A very large colony of very tiny ants was discovered inside a tree (at head height) cut down yesterday in my backyard. The hollow where they were living was inside of the trunk and goes all the way to root level. The ants are very tiny but the colony had huge numbers. I've checked with a termite control firm and they advise that they are in fact ants but could not tell me the species. They are pale coloured and hard to spot on the ground due to tiny size and colour. I'm curious if anyone can identify them.
Veronika
Hard to say because it depends on what is 'very tiny' and 'pale' but I would suggest Argentine ants. Catch some with a strip of sticky tape so they can be examined by an expert.
I have only seen worker ants in trails across the floor and up the walls but these could be Argentine ants Linepithema humile. I always expect the worst in house and garden sightings.
One of the ants (top of the image) has a very large head and mandibles, characteristic of a Pheidole major worker. And the minor workers of Pheidole are certainly small.