Monday, 17 February 2014

musings on roosting gulls

I've always (well for the last few years since I moved up the valleys) thought that all the gulls around this area roosted on Pontstic' res, except their rare shift to Llwyn Onn. Walking home from the station this evening I noticed a group of large gulls flying down the Taf, from the Merthyr direction. In a 10 minute period I counted over 200 heading down the valley, towards Cardiff. I guess they were heading to roost in Cardiff Bay area as I can't think of any large water body that way before you hit the Bay. I've not noticed any significant movement og gulls down the valley previously, though I have noted gulls flying up the valley early in the morning., so it shouldn't have been much of a surprise. This number of gulls would constitute some 10% of the Pontstic' roost (Mike, correct me if I've got my maths wrong). A portion of the Merthyr feeding gulls roosting down the Bay would go some way to explain the occasional Great Black Backed, Yellow-legged, Iceland and Glaucous turning up in the area.


  1. The gulls I had doing the WeBS on Sunday were flying up the Cynon Valley.

  2. A similar tale in the Rhondda. Each morning we have a steady flow of birds following the river up the valley. These are mostly Black-headed Gulls with lesser numbers of Lesser Black-backed Gulls. Herring Gulls are present in low numbers. I've seen Common a Gull just once and no white-wingers.
    At Treforest each evening there's a steady movement of

  3. ... gulls down river. Cormorants too.

  4. RE;Gulls:I've been watching them for a while and I'm still not sure what they get up to but in general terms;
    (i) They are part of the Severn Estuary group, we've had gulls ringed at Gloucester Landfill on the roof of Peacocks so the whole group appears to be mobile and anything can turn up. A pair of GB have summered at Merthyr in the past, 2005 & 2009 using Llwyn-onn reservoir on numerous occasions.
    (ii) Merthyr has one of the oldest inland gull breeding colony in the UK, c70 - 100 pairs on Hoover rooftop alone, made up of HG & LB some of which appear to have returned in the last weeks. Birds from this colony currently fly over my house heading south most mornings (others are probably heading for Trecatti).
    (iii) Pontsticill reservoir appears to provide a night roost for many of the gulls along the HoV but they occasionally use Llwyn-onn and Garnlyddan. Species make up is largely HG (highest historical winter count c4500) with LB using Llangorse and occasionally Talybont. In Autumn BH numbers can reach into the 70's at Pontsticill but almost disappear by mid winter (Dec & Jan).
    (iv) LB return to Merthyr for breeding where day numbers at Rhaslas can reach c150 but almost disappear again by Autumn/Winter.
    (v) The Pontsticill roost almost always empties before dawn, at least I've never found more that a score or two when I've passed. They may go post clubbing on street clean up around the valleys, Ponty, Cardiff etc.

    I visited Biffa at Trecatti many years ago to ask if we could start recording perhaps trapping and ringing gulls but I was shown the gate. They see gulls has a problem full stop and a bloke with a pair of bins as an eco-terrorist.

  5. Cheers guys, it just seemed a bit strange that the gulls were making their way south when there is a well used roost at Pontstic'. But as Mike says the large gulls appear to be big wanderers outside breeding season, capable of (to us) unfathomable behaviour

  6. Interesting debate about gulls in the Heads of Valleys area. Check out my blog for more gulls musings in vice county 35.

    Steve Williams

  7. Also I think the ferocity and number of recent storms has attracted many gulls to the coast i.e. smashed up shellfish beds, dead auks etc. Last night count at Pontsticill just 17 birds, all adult, LB 16 and just a single HG arrived at 17:10 and left by 17:30. RE: Valley Naturalist, cheers Steve, I'm already a regular visitor, tidy site.

  8. As my house is a fair way up the hillside and has a good view S. West, out over the mid Cynon valley, I commonly see large flocks of larger gulls, or a steady procession of smaller flocks, flying down the valley as dusk approaches. They often take advantage of the thermals produced by the factories on Aberaman industrial estate to gain a thousand feet or more of altitude, before heading off in the direction of Cardiff. Having gained all that altitude for little effort, they can probably see their destination and get a fair way towards it by just gliding, possibly taking advantage of similar thermals above Treforest industrial estate on the way.
    Similarly, at dusk,I have also witnesses flocks of gulls heading from Bryn Pica tip, down the Neath valley, destination presumably Swansea bay. A similar but less concentrated movement of gulls flying from the Cardiff and Neath directions to Bryn Pica can usually be seen around (especially after) dawn.