Predator disturbance contributed to Common Murre Uria aalge breeding failures in Cook Inlet, Alaska following the 2014–2016 Pacific marine heatwave

The 2014–2016 Pacific marine heatwave caused unprecedented die-offs and multi-year reproductive failures for Common Murres Uria aalge along the west coast of North America. Lingering impacts, such as declines in colony attendance and productivity, have persisted at some colonies following the heatwa...

Full description

Saved in:
Bibliographic Details
Published in:Marine ornithology 2024-04, Vol.52 (1), p.129
Main Authors: Marsteller, Caitlin E, Arimitsu, Mayumi L, Schoen, Sarah K, Stark, Samuel B, Piatt, John F
Format: Article
Language:English
Subjects:
Annual variations
Breeding seasons
Disturbance
Failures
Heat waves
Inlets (waterways)
Laridae
Marine fishes
Nesting
Ova
Predators
Seabirds
Seasonal variations
Seasonality
Uria aalge
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The 2014–2016 Pacific marine heatwave caused unprecedented die-offs and multi-year reproductive failures for Common Murres Uria aalge along the west coast of North America. Lingering impacts, such as declines in colony attendance and productivity, have persisted at some colonies following the heatwave and are attributed largely to changes in prey availability and quality. Here, we present evidence of an additional, top-down mechanism contributing to Common Murre breeding failures on Gull Island (Alaska): disturbance of nesting birds by aerial predators and associated egg depredation. We collected time-lapse images over five murre breeding seasons (2016–2020) on Gull Island to document the frequency, duration, and intensity of disturbances caused by aerial predators, as well as to quantify disturbance-associated egg depredation. To identify seasonal and inter-annual variability of disturbances, we calculated a daily disturbance index and compared years using generalized additive models. In all years, Bald Eagles Haliaeetus leucocephalus were the primary cause of disturbance, which led to periods of prolonged colony abandonment by murres and facilitated high levels of murre egg depredation by Glaucous-winged Gulls Larus glaucescens and Herring Gulls L. argentatus. We found that the seasonality of disturbance was an important factor in determining egg depredation rates. In years when disturbance levels were high and persisted later in the season, the colony experienced complete breeding failures due to disturbance-associated egg depredation. Our study revealed that the response of nesting murres to a strong environmental perturbation, such as the Pacific marine heatwave, can be complex and involve multiple stressors from both bottom-up and top-down factors.
ISSN:1018-3337
2074-1235