I have devoted a large part of my life to swift conservation but in recent years I have felt anxious that many other species deserve the same level of attention- starlings, spotted flycatchers, house and tree sparrows etc.. The house martin is another of these species. They are now red listed as birds of global conservation concern and numbers seem to have declined considerably in the last three years on top of an already long term decline. Sadly they don’t seem as easy to help as swifts- attracting them to new areas with artificial nests can be difficult. However if you can attract them, artificial nests provide a guaranteed safe nesting place for house martins. At a time when numbers are low these nests encourage maximum breeding efficiency because they don’t have to spend around two weeks building a new nest. Well designed artificial nest cups also prevent take over from house sparrows and predation from great-spotted woodpeckers, grey squirrels, tawny owls etc.
Personally I would not like to to see a world where all house martins nest in artificial nests. As a child I remember the fascination I had looking at natural house martin nests on my walk to school and marvelling at their construction and structure, but good artificial nests ensure a stable and safe breeding solution for these birds while their population struggles against decline- many of the fledged young will return to nest naturally in other areas. We need to educate people about house martins- fewer and fewer people have even seen house martins because their nests are no longer a common sight in our streets.
We have been very fortunate to attract house martins to four of the houses we have lived in; once you have lived with these birds it is hard to live without them. They are delightful companions through late spring to late summer and remain for weeks after the swifts leave, keeping the sounds of summer alive. They nest very happily alongside swifts and the two species seem to attract each other. I have mounted house martin nest cups next to and under swift boxes and there is rarely any conflict. I have described here some of my efforts to attract house martins starting with a diary of a typical house martin summer. Finally there are some links to recommended artificial nest cup suppliers which I have used and found effective against predators and takeover by house sparrows.
Previous spring and summer blogs featuring house martins can be read in my blog archive on this site.
A summary of a typical house martin season in the UK
This is a guide to a typical summer in the UK. There will be many variations but I have tried to describe an average summer from many years of my notes of house martin behaviour.
April
The first house martins arrive. These early birds are mainly birds that bred last year. Here in Yorkshire they usually arrive from the middle of the month and clearly recognise local nest sites as they tour around them to see if other martins have arrived. This early arrival may give them an advantage as they roost in and occupy the most well preserved nests. They are the ‘tip of the iceberg’ and often remain in low numbers or even alone until early May. Nevertheless in warm weather, particularly towards the end of April a few pairs may form and start to breed. These early birds take a gamble and often experience very cold weather, especially further north- I have watched house martins in snow showers. They can often be found feeding over local lakes and reservoirs during the day where most insects are found, only visiting nests to roost.
May
Good weather in early May sees big arrivals of last year’s breeding house martins. Pairs form quickly and both sexes start building a nest or repairing last year’s nests before laying eggs. Birds using artificial or undamaged natural nests can start breeding immediately, usually lining the nest cup with bits of grass, moss and feathers. Poor, cool weather can push this activity back and delay the breeding season. In such weather throughout the summer house martins often have to feed very low over water, or very close to tree canopies to glean insects. They often feed on the sheltered side of woodland in windy weather.
From mid May into June the first time breeding birds (born last year) arrive- this new influx can be very obvious as activity at colonies becomes more frantic. They start touring existing nest sites or looking at new buildings searching for a place to start building a nest. These are the birds most often attracted to new areas with artificial nest cups so this is a great time to play calls. They can start nest lining and egg laying right through to late June or July.
Males perch on potential nest sites or enter last year’s nests and attempt to attract a mate. They use a harsh “chi chi chi” call from the site as a female approaches. With luck she will stay. The pair may ‘chatter’ intensely at the nest site. If a new nest is being built the pair will roost on it as soon as a substantial foundation ledge has been constructed. A new nest takes around two weeks to complete though this can vary according to weather conditions.
This is also the time when you can make a big difference by maintaining mud supplies if the weather is dry. I recall one spring in Ampleforth when birds totally stopped building in fine weather. I watered the main source of mud which had dried up and they started building immediately.
June
Some first time breeders are still looking for nest sites, so it is well worth playing calls if you have artificial nests on your house. It is common for first pairs to be attracted in late May and the first half of June. In addition there is always the possibility of attracting older breeders whose nests have collapsed continuing into July and even August.
Meanwhile established breeders that laid eggs in May are feeding young. By the middle of the month the first young martins will have fledged. These fledglings will roost in the nest for a while before the adults begin laying a second clutch.
First time breeders might be laying eggs or incubating by the end of June.
July
July sees the peak of colony activity with first time breeders and last year’s breeders all on eggs or feeding nestlings. Non-breeding birds may well be visiting colonies. Fine weather often sees the martins feeding very high especially in the afternoon.
Juvenile house martins independent of their parents can sometimes be seen going to roost in trees. Fast flying groups whizz around tree tops at dusk then suddenly disappear. They enter the tree canopy very fast and often near the top so you have to watch very carefully.
You may well see non-breeding swifts being attracted to the house martin colony. They often follow individual house martins in towards the eaves and frequently land on house martin nests for a look. Last year we had 3 pairs of swifts and 3 pairs of house martins in a 7 ft section of eaves. The two species live harmoniously together. It is not uncommon for recently fledged house martins to enter a swift box. Usually this is a brief mistake, however last July one entered swift box 2 and spent 11 nights roosting there. It left by day and was fed by its parents, but always returned to roost with the swifts who totally accepted it in the nest. Similar happened the year before when a young house martin stayed with swifts for several hours.
August
Lots of house martin nestlings are still in nests. Some of these are the second broods of older birds. Particularly during the second half of August large numbers of house martins from nearby colonies may gather at your colony and enter different nests including unoccupied nests. Some may add nest material but do not breed, probably in preparation for next year- these pairs may roost each night until it is time to migrate. Others randomly visit nests and sometimes roost in them- some of these birds may be on passage using the nests as a temporary roost.
If you look closely many of these birds are young from this year with browner plumage and obvious pale fringed tertial feathers. Playing calls can often attract these pre migration flocks which might help you attract new birds next year? These gatherings can be quite spectacular with dozens of birds involved especially on sunny mornings.
September
Lots of gathering flocks are preparing to migrate. These can involve hundreds of birds. Large numbers leave around the middle of the month with some spectacular gatherings around cliffs on the South Coast of England involving thousands of birds. Some late broods are still in nests being fed by adults that resist the urge to migrate with the aforementioned flocks. These late nestlings may fledge later in the month, though by then they can be vulnerable to cooler weather.
By the end of the month a small proportion of the summer’s house martins remain. You may well see straggling groups into October before finally sightings become very scarce then non
existent.
A history of our house martin colony in Gilling East
To progress from no house martins to 31 fledged young in just three summers shows how rewarding providing artificial nest cups can be!
2017- 2019 6 artificial nest cups installed but no nesting pairs attracted. Calls frequently played and usually ignored despite house martins nesting about 100m away.
2020 first pair arrives June 26th(I had stopped playing calls) and breed, fledging three chicks. A second non-breeding pair occupy another nest cup throughout August, roosting every night and adding some nest material. Total: 3 young fledged
2021 3 artificial nest cups occupied. 2x double broods, 1x single brood. Total: 15+ young fledged
2022 6 nest cups occupied. 4x double broods, 2x single broods. Total: 31+ young fledged
2023 5 nest cups occupied. At least 32 young fledged.
House martins in 2021
We were fortunate to see our colony grow from one breeding pair in 2020 (our first) to four pairs in 2021. These four pairs fledged at least 15 young. But this felt bittersweet because across the UK many established colonies saw a big reduction in numbers or a total collapse.
Our first bird, a male, returned on April 26th, joined by a few more in early May. We attracted four pairs which raised a total of six broods. We do not know the cause of the sudden drop in house martin numbers in 2021, it is more than likely the cold spring had an effect, but the question is were the birds prevented from coming here by the cold or did some migrate into the cold and die? The second wave of first time breeding birds seemed to arrive as usual later in May and June, at least they did here in Gilling East.
House martins 2022
I am very happy to say 2022 was up on 2021 with six pairs breeding in artificial nest cups. Those six pairs fledged a total of at least 31 chicks. 4 pairs were doubled brooded and two pairs were single brooded.
The artificial nest cups have again enabled them to start breeding quicker than they would if they had to build or repair nests. This maximised breeding potential so hopefully our house can serve as a reservoir for the wider local house martin population.
Sadly though our colony doesn’t tell the real story of general decline in the area with many former breeding sites deserted. We can only speculate on the true cause, but I suspect it is a perfect storm of different factors, but especially poor weather with Northerly prevailing wind on spring migration 21/22 and low average temperatures in May/June 2021. Add to this mud supply, reduced insect numbers and climate change which could influence them throughout their range.
Still we are doing our best for them here in Gilling East. I put a leaflet holder on our gate to dispense HMCUK-IE leaflets which are certainly disappearing quickly. I am adding sections on house martins to all my swift talks and generally doing my best to communicate with those lucky enough to have these gorgeous little hirundines.
House martins 2023
We had five artificial nests occupied in 2023 but productivity was better meaning at least 32 chicks fledged. The season got off to a very cold start with cold winds off the North Sea lasting well into June. From what I could see though most villages saw an increase on 2022 numbers with some people reporting returning house martins after a couple of years of absence. About two miles from here the large colony at Ampleforth Abbey looked much stronger compared to 2022. So some grounds for hope of a recovery from the very poor summers of 2020/21.
House martins and swifts
We have eight artificial nest cups on our house and this undoubtedly give our pairs an advantage because they don’t spend time and energy building new nests after their long spring migration. It was a great joy to have them nesting on the house and to know that we gave four pairs the best possible chance of success in such a poor year. They shared the eaves with three pairs of swifts without any problems and on many occasions it has been easy to see that the two species benefit from the other’s company, especially in signalling the alarm when predators are near. They also share similar feeding habits, both feeding on insects high up in the air during fine weather and much lower down in poor weather.
At each house we have owned with both species nesting (3 houses now) it has been common to observe non-breeding swifts following house martins in to the eaves or prospecting house martin nests. House martins can attract swifts to your eaves and swifts can attract house martins to your eaves. Occasionally this was a problem as the ‘banging’ swifts knocked chunks of mud off natural martin nests with the extra force of their landings, but these nests were soon bolstered up by their rightful owners. But having house martins certainly seems to help in attracting swifts and vice versa. Last year in section of eaves just 7ft long we had 3 pairs of swifts and 3 pairs of house martins breeding.
Some artificial house martin cups are placed directly underneath or next to swift boxes and all were occupied. One house martin cup is positioned so my son can watch the martins from his pillow; careful positioning can offer a great opportunity for children or adults to engage with nature. Turning the boxes to face along the eaves allows great viewing from inside the house.
Playing house martin calls
I played house martin calls each year from 2018. The first two seasons saw no effect; despite having house martins nesting within 200m a wide variety calls were almost completely ignored. I had completely stopped playing them in June 2020 when a pair suddenly occupied a nest box. Soon after this two other pairs occupied nest cups for most of July until September, but only the one pair nested. The two non-breeding pairs acted very like non-breeding swifts, always roosting at night and visiting and nest building during the day but never actually laying eggs.
Before our first breeding pair we often had large numbers of house martins attracted to our house and even entering artificial nests when calls were played in late August and September. These were presumed to be passage birds that returned to their chosen breeding areas the following spring. This was exciting to watch but it never resulted in a nesting pair the following spring. I have regularly attracted house martins to calls, but they were always enticed away to existing nesting areas- in other words attracted more by the sight of real house martins. That said, it is quite possible that the calls put our house ‘on the map’ for prospecting martins who later returned. Plenty of observers report success with calls so definitely try them from April to September, but particularly May and June when first time breeders arrive. There is plenty of room for experimentation in this area. Like swifts preference for prospecting martins seems to be early to mid morning with the addition of regular midday, late afternoon and evening prospecting sessions.
Anyone can try experimenting with calls to attract house martins to nest. I have not seen any evidence that calls have worked at three different houses, but others report differently so give it a go and share your results with others.
Predation and nest take over
House martins are very vulnerable to predation. Natural nests are easily dismantled by great spotted woodpeckers, some crows and even tawny owls. Once one individual of any of these species learn that the nest contains food it can be a serious problem easily wiping out colonies. In recent years I have received at least three reports of tawny owls predating house martin nests at night. My wife saw a tawny owl sat on our bedroom windowsill looking up at an artificial nest containing adults and chicks- fortunately in an artificial nest they were safe.
We have learned that house martins can use nest entrances of just 20mm depth. Well designed nest cups can prevent sparrows from gaining entry. As sparrows have declined provision of nest boxes for them perhaps away from the martins is beneficial.
Droppings
House martins are not great at their own PR! They do create piles of droppings but these are easily cleared. A temporary covering over vulnerable paintwork or white UPVC can be a good idea, but the privilege of having these birds nest so close far outweighs the disadvantage of a little bit of cleaning up every so often. Shelves can be put up above doorways if necessary, but always place these at least 2m below the nest site so as to not give predators a perch and to allow safe approach by the martins. If current house owners are not keen try to educate them about this amazing species and offer some solutions.
A final thought
The joy these birds bring to our family is immeasurable. We see their breeding cycle play out just a few feet from where we sit. Waking up to their calls and song by an open window is one of summer’s greatest pleasures. But they are also incredibly beautiful to look at- study a house martin closely and just look at the inky blue upperparts contrasting with clean white underparts. Their flight is spectacular as they gracefully arc down to their nests, sometimes narrowly avoiding swift screaming parties! On fine days you can watch them leave their nests and ascend to great height to join swifts feeding on airborne insects. I love to lie on my back and see them feeding as specs in the sky even through 8x magnification binoculars. Unlike swifts they tend to stay close to the colony more often as they cannot carry a bolus of insects and as I’ve mentioned they stay long after most swifts have gone providing pleasure right through to September.
Artificial nest cup suppliers
All nest cup suppliers are not the same. Some are distinctly substandard, for example many have entrance holes easily big enough for house sparrows to enter. This would probably also mean a great spotted woodpecker could hook the contents out by turning its head and using its long beak. In recent years I have only bought nest cups from the following suppliers.
Paul Stevens makes very realistic house martin nest cups. They have minimal entrance hole height which excludes sparrows. They are also nice and deep to allow a nest cup at good distance from the entrance. Enquiries by email to
paulnatterjack@googlemail.com
Peak Boxes make a superb lightweight artificial nest cup with a minimal sized entrance hole which will prevent takeover by sparrows.. They also make house martin towers. Click here to order https://www.peakboxes.co.uk/species/house-martin Peak Boxes also make a superb range of swift boxes.
Schwegler house martin cups. They make a variety of configurations, have small sparrow proof entrance holes and a nice deep nesting area. This is Schwegler’s website- there are several UK suppliers of their nest boxes. I have used these since 2004 and they have been faultless.
https://www.schwegler-natur.de/vogelschutz/
CJ Wildlife sells a good range of durable nest boxes for house martins. See link here https://www.birdfood.co.uk/nest-boxes/specialist-nest-boxes
HOUSE MARTIN CONSERVATION UK AND IRELAND
I am very glad to serve on the committee of House Martin Conservation UK and Ireland, an official charity founded by the incredible Ian Donovan who like me saw an urgent need to give this bird some tlc!
Here is a link the House Martin Conservation UK- IE website: https://housemartinconservation.com/
Please feel free to download and display or distribute the A5 flier below. Putting this on display in local shops, village halls, notice boards etc. may encourage your community to care for and enjoy house martins when they return.
Download and print the House Martins Welcome Here poster to put on buildings with house martin nests. It is an effective way of raising awareness of the species. https://housemartinconservation.com/resources
Gallery- sketches of house martins at our colony
All these watercolours are sketched from life, sometimes with the aid of a telescope to obtain really detailed views. Some of these sketches are available in my Big Cartel shop, please see link https://jonathanpomroy.bigcartel.com/
Alternatively please ask if you are interested in purchasing original artwork.
All images and text on this website are copyright Jonathan Pomroy 2024
Jonathan Pomroy 