Did people use pigeons to communicate?

Yes. The U.S. Army's Signal Corps famously lucked out in October of 1918 when their Blue Check hen (named Cher Ami, French for 'dear friend' in the masculine) heroically delivered a messsage from the now-famous "Lost Battalion", who was not only surrounded by the enemy, but was also being artillery-barraged by friendly fire. She'd been shot through the breast, blinded in one eye, and the message capsule was attached to her left leg- which was itself barely still attached by one ligament.