But right now the tern season is about to begin. It is the end of March and the birds are due to fly in from Africa next month; hopefully they will breed and settle, have their chicks and watch them fledge, then leave again in August or September. 

Halpin makes me a cup of tea. He’s happy here, he tells me. Even on his days off, he tends to stay on the point, rather than go and live it up in nearby Morston. His girlfriend, another birder whom he met on the osprey project five years ago, is currently in the South Atlantic tagging albatrosses.  

‘I like living on site, it’s the best part of the job – it means you absorb the place in ways that you don’t if you’re commuting. It almost becomes a part of you and you get a much finer appreciation for what’s going on. It’s like my garden, and just being amongst the wildlife is such a big plus.’ 

A lot of his job involves protecting the wildlife from predators: rats have always been a problem – they have laid down 280 tamper-proof rat boxes with poisoned bait – the idea being to limit the rat population, rather than wipe them out completely which would be impossible anyway. 

Then there are the kestrels, which are partial to snatching the chicks. The solution is to distract them with alternative food during the terns’ chick-rearing period. ‘We have a little table set up, ideally close to where the kestrel is nesting, because birds of prey in particular are fundamentally lazy and would rather help themselves to food nearby than have to bother with a load of angry terns.’ 

A picnic table? What do you put on it? 

‘Day-old chicks,’ he says. ‘And dead mice.’ 

Nice. 

Halpin smiles. ‘We get them online. They come in vacuum-packed bags from a reptile place, called something like deadmice.com.’ 

They can’t do much about foxes but there aren’t many of them; if they have a persistent offender a contractor will come and shoot it. ‘It’s not pleasant but it’s the reality of conservation and it has to be done – we can’t afford to lose the terns.’ Large gulls are another problem. The rangers have to conduct an activity called ‘gull disturbance’. It’s a tricky one, says Halpin, ‘because they’re not doing very well either. Herring gulls are red-listed [highest priority] and lesser black-backs are amber-listed.’ So they have a few different techniques to discourage them – devices that play recorded distress calls of gulls, for example. 

How about rap music? ‘Gulls can habituate very quickly and are very clever, so it doesn’t take long to figure out that something is not a threat. The distress call is species-specific and has a bit more of a biological impetus.’