Non-significant Effect of El Niño on the Nest Occupancy and Breeding Success of Markham’s Storm Petrel <i>Hydrobates markhami</i>

The impact of the El Niño varies across seabirds, usually altering the distribution and causing population declines. Understanding El Niño’s effects is thus critical for conservation. We monitored 296 nests of the little-known Hydrobates markhami during three seasons (2021–2023). We tested annual differences in individual breeding success and nest occupancy against the Southern Oscillation Index and found no effect. Our findings can be explained by the storm petrels’ diet, which is more closely related to primary production than is the prey of other seabirds. Alternatively, individuals may compensate for the effects of El Niño by changing foraging strategies.