Dear Readers, the London Natural History talk this week was of particular interest to me. When we had a bird survey done in 2019, Coldfall Wood was found to be particularly rich in breeding birds for an urban woodland, but the increased footfall during lockdown, coupled with the threats to the environment itself, have made me worry about the additional pressure that is being put on the animals and plants that live there.

Jeff Waage was part of a team that undertook a survey of Hampstead Heath last year. Part of the reason was to determine which birds were displaying breeding activity, and where: disturbance from walkers and dogs is widespread even if there isn’t a pandemic, and there has been an increased demand for Forest Schools, ‘Forest Bathing’ and professional dogwalking. In the past year the Heath has had an estimated 50 million visitors, which is pretty much equivalent to most of the population of the country popping in. But data can help, and so Waage and his team walked transects of between 1 and 3 kilometres through the Heath on at least six occasions, looking for breeding behaviour.

Kenwood, Hampstead Heath (Photo One)

Breeding behaviour was defined as territorial singing, birds carrying nesting material or food or fecal sacs, birds actually sitting on a nest, territorial disputes or sightings of fledglings. In my experience birds are very good at hiding nests, but you can fairly easily spot them ‘eating for two’ (or a dozen in the case of blue tits).

At the end of the survey, there had been 2169 sightings of 41 species of bird. Compared with the 26 species seen in Coldfall Wood this probably sounds pretty good, but the Heath has a much wider range of habitats. However, it’s clear that the Heath’s biodiversity has been under stress for some time: in 1992, a survey revealed 71 species. Many of those lost have been ground nesting birds, who are always the first victims of too much footfall and too many dogs, but even birds such as the mistle thrush and the common whitethroat appeared to be in decline.

Common Whitethroat (Curruca communis) (Photo Two)

Waage estimated that 40% of the Heath’s bird species were red or amber listed: he explained that this designation was arrived at by looking at both the vulnerability of the species (i.e. was it nesting in an area of high disturbance) combined with its ‘patchiness’ (i.e. were there just a few isolated populations within the Heath). For example, the whitethroats nested in scrubby areas where there was a lot of picnicking and dog walking, and there appeared to be only one pair of sparrowhawks.

Female sparrowhawk (Accipiter nisus) (Photo Three)

The approach to maintaining and increasing the bird biodiversity of the Heath was multi-pronged.

Firstly, there was a need to identify areas of the Heath where there would be the least impact on breeding birds for commercial activities such as the forest schools, and this was possible following the survey.

Secondly, where birds were vulnerable there was to be a bid to raise public awareness, through new signage and articles in local newspapers.

A third area was to improve and even create habitat, such as reed beds for reed buntings.

Finally, resources such as food and nest boxes could be made available.

There was also a need to investigate what was happening on the fringes of the Heath – there were surprisingly few nesting finches, for example, and the group felt that this was probably because the finches were nesting in local parks and gardens instead, where there was a higher availability of food.

And lastly, and probably most importantly, the Heath needs continued monitoring to see what’s happening with the bird populations. Data can be our most powerful tool in gaining an understanding of what’s happening in an area, and over time. It will be interesting to see what future surveys reveal.

I’ve always been very happy to just enjoy nature, and to be thrilled at the arrival of a new bird or the sight of an unexpected insect. I’m still thrilled, but it seems to me that collecting data is a way of putting meat onto the bones of the anecdotal picture that you build up over the years. Citizen science is becoming increasingly popular, and I hope that, just as the Big Garden Birdwatch has become a major way of recording trends in garden birds, so other surveys will build up a picture of what’s going on with other plants and animals. In fact, there’s an online conference on this very subject being run by the Field Studies Council in May, with the added bonus that it’s concentrating on urban wildlife recording. I’ll be there, and will report back, but for £5 it seems like a bargain for anyone interested in getting involved with recording. With habitat destruction and climate change in full swing there has never been a better time to take notice of what’s going on around us.

Photo Credits

Photo One by Dudley Miles, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

Photo Two By Andreas Trepte – Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=32563057

Photo Three By Meneer Zjeroen – https://www.flickr.com/photos/nuskyn/4028311597/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=8528830