The Cuckmere is the only major river in Sussex that remains undeveloped at the mouth (the Arun, Adur and Ouse are built up right to the shoreline, and the Rother has Rye Harbour just a little way inland). A few old coastguard cottages perch precariously on the edge of an ever-retreating cliff to the west, WWII military remains are dotted here and there and every now and then a fleet of excavators comes down to dredge the mouth (they were at work last week). Apart from these intrusions, and the faint sounds of the A259 between Eastbourne and Seaford at the head of the valley, quiet sheep graze the fields and Cuckmere Haven is a refuge for wildlife.

A couple of miles upstream from the mouth, High and Over Lookout gives amazing, almost aerial, views: out towards the sea both at Cuckmere Haven and west towards Brighton; down into the lush green valley and glinting waterways; east across Friston Forest; and north over a number of tiny villages and into the Low Weald. The lookout perches just above the White Horse, a figure carved in the chalk hillside. The horse, first created in 1838, is a younger cousin to the Long Man of Wilmington just around the corner, which was probably carved a couple of centuries before. Some stout, quiet ponies go about their “conservation grazing” work in a field beside the chalk horse. Half a dozen desperate-looking Duke of Edinburgh Award teenagers sit beside the car park, hiding their heads in their arms.

I could happily spend days exploring this part of the Cuckmere valley. Swans glide over flooded pools, white egrets and big grey herons stalk their prey, geese honk and flap noisily overhead, groups of ducks cackle at all and sundry and countless little birds flit through the reeds. Hand-painted signs warn drivers to look out for toads, which migrate en masse at this time of year, mainly at night. The woodlands are netted with footpaths and cycle paths, while the pretty historic villages offer more laid back options for exploring. Most of the shops, tea rooms, restaurants, pubs and amenities are squeezed together in the picturesquely cramped high street at Alfriston. Alfriston also boasts the thatched Clergy House beside the church - the first property purchased by the National Trust in 1896. There are other pubs scattered around the valley, the Long Man Brewery (they're thinking about opening for public tours), tea gardens at Litlington (open from April), Drusillas Park (if that’s more your thing) up near the A27 and, next door, the English Wine Centre. 

Going on a driving tour is a pretty rare experience for us. It’s nice to be on a relaxed schedule, too. We turn down interesting-looking lanes without weighing up how long each detour will take, how annoyed we’ll be if we don’t find anything at the bottom of the hill, or how hard it will be to climb back up. We pull into Michelham Priory and take a peek at the watermill, which they’ve restored and now use to grind flour. We go on a quick hike around Bede’s playing fields and through a horse paddock to find the Cuckmere just before it flows into the Michelham Priory moat. We look at the river from the bridge at Horsebridge, spotting (and failing to photograph) the ruins of the old  flour mill. We go on a meandering cruise through Hellingly and find a probably-now-ornamental water wheel and mill race beside a house close to the Cuckoo Trail.

At Rushlake Green, we head down the steep hillside from the end of the enormous, eponymous green to find one of the Cuckmere's tributaries: the Flitterbrook. At the bottom of the valley, we’re greeted by a bright rust-orange stream. The first time I saw this phenomenon, a couple of months after moving to East Sussex, I thought there was some horrible pollutant in the water. I now know better: it’s iron. There was an iron industry in the High Weald from pre-Roman times and its history can still be read on maps. Look for words like Pond Bay, and Bloomery, or names like Forge Cottages and Furnace Lane. There’s an “Ironworks (site of)” marked here, so we pretend to be knowledgeable archeologists and look for lumps and bumps. Unfortunately, there are no BBC graphics in sight, so history remains hidden. Further along the field, someone has attached a rope to a few trees, leading down towards the stream. “Well,” says Dan, “If someone’s gone to all that effort, it would be rude not to follow it.” To our delight, the rope leads us to a tiny, iron-rich spring, bubbling straight out of the earth. I lick a few drops from my fingers and find it tastes, unsurprisingly, like an iron railing or blood. We’re pretty stoked about this unexpected discovery - it’s everything we could want from a source of the River Cuckmere!

Finally, it’s up Flitterbrook Lane to Punnett's Town and east to Three Cups Corner and The Three Cups Inn. I’d always assumed this settlement  (or crossroads) was named after the pub or vice versa. I’d never wondered where the name "Three Cups" came from in the first place. Mystery solved: tributaries of three rivers rise at this point - the Cuckmere, the Dudwell (which joins the River Rother and runs out to Camber Sands, near Rye) and Christians River (which joins the Ashburn and runs out across the levels to Normans Bay near the Star Inn). It seems only right to mark the end of our journey here, so we stop at the packed pub and share our favourite bits of the day over a quiet half pint.

It’s hard to imagine what the locals must have thought of Bodiam Castle when it appeared on the scene in 1385. Even now, through modern eyes accustomed to epic feats of architectural engineering, it’s a wonderful sight: the round towers rise sheer from the surrounding moat and the stone walls glow pale gold in the sun. And it’s still a surprise to come across it, nestled amid vineyards, hops farms and white-tipped oast houses, looking out across the lush pasture of the Rother valley.

The winter sun sparkles on the frost as we head east from the castle along a farm track, crunching ice beneath our boots. It’s a glorious day under a big, blue sky, and we’re not the only ones outside enjoying it.

To the north, the square tower of St Nicholas church at Sandhurst Cross hoves into view. As the river twists away to our right, we cross Kent Ditch and head uphill, leaving East Sussex behind.

We pick our way across a muddy field and through an even muddier wood. A frantic volley of gunshots erupts close by and, realising it’s a party of duck shooters, I briefly consider turning saboteur. Instead, we push on, appreciating the open views towards Sandhurst with its clock tower and windmill.

At St Nicholas, the congregation is leaving after the Sunday morning service. We sit in the churchyard for a while, drinking in both the view and a thermos of tea, trying to keep warm in the wind.

Inside the church I read about the bells, including the John Bell, which was cast in the late 15th Century, cracked in 1961, then repaired with new technology and re-hung in 2009. We also admire a window constructed of salvaged fragments of old glass and prayer cushions decorated with everything from hovercraft and Boeing jets to badgers and biblical quotes.

From Sandhurst Cross, walkers can take the road straight back to Bodiam, but we venture on to join the Sussex Border Path.

If the first half of the walk was characterised by big things - castles, skies, views, churches - then the joy of the last section lies in the details. The first crocuses are blooming, joining snowdrops and daffodils at the side of the road. We pass a well-used badger sett. Multicoloured lichen adorns a fallen tree and a bright orange jelly-like fungus emerges from a fallen branch.

After weaving our way over the hills, we slip down a narrow path beside a vineyard to emerge back at Bodiam Castle, just in time for lunch at the the National Trust tea rooms.

Mags spotted foxes, squirrels and birds around her home in the English countryside, and even managed to get a couple of clear shots. Read her post here.

Emily threw herself into this challenge - she recorded a huge variety of wildlife (native Australian and introduced species) in Melbourne. She spotted 3 species of mammal, 1 species of reptile, 7 species of fish/aquatic life and a whopping 29 different species of bird! Read her post here.

Dan and I had fun tracking our sightings and spying on the birds and other visitors to the seed and nut feeders in our courtyard. We didn’t get any good shots: I used photos by far superior photographers (licensed through Creative Commons) in my post.

Abby and Kieran are the lovely friends who invited us to Wildwood in Kent. Kieran's uploaded a G+ album of the visit here.

February galloped by and we procrastinated about our overnighter. It was too cold. We had visitors. It was rainy. Our friends weren’t up for it. We were sick. We didn’t want to do it on a work night. It was going to snow. All in all, we were being a bit feeble.

What we needed to do was set a date and stick to it. Mags had acquired an Alpkit bivvy bag for Christmas and was yet to use it. With a bit of encouragement from us and some prodding from her colleagues, she agreed to join us after work one night for her first bivvying adventure.

We met up on the country property where she works and slept out (with permission) on the verandah of a beautiful wooden barn. It felt quite luxurious to have a nice dry platform to sleep, cook and eat on - and to have a roof over us when it started raining during the night. It wasn’t exactly a wilderness experience, but we all enjoyed it and it was a good way for our friend to join the world of bivvying microadventures.

The sky was lovely and clear at the start of the night, with a bright moon and stars. We saw a satellite go over and listened to owls calling. We didn't see the owls (sad!) but we did find some pellets on the verandah of the barn.

I’d bought a £10 fleece sleeping bag liner to beef up my summertime sleeping bag. Although it took a few minutes to get in and adjust myself properly (not a problem when you’re on a dry verandah, probably more annoying if you’re in a field during a rain storm) I’m happy to report that it made a big difference. I was mostly toasty warm. My feet were still cool but not cold enough to stop me sleeping, and my thighs (the other strange problem area I’ve noticed) were fine.

We also took our beer can stove for its first outing. It worked . . . at least, it worked when we balanced the pot of water properly! Our friend had a lightweight travel kettle with a removable infuser for loose leaf tea, which was pretty impressive: it’s the tea equivalent of a moka pot.

It was a fun night. I think Mags will soon be out in her bivvy bag again!

We tried to keep an extra keen eye out for animals and birds this month. Around East Sussex and Kent we saw (in addition to the species in our courtyard): wood pigeons, collared doves, jackdaws, crows, rooks, herons, herring gulls, black headed gulls (they look like they’ve face-planted in black ink), a buzzard, a kestrel, geese flying over, wrens (or other Little Brown Jobs), chaffinches, rabbits, foxes and deer (though these were in a deer farm). We also heard woodpeckers and found owl pellets, though we didn’t see the woodpeckers or the owls.

At the end of the month, we were in London and Norfolk. In London we saw (in addition to species mentioned above) a scruffy mouse at a tube station, then in the outer suburbs we saw nuthatches, parakeets and woodpeckers. On the way to Norfolk, we drove past two camels at a funfair, saw many rooks in rookeries, spotted a number of kestrels and a couple of buzzards. 

During our stay, we spied oystercatchers, a little egret, a skylark (or something equally noisy in flight), moorhens, ducks, house sparrows, several hares (on the last day of February, so they weren’t mad March hares yet), a bar-tailed godwit and a smaller wading bird that might have been a redshank.

This was a fun challenge. It reminded us to pay special attention to animals and spend a few extra moments trying to identify them. We were pretty happy with our species total, too - not bad for people who get most of their wildlife knowledge from Springwatch.

But during the course of the month, I started to realise just how few animals we were seeing. For example, it seems normal to us to be excited by a skylark, but this was an extremely common bird within living memory. Likewise, it would have been inconceivable to someone doing this challenge in a rural area in the 1980s to not see a hedgehog - not even a squished one on the road. So many of the animals we spotted have experienced alarming declines in population over the last ten, twenty, fifty years. Even house sparrows and starlings are now red listed in the UK .

There have been some recent success stories: buzzards and red kites have made a comeback, some birds that live well alongside humans (blue tits, robins, blackbirds) are flourishing and although we didn’t see any wild otters they are also scrabbling back from “the brink of extinction”.  But overall, there are huge declines in UK bird populations (especially farmland birds), invertebrate populations worldwide and UK wildlife in general.

Something I read this month, which made me stop and think about this issue, was a fascinating piece of community research by a local primary school and conservation volunteers. They'd published a little pamphlet outlining the history of a village water meadow. As part of the research, they’d collected oral histories from local residents, who were first-hand witnesses to the decline of wildlife in the area. One account was from a person who described how as a child they could go to the meadow and see hundreds and hundreds of frogs: now the school children were lucky if they managed to spot a handful.

This reminded me of a chapter in Collapse, where Jared Diamond talks about the deforestation of Rapa Nui (Easter Island) and its disastrous effect on the human population there. Reading that story, our inclination may be to wonder why an islander chose to cut down the last tree, what went through their mind when they did so, how they could have destroyed that final specimen of what was once a forest. But Diamond reminds us that this deforestation took generations to complete: the person who felled the last tree had never seen a forest.

Such is the case with declining wildlife populations. I think it’s one reason that going out wildlife spotting - with children, with great-grandparents, with migrants, with people from multiple generations, with city people and country people - is so important. It’s one thing to say: “Species X has declined 70% in the last 35 years.” It’s another thing to engage a child in a story: “When I was your age, I would see dozens of Species X on this walk. Why do you think we’ve only seen one pair?”

It's not just children who need this. I’ve been in the UK for over three years and I have never seen a (live) wild badger, wild otter or wild hedgehog. I've seen one slow worm and two snakes. I don’t know what else I’m missing. It’s relatively easy to notice what’s there. It’s much harder to notice the absence of something you’ve never seen.

So, go wildlife spotting! Talk about what you see. Talk about what you don't see. Talk about why that might be. Talk about what you might be able to do to help wildlife survive and, hopefully, prosper.