young swifts remain in their nest for about 6 weeks after hatching, during which time they are regularly fed by their parents. They have a special adaptation to cope with periods of bad weather: when the parents aren't able to find much food, they can go into a state of torpor to save energy. 

Before their first flight, they need to slim down to reach the optimum weight of around 40g (sometimes losing a third of their body weight), or they will literally fall out of the sky. To limber up, they perform swift 'push ups': where they extend their wings and push against the wall of a nest box or floor of a natural nest site. 

This 'push up' and wing-stretching behaviour is an important point to consider when buying or building a swift nest box, as young birds need enough room to do their exercises to ensure a successful fledging: they only get one chance. 

I think the minimum size I would recommend for a swift nest box is 32cm x 15.5cm x 15.5cm, which is larger than some boxes on the market. The size of the entrance hole is also very important. I use nest boxes with an entrance hole of 29mm x 65mm, which is perfect for swifts. 

A swift with a visible food pouch

What do swifts eat? 

Unsurprisingly for a bird that spends most of its life in flight, swifts are aerial feeders that prey on flying insects: aerial plankton such as midges, flying ants and airborne spiders. Swifts have evolved to be fast (they can fly at speeds over 100kph) and very manoeuvrable, making them highly effective insect predators. 

A single swift can eat as many as 100,000 flying insects a day - so if you are bothered by midges around your house, attracting a swift colony may help! 

A nutritious swift 'Bolus'

During the breeding season, the swifts have an unusual way of collecting food to bring back to the nest for the chicks: they collect and store insects at the back of their throat. The ball of crushed insects (referred to as a 'bolus') is bound together with their saliva, and is brought back to the nest to feed chicks in the breeding season. 

I have supplied some images which include the photo above showing a swift returning to the nest with a bolus of food clearly visible in its throat pouch. You can also see the bolus itself, which can contain between 500 and 1000 nutrient-rich insects. 

Castlebar ATU

Can you tell me a little about the success you have had in building swift numbers in Co. Mayo, and how you have managed it? 

The decline in national swift numbers is somewhere between 40 and 50%, with the worst areas being city centres like Dublin and Galway where numbers have plummeted. As we've said, the main reason for the sharp drop is the loss of nesting sites when our urban buildings are renovated or demolished. The remedy, then, is a relatively simple one: provide more nesting sites. 

We have been adding purpose-built swift boxes to buildings in Co. Mayo since 2012, and are very happy to report that we are now seeing a 30% recovery so far. This is good going, as the Mayo landscape was not initially considered ideal for the swift. The scale of the recovery is such that we can be confident that, if nest boxes are provided across the country, then populations will recover over time. 

Swift box screwed on to facade

Jarek Majkusiak did his Masters research on the Breeding Biology of the swift in the west of Ireland, and during this research he viewed and analysed tens of thousands of hours of recordings from the ATU Castlebar nest box project. 

He was able to confirm that the chicks developed well, and were well fed and fledged in the normal time of around 42 days old. We can therefore conclude that, for the Mayo swift at least, we had an accommodation problem rather than a decline in the swift's food source. 

Built-in swift boxes within the facade of Westport Town Hall

If readers would like to help support the swift, what are the best nest boxes to use? 

There are a number of different types available on the market, including wooden or masonry designs and units that can either be fixed on a wall or built into a wall. 

I personally prefer not to use wooden boxes because we are trying to build permanent swift colonies. If we take into account the 10 year lifespan of a swift, and the fact that they return to the same nest site every year, a wooden box will rot over that time and leave breeding pairs homeless. 

While it is not always practical, the very best option is a built-in swift brick or multiple swift box unit, as these nesting sites will then last the lifetime of the building. A built-in block will also regulate temperature better as it is part of the wall, so is more protected from the elements. A built-in system takes no extra time to install in a new build situation, but can also be retrofitted in suitable brick or block facades. 

The picture above shows swifts inspecting built-in nest boxes on the facade of the recently renovated Westport Town Hall in Co. Mayo. This was the first project in the Republic of Ireland to incorporate swift nest boxes into the fabric of a new wall. This was very quickly occupied by swifts, and proved to be so popular with the birds that there are now new public buildings in most towns in Co. Mayo that have built-in nest boxes. 

A swift box at ATU Mayo campus

The same built-in triple box unit (the Schwegler 17A) can also be fixed to the outside of a building. This is the option used at ATU Castlebar on the cut stone faced buildings. These nest boxes are made from a breathable concrete, clay and wood fibre mix which is very strong and long lasting. The ATU project has 6 such boxes installed in 2012, and they are all still in perfect condition. 

Swifts are colonial nesters and for this reason I ensure that every project I set up has several nesting compartments. This can be either using a multiple compartment box like the Schwegler 17A, or several single boxes such as the Vivara GZ 10. Once you have one pair in residence then your colony should grow year on year. 

Andrew's note: Quickcrop now stock the Schwegler 17A and expect to also be carrying the Vivara GZ10 in the coming weeks. 

a swift exiting its nest

When you mention new builds earlier, it reminded me that some people may be concerned about swift droppings making a mess on their lovely clean walls. Is this an issue? 

No, swifts have very clean nest sites because they don't perch at the nest entrance. There are no droppings from them either on walls or below the nest site. Because there are visual similarities, swifts, housemartins and swallows are often confused with each other, but their nests and nesting habits are very different. 

Housemartins build mud nests under the eaves of houses and swallows build mud in outbuildings. Both the housemartin and swallow leave droppings below their nest sites. This is because the chicks put their droppings over the edge of the nest rather than make a mess inside the nest. 

However swift chicks put their droppings close to the nest bowl, and the adult swifts recycle the droppings by eating them so also keep the nest site clean in this way. This also means the nest boxes don't need to be cleaned out, as swifts are excellent housekeepers themselves! 

a Swift caller system

If bird calls attract new breeding pairs to the nest site, how do you encourage birds to colonise a new site where there aren't any existing swift nests? 

An essential part of any swift nest box project is a swift caller system. This is simply a small electronic device that plays a recording of the swift call through a speaker. There are plenty of articles online detailing how to make a budget system from readily available parts, but there are also pre-built systems available if you aren't tech savvy. 

If you are starting a new colony of swifts, you will be attracting birds that just happen to be passing - so I would say don't get disheartened if your box doesn't get occupied in the first year. In some cases it can take a few years to attract a new pair but, once they have occupied the box, they will return every year. 

a blue tit on a branch

If I put up swift boxes and they are not occupied, do other bird species use them? 

Yes, tits or sparrows may use the boxes if they are not occupied, but a swift will oust them if they want to take over. The reason why I recommend a nest box with an entrance hole of 29mm x 65mm is because this is generally small enough to prevent starlings from entering. 

Starlings are lovely birds but they can be an issue because they will oust swifts from a nest site and also because they bring in unsuitable nesting material which may prevent swifts from occupying the box in the future. Tits or sparrows use similar materials to swifts so don't pose a problem, in fact they can provide a very comfy ready made mattress for a swift nest bowl where they can lay their eggs. 

Peekaboo!

If I am adding a nest box to my house, how high does it need to be and does it need to face a particular direction? 

A nest box should be a minimum of 4.5 metres above the nearest flat surface: this may be the ground or an adjoining flat roof. As regards which direction to face, a north or east wall is best to avoid temperatures inside the box getting too high. 

Installation is possible on a west-facing wall, provided there is an overhang to provide shade for the full day. Never install a box on south facing wall, even if there is shelter. Chicks can die if a nest box gets too hot or will eject themselves to escape the heat. 

a swift drinking

That's it! 

I would like to take this opportunity to thank Lynda for her time and for providing me with so much interesting information. I think you would have to agree that the swift is a fascinating bird that deserves all the work that Lynda and other conservationists are putting in to reverse its decline. 

It is also very encouraging to hear how successful Swift Conservation Ireland have been in Mayo, especially as the county would not have been seen as prime swift territory. It is nice to see the old adage 'build it and they will come' applying to a work of conservation rather than a new shopping centre or leisure complex. 

It is all the more satisfying as Lynda and other Swift Conservation Ireland volunteers have shown that, in the case of the swift, it really works.

Where can I get more information?

Swift Conservation Ireland - website 

Birdwatch Ireland - Saving Swifts - online book