Estimates of daily apparent survival ( Φ ) from all sub-sample models for post-fledging days 1 to 40. a) Daily apparent survival rates (one line per model). Most models reveal a drop in daily survival around 15 days post-fledging; however, the variation in point estimates is large and several samples deviated strongly from the general pattern. The bold gray line indicates estimates from the full sample size (n = 538). b) Cumulative post-fledging survival as estimated from four categories of sub-samples size in relation to time post-fledging (x-axis gives category means). Small subsamples dramatically underestimate the proportion of birds surviving to the end of the observation period. Dots and whiskers give means and 95% confidence intervals per sample size category and re-encounter interval.