Sunday, 4 June 2017

CES update

With the first four CES visits at Llandilo out of the way, we now have an indication of how some of the common bird species are faring compare to the previous two seasons. Catch sizes at this site are typically fairly small, with an overall average of 25 birds per session (ranging from a high of 40 down to a very desperate 9 in August 2015). The earlier visits tend to be very slightly busier with an average of 27 birds during the first four sessions and this year is identical to the average for the period. However, its not as run-of-the-mill as it first appears, and there has been a 20% decline in overall adult abundance with the difference made up by more early juveniles than usual. In particular, the number of juvenile robins is already equal to the entire year's worth of the past two seasons, which have both been pretty rubbish in terms of productivity. As an indication of how bad a season 2016 was, only 2 juvenile blue tits were ringed all season! Whilst some ringers might celebrate that (blue tits can be vicious), it hopefully will be a more productive season in 2017 for juveniles, and who knows?, we may even break the record catch of 40.

Even though catches are small, they often result in something a bit interesting being caught, and they are an ideal pace for trainee ringers.

Adult male redstart from CES 2

Spotted flycatcher

Juvenile long-tailed tit

A big surprise was this juvenile dipper caught during CES visit 4. It was unusual in that it was caught away from a stream, flying through woodland, and also in that it was already ringed elsewhere. It turned out to be one of Karen's from Teifi RG and it was ringed as a nestling in April in the Gwaun valley. Although only 10 km away in a direct line, it had clearly jumped catchments, probably crossing the Preseli hills. By coincidence, Karen was also helping out with the session, so she got a chance to catch up with it.