Sand martins are arriving at the gravel pit, and time is of the essence! After three days of transporting 1600 tons of material to our second location, the second stock was formed last week. It is significantly bigger than the previous one, reaching about 5 meters high.The materials we chose are the same as the ones used for the first stock: crushed aggregates to form a sturdy base (0/20 mm grain size), crushed sand (0/5 mm grain size) due to its high compactation properties, and unwashed sand (0/5 mm grain size) due to its high percentage of fine grains. The order of the two finer grained layers was reversed. This way, we hope to eliminate the height factor of the material which could be preferred for nesting.We decided to wait a few days before giving the final touches to the stock's shapes, due to the heavy rains we were having. Hopefully, this has helped them be more compact, which we think will be crucial to attract the Sand martins.With the inestimable aid of the gravel pit workers, we proceeded to cut both stocks this week, so as to create vertical surfaces. Both of them have four faces, facing the cardinal directions. Even though we tried to compact them as much as possible, creating these vertical faces proved to be technically very difficult.The final touches were to make some small holes ourselves, hoping to attract the attention of the Sand martins!