Biology subjects

Slettenhaar, A. J.

Publications and source records attributed to Slettenhaar, A. J..

2 recordsLinked to original sources

bioRxiv2024

Diel and seasonal rhythmicity in activity and corticosterone in an Arctic migratory herbivore: A multifaceted approach

Birds that migrate from temperate areas to the Arctic to breed lose their strongest Zeitgeber of circadian organization when they cross the Arctic circle in spring: the 24h light-dark cycle. Under continuous daylight, diverse behavioural and physiological patterns have been detected in both free-ranging and laboratory animals. To better understand the evolution of plasticity in circadian clocks, it is essential to study behavioural and physiological rhythmicity in the context of a species ecology. Employing a multifaceted approach, which included wildlife cameras, accelerometers, and non-invasive sampling of hormone metabolites, we investigated activity patterns and corticosterone rhythmicity in a migratory herbivore, the barnacle goose (Branta leucopsis), during its Arctic breeding season in Svalbard. We found that females showed a combination of both ultradian and diel rhythmicity in nest recesses and sleep during incubation. In both parents, these rhythms in activity continued also during the gosling rearing period. During moult, many geese aligned activity with the tidal rhythm. Barnacle geese showed weak diel rhythmicity in excreted corticosterone metabolites. This suggests that while Arctic geese may adopt an alternative Zeitgeber during the Arctic summer to maintain a diel rhythm, ultradian rhythmicity remains essential, allowing the geese to flexibly adjust their rhythms to environmental conditions.

ecology↗

bioRxiv2024

Dads on duty: First account of nest sitting in barnacle ganders

In most Anseriformes (ducks, geese and swans) only females are known to incubate. Here we scientifically describe, indicidents of male nest sitting in barnacle geese (Branta leucopsis) as a form of paternal care of nest attendance. Based on pictures from wildlife cameras we identified males, which sat on their nests when their mates took incubation recesses. Wildlife cameras were placed at nests of which either the male or female was fitted with a GPS neck collar in the year prior, which aided with identifying individual birds on the nest. To attach transmitters, some geese were caught while defending their nests, thus we may have unintentionally selected bolder males which defended their nests more aggressively and were easier to catch. Nest sitting occurred relatively frequent, i.e. in 6/15 individuals. Our results show that males with collars were more likely to nest sit, but this does not deflect from the fact this behaviour exists in geese. In the course of this finding we discuss several possible functions of this behaviour, i.e. against raiding of nests by aerial predators, thermal control of nest temperature, and intraspecific brood parasitism. At this time we cannot demonstrate a possible function, as chances of successful hatching were not increased in nest-sitting males and we lack sample size for more in depth analyses. Lastly, we argue that male incubation is misleading in the waterfowl literature, as it is truly justified for only two species, the black swan (Cygnus atratus) and black-bellied whistling duck (Dendrocygna autumnalis).

animal behavior and cognition↗