Slow down and the water starts to show you things

Britain's canals and navigable rivers are, in effect, long thin nature reserves. A mile of waterway can hold heron, kingfisher, water vole and a dozen species of dragonfly, yet most of it goes unobserved because boats pass at cruising speed and eyes stay fixed on the next lock. The trick is to treat a stretch you know well as if you had never seen it before: potter along at two or three miles an hour, keep the engine note low, and scan ahead rather than sideways. Most sightings happen thirty or forty metres in front of the bow, where the water is still undisturbed.

Timing matters as much as pace. The first two hours after dawn and the last two before dusk are reliably the most productive, and early mornings on a misty canal in late spring can be extraordinary. Winter, when bankside vegetation has died back and water is clear, is the best season of all for seeing birds that are usually hidden.

Looking for the flash of blue: kingfishers

The kingfisher is the bird most boaters want to see and the one most often glimpsed as a vanishing speck. Learn its habits and your chances improve dramatically.

• Watch for a low, straight, fast flight just above the surface, usually between two perches. That is a kingfisher moving territory, not a sparrow or a swallow.
• Listen for a thin, piercing whistle — a single high "seee" — given in flight before the bird appears. Once you know the call, you will hear kingfishers long before you see them.
• Scan overhanging branches, dead sticks and mooring posts about a metre above the water. Those are favourite fishing perches.
• Look in winter, when clear water and bare banks make the blue far easier to pick out, and birds are less territorial and more willing to sit.

If you do flush one, resist the urge to follow at speed. Drift, stop, and wait where you are. Kingfishers often work a beat in a loop and will return to the same perch within ten or fifteen minutes.

Herons, egrets and the working shallows

The grey heron is the most obliging large bird on the system. It stands hunched and motionless in the margins, on lock gates, and even in fields beside the cut, and it will often tolerate a boat that passes quietly and steadily rather than one that changes speed or veers towards it. Aim to keep a good twenty metres of distance where you can.

Little egrets, now widespread, feed more actively, dashing about in the shallows and startling small fish with their yellow feet. Look for that bright white shape on the inside of bends and over gravel shallows in summer. Cormorants and great crested grebes are also frequently mistaken for one another from a distance: cormorants sit low and often perch with wings spread on posts and buoys, while grebes swim low with their heads held high and dive for long periods.

Otters, water voles and the quiet hours

Otters are far more common on our rivers than most people realise, but they are crepuscular and wary, and a boat is a noisy thing. Your best evidence is often in the mud rather than on the water.

• Spraint — small, dark, distinctly fishy-smelling deposits on flat stones, ledges and beneath bridges. These are territorial markers, often in prominent places.
• Five-toed footprints in soft mud at the water's edge, with a broad pad and often a tail drag.
• Holts in undercut banks and among tree roots, sometimes with a well-worn slipway down to the water.
• A trail of bubbles and a roll in a calm pool at dusk usually means an otter feeding, not a fish.

Water voles are a different pleasure: a sudden "plop" from the bank, a small brown body swimming with its head up, or burrows in the side of the cut with nibbled grass stems cut at forty-five degrees. Keep to the centre of the channel through known vole banks and keep dogs out of the water in those stretches.

Dragonflies and damselflies in the reeds

From May onwards, sunny, still mornings bring out dragonflies in numbers. Reedbeds, lily pads, floating pennywort mats, and the sunlit leaves of willows and alders along the towpath are all good places to look. Emperor and four-spotted chaser dragonflies patrol open stretches of canal, holding a territory and returning to the same spot; banded demoiselles, with their dark thumbprint-like wing patches, favour flowing rivers and flit among marginal plants.

Damselflies rest with their wings folded along the body, dragonflies hold theirs open and flat. A patient ten minutes moored quietly beside a good reedbed will usually produce both, plus the odd depositing female dipping her tail into the water. Look also for the empty husks of larvae, or exuviae, clinging to stems where insects have emerged.

Boating with care: kit, timing and etiquette

Good wildlife watching from a boat is mostly about not disturbing what you have come to see.

• Carry binoculars — 8x42 is the sensible compromise for boat use, plus a small notebook and a camera with a decent zoom.
• Cut the engine and drift past reedbeds, nesting banks and moored birds. Sand martins, terns and grebes nest in places where wash and noise do real damage.
• Keep 20 metres plus from nesting swans, and never feed bread to wildfowl; it fouls the water and draws rats.
• Take all line and litter away, especially fishing line and hooks, which maim swans and gulls.
• Moor considerately, away from sensitive banks, and check local navigation notices for seasonal wildlife restrictions.

Wear dull colours, stay low on the bank when you step off, and keep voices down. Do all that, and a quiet morning on a familiar stretch of canal will start to feel less like a journey and more like a stakeout that keeps paying off.