ALBERT

Description: In colonial species, it is often assumed that locations in the center of the colony are of highest quality and provide highest breeding success. We tested this prediction, known as the "central-periphery model," in a King Penguin colony in the subantarctic Crozet Archipelago. Breeding activity and survival of 150 penguins, fitted with transponder tags, were monitored over an entire breeding season. Among these 150 birds, 50 bred on the slope at the upper periphery of the colony, where the rates of predation and parasitism by ticks were high. Fifty birds bred in the center of the colony, where rates of predation and tick parasitism were low, and 50 bred at the lower end of the colony, where the rate of tick parasitism was low but predation and flooding were important risks. We predicted that the center of the colony should provide the safest breeding place and consequently be characterized by the highest breeding success and be used by the highest-quality individuals. Yet we found that penguins breeding in the center of the colony had the same breeding success as those at both peripheral locations. In addition, penguins breeding on the upper slope had a higher survival rate than penguins breeding at the center or bottom of the slope and were likely of higher quality. Our study does not support the central-periphery model and emphasizes the complexity behind the relationships among breeding site, breeding success, and individual quality.

Description: King penguins are sexually monomorphically ornamented seabirds that perform a complex visual and acoustic courtship display. Coloured beak spots and ear patches contain information about the condition and physiological status of adult males and females, but their role as a signal of age has previously only been studied in young birds. Vocalizations have mainly been studied as signals of individuality and not in the context of courtship. We investigate two multicomponent signals in the context of mate choice by analysing beak spot, ear patch, and call parameters of wild king penguins. We explore the relation between those signals and age as well as age-classes (chicks, juveniles, adults). Ornament parameters were weakly correlated to continuous age in males, but not in females, while acoustic parameters were highly correlated to continuous age in both sexes. The calls' fundamental frequency and energy parameters, and all the beak spot parameters reliably classified individuals into their age-class. Since age-class was redundantly encoded in both acoustic and colour parameters, we hypothesize that calls and ornaments function as back-up signals that increase the chance of accurately conveying the age-class of the sender to receivers. King penguins might sequentially analyse age-class signals during courtship, where acoustic signals serve as long-range communication when sender and receiver are out of sight, and ornamentation signals become important at close range. We show the importance of considering bimodal, multicomponent signals when studying complex behaviour and discuss how signalling environment, the species' life-history and mating system influence the evolution of communication signals.