Results of ten years Retrapping Adults for Survival (RAS) project on breeding Redshanks (Tringa totanus) at Wieringen, Netherlands
Wim Tijsen, Hans Schekkerman
Between 2000 and 2009, 203 breeding adults and 77 juvenile Redshanks were colour-ringed in meadows along the DutchWaddenSeacoast of North-Holland The study is conducted in two areas to determine if there is a difference between survival and reproductive success in nature reserve areas and in agricultural areas with nature management schemes.
Overall breeding success varied between years from 25,53 to 58,49% while between 43 to 64 nests were followed. Chick-survival can be improved by sympathetic mowing schedules, creating wet-grassland-areas, and other protection methods in the standard agricultural world. Used catching methods are a landing net and walk-in-traps. We used the program MARK for measuring survival and resighting rates. The selected model depends on sex and age for resighting rate p: For 1st years birds the resighting rate was 0.16 (0.04-0.49). Adult males showed a resighting rate of 0.95 (0.91-0.98), for females this turned out to be 0.86 (0.81-0.90). The apparent survivale rate depends of age and year, with no effect of transients. First years birds mean survival rate was 0.24 (0.13-0.41). For adults mean survival rate between 2000-2009 was 0.83 (0.80-0.86). During these ten years of studying Redshanks, they were highly site-faithful to their breeding territories.
So we can say more about breeding site fidelity, natal philopatry, dispersal and pair courtship. The avarage dispersal for juveniles (n=32) is 2,123 meter. Mean dispersal for males(n=19) is 1,746 meter and for females(n=9) 2,713 meter and ranged between 82 and 9,660 meter. Mean duration of pair bonds(n=118) was 3.24 years. The reasons for stopped pairbonds can be analysed. In 65.26% of the cases one of the partners did not return, for 6.32% the reason was a disappearce of both partners and in 28.42% a divorce was involved. Divorces occurred in 60% of the cases after a year with hatching succes, while the mean hatching succes overall in years was 43%. Experienced pairs use their knowledge to raise their young successfully. This study will be continued in the next ten years.