Inka Pleiss: Carbon Crumbs: Tracing tītī diet and stress through feather chemistry

<p dir="ltr">Sooty shearwater/tītī are native to New Zealand and hold cultural significance for Māori. However, they are under threat from climate change. Understanding dietary differences between colonies and potential impacts on stress is a key first step in determining this species’ resilience to oceanic changes, and to inform conservation measures. We found that prey type differs between North and South Island colonies, despite them likely feeding in similar locations based on the stable isotopic signatures found in chick feathers. Prey preference did not appear to have an impact on chick feather corticosterone, a measure of stress. However, stress was elevated in chicks from the northern most colony in 2024. This is hypothesised to be due to lower prey availability under El Niño conditions and the greater distance between this colony and key foraging grounds. As such, conservation measures should prioritise setting up new colonies in close proximity to known foraging hotspots. </p>