Hampstead Heath: Does an increase in visitors mean fewer birds?

Today, in the midst of a pandemic, more and more of us are using the Heath in this way to keep sane.

Hearing and seeing birds and other wildlife is an important part of that calming nature experience. But what does growing use of the Heath mean for its habitats and wildlife?

How will the wear and tear to the Heath and the high numbers of visitors we are now seeing affect the behaviour and survival of wildlife there?

In 2020, the Heath and Hampstead Society, organized what may be the Heath’s first nesting bird survey.

Working with our partners in Heath Hands, City of London, and English Heritage, its aim was to get a measure of how well birdlife was doing in the face of increasing public use, climate change and urban pollution.

Across the UK, there has been a documented and dramatic decline in numbers of birds and other wild species. Was this also happening on the Heath?

Of course, a single survey cannot show a trend without something for comparison, and our aim is to repeat this in years to come. However, we have already learnt much from this first year.

To do the survey, we walked specific paths, or transects, every two weeks, recording any birds that we saw showing nesting behaviour, such as territorial singing, carrying food to nests, etc.

During the nesting season from April through June, we recorded over 3,500 such activities from 41 species of birds. As our transects covered only parts of the Heath, we may have missed a few.

We can compare our findings to historical records. For instance, in the last half of the 20th century, an estimated 70 bird species nested on the Heath. Hence, in the past 70 years, we seem to have lost a good proportion of our nesting bird species, about 40%.

The Heath has lost its ground-nesting birds, such as skylarks (Image: Wikimedia Commons)

Some of these losses mirror national declines, others are probably due to increasing visitor pressure. For instance, the Heath has lost all of its ground-nesting birds, like skylark and pheasants, which is typical for green spaces with lots of dogs off leads.

Recent scientific research on the Heath has actually measured the direct effects of visitors on birds. It shows that woods frequented by lots of people and dogs have fewer visits by some birds than quieter woodland.

Blackbirds, for example, not only make fewer visits to search for food, but shift these to early mornings, before the first walkers appear. Without time and space for undisturbed feeding and nesting, these species may decline. And we will see and hear fewer birds on our visits.

Blackbirds have changed their visiting patterns (Image: PA Archive/PA Images)

Last year’s survey revealed which birds are doing well on the Heath and which are just hanging on.

Our most commonly recorded nesters were, from the top, wren, blackcap, robin, chiffchaff and blackbird.

At the other extreme, we concluded that 16 nesting bird species on the Heath, 40% of our total, may be in decline or at risk of extinction there. These birds were typically rare, or found in just a few spots, or both. Some birds most at risk include two spring songsters, song thrush and mistle thrush, whose numbers are also falling nationally, and our nesting hawks – kestrel and sparrow hawk.

The kestrel is one of the species in decline on the Heath (Image: PA Wire/PA Images)

But our pick for a “save this bird” campaign would probably be the green woodpecker.

Unlike our more common great spotted woodpecker, green woodpeckers feed mostly on the ground in meadows. Here they eat ants that build clusters of grassy mounds familiar to Heath visitors. Increasingly we see these anthills being destroyed by people walking or cycling on them, or dogs digging them up. If this continues, the green woodpecker may be our next Heath extinction.

The Heath and Hampstead Society is concerned about the loss of birds from the Heath. So to celebrate the 150th anniversary of the Heath as a protected space for visitors and nature, we are working with our partners, City of London, English Heritage, Heath Hands and the Marylebone Birdwatching Society to place nature display boards at Heath entrances this year.

These seasonal boards will introduce visitors to distinctive Heath birds and other wildlife.

Most importantly, they will explain what is being done to protect wildlife, and how all of us can help to ensure that an experience of nature on the Heath remains rich and rewarding. We hope that you enjoy them.

• Jeff Waage is from the Heath & Hampstead Society.