Data from: Are thyroid hormones mediators of incubation temperature-induced phenotypes in birds?

Incubation temperature influences a suite of traits in avian offspring.
However, the mechanisms underlying expression of these phenotypes are
unknown. Given the importance of thyroid hormones in orchestrating
developmental processes, we hypothesized that they may act as an upstream
mechanism mediating the effects of temperature on hatchling phenotypic
traits such as reduced growth and thermoregulation. We found that plasma
T3, but not T4 concentrations, differed among newly-hatched wood ducks
(Aix sponsa) from different embryonic incubation temperatures. T4 at
hatching correlated with time spent hatching, and T3 correlated with
hatchling body condition, tarsus length, time spent hatching, and
incubation period. In addition, the T3:T4 ratio differed among incubation
temperatures up at hatch. Our findings are consistent with the hypothesis
that incubation temperature modulates plasma thyroid hormones which in
turn influences multiple aspects of duckling phenotype.