Inter-annual consistency in the phenology and trophic niche of the Southern Rockhopper penguins from Isla de los Estados, Tierra del Fuego, Argentina

DODINO SAMANTA; HART T; RICCIALDELLI LUCIANA; JUAREZ MARTINEZ I; EDNEY A; PÜTZ K; POLLITO M; RAYA REY ANDREA

Viña del Mar

Congreso; 11th International Penguin Congress; 2022

Phenological and trophic niche consistency are known to impact the ability of species to respond to climate change. Understanding these ecological variables is key to assessing the potential adaptability of endangered species like the Southern Rockhopper Penguin (Eudyptes chrysocome). To study their phenology and colony attendance we deployed time-lapse cameras from 2013 to 2017at Isla de los Estados (Argentina) and processed the images using the citizen science project Penguin Watch. We also collected adult feather samples to study their pre-moult foraging niche and trophic position (TP) using stable carbon (δ13C) and nitrogen (δ15N) isotope analysis. To estimated their TP, we used previous information of baseline’s stable isotope values of the food web around the colony. We found phenological consistency between years with little variation in arrival (~October 1th) and departure dates (~March 30th) for the breeding season as well as in departure (~February 1th) and arrival (~February 20th) for the pre-moult trip. Nonetheless, we found significant differences in 13C and 15N values between years, with 2014 and 2017 having the lowest values for both isotopes for the pre-moult period. Regarding TP, we found no differences between years. Results indicate that Rockhoppers are consistent in their phenology and their TP across years, with differences in isotope composition possibly related to variation in foraging areas. This data provides key information for evaluating their adaptive capabilities, resilience and their risk of phenological mismatch, all important in order to assess their vulnerability to future environmental changes.