Bulrush are (unsurprisingly) well established in the new Trumpington Meadow Nature Reserve
Their seeds are bursting those cylindrical, velvety, tight confines now and are drifting far and wide on the wind …
As I walked round the pond I spotted a couple of birds busily helping to strip the downy seeds (apologies for picture quality – it was the best my phone could do). I looked them up later and I think I’ve identified them as Reed Buntings, Emberiza schoeniclus
Helped by birds eating the seeds
I think they are Reed Buntings, Emberiza schoeniclus
Frogend dweller's Blog 
Lovely fluffy clouds in the blue blue sky, and pretty fluffy seeds too. 😃
We’ve been enjoying some brilliant weather recently, with days of completely clear skies … so it was actually nice to see these clouds adding to the general fluffiness quotient of the walk. 😉
I always thought this was a North American native, but I see now that several species are common in both America and Europe. It is a valuable food source here for muskrat, beaver and birds, which also use the fluff for nesting. A handsome plant!
I can definitely understand its use as a nesting material. It was super soft!
You say ‘bulrush,’ but it certainly looks like our cattail. When I checked, I found that there are about thirty species in the Typha genus, so ours certainly are related to yours, even if not the same species. I’ve never seen a bird in the act of pulling out fluff; lucky you to have found them.
It is interesting that is such a good food resource, because the fluff looks completely inedible with no seed content to speak of. It must be there though!