The summers breeding birds – a tale of ups and downs

Huge thanks to Toby Branston, our Dorset Ecology Manager, who's sent this update of the 2013 breeding season at our Weymouth reserves.

The RSPB do not only create the perfect places for wildlife to thrive, we also check up on them with habitat surveys to see if our management is working or if any tweaks are needed. Birds are no different, summer may now be long past us and the days short and dark but to add to the excitement of the occasional rare gull we thought we would do a quick round up of RSPB Weymouth reserves breeding birds of this past summer.

Marsh harriers again nested on both reserves with the Lodmoor nest producing 3 fine fledglings. However, the Radipole nest was flooded out early on and no attempt was made to re-nest. The good news does continue though as the Weymouth harrier factory may have produced a further knock on this year with the news that a pair also raised 2 young for the first time in 65 years in Poole Harbour right next to RSPB Arne.

Bearded tits are a firm favourite with visitors to the Weymouth reserves and we were happy to find that their numbers were up this year with 7 pairs at Radipole and 4 at Lodmoor, some had multiple broods including one with 3 broods near the discovery centre, they deserve a bit of a rest now, I should think. The team also hopes that there are yet more pairs of these fantastic looking birds out in the more inaccessible areas of reed bed or near the Marsh harriers nest sites which we avoid to give them some peace.

The musical and noisy warblers also seemed to have a good year with good numbers of reed and sedge warblers as well as a increasing healthy population of Cetti’s which is particularly pleasing as Radipole was the first confirmed UK breeding site since they first turned up in the UK in 1965. Lesser whitethroat, whitethroat, blackcap, chiffchaff and willow warbler all bred on the reserves showing that both Radipole Lake and Lodmoor hold a huge array of species. How long is it before we get breeding Savi’s or marsh warblers as new colonisers to the reserves?

Another piece of well known but sad news was the ongoing (mis-) fortunes of the common terns on Lodmoor. After being flooded out last year and loosing an estimated 75% of the chicks, the whole colony of over 62 nesting pairs decided to mass abandon over a single night in June. Two pairs were even using the floating raft installed as a safety feature! This has been seen in other common tern colonies elsewhere and the cause still remains a mystery. Let’s hope they return for another try next summer, after all they have the success of the little terns on Chesil this year to spur them on!

Good numbers of ducks, grebes, moorhen and coot bred on the reserves with some added excitement early on with a pair of garganey showing breeding behaviour at the north hide pool but alas no actual nest was found. Generally though, duck productivity was low and it is thought that the marsh harriers may have impacted on their numbers as they are known to take ducklings as well as the abundant coot chicks.

Mute swan pairs increased on both reserves this year with 4 confirmed pairs on each and with many signets doing well and growing big enough to be safe from predation. However, a recent unexplained sickness in the swans on Radipole Lake has been investigated by EA and RSPCA with no confirmed cause found.

A small light at the end of the tunnel is that 2 of the swans have since recovered well at the RSPCA West Hatch centre and gained enough weight to be released back onto Radipole Lake where they seem to be doing well. So say welcome back if you see them!