Wild Barcelona: Wild Balconies

Last April a mysterious set of wings appeared on my balcony, the sun shining through their intricate veins. Their owner was out of sight, clinging to the other side of the railing. But for an expert, there were enough clues for an identification, mainly the small yellow segments on the outer edges. Many insects, including dragonflies, have these pterostygma, which provide extra weight to stabilise gliding flight. The visitor was one of thousands of Vagrant Emperor dragonflies on migration that spring, whose incredible journey would take them from their breeding grounds in north Africa to destinations as far north as the Faroe Islands.

I'd witnessed a similar phenomenon a couple of years back while reading on the balcony one sunny morning. A continuous stream of butterflies proved increasingly distracting, many of them drawn to the brightness of the open page. As with the Vagrant Emperors, unusually good breeding conditions in Africa had triggered a boom in the Painted Lady population, and they were heading north.

Other, less transient, wildlife can be found on a balcony, especially one with unswept corners and neglected plant pots. Jumping spiders can be observed waving their palps about and ambushing prey. Geckos scuttle up walls, and will make a dash for the interior of your flat through an open window. Their voracious diet for insects makes them useful house guests. Once I saw a bizarre Thread-waisted Wasp enjoying a quiet groom on the railing, providing an opportunity for closer examination. Its thorax and abdomen seemed on the point of separating, joined together by the thinnest waist imaginable.

And in the winter, there are many birds in town, looking for food in the warmer urban climate. If you refrain from spraying with pesticides, Chiffchaffs will come to pick the bugs off your plants, their small sharp bills able to handle tiny insects.

Lucy Brzoska runs nature tours and writes for www.iberianature.com.