Most likely bat guano.
Round droppings in attic.
The place where you find droppings can help distinguish between kinds of pests.
To identify the rodent feces in your attic the best bet is to look at the size.
Since squirrels are among the most common animals to take up residence in your attic you will want to know what their droppings look like.
In the bottom rafters of your attic.
However as with many creatures there s a benefit of having them near but not in your home.
Droppings left by other pests.
Smaller is mouse larger is rat or squirrel.
Rat droppings are usually going to be found in larger places such as behind storage shelves along the wall of a garage or shed in attic spaces underneath kitchen appliances and behind stored boxes.
Under or in your kitchen cabinets.
The precise look of droppings can distinguish one animal from another when factors like location are no help.
Their waste looks and smells different than that of other animals and is typically 3 8 of an inch in length with a diameter of up to 8 millimeters.
You are probably looking at mouse poop or rat feces.
Squirrel poop will often be found in clusters that is if you can find them at all.
Their droppings can cause structural damage create a bad odor and even grow fungus which can cause respiratory problems.
How to get rid of mouse droppings in the attic the best approach is a full cleanup with either vacuuming of feces or insulation removal and fogging of the attic with a special enzyme cleaner.
Squirrel droppings are quite tiny less than 8mm in diameter and about 1cm long oval shaped with rounded tips and slightly bulged in the middle.