Winter is the best season to get started

Because northern Europe freezes and the south doesn't. Thousands of ducks, waders, geese, herons and gulls come down to winter on Iberian wetlands, where the water stays open and food is available. What's a quiet lagoon in summer can be a city in January.

On top of that, birds in winter are concentrated and predictable. They need to save energy, so they spend hours in the same spots: roosts, feeding grounds and resting areas. That turns the patient watcher into the lucky one.

There's a trade-off: plumages are duller. Many ducks, waders and passerines are in drab winter plumage, so it pays to look at shape, size and behaviour before colour.

Before full daylight. The first half hour is when birds leave their roosts: flocks on the move, geese heading out to the fields, herons switching perches. Arrive at eleven and you'll see the same species dozing far away.

Dusk is the other good window, especially for birds returning to roost. On foggy days, wait: once the fog lifts, there's usually a concentrated twenty minutes of activity that makes the wait worthwhile.

Avoid midday with strong sun and glare off the water. Flat light washes out detail, and heat haze distorts the image at long range, especially through a scope.

First scan with the naked eye: shapes, movement, large silhouettes. Then work through with binoculars in bands: near shore, mid water, island or spit, far edge, and finally the sky. Repeat the cycle every few minutes, because the wetland is always changing.

Sort into groups before you attempt species. Diving ducks versus dabbling ducks; short-billed waders versus long-billed; herons by size and colour. A pochard is told apart from a mallard by how it dives and how it sits on the water, not by a plumage detail.

Count in blocks of ten. Nobody counts 800 ducks one by one: you count a group of ten, work out how many times it fits into the flock, and record it as an estimate. That's more honest and more useful than a made-up figure.

Leaning over the top of the hide for a better view. That very natural instinct puts a human silhouette on the skyline and empties the shore in seconds. Look through the slots, even if it feels awkward.

Walking along the open shore to "get a better shot". Waders spend hours feeding to build reserves for the night; every flight they're forced into costs energy they genuinely need.

Talking loudly on arrival and slamming the car door. In small wetlands, the car park is fifty metres from the water. Close the door gently and keep your voice down, and you'll start the morning with the birds still where they were.

By layering up and accepting that standing still gets you far colder than walking. Thin gloves that still let you turn the focus wheel, a hat, and an outer layer that doesn't rustle when you move — fabric noise is the biggest giveaway in a hide.

Here the criteria for clothing matter more than the brand: dense, matte fabrics, with no swish and no shine, in muted tones. A small flask and some food stretch out a session more than any optical accessory.

Bring a folding seat or a mat if you're staying a while. Discomfort is the number one reason people leave right before something interesting turns up.