We're often asked what time Minsmere is open, and when the best time to visit is. The simple answer to the first question is always - although we don't recommend that you try to walk around the nature trails in the dark, and the reserve is completely closed on Christmas Day and Boxing Day. However, for most people, visiting will be confined to the hours during which the visitor centre is open - 9 am to 5 pm.

I'm always surprised, especially with the long summer evenings, that the car park is almost empty by 5 pm, because the answer to the second question is often, "as early or as late as possible." It does, of course, depend on what wildlife you are looking for, because if our amazing insects are your target then you probably want to visit during the day when they are most active. Similarly, the activity on the Scrape is continuous, throughout the day, although you should try to select a route that keeps the sun behind you as much as possible.

For some species, though, an early or late visit should improve your chances of success. Otters and bitterns, for example, are typically more active at either end of the day, although you still have a good chance of seeing them during the day. Likewise, birdsong will peak during early morning, and again in late evening. Having said that, I'm sitting in sweltering office just before midday listening to chiffchaffs and garden warblers singing outside.

For a small number of species, though, a visit at dawn or dusk is essential. This certainly applies to most of our mammals, with red deer, foxes and otters being more active then, while badgers and bats are very rarely seen during daylight hours. Dawn or dusk visits are also essential to spot one of Minsmere's most fascinating birds, the nightjar.

As their name suggests, nightjars are nocturnal, or, more accurately, crepuscular birds. They spend the day roosting, using their superb cryptic plumage to remain hidden from view, so that anyone lucky enough to see one by day is, indeed, very lucky. But as the light fades, they wake from their slumber and that's the time to search for them.

Nightjar by Andy Hay, rspb-images.com

Nightjars occur throughout most of England and Wales where suitable habitat occurs, but are rare in Scotland. They breed on heathland, moorland and forestry clearings. They are summer visitors, not returning to the UK until mid May, and heading back sub-Saharan Africa from mid August. At Minsmere we have several pairs of nightjars breeding on Westleton Heath, as well as the nearby Dunwich Heath National Trust reserve. If you are planning a visit, please ask at the visitor centre for directions.

As with any nocturnal wildlife, sightings are brief, if at all, but luckily male nightjars are very vocal, and their song is unmistakable. So much so, that it doesn't even sound like a bird. The song, referred to as "churring" sound mechanical, with an insect-like quality. Males start to sing just before dusk, and if you are lucky you may catch a glimpse of one perched on a heathland pine or birch tree. When the churring stops, listen carefully for a "ke-wick" flight call, or a loud wing-clap and you may spot one flying across the heath.

Nightjar at dusk by Christine Hall

Everyone should take the opportunity to look (and listen) for nightjars at least once. I always make sure I try once per year, usually in late May or early June. This year we chose the longest day, 21 June, for our annual nightjar spotting visit to Weslteton Heath. As a result, dusk came late, but at 9.50 pm, five minutes after my predicted start, we heard the distinctive churring begin. The next 30 minutes was magical as three nightjars churred away to each, establishing and marking their territories. A few brief views proved typically frustrating, and I never did find the perched birds, but eventually we heard the loud wing-clap of a displaying male close by and watched as it put up a female and they chased each other across the heath.

Of course, the churring was not the only nocturnal sound to be heard, with a little owl calling, stone-curlew wailing and muntjac barking in the distance - once the large gathering of rooks and jackdaws had headed off to their roost and their calls had faded into the night.

The evening had begun with a walk to Island Mere Hide, where we heard another insect-like birdsong as one of the Savi's warblers reeled away. We weren't lucky enough to spot otter or bittern this time, but did enjoy watching the great crested and little grebes fishing and marsh harriers quartering over head. Bitterns have, however, been seen every day, and a couple of lucky visitors spotted an otter crossing the path by South Hide this morning.

The excitement continues on the Scrape, too, where three little tern chicks continue to utilise the shelters that we've installed for them, with the kittiwakes still sitting on their nests. Many other birds have chicks on the Scrape, including mallard, gadwall, tufted duck, avocet, oystercatcher and redshank, as well as the gulls, terns and feral geese. The first returning spotted redshanks, in their finest black plumage, have been joined by a couple of green sandpipers, and upto four little gulls can be seen among the terns on South Scrape. A second-year Arctic tern was seen today, too.

The warmer weather has proved beneficial for insect watchers too. A visitor photographed the first purple hairstreak butterfly along the North Wall this morning, and the popular six-belted clearwing moths have re-appeared along the North Wall too. I expect to hear reports of pantaloon bees and bee-wolfs along Digger Alley this week, providing the forecast thunderstorms don't wash out their burrows. There are good numbers of painted lady butterflies and seven-spot ladybirds around the reserve, as well as several interesting beetles, all with aptly descriptive names: wasp beetle, bright green thick-thighed flower beetles, violet ground beetles and the huge great silver-diving beetles. It's also a good time to spot caterpillars. Look carefully on ragwort for the yellow-and-black cinnabar caterpillars, and on mullein for the beautiful mullein moth caterpillar.

  

Wasp beetle and violet ground beetle - no guesses why either of them got their names

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