More than half of British Swifts have been lost since 1995, but the reasons underpinning this decline are unclear. BTO scientists are involved in research aiming to address these knowledge gaps, including tracking work using the latest technology.
Between 2010 and 2016, we deployed tiny geolocators on adult Swifts breeding in the UK to investigate where Swifts go on migration, and identify which areas are important for them on their journeys to and from Africa and once they get there. Even our initial results, as illustrated in the map below, showed just how incredible these small birds' annual journeys are. We now know that the wintering range of individual Swifts is huge, with birds visiting several countries across Africa once they've completed their post-breeding season migration (see first map).
Swifts also live up to their name, with one individual taking only five days to travel 5,000 km from West Africa back to the UK. This bird had stopped for 15 days in Liberia before embarking on this leg of its return journey, indicating the location of a previously unknown stopover site for refuelling, where conservation efforts could now start to be focused.
Since 2014, we have used GPS tags to study local movements during the breeding season (see second map), as well as to give a more detailed picture of Swift migration. We have used this expertise to assist collaborators with their research, including RSPB, and have also exported our knowledge, for example to track Swifts nesting in Beijing (see third map), revealing their migration routes to Africa with GPS-level accuracy for the first time.
One bird, twelve journeys, 60 000 miles and invaluable scientific data: PJ the Cuckoo has left an incredible legacy.
Songbird migration across the Sahara
Mark Wilson, BTO Research Ecologist, reflects on his work tagging songbirds to collect data about their migration routes over the Sahara.