
Marbled murrelet
Photo Credit: Kim Nelson and Dan Cushing.
Scientific Frontline: Extended "At a Glance" Summary: Climate-Driven Predation Risk in Marbled Murrelets
The Core Concept: Poor ocean conditions require marbled murrelet chicks to undergo an extended nestling period, which significantly increases their vulnerability to nest predators. This dynamic establishes a critical, direct link between marine food availability and the terrestrial reproductive success of a threatened seabird.
Key Distinction/Mechanism: Unlike most seabirds, marbled murrelets nest up to 60 miles inland in mature, old-growth conifer forests, requiring parents to commute vast distances to deliver single forage fish (e.g., smelt, anchovy, or herring) to their chicks. During years with warmer waters and reduced marine productivity, chicks receive fewer feeding visits and take an average of 25% longer—approximately eight additional days—to fledge, critically elevating their exposure to corvid predators like Steller's jays, American crows, and common ravens.
Major Frameworks/Components:
- Oceanic-Terrestrial Linkage: The dependence of a forest-nesting avian species on coastal marine productivity and prey populations.
- Reproductive Buffering: Parental care adaptations, such as delivering larger, more energy-dense fish during poor ocean years, to attempt to maintain chick energy intake.
- Climate-Driven Trophic Cascades: The cascading ecological impact of ocean warming on the availability of forage fish, which limits the reproductive output of dependent apex predators.





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