Estimating natal dispersal movement rates of female European ducks with multistate modelling

1. We used up to 34 years of capture-recapture data from about 22 100 new releases of day-old female ducklings and multistate modelling to test predictions about the influence of environmental, habitat and management factors on natal dispersal probability of three species of ducks within the Engure Marsh, Latvia. 2. The mean natal dispersal distances were very similar (c. 0.6-0.7 km) for all three species and were on average 2.7 times greater than breeding dispersal distances recorded within the same study system. 3. We were unable to confirm the kinship hypothesis and found no evidence that young first-nesting females nested closer to their relatives (either mother or sister) than to the natal nest. 4. Young female northern shovelers, like adults, moved from small islands to the large island when water level was high and vice versa when water level was low before the construction of elevated small islands. Movement probabilities between the two strata were much higher for young shovelers than adults, suggesting that young birds had not yet developed strong fidelity to the natal site. Movements of young female tufted ducks, unlike those of shovelers, were not dependent on water level fluctuations and reflected substantial flexibility in choice of first nesting sites. 5. Data for young birds supported our earlier conclusion that common pochard nesting habitats in black-headed gull colonies were saturated during the entire study period. Young females, like the two adult age groups, moved into and out of colonies with similar probability. Fidelity probability of female pochards to each stratum increased with age, being the lowest (0.62) for young (DK) females, intermediate (0.78) for yearlings (SY) and the highest (0.84) for adult (ASY) females. 6. Young female tufted ducks, like adults, showed higher probabilities of moving from islands to emergent marshes when water levels were higher both before and after habitat management. The relationship between the spring water levels and movement was much weaker for young females than for adults. 7. Young female diving ducks exhibited much stronger (compared to adults) asymmetric movement with respect to proximity to water, with higher movement probabilities to near-water locations than away from these locations. 8. Local survival of day-old ducklings during the first year of life was time-specific and very low (means for different strata/states 0.01-0.08) because of high rates of emigration and prefledging mortality.