If you're looking for something to do near Glasgow this summer, then why not take a cruise to the RSPB Scotland reserve at Inversnaid. This Atlantic oak woodland is like something from a Tolkien novel, with ancient trees dripping in mosses and lichens. Franziska Schmidt, a volunteer for the Great Trossachs Forest project, which Inversnaid is part of, took the trip earlier this year to see what it had on offer. 

 A springtime walk is a lovely thing. Even more so when it is accompanied by knowledgeable local guide and framed by a loch cruise! That's precisely what RSPB Scotland offers to visitors on their guided walks around Inversnaid reserve, and I have picked a beautiful day to accompany Fraser and RSPB volunteer Alan on a tour. We meet at Tarbet pier on a sunny Tuesday to catch the 11.30 boat to Inversnaid.

The idea to combine a cruise to Inversnaid with a guided tour around the reserve was born when he met the Cruise Loch Lomond's owner and manager at a local conference, Fraser tells me as we queue up for the boat. The crossing to Inversnaid takes about 20 minutes and offers good views of the oak-covered hillsides that make Inversnaid so special. While Fraser and Alan are scanning our surroundings with binoculars to spot birds and other beasts, I'm enjoying the wonderful fresh greens of the trees’ spring canopy. The perspective from the boat offers a rare opportunity to appreciate just by how abruptly the hillsides plunge into the loch here.


 We share the boat with all kinds of visitors travelling to the other side of the loch – families, older people, some young couples – and at this point our only way of telling who might join us for the guided walk is by assessing boots and looking out for binoculars. So it is that we only meet Emma and Mark at Inversnaid pier, where they quickly make a beeline for Fraser's blue RSPB t-shirt. After initial introductions have been made, the five of us are off in pursuit of the local wildlife.


 As we make our way to the beginning of the track, Fraser summarises the reserve's history: we learn that the RSPB bought one half of the current reserve in 1985 precisely for those oak woods I had so admired a moment earlier. In fact, they represent both a 'temperate rainforest' and an ancient woodland, and as such are extremely diverse, very rare, and hundreds of years in the making. What's more, they are home to pied flycatchers, tree pipits, wood warblers and redstarts – all birds that need woodland to survive and to feed their young. While the shores of Loch Lomond lie at almost sea level, the highest point of the reserve reaches 770 metres - a difference in elevation that creates many distinct habitats and vegetation zones, Fraser points out. Inversnaid forms the western-most point of the Great Trossachs Forest, and the reserve was expanded eastwards in 2000 to create the missing link with the Forestry Commission lands around Loch Katrine.

A few metres into our walk, we pass the first nesting box on a nearby oak. It looks – and is – very solid, built from a mixture of sawdust and concrete. This protects the eggs and chicks from pine martens and woodpeckers, for whom wooden boxes present no challenge at all. It's not only popular with migratory birds such as pied flycatchers, wood warblers and redstarts arriving back from sub-Saharan Africa though, but also with the humble tit. Fraser has equipped Emma and Mark with a pair of binoculars each, and so passing walkers along the West Highland Way seem slightly mystified by our small group all staring at a seemingly average tree.

Being so still, in the end it's not what we see but what we hear that reveals the resident wildlife. Fraser draws our attention to a peculiar birdsong peculiar sound of a coin spinning an and coming to a rest on a tabletop: the song of the wood warbler. While we're not able to spot the green-and yellow bird amongst the foliage, its chracteristic song accompanies us for the rest of the walk.


Birds aren't the only attraction along the way, though. As we walk along a short section of the West Highland Way, we spot stitchwort, ramsons, wood sorrel, bugle, tormentil and of course bluebells. Our slow, attentive walk, always on the lookout for resident wildlife, means that I experience the flora hiding on the verges much more fully that I would usually. And the fauna - I certainly would have missed the buzzard floating on a lazy air current above our heads otherwise. The wildlife walk certainly heightens my sensory awareness of the world surrounding me - sounds, smells, colours, movement. And a beautiful environment for heightened awareness it is, too.

Only a few weeks ago, in April, migratory birds such as pied flycatchers, wood warblers and redstarts arrived back from sub-Saharan Africa to breed and raise their young in the Scottish spring and summer. They take advantage of the abundant insects and caterpillars to raise their young in the Scottish spring and summer, and sure enough, soon we pass a venerable-looking oak that is alive with green-and black caterpillars dangling on threads. Usually I would very likely have walked past this silent spectacle of dozens of caterpillars floating under the tree's wide canopy. Today I learn that the caterpillars feed on the the oak's leaves, which indeed resemble a Swiss cheese. Oaks are a favourite with many native caterpillars because their leaves appear so early, offering vital shelter and nourishment for broods of moths and butterflies. Fraser explains that oaks can replace their snacked-upon foliage by producing a new set of leaves – a great way to keep things balanced.

As we continue our wander through the site, Fraser explains that the woodland is in fact the result of careful management, past and present. The trees were coppiced for charcoal production in days gone by, and we are able to spot the remains of a small settlement that would have housed a small resident local community. Would I have noticed those half-hidden stone walls on my own? Perhaps, but I'd not have been able to make half as much sense of them. I also learn more about contemporary management of the site – bracken control and targeted replanting and fencing to help the woodland along. Inversnaid is very much a forest in progress, and it's fascinating to witness that.

As we reach the highest point of the walk - with lovely views back over Loch and Ben – we're suddenly lucky: a tree pipit settles itself on a high branch right in front of our loch panorama, then soars up into the air and parachutes down with a drawn-out call that sounds a bit like zia zia zia zia. Quite a display!

As we make our way past a tree stump bearing the distinct marks of an enthusiastic woodpecker, another characteristic call is heard – cuckoo, cuckoo! My personal favourite of the many beautiful sounds of spring. While Fraser tells us how the cuckoo gets away with laying his eggs in another bird's nest.


Soon we arrive back at our starting point, and our small group gathers round the RSPB observation board to record our sightings. We accrue quite a list – on our less-than-2-hour-walk, we heard or saw six species of bird, two types of moth, a green-veined white butterfly, and countless wildflowers at their best. All in all, a very good afternoon!

Inversnaid website http://www.rspb.org.uk/discoverandenjoynature/seenature/reserves/guide/i/inversnaid/index.aspx

Cruise Loch Lomond website http://www.cruiselochlomond.co.uk/

Vote for the Great Trossachs Forest in the National Lottery Awards! http://www.lotterygoodcauses.org.uk/awards/environmental