Forsøksdyr: Diurnal and seasonal rhythmicity of hormones and behaviour in Arctic-breeding barnacle geese (Branta leucopsis)

Godkjenningsdato 17.04.2020

Godkjenningsperiode 08.06.2020-08.06.2022

The project is intended to investigate for the first time relationships between three rhythmic hormones and their influence on daily and seasonal activity in Arctic barnacle geese. Aims: (1) Decipher interactions between behavioural (activity patterns) and physiological rhythmicity of individual geese over the complete breeding season under 24-hours of daylight, (2) Investigate the interplay of hormones when focal individuals reach (fall and spring migration) and reside in temperate zones (wintering grounds in Scotland), characterised by clear day and night cycles, to understand when and how adjustments of the relationships between these hormones take place.

The methodology was chosen to minimize discomfort for focal individuals during all stages. Hormones will be determined non-invasively from droppings. To locate focal individuals precisely at various locations and monitor activity patterns and migration, we will attach solar-powered GPS-GSM neck collar trackers. Our chosen model (OrniTrack-NL40 3G), suitable for barnacle geese, was designed specifically to minimise its size (21 mm) and weight (20 g). The model sports no external antenna, therefore, does not interfere with regular behaviours, e.g. feeding. Slipping on devices is fast (< 5 min.). To attach trackers, catching geese is necessary.
We will apply two methods for catching: (1) a small noose attached to a pole, which is slid around the neck. This is suitable when geese are on the nest or (2) the annually performed catches, during which geese are driven into corrals. Both are standard procedures and were already approved in past applications.

The study is timely and of interest not only to researchers in the fields of behavioural ecology, physiology, Arctic ecology and human impact on ecosystems, but also to the general public due to a heightened awareness of increasing adverse effects of global warming, particularly in the polar regions. In times of global warming, optimal timing throughout the year is essential. This is particularly relevant for birds, as all but one terrestrial species that breed on Spitsbergen, migrate. They need to adjust not only to an earlier breeding in the North, but also while én route. The study should lead to a deeper understanding of the underlying mechanisms and possibly far-reaching fitness consequences of disturbed biological rhythms. Future work could investigate effects of other anthropogenic sources (light, noise, thermal pollution) and the potential disturbances these may cause in rhythmicity of hormones and behaviour.

60 wild barnacle geese from the Kongsfjorden colony. 24 geese will be fitted with collar tags from 2020 - 2022, 6 additional geese will be fitted with collar tags from 2021 - 2022.

The aim of the study is to understand the interplay between hormones and behaviour of geese under natural conditions year-round. This cannot be simulated, therefore, we have to perform the study in the field with live geese. Power analyses revealed the minimum number of geese necessary to obtain meaningful results. As goose pairs are always in close proximity to one another, we will put trackers on only half of the pair, but collect data on both partners. This reduces the number of experimental manipulations without challenging sample size. No animals will be sacrificed in this study