A new robin's nest is coming together about 6 feet from where I'm sitting

Earlier this morning I saw a couple of robins collecting nesting material in the yard but I saw them fly around the end of the house toward the big honey locust tree. Then I was sitting at the table taking a break from yard work, drinking some coffee and reading and a robin landed on the railing with a beakful of nest material. After looking around for a minute it popped up into a planter right in front of me and I realized there was a nest coming together. ?