Drawing a heron plan of a feeding ground

A heron plan is a rough drawing of one feeding ground. It shows where the bird stands, where it flies in and out, and where you watched from. It turns scattered sightings into a picture you can compare from one visit to the next. The drawing does not need to be exact. It needs to be consistent.

Steps

1. Draw a rectangle on plain paper to stand for the area you can see. Add a north arrow and a short scale bar, with one mark for each ten paces you walk.
2. Draw the water edge as a wavy line along one side of the rectangle. Mark the shallows, the margin of reeds and any obvious bank.
3. Mark the standing spots with small circles, one for each spot a bird used more than once. Use a different symbol for a spot used only once.
4. Draw your vantage point as a triangle at the edge of the sheet, with a dotted line showing the direction of your view.
5. Add flight lines as arrows from the trees or banks where birds come in. Make the arrow thicker for a route you saw more often.
6. Pace out the distances from your vantage point to the two or three most used spots, and write the paces beside the lines.

What can go wrong

The most common mistake is to draw too much. A plan crowded with every sighting hides the pattern. Keep only the spots used more than once, and leave out single sightings unless they are unusual.

Pacing drifts on slopes and through reeds. Pace along level ground where you can, and label the plan as approximate. Another error is to draw the plan from memory after a visit. Draw it on the spot if possible, or straight after, while the layout is fresh.

How to tell it went right

A good plan shows a pattern you can see at a glance: a cluster of standing spots near one bend, and a flight line that crosses the same reed bed each time. When you return, you can check the plan and see whether the birds still use the same places. If the plan confuses you, simplify it.