What did the robins conclude about the children?

The robins concluded that the children were not dangerous, and their eggs were safe. The mother robin even found the children entertaining.

When the boy was walking and running about and digging and weeding like the others, the nest in the corner was brooded over by a great peace and content. Fears for the Eggs became things of the past. Knowing that your Eggs were as safe as if they were locked in a bank vault and the fact that you could watch so many curious things going on made setting a most entertaining occupation. On wet days the Eggs’ mother sometimes felt even a little dull because the children did not come into the garden.