July week 4, and our RAS season finishes

With unsettled weather, there was only one roost visit this week, and Peter, Alan J and Jerry were there on Thursday 29th. The Sand Martin flock was again disrupted by a Hobby, probably causing them to roost elsewhere (one of the other reed beds). Soon after setting the two main nets, a Hobby made a pass low along the length of the jetty ride, responding to the tape. The catch ended on 12 + (1), with 5 Sand Martin, 1 Swallow, 2 Willow Warbler, 2 Chiffchaff and 2 + (1) Reed Warbler, ending just before a light shower arrived (the forecast was for a low chance for light rain).

On Saturday 31st, the last RAS sessions were completed by Andy at the jetty - total 17 + (3), and Rachel/Jerry in rb2 - for an excellent catch total 80 + (8). After a busy first couple of net rounds in rb2, the catching then became "steady". The species mix for the day was 1 + (2) Wren, Robin 2, Redstart 1, Willow Warbler 7, Chiffchaff 12 + (1), Blackcap 2, Garden Warbler 1, Lesser Whitethroat 1, Reed Warbler 50 + (7), Sedge Warbler 19, and Reed Bunting 1 + (1). The total ringed during July was 518, making the YTD 912.

A couple of shots of our first Lesser Whitethroat of the year. It was also possibly our last Lesser Whitethroat of the year, as except for years where they breed very locally, we usually only catch one or two a year on passage

We had a very successful RAS season with 48 adult Reed Warbler recaptured - 20 in rb2, and 28 at the jetty. These birds were ringed in 2015 (2), 2016 (3), 2017 (4), 2018 (8), 2019 (16) and 2020 (15) - incl 10 ringed as juveniles in 2020. With comparable effort of the RAS visits at the two sites, it is possible to gauge how successful the breeding season has been. The total number of adults caught (newly ringed plus recaptures) was 44 in rb2, and 51 at the jetty, reflecting the greater extent of reed bed at the jetty. However the number of juveniles caught was 62 in rb2, but only a very disappointing 36 at the jetty. Last winter, NRW cut an extensive area of reeds at the jetty and along the adjacent western reed bed. Although the reeds had regrown by the time we started catching in late June, the cutting will have had an adverse effect on the breeding habitat for Reed Warbler, as they require old reed stems on which to build their nests. Despite good numbers of adults around the jetty, it looks like the shortage of breeding habitat, accounted for the relatively low numbers of juveniles raised there. Surely a lesson to be learnt when any future cutting of the reed beds is being considered.

Below are two similar views in late March and mid May.