First Insights into the Diet Composition of Madeiran and Monteiro's Storm Petrels (Hydrobates castro and H. monteiroi) Breeding in the Azores

Abstract

Although studying the diet of threatened species is crucial in terms of conservation, the diet of the Madeiran Storm Petrel Hydrobates castro and the vulnerable and Azores-endemic Monteiro's Storm Petrel H. monteiroi is mostly unknown. The only information available to date comes from anecdotal observations, analysis of mercury levels and stable isotopes. Here is presented the first insights into prey consumption by adults and chicks from the two species breeding in the Azores. The rapidly developing field of metabarcoding was used to identify dietary items from fecal samples, to species level where possible. A total of thirteen fish, five cephalopod, one crustacean and two oligochaete operational taxonomic units (OTUs) were detected. Results suggest that both petrel species feed mainly on myctophid fish. However, differences were detected between the prey species consumed by (i) H. monteiroi and H. castro, (ii) two distinct H. castro populations (Vila and Praia islets), and (iii) chicks and adults within the same population.

Phenological divergence, population connectivity and ecological differentiation in two allochronic seabird populations

“…We also found that isotope values in tissues generated during the breeding season (blood and P1) did not differ between the two populations, suggesting both populations were exploiting similar resources. This result contrasts with what was found in two allochronic species of storm-petrels in a temperate archipelago (Azores), where DNA metabarcoding data revealed that the two populations had different diets (Carreiro et al, 2022). In contrast, the isotopic values of the tissues regenerated during the non-breeding period (R6, S8, and body feathers) showed significant differences between the two populations.…”

“…Our understanding of the meaning of the isotopic overlap could be enhanced by measuring the trophic niche through other approaches, either analyzing the diet with DNA metabarcoding (e.g. Carreiro et al, 2022), or collecting baseline samples from the oceanic system to better understand annual fluctuations (e.g. Price et al, 2014).…”

Breeding Thin-Billed Prions Use Marine Habitats Ranging from Inshore to Distant Antarctic Waters

“…This energy constraint may also shape the differences observed here, e.g., if females use the more distant sites to forage more efficiently and thus, replenish body reserves or specific nutrients. In this context, another interesting aspect would be possible diet differences between males and females in relation to differences in foraging, and further studies could use biomarkers or genetic diet determination, for example based on fecal samples (e.g., [ 37 , 38 ]).…”