Author Contributions
The study was conceived by CSD and DSR. CSD and DSR conducted lab work. HLD conducted the parentage analyses. CSD, DSR, HLD, JK, MH and TAB performed fieldwork. CSD performed analyses and drafted the manuscript with supervision from DSR. DSR, HLD, JK and TB managed the Seychelles warbler project. All authors contributed critically to the work and approved the final manuscript for publication.