Territory size, site fidelity, apparent death of partner, and mate fidelity of songbirds spot-mapped in forested landscapes surrounding Seattle, WA, USA, from 2003–2010.

Assessment of site fidelity was done within each landscape and summed here for an overall proportion because territory size varied among species and among landscapes (S1 Table). When a banded bird remated with a new partner and it’s mate from the prior year was not detected in the study area, we concluded the prior mate was apparently dead. Species abbreviated as follows, Bewick’s wren: BEWR; dark-eyed junco: DEJU; song sparrow: SOSP; spotted towhee: SPTO; Swainson’s thrush: SWTH; Pacific wren: PAWR.