The hairs on the rear-end are the give-away that it is a Carpenter Ant.

Picture of 

Dead Carpenter Ants. You see workers and winged swarmers. Of those winged ones Carpenter Ants; the big ones are females and the small ones are males.

These Carpenter Ants are guarding the entry to the colony. Notice the sills are Pressure-Treated wood.

Carpenter Ants don't care, they don't eat the wood, they only chew it apart for a place to live.

Picture of 

Carpenter Ants in the wild often travel on plants to get food from Aphids or plant saps.

If you see many ants traveling on a tree then they are colonized very close by.

Picture of 

Carpenter Ant.

Picture of 

Chewings dropped from a Carpenter Ant colony above.

Picture of 

Close-up of that pile of frass they dropped down.

Picture of 

Carpenter Ant trail.

Carpenter Ants are mostly active at night.

Picture of 

Carpenter Ant

Not all Carpenter Ants are all black. These are Carpenter Ants too. Look for the small hairs on the rear section, this will tell if they are Carpenter Ants.

Picture of 

Carpenter Ant

The hairs on the rear-end are the indication that it is a Carpenter Ant.

Unlike many other ants,  Carpenter Ants vary in size.

They don't have to be big ants. Carpenter Ants do not have to have wings either.

We found a Carpenter Ant colony.

Carpenter Ants with Pupa / Larva.

Picture of 

Carpenter Ants with Pupa / Larva.

Picture of 

Carpenter Ants with Pupa / Larva.

Picture of 

Carpenter Ants with Pupa.

Picture of 

Carpenter Ants with Pupa / Larva.

A picture of a carpenter ant carrying a small caterpillar back to the colony. The ants need this kind of food for protein when a lot of ant eggs are being laid.

Close-up picture of a Carpenter Ant Colony.  Obviously this ant colony is going to have a big population increase. This may be going on inside your structure somewhere.