Black Redstarts - The Boomer Bombsite Bird
When you run a website it can be very tempting to spend too much time digging into the multitude of stats you have at your fingertips rather than actually, you know, running the website.
Checking in on your daily traffic numbers, your bounce rate, new visitors and the keywords you’re ranking for is of course important but it’s easy to get lost in the minefield of numbers available to you. However, there is one stat that has stood out now for a number of months and was too interesting not to delve into. And that’s the number of people who arrive at Bird Spot looking for information about black redstarts.
With just 400 wintering birds and only a handful of breeding pairs the numbers seem disproportionate. We also notice an unusually high number of photographs or ID requests for black redstarts posted on our Facebook group.
Until the first half of the 20th century the black redstart was an even rarer bird in the UK. There are two isolated records of it breeding in Co. Durham and Sussex in 1841 and 1909 respectively, and it is first reported to have bred in London at the Wembley Exhibition Centre, in 1926. But it wasn’t until World War II that its population started to increase.
Black redstarts are much more numerous in continental Europe with the breeding population estimated at anything from 5 to 10 million pairs. Its natural habitats include cliffs, rocky hillsides, and mountain gorges and gullies, where it spends its time perched amongst the sparse vegetation in an upright stance quivering its tail, before hopping to the ground to search for insects and berries.
After the Blitz the bombsites of central London provided an ideal habitat for the black redstart with the shells of buildings and weeds growing amongst the stony wastelands mimicking its home abroad. By 1964 it was estimated that there were 16 pairs of black redstarts in Cheapside. As it moved across London it found a home in the old docks of East London with the disused buildings and close proximity to open water providing it with shelter and insect food such as gnats and midges.
The black redstart also thrived in other cities in the UK, in particular in Sheffield and the Black Country, where the collapse of the manufacturing industries gave them suitable nesting sites. Black redstarts seem to prefer structures with vertical features such as gantries, cranes, stairways, and gas holders and are sometimes referred to as the ‘power station bird’.
However, with the redevelopment and regeneration of these sites in the 1970s and 80s the black redstart population began to decline. Although the birds in London moved further east along the Thames to areas such as the Lee Valley as well as to industrial complexes at Park Royal, White City, and Croydon, the overall numbers diminished. Similar effects were noted in Sheffield, Birmingham, Nottingham, and Ipswich. In 1986 it was estimated that there were an estimated119 pairs of breeding redstarts in the UK: by 1991 that number had dropped to just 69 pairs.
A protected species
In 1981 the Wildlife and Countryside Act was implemented in the UK to comply with the European Council Directive on the conservation of wild birds. The black redstart was given Schedule 1 protection under the act which means it is an offence to intentionally or recklessly disturb it, its eggs, or nestlings during breeding season.
In 2000 the legislation was strengthened which meant that the disturbance of Schedule 1 birds during breeding season could lead to prosecution.
What this meant was that operations such as the demolition of buildings was controlled by the act and landowners and site managers had to take more responsibility of sites where black redstarts were known to have bred or were likely to breed.
Initiatives such as green roof habitats in London and Sheffield have encouraged these little birds back into the inner-city developments they adopted as their second homes. Bill Oddie in Radio 4’s Tweet of the Day said that he had heard a black redstart at Kings Cross station and since 1990 breeding black redstarts have been recorded in a number of London boroughs including Camden, Greenwich, and Tower Hamlets.
Despite this work the RSPB estimates that there are still only between 19 and 44 pairs of breeding black redstarts in the UK.
Doing the maths
Which brings us back to the numbers. The more we looked into things the harder it was to get a definitive answer about the black redstart’s population size. For example, although it was estimated there were 119 pairs breeding in 1986 only 81 were confirmed. In 1995 there were 19 confirmed pairs but an additional 63 possible pairs. So why the discrepancy?
It turns out that the black redstarts of Wembley may give us a clue.
The Wembley birds started breeding the year after the British Empire Exhibition shut its doors. 3 pairs bred every year from 1926 to 1941 and they were joined by a fourth pair in 1937. The first three pairs chose a spot on a ledge above a door used for deliveries in the Palace of Engineering while the fourth pair built its nest in the old power station.
In 1942 the Palace of Engineering once again opened its doors to lorries and the black redstarts moved out.
Despite 15 years of observation by both a caretaker employed by the Wembley Trust and a leading ornithologist, the presence of black redstarts at Wembley was never officially recorded because it was considered so unlikely.
Another clue comes from the big increase in numbers of black redstarts recorded after the war. The large increases in recorded breeding pairs in the late 1940s was not necessarily due to an actual increase in the number of birds but partly due to bird watchers returning from the battlefields who started counting and recording black redstarts again.
We know black redstarts nest in urban areas that people don’t often go on a day out birding. Some of their chosen breeding areas may in fact be too dangerous for humans to access and we can’t imagine many bird watchers choose to spend a day at their local railway station looking for birds if they have an expanse of open countryside on their doorstep.
The ‘plural of anecdote is not data’ is often used to prevent us from using a single example of something we have observed or heard to extrapolate to a broader rule. But did you know that the phrase is actually a misquote and the original quote by Ray Wolfinger a political scientist and professor at the University of California at Berkley, was the exact opposite? When Wolfinger said ‘the plural of anecdote is data’ he was asking us to look deeper into our experiences to find out whether a compelling anecdote was merely an interesting one-off or preliminary evidence that could help us discover a wider trend.
The only evidence Bird Spot has about black redstarts in the UK is visitors to a website, photos posted to a Facebook group, and a few reports from over half a century ago. Even though their numbers swell tenfold during migration it still surprises us every day by the number of people who know about and have seen a black redstart, one of the UK’s rarest birds.
Have you spotted a black redstart? Let us know where and when you saw it in the comments below.