The recent stretch of good weather has seen the return of that most seasonal of visitors to the island: the tourist.

There are a variety of different species of tourist to be seen in Fair Isle during the course of the year. These include the ‘relaxers’: middle-aged couples and families who come to sit down for a few days, and occasionally stroll slowly down to the beach then back again, just in time for tea. The more elderly relaxers tend to be a little more adventurous, and sometimes make it as far as the shop during their stay.

Then there are the ‘explorers’, who come to island in mid-summer dressed for trekking in the Arctic tundra. They are easily spotted, wearing expensive hiking gear in pristine condition, striding assuredly around the island’s roads with a walking pole grasped tightly in each hand and a compass dangling pointlessly from their huge rucksacks. I’m not entirely sure what these people do once they have completed the few miles of roads; I have certainly never seen any of them venture off the tarmac. Perhaps they sit down and join the relaxers by the window, eager to tell their friends back home about their adventure.

By far the most numerous visitors to Fair Isle, though, and certainly the earliest arrivals, are the birders.

For over half a century Fair Isle has been a Mecca for bird lovers, particularly in spring and autumn, when rare migrant species take a break from their long journeys, or else arrive on the island lost and confused, after getting blown completely off course. The sight of a “mega rare” American warbler, half dead with exhaustion after its accidental journey across the Atlantic, is enough to send grown men (they are, invariably, men) into a terrifying frenzy, and anyone or anything that stands in their way is likely to get crushed in the stampede.

But birders too come in a number of different sub-species, or perhaps a hierarchy is a better description. At the bottom are the common or garden ‘birdwatchers’: people who enjoy looking at blackbirds and starlings from their kitchen windows, and who may even confuse the two.

Above them are ‘twitchers’, who are basically checklist birders. Like trainspotters, their interest is in amassing the longest list in a given year, area or lifetime, and they will often go to unbelievable lengths to see a new species. When the rarest birds appear in Fair Isle (usually in September or October) it is not unusual for twitchers to charter flights from England up to the isle, occasionally coming back again days later if another rarity appears. Our airstrip can be a very busy place at such times.

‘Real’ birders, at the top of the ornithological social ladder, tend to take themselves and their hobby very seriously, and they also like to exaggerate the difference between themselves and twitchers. The main difference, so far as I can see, is simply that twitchers have got the time and money to do what birders would like to be doing.

My brother is a recent convert to birding – a born-again birder, you might say – and like all converts he suffers from a certain over-zealousness. Everything else in his life, including his sanity, has been sacrificed to his binoculars. He wears them at all times now, even when in bed, just in case a bird should fly in through the open window and perch atop his wardrobe at night. He talks about birds, reads books about birds, watches DVDs about birds, listens to CDs of birds making bird noises.

I have disowned him.