Prenatal Corticosterone Impacts Nestling Condition and Immunity in Eastern Bluebirds

Area of Science:

• Avian ecology
• Immunology
• Stress physiology

Background:

• Maternal stress impacts offspring development and physiology in birds.
• Effects on wild bird immunity are not well understood.
• Eastern bluebirds are a model species for studying avian life history.

Purpose of the Study:

• To investigate the effects of maternal stress on Eastern bluebird nestling immunity.
• To assess the impact of prenatal corticosterone exposure on immune responses.
• To determine if maternal stress affects immunocompetence and fitness prospects.

Main Methods:

• Eastern bluebird eggs were injected with corticosterone or a control solution.
• Nestling morphology and condition indices were measured.
• Two measures of immunity were assessed: bactericidal capacity and phytohemagglutinin swelling response.

Main Results:

• Corticosterone-exposed nestlings had lower initial condition indices but recovered by Day 5.
• Nestlings exposed to corticosterone showed reduced swelling responses to phytohemagglutinin.
• Bactericidal capacity was not significantly affected by corticosterone exposure.

Conclusions:

• Prenatal exposure to maternal stress can impair offspring immunocompetence in wild birds.
• Reduced immune function may affect fitness prospects and disease resistance.
• Further research is needed to understand long-term consequences for wild populations.