By Jeremy Coles
Reporter, BBC Nature
Cape vultures in southern Africa are using expanding networks of pylons and power lines to extend their range, say scientists.
At the same time these lines are also contributing to this threatened bird of prey's decline through fatal collisions and electrocutions.
The study involved a team of experts from the UK and South Africa tracking individual bird movements using GPS.
The results are published in the online journal PLoS One.
Southern Africa's Cape vultures (Gyps coprotheres) - like many other species of vulture - are in decline. Contributing factors include feeding on illegally poisoned carcasses and fatal collisions with wind turbines and power lines.
To understand more about their movements, and how these vultures interact with power lines, a team of scientists fitted GPS devices to five adult and four immature birds.
"What we were trying to find out was how far they were going and what sort of areas they were feeding in," explained lead researcher Louis Phipps from Nottingham Trent University, UK.