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Data and code from: Collision with linear infrastructures reduces survival of a long-lived migratory bird

Wen, Lijia12; Guo, Yumin1; Lehikoinen, Aleksi2; Sandercock, Brett K3; Santangeli, Andrea4; Pavón-Jordán, Diego3; Li, Xianda1; Xu, Yanjie5

Research facility: Local wildlife management stations across the Qinghai-Xizang Plateau
Published Sep 08, 2026 on Dryad. https://doi.org/10.5061/dryad.70rxwdcfh

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Abstract

Human infrastructure, particularly power lines and fences, poses a growing threat to birds worldwide. Quantifying the impact of collisions across different life stages and spatio-temporal contexts is critical for developing effective monitoring and conservation strategies.

We analyzed satellite-tracking data from 203 black-necked cranes (Grus nigricollis) and combined transmitter information, field surveys, carcass examinations, and satellite imagery to determine individual fates and infer causes of mortality. We estimated annual variation in survival among different age classes using Kaplan-Meier survival models. We then used Cox proportional hazards to test age-specific mortality patterns from different causes of mortality including power line collisions, fence collisions and other causes and generalized additive models to compare seasonal and diurnal collision patterns of different causes.

Immature individuals (first-year individuals and subadults) had a significantly lower probability of annual survival (0.598) than adults (0.893), with first-year individuals particularly vulnerable. Power line and fence collisions accounted for 71% of all confirmed mortality cases. Although mortality risk declined with age class, power line and fence collisions affected cranes across all age classes.

Power line collisions exhibited a bimodal diurnal pattern with peaks around midday and sunset, but no significant monthly variation. In contrast, fence collisions were concentrated in August but showed no clear diurnal pattern. The timing of peaks in mortality aligned with crane behaviour: daytime power line collisions coincided with juvenile flight practice and evening returns to roosts, whereas fence collisions occurred when juveniles were still flightless and adults or subadults were moulting flight feathers.

Synthesis and applications. Our findings demonstrate that collisions with human infrastructure represent a major threat to cranes and likely other migratory birds. The identified non-random patterns of infrastructure-specific collision peaks were consistent with variation in flight ability and visibility across different stages of the annual cycle and times of day, improving the accuracy of predictive collision-risk models and supporting more effective mitigation efforts. Based on these findings, we recommend that fences should not be constructed in key breeding and moulting areas. For power lines, monitoring and mitigation approaches, such as the installation of line-marking devices that are visible under both low-light and bright conditions, should be prioritized and applied to key movement corridors.