Every Riverbank Is a Diary

The river writes in mud, in nibbled stems and in feathers left on a gravel bar. Most people walk a towpath and see only water and willows. Look down instead and you will find a record of everything that passed before you, often within the last twelve hours. Reading those clues is nothing more mysterious than patient looking — the sort of looking that turns an ordinary Sunday walk into a small piece of detective work.

You do not need expensive gear. A notebook, a pencil, a tape measure or a length of knotted string, and a torch for peering under banks will do more for your understanding than any gadget. The tracks themselves are free, and they renew every time it rains.

Where the Mud Lies Best

Tracks survive where the ground is soft but not sloppy. Think of the silt left behind as a spate drops, the poached edge at a cattle crossing, the strip of exposed mud under a footbridge, and the smeared film on a gently sloping bank where animals come down to drink. After heavy rain, wait a day. The water clears the old surface and the new prints sit sharp and readable.

• Early morning is the golden hour — few people, fresh marks, better light for photographs.
• Winter and early spring give you bare banks, open water and clean mud.
• Summer gives you feeding signs: gnawed stems, stripped cones, nibbled leaves.

Always approach a bank low and slow, and stay on the path where ground-nesting birds might be nearby. A print is worth a photograph; it is never worth a crushed nest.

Telling Otter from Mink

The big prize on many a British river is an otter print, and it is surprisingly recognisable. Look for a broad, rounded pad with five toes and often a hint of webbing, set on the lower bank rather than on the path. The tracks tend to wander in a loose, unhurried line, sometimes with a tail drag in soft silt.

Otter spraint — their droppings — is the other giveaway. It is deposited on prominent stones, bridge ledges and tussocks on purpose, as a message to other otters. Fresh spraint is dark and tarry, full of fish scales and small bones, and smells faintly of hay, jasmine or a mown lawn. Old spraint dries pale and crumbly.

Mink prints are smaller, neater and more often found along the waterline in a determined straight line. If you can lay a pound coin beside the print for scale and photograph both, you will learn faster than any diagram can teach you.

Chewed Twigs and Other Small Tragedies

Water voles are our fastest-declining mammal, and their field signs are worth knowing well. Look on the bank for stems cut at a clean 45-degree angle, as though sharpened with a pencil, and for short green droppings like tiny tic-tacs on a flattened ledge — a latrine. Their burrows are holes about the size of a fist in steep, soft banks, often with a grazed lawn of short turf outside and runways pressed through the bankside vegetation.

Other useful marks include:

• Grey heron prints — long, spidery toes with the middle one longest, often found stalking along the shallows.
• Roe deer slots — two slim, pointed hoof marks, narrow and neat, usually on a crossing or a drinking gap.
• Badger and fox footprints — badger shows five toes with a broad pad and clear claw marks; fox shows four toes and is narrower.
• Kingfisher remains — a scatter of small fish bones and bright blue or orange feathers on a favourite perch stone.

Hazel nuts and alder cones tell their own stories. A neat round hole with tooth marks around the rim means a small rodent; a nut split cleanly in half is usually grey squirrel.

Reading Feathers and Pellets

Feathers are underrated clues. Note the length, the colour, whether the tip is rounded or pointed, and whether there is down at the base. A single electric-blue feather on a branch overhanging the water is a kingfisher's calling card; a soft grey one could belong to a heron. Record where you found it — on the ground, caught in a bush, floating — because that tells you as much as the feather itself.

Owl pellets are another riverside regular, especially under tall trees near water. They are dark, oval and felted with fur, and they fall apart into tiny bones if you tease them gently with tweezers. Leave them where they are unless you are collecting for a licensed study.

Keeping a Field Notebook

Your notebook is the real skill. A rough sketch with a scale beats a beautiful drawing every time, so draw what you see, not what you wish you had seen. For each entry, note the date and time, the weather and wind, the state of the river, and a grid reference if you carry a map. Describe the ground you found the track on: wet silt, dry sand, frost-hardened mud.

• Measure print length and width, and the stride between prints.
• Sketch the track pattern — straight line, wandering, bounding.
• Note anything you did not see, such as human boot prints or dog paws nearby.

Wash your hands after handling anything, and never pick up spraint or carrion with bare fingers. Several riverside species are protected by law, so take photographs and measurements rather than specimens, and keep dogs out of the water in sensitive stretches. Over a season, your notebook will become a proper local record — and you will start to notice the small, patient dramas that most walkers miss entirely.