Exploration during early life: distribution, habitat and orientation preferences in juvenile king penguins

Abstract

BackgroundThe early life of marine apex predators is poorly known, particularly for diving species. The orientation and foraging skills are presumably less developed in juveniles than in adults, especially during their first year at sea when juveniles might disperse further than adults.MethodsOver two years of monitoring, we tracked the movements of 17 juvenile king penguins (Aptenodytes patagonicus, ~ 1 year old) using satellite relay tags from Crozet Archipelago (Southern Indian Ocean), starting when birds left their natal colony for the first time. For comparison we also tagged 6 non-breeding adults, which at that stage, similar to juveniles, are unhampered by reproductive constraints and might roam further than breeders. We used a combination of cluster analysis and habitat modelling to investigate and compare the movement patterns and habitat use of experienced (non-breeding adults) and non-experienced (juveniles) individuals.ResultsWhile juvenile penguins and non-breeding adults followed similar routes, the movements by adults started later in the season and ranged over a considerably smaller area than juveniles. Net squared displacement analysis revealed that both groups did not move to a specific wintering area. Changes in direction of juveniles in respect to their departure island were similar and synchronous for both years. Habitat models revealed that foraging behaviour was affected by environmental variables such as wind or current speeds, sea surface temperature, or oceanic productivity, for both stages. Analysis of tracks revealed that birds moved predominately perpendicular or against the main direction of the Antarctic Circumpolar Current and the prevailing wind during austral summer (juveniles only) and autumn (juveniles and non-breeding adults). However, both juveniles and adults were more likely to move against the prevailing winds if productivity increased along their trajectories.ConclusionsThe exceptional duration of our tracking study provided unprecedented insights into the distribution, habitat preferences and orientation of two poorly known life history stages of an expert avian diver. Our study suggests that juveniles might use both innate and learnt skills to reach profitable foraging areas during their first year at sea, which is critical in long-lived species.

A role for lakes in revealing the nature of animal movement using high dimensional telemetry systems

“…Across species, details were revealed mostly from controlled laboratory experiments on captive animals [30,215,270], whereas field studies have been much less frequent, and studies based on movement data collected from free-ranging animals in the wild have been scarce and focused on terrestrial systems (e.g. [108,218,219,267,285]).…”

The early life of king penguins: ontogeny of dive capacity and foraging behaviour in an expert diver

“…Investigation of whether juvenile birds engage in nocturnal foraging activity requires the identification of night periods. As we did not record the geographical position of birds and because juvenile king penguins roam over large oceanic areas during their first year at sea (Orgeret et al, 2016(Orgeret et al, , 2019, moving between time zones, the exact start and end of night periods, as experienced by the birds, were unknown. Accordingly, we used changes in bird diving behaviour to estimate the approximate night periods.…”

“…King penguins (Aptenodytes patagonicus Miller) are the second largest penguin species and, in the avian world, their dive performance is surpassed only by the larger emperor penguins (Pütz et al, 1998;Pütz and Cherel, 2005;Wienecke et al, 2007). Recently, studies have investigated behavioural and physiological aspects of king penguins during their early life at sea (Orgeret et al, 2016(Orgeret et al, , 2019Enstipp et al, 2017Enstipp et al, , 2019. These birds spend the first year of their life at their natal colony and, upon completion of their first moult into waterproof plumage, enter the sea during the austral spring.…”

“…These birds spend the first year of their life at their natal colony and, upon completion of their first moult into waterproof plumage, enter the sea during the austral spring. During the following 1-3 years, they roam over a large oceanic area (Orgeret et al, 2016(Orgeret et al, , 2019, only returning to land for their annual moult (Enstipp et al, 2019). Unfortunately, no information concerning their physiological status at the time of fledging is available (e.g.…”

“…Besides dive capacity, detailed behavioural patterns of juvenile king penguins during their initial phase at sea are unknown (depth utilization, temporal organization of foraging). Previous studies investigated the dive behaviour and movement patterns of juvenile king penguins by deploying satellite relayed loggers that provided summary data for dive behaviour and location (Orgeret et al, 2016(Orgeret et al, , 2019. This led to the suggestion that the development of dive capacity is crucial for the survival of juvenile king penguins (Orgeret et al, 2016).…”