Updates from our Cuckoos

PJ has finally set off on his sixth southerly migration. Having spent the last couple of months in Suffolk, by 22:50 on Thursday night he was approaching Hatfield Peverel in Essex and by 23:39 he was crossing the Thames close to Canvey Island. At 06:27am Friday morning he was over the Forest of Fontainebleau in France. By 05:24 on Sunday morning PJ had flown a further 485 km (301 miles) south to the south of France to his current location in the west of the Gers region, close to the town of Estang. He is now 70 km west of PJ who is in the far north east of Gers. Since leaving his breeding grounds in Suffolk on Thursday night, PJ jas already covered 941 km (585 miles). 

After five years and a staggering 50,000 miles, Suffolk Cuckoo PJ has once again returned from Africa to his breeding grounds in the King's Forest, Suffolk. He is the first of our tagged Cuckoos to survive five complete migrations with his tag still functioning. When we last updated you he was having a well deserved rest on the Isle of Wight, but despite the many attractions of that fine place, it couldn't keep him away from East Anglia for long. New updates received from PJ's tag at 07:30 yesterday morning (Friday 22nd April) showed that he had covered the final 223km (139 miles) from the Isle of Wight to Suffolk. Further updates since show him flying around his breeding grounds, less than 5 miles from us here at BTO HQ in Thetford. He will stay here until early July before beginning his journey back to Africa once again.

We caught and tagged Cuckoo 'PJ' in the King's Forest, Suffolk, in June 2016, and since then he has provided us with a wealth of valuable data. Through tracking PJ's migrations between UK and Africa, we have discovered that he spends the winter months in north-western Angola. Recently, while en-route to the UK he has spent several weeks feeding up in Ivory Coast and over the last few days we can see that he has tackled the mighty Sahara. He was in, or over, Mauritania on Sunday morning and by 8am yesterday morning (Monday) he had reached Morocco! The most recent update, which arrived at 19:40 last night, showed him in northern Morocco. He is currently in the Middle Atlas Mountains, approximately 95 km (59 miles) south east of Fes. From here, he will move up through Spain and France before crossing into England.

If he makes it back to Suffolk this year, PJ will have completed his fifth tracked migration, which is the most for any Cuckoo that we have tracked so far! It has been a nerve-racking time waiting for PJ to tackle the desert and we'll be keeping everything crossed that the rest of his journey goes smoothly. In previous years, he has successfully completed his desert crossing between 7th and 17th April and arrived back at his breeding grounds in Suffolk between 18th and 30th April, so he is close to his usual schedule.

PJ, who is on his fifth tracked annual migration to the UK from Africa, has spent the last couple of weeks in Ivory Coast. The rains are well established in the area that he's stopped off in - in fact, there's been a bit more than expected over the past month (up to 75mm). This should mean there's plenty of food for him. We don't know exactly what he'll be feeding on but expect that this will include some adult insects that have been aestivating over the dry season and have emerged in response to the start of the rains.

The area PJ is in was originally deciduous forest that has been transformed into secondary growth - this transformation might originally have been beneficial for Cuckoos, but depending on the extent of tree loss, it could reduce habitat quality for them. As it's now a few weeks since the rains commenced, it's likely that in addition to emergent insects, there could also be plenty of caterpillars (Cuckoos preferred prey on the breeding grounds) for him to eat by now. He's likely to use this fuel to put on fat amounting to at least 50% of his lean body mass, as well as enlarging his flight muscles, before migrating over the Sahara. He usually spends most of March in Ivory Coast before heading north across the Sahara.