Scouting for boys

"Hi! Stop Thief!" shouted old Blenkinsopp as he rushed out of his little store near the village.

"He's stolen my sugar. Stop him."

Stop whom? There was nobody in sight running away, "Who stole it?" asked the policeman.

"I don't know, but a whole bag of sugar is missing. It was there only a few minutes ago." The policeman tried to track the thief but it looked a pretty impossible job for him to single out the tracks of the thief from among dozens of other footprints about the store. However, he presently started off hopefully, at a jog-trot, away out into the bush. In some places, he went over hard stony ground but he never checked his pace, although no footmarks could be seen. People wondered how he could possibly find the trail. Still he trotted on. Old Blenkinsopp was feeling the heat and the pace

At length, he suddenly stopped and cast around having evidently lost the trail. Then a grin came on his face as he pointed with his thumb over his shoulder up the tree near which he was standing. There, concealed among the branches, they saw a young man with the missing bag of sugar.

How had the policeman spotted him? His sharp eyes had described some grains of sugar sparkling in the dust. The bag leaked, leaving a slight trail of these grains. He followed that trail and when it came to an end in the bush he noticed a string of ants going up a tree. They were after the sugar, and so was he, and between them they brought about the capture of the thief.

Old Blenkinsopp was so pleased that he promptly opened the bag and spilled a lot of the sugar on the ground as a reward to the ants.

He also appreciated the policeman for his cleverness in using his eyes to see the grains of sugar and the ants, and in using his wits to see why the ants were climbing the tree.

The details of this story show that no one is present at the scene. Who is likely the narrator of this selection?