Amorphous, slate-grey cloud loomed over the harbour, blocking out the weak winter sun. By the time I reached the mill pond, fat raindrops had begun to fall, dimpling the surface of the water, which shimmered like hammered pewter. Two grey herons stood hunched on a partially submerged branch, while a third hunkered down on its tree-top nest. Along the far bank small rafts of teal and wigeon sought cover beneath the overhanging vegetation, but the weather appeared to have done little to dampen the spirits of the resident mallards, which had gathered en masse in an expanse of open water adjacent to the footpath.

Mallards are the most numerous, widespread and confiding species of duck in the UK, so it’s easy to overlook them in favour of rarer or “wilder” waterfowl, but the amorous behaviour of the flock caught my eye. Mallards tend to establish pair bonds during October and November. But, irrespective of their status, males continue to participate in communal courtship displays throughout the winter. Though frequent, these displays are brief and lack the elaborate, ritualised posturing performed by other species.

Facebook Twitter Pinterest ‘Male mallards continue to participate in communal courtship displays throughout the winter.’ Photograph: Blickwinkel/Alamy

By focusing my attention on individual ducks, I began to pick up on their subtle gestures – head flicks, tail shakes and mock preening, where the bill is drawn along the underside of a partially raised wing. Groups of three to four drakes circled the hens, the males taking it in turns to whistle and flick an arc of water towards their chosen female, then rearing up to flash their chestnut-coloured breast – a behaviour known as grunt-whistling. Other males thrust back their iridescent emerald green heads, briefly raising their tails and wingtips, before paddling with outstretched necks, their heads hovering just above the water.

With the sex ratio skewed towards males, the females could take their pick of the unpaired drakes. I watched one hen nod-swimming to elicit a response from her admirers. Heads pumping, two drakes steamed over to flank her. She immediately spun round and began to pursue one of her suitors across the pond. Snapping her bill at his curled black tail feathers, she delivered a volley of strident, staccato quacks, but whether this was a zealous show of selection or rejection, I couldn’t tell.