Hi Phil, I would be very surprised to see Red Grouse along the Pendam to Ponterwyd Road as there is very little if any, suitable habitat i.e. extensive areas of heather. Going back a few years there was a good population on the slopes of Plynlimon but nowadays only the exceptional sighting has been reported towards the Bugeilyn area. A few years back there were some Blackcock around the edges of the Forestry in the Pendam/Syfydrin area but again no reports in recent years.
Perhaps the Grouse may in fact have been Partridge as some were recently reported on this blog, as being seen in the Ystymtuen area. It is only a short flight from there over the mountain to Pendam.