Stop mowing the lawn – and five more ways to save Britain’s ‘charming’ and ‘polite’ gatekeeper butterflies

Conservation can be hard work. But not when it comes to helping these little orange and brown beauties

You’ve almost certainly seen gatekeeper butterflies, even if you don’t know them by name. The gatekeeper is, says naturalist and butterfly enthusiast Matthew Oates, “a charming butterfly; a charming meditation of soft oranges and browns”. Traditionally found in the “scrub edges” (the borders between grassland and woods) and at hedge margins, they are frequently seen in suburban and urban areas, near garden gates (hence their name) and at the base of shrubs. The gatekeeper is in no hurry, so you’ll get to enjoy it. “It doesn’t dash about at great speed,” says Oates. “It flops around; both males and females bask a lot.” As a bonus, Oates adds, gatekeeper males are “extremely polite to each other”, unlike lots of other butterflies, which are highly territorial. “They’re gentlemen.”

Why do they need to be saved?

Gatekeepers are far from our most endangered butterfly species – another formerly frequent garden visitor, the small tortoiseshell, has declined 82% since surveys began in 1976 – but they do need our help. The UK population of gatekeepers is down 38% since 1976, says Dr Richard Fox, the Butterfly Conservation’s head of science, for reasons that are unclear. For once, climate is unlikely to be the culprit in the UK: generally, butterflies thrive in warmer weather and gatekeepers in particular can tolerate a wide range of temperatures, according to Fox. But changing plant communities due to increased nitrogen in the soil and pesticide use are possible causes.

How can you help?

Don’t cut (all) your grass
Long grass is vital for butterfly survival, because it provides food for caterpillars. “It’s all about caterpillars,” says Fox. “Providing flowers for butterflies is lovely: it makes your garden look nice; you see more butterflies. But that’s not going to turn around the decline.”

Adult butterflies, he says, are “pretty generalist in what flowers they’ll visit to drink nectar from; caterpillars are not like that”. The gatekeeper is one of the species that only eats grass. “It spends its caterpillarhood in pockets of rougher grass,” says Oates. “The thing that’s beneficial is allowing these pockets of mixed grasses, finer grasses and coarser-leaf grasses, along scrub edges. It’s quite probable that the best way we can help out is simply by not pushing the mower under the shrub.” Even a narrow strip of long grass can make a huge difference, he says. And if you do mow under shrubs or along hedges: “Put the mower in high – lift the cut.” That preserves some longer grass. No Mow May is great, Fox says, but please don’t stop there. “Almost the worst thing you can do is mow on 1 June, when the grass is full of caterpillars and eggs.” Your long grass won’t just help gatekeepers: lots of caterpillars eat grasses. “Our study on long grass and gardens showed that if you have some long grass – any long grass – in your garden, you see more butterflies and a greater variety of butterflies over the course of the year,” Fox says.

Provide a fuelling station
If you only have a window box or balcony, it can still be what Fox calls “a motorway service station” for butterflies: “You could be providing a bit of fuel; that’s good to help things along.” Lots of flowers are rich in nectar – most famously buddleia; also verbena and lavender – but Fox says gatekeepers “absolutely adore” flowering herbs, particularly oregano and thyme. Putting some in a pot or planter in a warm and sheltered spot will encourage butterflies to feed there. It’s also good to plant strategically so flowery food is available from spring right through to autumn – Butterfly Conservation’s list of nectar-rich plants divides them by flowering season.

Advocate
“Tolerating and celebrating the benefits of long grass in public green space” is vital, Fox says. Lobby for long grass in public spaces in your area – parks, school grounds, graveyards, road verges and more. And explain to haters why it is important: “It’s because our butterflies are declining drastically, and that’s a place that’s helping us turn around butterfly population.” If you can also encourage local authorities and other custodians of public space to leave nettle patches, you’ll be doing the much more endangered small tortoiseshell, whose picky caterpillars only eat nettles, a great favour.

Do the Big Butterfly Count
From 17 July to 9 August this year, take 15 minutes and count how many butterflies you see. It’s that simple. “Anyone can do it, if they can get outside,” says Fox. “It’s really easy – anywhere in the UK, any time of the day, you could do it in your garden, you can do it sitting or standing still, you can do it walking the dog, while the kids are in the playground or on a family walk. Any way you like.” There’s a free app for Android and iPhone to log your count, which also provides information and guidance on identification. You can do as many 15-minute counts as you like over the three-week period, and the information gathered during the count helps conservationists plot shifts in population and track how butterfly populations are faring.

Or keep an eye on butterflies all year round
To help out with data collection and monitoring throughout the year, you can download the free iRecord Butterflies app (on Android or iPhone) which allows you to record sightings of “any butterfly or its egg, caterpillar or pupa in the UK, any day of the year, year after year”, says Fox. The app provides detailed guidance on identifying species and suggestions based on past data on which butterflies are likely to be “on the wing” in your area at any given time.

Enjoy them
The more we appreciate our garden butterflies, the more likely we are to become advocates for them and support their future survival. Oates says there’s a good chance this summer might be a bumper one for butterflies, since last summer was warm and dry – “truly great” butterfly years are the second or third in a sequence of hot summers. If that’s the case, he says, one of the best things you can do is “enjoy your butterfly summer”.