Homeward bound

Just back-blipped the end of our lovely holiday in Madeira here and here.

Now back home to the cold and wet of a British January. Ugh! Took this as we sped along the M5 as these trees intrigue me. I noticed them on the way up, a week ago, and managed to grab at least this one hazy pic on the way down again.

Does anybody know what the fuzzy spheres are? Are they a part of the trees or old nests of some sort? They only appear on this one short stretch and I don't know what sort of trees these are ...