Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Examples of variation in first-year (A and B) and adult (C–F) annual survival probabilities of cliff swallows in relation to natal or breeding colony size in years with significant positive (A and C) and negative (B and D) directional selection on colony size and in years with stabilizing (E) and disruptive (F) selection on colony size. The estimated survival function, solid line; 95% confidence interval, dotted lines; males (blue lines), females (red lines).
