2.3. Natural observations: males

We captured 20 wandering and 20 resident females and released them individually onto the mudflat at least 2 m away from their capture point. We documented the second visit of the female to a waving male (we did not document the first approach to avoid the initial female escape response). We noted the total number of waves that the visited male gave to the female and the total number of males that waved at the female during her approach to the visited male. We also noted whether males gave aggressive waves (these are choppy vertical waves that are easily distinguished from the courtship wave) and whether the male allowed the female to enter his burrow.