Out of Africa
Our summer migrant birds face incredible challenges in their daily lives but none more so than their annual journeys to and from Africa, to escape the British winter and reach warmer climates, returning again in spring. However, numbers of our summer migrants, such as the Cuckoo and Swift, are declining and we need to understand why.
Going Cuckoo with the BTO
The Cuckoos you see and hear in the UK have been on an amazing journey. They have travelled thousands of miles, crossed deserts, evaded predators and timed their arrival back to the UK to, hopefully, coincide with the breeding season of their host species such as Reed Warblers, Dunnocks and Meadow Pipits.
For the first time ever, we captured a year in the life of a British Cuckoo through satellite-tracking individuals to and from Africa. Kasper, Martin, Lyster, Chris and Clement the Cuckoos helped us to learn an amazing amount about migration over a year including where Cuckoos wintered, how they got there and the timing of their arrival and departures. But out of five Cuckoos, just two made it back. Since then we have tagged Cuckoos from England, Scotland and Wales too in an effort to further our understanding.
This information is critically important because Cuckoos in England declined by 50% between 1998 and 2008, while Cuckoos from Wales and Scotland fare
d much better. We think this might have something to do with their epic migratory journey and differences within this. Learning more will help us to understand the declines and inform conservation action.
Follow their journey and find out how you can support this ground-breaking research at www.bto.org/cuckoos
As for other migrants, the arrival of the Swift, reminding us of sweltering summer days, really signifies that summer is here but there seem to fewer in our skies year after year. The descending trill of the Wood Warbler and the distinctive song of the Pied Flycatcher is also missing in oak woodland.
Where are our summer migrants?
It is hard to know what is happening to our birds to cause these drops in numbers, but it looks likely that habitat change in Africa (south of the Sahara), caused by changes in land use and land degradation, could play a part. Migrant birds could also be facing hardships on their journeys to and from Africa and in the UK.
Further research is crucial; without knowing what is causing the declines, how can anything be done to stop them? We have to act now because time is running out. Wood Warbler numbers have dropped by 60% in just 15 years. The Out of Africa appeal is funding a range of projects which looks at the challenges faced in Africa and the UK, and on the journey between the two.
Knowledge gaps about wintering grounds
There are striking differences in trends for those migrants wintering in different areas.Those closer to the Sahara are increasing whilst those wintering further south in the rainforests, are generally declining. This could indicate that there is a problem in Africa which is affecting migrant bird populations.
The fieldwork in Africa is one of the main projects funded by the appeal and has helped us to learn more about how species use the various habitats.
We will also be investigating where species 'stop-over' to refuel and rest during their journeys as these are vitally important for birds and could also play a part in the declines we are seeing.
Nesting problems in the UK
Choosing a time to nest is very important as birds need to match the rearing of their chicks with the time when insects are readily available. Resident British birds which winter in the UK have a head start on those that spend the winter elsewhere. Migrant species must try time their arrival in to the country to coincide with the beginning of spring and the wealth of food - no easy feat!
With traditional nesting sites disappearing, perhaps species like the Swift and Swallow, are finding it harder to find suitable spots for their breeding attempts? Data collected here in the UK by volunteers in the BTO Nest Record Scheme and the Ringing Scheme may well give us some clues about whether nesting is taking place earlier, and assess the relative sucess of breeding attempts, in an effort to understand what is happening to these birds in the UK.