During soft-release reintroductions, biotelemetry devices are often used to track the movement patterns of released individuals. Very high frequency (VHF) and Global Positioning System (GPS) are commonly used telemetry methods, providing accurate locations. An alternative is dead-reckoning, providing high-resolution movement paths from heading and speed measurements, showing fine-scale changes that VHF may not identify. Errors in speed estimation can accumulate, however, producing wide error margins in flight distances and locations. I assess the utility of both techniques in relation to the release of red-billed choughs (Pyrrhocorax pyrrhocorax) on Jersey, UK. First, I use VHF locations to examine dispersal and habitat selection. I then go on to consider the potential of dead-reckoning for future monitoring, by examining the main determinants of error in flight distance and bearing in a similar-sized bird. The reintroduced choughs undertook small movements close to the release site, with individuals travelling as a flock, and dispersal distance showing no clear increase through time. Coastal grassland was the most used habitat, despite low availability, raising the possibility that dispersal may be limited by a lack of suitable habitat. The chough’s relatively short flight distances and tendency to return to a verifiable location, mean that dead-reckoning could potentially work well as a method to reconstruct their movement paths. However, drift was influenced by flight height, tailwind support and tortuosity. The effect of even low wind speeds on drift shown here suggests this would likely have an even greater influence in locations with higher wind speeds, such as Jersey. Ultimately, the use of multiple low-power telemetry systems could prove powerful, with corrected dead-reckoning providing new insight on the movement frequency, distances and paths as well as habitat selection, that could better inform conservation policy
