Swifts are quintessential birds of high summer here in central Scotland, arriving to breed during May, departing again in August leaving only echoes of their screaming, acrobatic flight along with our memories of warm days. At this time of the year, I begin to anticipate their return and look out for them.
Thanks to the development of miniature tracking devices, we now know that they spend the rest of their year on the wing, more than 99% of their time, 24/7, reaching south as far as central Africa before returning to their exact point of departure (allowing the trackers to be recovered)1. It is hard to begin to grasp how our world looks from a swift’s point of view, “…intelligent in ways that are different from ours…”2. They clearly know where they are and where, and when, to go. They can find their food, for example swifts have been observed patrolling advancing storm fronts, scooping up insects caught in the updrafts. The trackers confirm that they habitually fly high at dawn and dusk, taking over an hour of sustained effort climbing to 8,000ft and beyond before gliding down. Nobody is (yet) quite sure why, perhaps simply an opportunity to sleep on the wing?
Swift numbers have gradually declined over at least the last 20 years, perhaps by about half3. Even when nesting, swifts range many miles in search of food so, as a result, reliable annual counts are difficult. So how can we best ‘look out’ for them (in a different sense)?
Long-term, swifts have benefited from expanding human habitation, our buildings, bridges and other structures providing nesting opportunities additional to natural crags and crevices4. But other changes are less positive. Recent studies provide evidence of massive and widespread losses of the flying insects which provide their food5, and the fuel for their long journeys. Climate change, air pollution, light pollution (affecting navigation) and other threats affect their migration routes.
Swifts benefit from co-ordinated international action. In 2014, the UN Convention on Migratory Species adopted an African–Eurasian Migratory Landbirds Action Plan6with the aim of improving the conservation status of swifts along with other long-distance landbird migrants, especially those that overwinter south of the Sahara. Wordy (and worthy) perhaps, but a framework for cooperation is in place and active7.
Here in Scotland we enjoy, and cherish, an iconic wide-ranging bird, the status of which is not obviously linked to land management. But the decline in insect populations is a consequence of more intensive land management, which squeezes out non-crop species. We must make space for nature – land management measures are needed to sustain the insect populations across our farmland so as to benefit our swifts, among others, and allow us to look forward to their return for many summers to come.
- Anders Hedenstrom et al. (2016) Current Biology 26 pp3066-3070 http://www.cell.com/current-biology/fulltext/S0960-9822(16)31063-6
- Adam Nicolson (2017) The Seabird’s Cry – Introduction
- …although many modern buildings are less helpful, with sleek external finishes.