Seasonal and diel activity patterns of the endangered taiga bean goose (Anser fabalis fabalis) during the breeding season, monitored with camera traps

Abstract

Taiga bean goose (Anser fabalis fabalis) is an endangered subspecies that breeds sporadically in remote habitats in the arctic and boreal zones. Due to its elusive behaviour, there is a paucity of knowledge on the behaviour of taiga bean goose during the breeding season, and survey methods for monitoring numbers in the breeding areas are lacking. Camera traps are a useful tool for wildlife monitoring, particularly when there is a need for non-invasive methods due to the shy nature of the species. In this study, we tested the use of camera traps to investigate seasonal and diel activity patterns of taiga bean goose in Finland over two successive breeding seasons, 2018 and 2019. We did this by modelling counts of geese from images with generalized linear and additive mixed models. The camera type (cameras placed by experts specialized in bean goose ecology vs randomly placed cameras) did not influence the count of taiga bean goose (p = 0.386). However, the activity varied significantly by region, Julian day, time of day and temperature, with the study site (individual peatland) and year adding substantial random variation and uncertainty in the counts. Altogether, the best fitting model explained nearly 70% of the variation in taiga bean goose activity. The peak in activity occurred about a month later in the southernmost region compared to the more northern regions, which may indicate behaviours related to migration rather than breeding and moulting. Our results show that long-term monitoring with game camera traps provide a potential unobtrusive approach for studying the behavioural patterns of taiga bean goose and can increase our ecological knowledge of this little-known subspecies. The results can be applied to planning of the annual censuses and finding the optimal time frame for their execution.

Genetic assessment reveals inbreeding, possible hybridization, and low levels of genetic structure in a declining goose population

“…The taiga bean geese are elusive, especially during the breeding period, and observing even neck‐banded geese in breeding areas is rarely possible due to the long escape distance of geese (Pirkola & Kalinainen, 1984a)—although camera traps have been shown to be a viable alternative for taiga bean goose monitoring on breeding grounds (Nykänen et al, 2021). Thus, catching geese and sampling blood would be very difficult and stressful for the birds.…”

Inter‐population variability in movement parameters: practical implications for population density estimation

“…We acknowledge that we monitored few areas with a pronounced winter severity (e.g., snow depth, extreme temperature) in which more marked seasonal differences could be expected. Contradictory results have been published in this respect, with some researchers reporting seasonal variability (Caravaggi et al 2018, Nykänen et al 2021, and others reporting seasonal stability (Diete et al 2017, Ota et al 2019.…”

Species Abundance Modelling of Arctic-Boreal Zone Ducks Informed by Satellite Remote Sensing

“…SAMs were developed using General Additive Mixed Models (GAMM) and were fit using the 'mgcv' library [56] within the R programming language for statistical computing. GAMMs, which allow for the incorporation of random effects, are an extension of generalized additive models and are widely used for modelling correlated and clustered responses; several studies examining waterfowl populations have used this approach [57,58]. Moreover, using GAMM's allowed covariate effects to be non-linear, with relationship complexities quantified through effective degrees of freedom (EDF; larger values indicate increasingly non-linear model effects).…”