Passuni G. auteur aut IRD Barbraud C. auteur aut IRD Chaigneau Alexis auteur aut IRD Bertrand Arnaud auteur aut IRD Oliveros-Ramos R. auteur aut IRD Ledesma J. auteur aut IRD Castillo R. auteur aut IRD Bouchon M. auteur aut IRD Bertrand Sophie auteur aut IRD text journalArticle eng text/pdf born digital access In the highly productive Northern Humboldt Current System, 3 seabird species, the Guanay cormorant Phalacrocorax bougainvillii, the Peruvian booby Sula variegata and the Peruvian pelican Pelecanus thagus, commence breeding in austral spring, coinciding with the lowest availability of their prey, the Peruvian anchovy Engraulis ringens. This strategy ensures the matching of increased prey availability when young achieve independence in summer. This pattern was observed during the last decade when anchovy was abundant. However, over the last century, the abundance of anchovy has varied widely due to contrasting interdecadal regimes in oceanographic conditions and fishing activity. We hypothesized that these regime shifts affected the abundance and availability of prey and may have conditioned the breeding seasonality of seabirds. We examined the timing and magnitude of the onset of breeding using dynamic occupancy models and related these parameters to the seasonality of oceanographic conditions, abundance of anchovy and fishing pressure. During a regime of lower anchovy abundance (1977-1990), cormorants showed the highest flexibility, adjusting the timing of breeding from spring to winter and skipping reproduction in the worst conditions. Boobies showed the lowest flexibility, maintaining the same magnitude and timing of onset of breeding in spring. Pelicans showed intermediate flexibility, foregoing breeding during the worst conditions, but maintaining the onset of breeding in spring. The 3 species used sea surface temperature as a cue for the initiation of breeding. Furthermore, given their better diving abilities, cormorants could monitor prey availability changes associated with the reversion in the seasonality of the oxycline depth. specialized Onset of breeding Environmental cues Oxycline depth NHCS Northern Humboldt Current System Phalacrocorax bougainvillii Sula variegata Pelecanus thagus PACIFIQUE PEROU 036 020 040 597 231-242 2018 0171-8630 https://www.documentation.ird.fr/hor/fdi:010073124 10.3354/meps12590 0171-8630 [F B010073124] https://www.documentation.ird.fr/hor/fdi:010073124 https://www.documentation.ird.fr/intranet/publi/depot/2018-11-06/010073124.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2018-09-03 2024-01-02 fdi:010073124 fre