Very Puzzled

Looks very much like Raccoon droppings.

http://www.dailymail.co.uk/sciencet...t-devastate-native-wildlife-expert-warns.html

 

They must think a solitary male or female still has a 50% chance.

 

Bats? I would say that the piles in the joints are as you say Birch seeds that have blown in and landed on the cobwebs but the piles underneath look like they are from an insect eating animal that is why I said bats,although it is a mystery if you can't see them hanging from the beams unless going up there disturbed them and they legged it until after you had left the loft.

Having said that there would surely be piles of bat poo everywhere and I am not sure if bats give off an odour when living in your loft.

I would contact the local pest control people and see if they can recognise what the problem is

PS,I see you have a little bit of bird poo on the joist in the top photo to the right of the pile of insects and whatever has done this it could be some sort of pellet that has been brought back up although I could be wrong

 

Hi @shiney could it be a squirrel? Their droppings I believe are a mixture of colours both dark & light. They can deposit their droppings in several places but they tend to leave them in one place!
The droppings look like they have nuts/bird seed in them from the photos, although my phone screen is cracked so I can't get a really clear picture. I'm wondering if you have a cheeky squirrel steeling your bird feed & somehow sneaking into your attick for a sleep!

 

Just one more thought...if it's bats poop I seem to remember someone telling me it would contain insects & it would really smell!

 

Interesting!
Zooming in for a closer look....a great deal in the heaps seems to be perfect seeds from Silver birch... without any sign of having been processed through a bird or animals digestive system!

http://m9.i.pbase.com/g1/51/659951/2/115248179.Aax0fIHa.jpg.

http://cdn2.arkive.org/media/AB/ABF...on.Large/Seeds-and-scales-of-silver-birch.jpg

No idea which creature might make a winter store from these.
Not sure mice would do this.
Maybe a remote camera trap to video the culprit would prove interesting.

Or could the answer be simple ..the seeds were blown in under the roof tiles and caught in spider webs above, which have got detached and fallen down in a small pile in recent gales?

P.S. Quite wrong for bat droppings...which look like grains of brown rice.
Which in the UK just contain insect wing cases etc and are dry...crumbling away to dust.
Even if you had bats in the attic they can squeeze into really tiny nooks and crannies and you might never see them... except at dusk as they leave the roof.

https://www.google.co.uk/search?q=b...ved=0CAcQ_AUoAWoVChMI5crK5NrYyAIVw7wUCh1dlABL

http://www.batsintheattic.org/poop.html

 

I suspect they are just cobweb balls.

 

I'd just like to say that I'm totally wrong! Squirrel poop is like pellets....so sorry
Hubby thinks it's probably a build up of cobwebs & seeds