Mystery Pest Leaving Black Spots

[johnobirches]

Hi all, our rebuild is nearing completion after three years but we have a mystery occupant who insists on leaving an unsightly calling card.

This takes the form of clusters of small black inky spots - each spot being maybe one or two millimetres in diameter. They are not round and have not bulk to them [so not eggs of any kind] and almost seem to have been sprayed or squirted.

They are very staining and we haven't found a method of shifting them yet.

During the extensive rebuild we have entertained all sorts of wildlife from birds and mice to spiders, woodlice and centipedes but now that the house is weathertight, dry and mostly decorated we don't see anything unusual - house flies, spiders and the odd wood louse.

Has anyone seen this or caught the culprit in the act?

PIcs attached [hopefully] with my thumb for scale.

Regards
John

 

[Baron de Gynes]

Look like 'fly spots' to me. Quite innoccuous but most irritating when you've put your best whites out.

 

[noj]

I agree - fly poo

 

[Zebra]

I would have said spider poo.

 

[Willsby]

My suggestion - do you have a cat? - we once had a similar problem with tiny droppings on one windowsill and on a routine visit to the vet were informed that our otherwise perfectly clean cat was "alive with fleas". They were flea droppings basically small pouches of blood.

 

[noj]

So it's either poo made by flies, or made of flies...

Either way they're a bugger to shift since they're so acidic they tend to burn into pretty much any substrate

 

[Baron de Gynes]

In my (albeit limited) experience, isn't spider poo more likely to be white?

Perhaps it depends on what the spiders have been eating? It's also a b*gger to shift.

 

[Matt Green]

Whereabouts exactly are you finding the spots in your house?

 

[johnobirches]

Hi, Thanks for the replies. I did some searching around on the net too and I'm coming down on the side of spider output.

We only find them on horizontal surfaces including stone steps, wooden sills and on flooring.

Fly spots appear often on the UPVC window frames of the caravan and lampshades etc. so we're ok on identifying those and there just seems to be too much at once for any fly.

Following the suggestions here and elsewhere I've looked vertically above the clusters and in some but not all cases found a cobweb - but in every case there was a beam or window header etc. from where the spots could have been dropped.

So my guess is that a spider catches something in it's web and when it eats it it chucks the waste overboard in droplets which spread as they fall and cause the clusters.

I'm surprised I've never noticed these before but maybe the house has just been too messy and dusty for them to stand out.

Look out spiders here I come!

Thanks again for the suggestions - relieved it's not death watch beetle droppings or some such.
Regards
John

 

[Penners]

Ha-haaaar - don' ee be afeared o' the black spot, Jim lad. It be the work o' Blind Pew!


Sorry - totally pointless contribution to this thread, but I couldn't stop myself. I agree that it looks like spider doo-doos.

 

[Keithj]

Part of the joy of an old house is the regular exercise with the hoover. Spiders may be my friends, but they can reside in the hoover anyway. The spiders round here seem to eat spiders.

Flies we rarely get (this is arable rather than cattle country), and wasps are attacked with vigour (and chemicals).