Research on migratory geese suggests attachment of GPS tracking tags could create survival risk

                                    

Tundra Bean Geese - research species for Chinese ornithologists 

DO GPS tracking tags put birds at survival risk?

The question is prompted by Chinese ornithologists who, following research  in China's Poyang Lake region, have identified apparent peril for migratory geese.

In a report in the journal, Ecology and Evolution, they say that  tracking devices were discovered significantly to influence survival outcomes of the two species chosen for the experiment, Tundra Bean Geese and Greater White-fronted Geese.

Those fitted with neckband tags had higher survival rates than those fitted with backpack tags.

The researchers' report states: "This finding resonates with recent biomechanical studies demonstrating that dorsal-mounted backpack devices substantially alter avian aerodynamics by shifting the centre of mass and increasing drag coefficients, thereby elevating flight energy expenditure 

" A study  on Northern Bald Ibises demonstrated that back-mounted trackers (secured via wing loops above the back) significantly reduced their migratory flight distance. 

"The neckband design used in our study offers several biomechanical advantages over backpack-style tags. 

"Unlike backpacks, neckbands avoid contact with wings and major muscle groups, thereby reducing aerodynamic drag and minimizing interference with flight mechanics. 

"This design also prevents constriction of the thoracic cavity, which may be critical during periods of intense metabolic activity, such as pre-migration staging and sustained flight. 

"While initial behavioural impacts of neckband tags (e.g., increased preening) typically subside within six days post-deployment, backpack devices may impose chronic physiological costs through altered gait mechanics and feather abrasion during prolonged use.

"It is theoretically plausible that backpack-style harnesses may restrict thoracic expansion during hyperphagic periods prior to migration, potentially limiting fat accumulation and energy reserves.

" Although our study did not directly assess this hypothesis, future research could explore this mechanism through comparative studies of pre-migration body condition in tagged versus untagged birds. 

"This could help clarify the physiological costs associated with different tagging methods during critical staging periods. 

"Although our study provides evidence that neckband tags are associated with higher post-release survival compared to backpack tags, it is important to note that this conclusion is based on a relatively modest sample size (17 neckband, 20 backpack). 

"While consistent with prior biomechanical research, these findings should warrant replication in future studies with larger sample sizes and additional species to assess potential interspecific variation in response to device type."

The full report can be read at : The Fragile First Year: GPS Tracking Identifies Post‐Release Survival Risks in Migratory Geese - Zhang - 2025 - Ecology and Evolution - Wiley Online Library