Although it’s a human-made inland diving site, the lake teems with wildlife. Over the past few months, I’ve been eyeballed by inquisitive southern hawker dragonflies, had a swallow skim deftly past my cheek, caught a glimpse of one of the sizable bottom-dwelling sturgeon as it ghosted out of the depths and witnessed the dizzying spectacle of thousands of froglets swarming the banks and invading the changing rooms. One of the greatest joys of swimming here regularly has been the opportunity to gain an intimate insight into the lives of the resident pair of little grebes and their brood of four. Encountered by birdwatchers, little grebes tend to be secretive and nervy birds. Their distinctive whinnying trills often give them away, but as soon as they’re approached, they flash their pale powder-puff rear ends and silently slip beneath the water, invariably surfacing on the opposite bank. But here at the lake, they are unfazed by swimmers, popping up next to us like buoyant bath toy ducks. When I first encountered the chicks, they were tiny, stripy balls of fluff. Though grebes can swim as soon as they hatch, they spent most of their time scuttering over the waterlily pads or riding on their parents’ backs, peeking out from beneath the shelter of their wings. Keeping them satiated has been a full-time job for the harried adults, but there are easy pickings – tadpoles writhing in the shallows, dragonfly and damselfly larvae clinging to emergent vegetation, floundering mayflies and free-floating great pond snails, their muscular feet turned to the sky as they crawl across the underside of the water’s surface film, a feat achieved by creating ripples of mucus that generate pressure and forward propulsion. Over the past six weeks, I’ve watched the youngsters grow in size and confidence. Now independent enough to feed themselves without parental assistance, they strike out across the lake on solo foraging trips. Today, the boldest heads straight for me, diving down in search of aquatic invertebrates and small fish. I take a breath and duck my head under, just in time to watch it glide beneath my prone body, powered by a pair of oversized sycamore-leaf-shaped feet.