Out in the field, if you're with a group, you may hear the field-trip leader say, "There's an indigo bunting at 1 o'clock in that large walnut tree." What does this mean?
Look at any tree and imagine a large clock face superimposed over it. The most vertical, top point of the tree would be 12 o'clock. Straight below this point, midway down the central foliage, would be the "dead center"; at the bottom, six o'clock. Three o'clock and nine o'clock would be at the outer right and outer left sides, respectively, and so on.
The clock technique is a helpful way for one birder to direct others to a hard-to-spot perched bird.