RAS at Cwm Clydach

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In a previous blog I talked about our Constant Effort Site (CES) at WWT Llanelli. A RAS is another programme initiated by the BTO and it means Retrapping Adults for Survival. Its aim is to catch or re-sight at least 50 birds of a predetermined single species during the breeding season. See link below for a full BTO description.

The species we have been targeting at Cwm Clydach is the Pied Flycatcher. Ringing Pied Flycatchers started way back in 1986 with 36 boxes. Today they have gone up to about 250 boxes which we monitor every Wednesday during the breeding season and record all the weekly results right up to the day of the last bird fledging. These results include any species of bird that uses the nest boxes. Besides the Pied Flycatchers we have Blue Tit, Great Tit and Nuthatch.

A few Pied Flycatcher facts from our data.

  • The peak number of Pied Flycatcher nests to the egg stage was 111 in 1997. 
  • Last year out of the 250 boxes we only got 21 nests to the egg stage which is an indicator of how productivity has become. This bird currently has an Amber status which reflects our concerns for this species. 
  • The oldest returning bird we have recorded was 8 years old. The oldest recorded Pied Flycatcher nationally was 9 years 0 months and 7 days. If our bird had returned last summer we may have held the record for the oldest bird recorded. Sadly it didn’t, it may not have died and we are hoping that maybe this year it will turn up, however, realistically this is probably not going to happen. 
  • A Pied Flycatcher ringed as a nestling in 2008 was picked up in Liberia, West Africa, the first British ringed Pied Flycatcher to be found there.
  • Our site was registered as an official RAS in 1998 with the BTO.
The pictures below I took yesterday as I was checking all my boxes.

Last week there were only 4 Pied Flycatcher eggs in this nest which were cold and covered. This week the seven eggs shown were warm and uncovered suggesting incubation has started. Incubation is between 13-15 days and fledging 16-17 days

We have blue Tit boxes at various stages and incubation appears to have started in this box. Many of our other boxes have Pulli at various stages as well.

These Great Tit Pulli are only a day or so old. The nests in both the Tit boxes have been lined with sheep’s wool.

Finally these Nuthatch Pulli will probably be Feather Small by next Wednesday and fledge the nest a week or so later.

RSPB Cwm Clydach is about 7 miles from Swansea

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