Grey clouds had drifted in and the sky was being inscribed with arcs cut by the flight trajectories of Common Swifts on scythe-like wings. The threat of rain brings swifts and martins to a lower flight ceiling. Not because they are in any way threatened by rain, but because their insect prey chooses to fly lower, or even come down to perch to avoid the passing rain. Intermingled with the swifts were Sand Martins. Whilst the swifts were uniformly dark, the Sand Martins are white underneath and sandy brown above. Somewhere amongst them was a House Martin whose white rump showed up against black upperparts. Shailesh Patel, a part-time staff member of the London Wildlife Centre and a former wildlife guide in Kenya picked out the House Martin from amongst the dozen or so hirundines that were putting on an aerobatics display. Together with Richard Bullock the biodiversity officer of the LWC, and Michael Howard a LWC volunteer, we were leading one of the twenty-five bird walks arranged a year by the London Bird Club; a section of the London Natural History Society.

The London Wetland Centre is a magical place for anyone with an interest in nature. I could go there every day and not tire of it. Every day is different and with Britain’s volatile weather, every hour is different. A group of twenty had assembled in the morning when the sun was out and temperatures had warmed to over twenty degree Celsius on a day in mid-June. We began the walk in the area known as Wildside and it was buzzing with activity. Marsh Frogs in a combative mood called out stridently, their air sacs ballooning out on either side. Red-eyed and Azure Damselflies were everywhere with pairs in tandem on mating flights. I explained to the group how the males literally grab the females by the back of the head with special claspers at the end of their abdomens. It seems quite brutal in a human context, but this was how evolution had endowed males with the ability ‘mate guard’ the female until she had finished laying her eggs. A twig floating on the water had a line of damselflies in tandem. Occasionally a new pair would drift in and alight, reflections shimmering on the pond’s surface in a June haze. The damselflies reminded me of spaceport scenes from Star Wars where fantastical spacecraft would alight. No flying machine real or imaginary has the manoeuvrability of the related dragonflies. Damselflies are predators, hunting smaller invertebrate prey and sometimes even other damselflies that are careless. Everything on the aquaport took off as a Common Coot appeared. With insect abundance high, the coot was repeatedly picking off damselflies and other insects off the aquatic vegetation to feed her brood. On a wooden bridge and a wooden bench two more predators were sunning themselves. On warm, sunny days, this is probably the nearest place to Central London to see Common Lizards. It is a scarce animal in Britain and most Londoners are probably not even aware that this animal exists.

Richard pointed out the ground orchids that were in bloom. Many people imagine orchids to be plants growing in the canopy in the tropical rainforest. But temperate latitudes in the northern hemisphere are also home to many species of ground orchids in the plant family that is the most species rich in the world. Despite the huge number of orchid species; over 26,000, they all have the same basic body plan with three sepals and three petals. The explosive calls of the Cetti’s Warbler, a recent colonist of Britain, periodically rang out. But Blackcaps; warblers which had returned from Africa to breed, had now fallen fairly silent. A Reed Bunting sang melancholically in the distance, its song struggling though the phragmites reed beds waving in the breeze. A Reed Warbler churred but lacked the vigour and stamina it had shown a few weeks earlier.

As grey clouds blocked out the sun and the damselflies vanished as though they had only been a dream in an afternoon siesta, the hirundines had burst in skimming over the waving reeds. Using our books, we pointed out the field characters to the newcomers to birdwatching. Around a hundred Sand Martins nest here in an artificial sandbank specially created for them. We learnt from the ‘guide in the hide’ that some birds may even raise three broods in a summer. The London Wetland Centre is one of conservation’s great success stories in the twenty first century and is a role model in the design of nature reserves and has even been an inspiration for luxury hotels overseas. The Sand Martins have a pale sandy coloured collar which the House Martins lack. But I pointed out that this is hard to see in flight. On cue, three Sand Martins hurtled past over the reed beds and diminished into receding dots.

Useful information

A number of groups in London organise a range of bird watching and other nature walks as well as day trips by coach or using public transport to sites further afield from London. Three groups which are especially suited for residents and visitors in central London are listed below.

The London Natural History Society has a number of active sections, which includes the London Bird Club. The LNHS organises around a hundred free events a year and is one of the most active nature societies of its kind in the world.