Species and housing
Between July and September 2018 we established 45 pairs of zebra finches
from a pool of wild-derived captive birds available at Macquarie
University. Randomly chosen groups of three males and three females were
placed in aviaries 230×175×410 cm (height ×width ×depth), containing
four nest boxes (22×12×15cm) located 175cm from the ground and shaded
from direct sunlight. Birds were fed dry finch seed mix and waterad libitum , with a daily supplement of hardboiled eggs,
cuttlebone and green seeds. After an initial week of acclimation, birds
were provided with November grass, cotton strings and Emu feathers to
allow nest construction. Clutches were monitored occasionally during the
first part of the incubation and checked multiple times a day when
approaching hatch date. When exact hatching date was ascertained, we
experimentally heated 13 nests with a minimum brood size of three and
simulated the same experimental procedure for 12 control nests (See
Tables S1-4 for a detailed description of the sampling protocol). Our
set up allowed us to control for food availability (Hall et al.2004) and prevented all sources of predation risk (Noguera & Velando
2019) that are also factors known to have reflections on telomere
dynamics.