Updates from our Cuckoos

It's only early June but our first Cuckoo has already left to start the journey to their wintering grounds! Recently named Peter, one of our New Forest Cuckoos tagged this year, had made it to northern France by the 8 June. This is early for our Cuckoos but by no means the earliest. In previous years Cuckoos have left as early as 3 June. Who will be next to follow?    

Stanley was the last of three birds to be tagged in the Thetford area in 2014. On a misty morning near Cranwich Heath, Stanley hurled itself at our dummy female Cuckoo and into the net from a great distance, despite the nets being highlighted by the mist.

Walpole was caught and tagged less than 1km north of where Chris the Cuckoo was originally found, three years before.

BTO's Cuckoo tagging team were accompanied by Anglian Water's Mike Drew to catch and tag Maji - who despite bright skies, and other birds avoid the nets, managed to fly in twice before before being caught.

Bolderwood, New Forest, Hampshire -  Six Cuckoos caught between 04:30am and 11:00am - the first three of which (two tagged, one too small) were in the first round, one in the middle of each of a triangle of nets set at Bolderwood. The other three were caught a couple of miles to the north and four were selected for tagging. This meant we completed our tagging in Hampshire during day, in a brief weather-window.

All three Devon birds tagged in 2014 (Emsworthy, Meavy and Wistman) were caught between 04:30 and 08:30 on May 15th at Emsworthy, a Devon Wildlife Trust reserve on the eastern edge of Dartmoor, along with one female cuckoo. Nets were set around an isolated Hawthorn bush on the upper valley slopes. A fifth cuckoo escaped from the net that morning.

The first of three Cuckoos taggged in Sherwood Forest, 134952 was caught flying between young alders near Shirebrook, after having failed to catch three cuckoos flying over our nets at Budby Common earlier that morning. The second two birds, 134955 and 134957 were trapped at Sherwood Pines the following morning, the second bird flying into the nets just as we released the first!

In the last few days we have been receiving signals from Tor's tag - surprising us as we last heard from him just north of the Congo Rainforest in March! These new signals show he made it to Morocco but unfortunately it does look like, despite successfully completing the crossing of the Sahara desert, he has since died there. This shows that tag failure was responsible for his initial silences but unfortunately it looks like the desert crossing was too much for him and he didn't have the reserves to continue onwards. 

By the evening of 13 May David was back in Wales! He left his last location in France sometime after the 9 May, making the 660km (410 miles) journey back to Tregaron, the area in which he was first tagged.

Last year, in spring 2013, he first returned to the UK much earlier, around 26 April but promptly turned tail and returned to France - no doubt  influenced by the cool daytime weather and falling evening temperatures at Sherborne, and by the general lack of advancement of the spring due to the unseasonably cold weather earlier on in March and April.  Having spent a few weeks there, he was back in the UK by the 6 May and at his tagging site by 9 May. 

It's interesting that despite much warmer daytime temperatures in the last few weeks, David has chosen to leave it even later than last year. Perhaps using his previous experience to ensure that he doesn't make the same mistake again. This choice however may mean that he finds it harder to find a mate, as other Cuckoos who have arrived earlier will have taken the best territories.  

Patch hadn't moved on northwards from his location in Spain like the other Cuckoos so our scientists took a look at the signals received recently. While we have been receiving signals, a closer look revealed that they were all lower quality signals, indicating that the tag may be on the ground. In addition the temperature associated with each transmission is now fluctuating with the external temperature, rather than remaining steadily at body temperature - as you would expect if the tag was still attached to a live Cuckoo. Together these two bits of information seem to suggest that we have lost Patch in Spain and he will sadly not be returning to his tagging ground in Scotland.