If the bird is large enough to touch two different phase voltage lines or a grounded conductor ans a voltage line simultaneously it will be electrocuted. Just touching one line (and not a conductor leading to the ground) will not create a potential difference and so no current will flow.
That is to warn birds so that large flock of birds do not fly into the power lines. Also helicopters.
Charles A. Goulty has written: 'Birds and power lines' -- subject(s): Bibliography, Birds, Conservation, Electric lines, Environmental aspects, Environmental aspects of Electric lines, Flight
Usually they don't.
The answer is yes they can touch one another when there on power lines
Wingbars are prominent lines on the wings (not the underwing) .
Smaller birds can fly through the gaps in power lines and bigger birds get stuck when they try to go through.
They are usually installed so birds can see them. A bird flying at full speed into a power line will surely kill it. They are common here in Washington state and are usually red and white.
Birds do not get electrocuted when sitting on power lines because they are not completing a circuit for electricity to flow through. The electricity in power lines travels in a closed loop, and birds are not grounded so there is no path for the electricity to flow through them. Additionally, most power lines are insulated to prevent electricity from leaking out.
Birds perching on power lines do not get electrocuted because they are not completing a circuit by touching another conductor. The power lines are insulated and the birds' legs are not close enough together to create a path for electricity to flow through their bodies.
the dodo bird is actually on the lines of a tucan without the colors
Birds navigate using lines of magnetism around the earth. Solar winds can disrupt these lines causing birds to read them incorrectly. therefore the bird may not be able to find where its going.
The path of an airplane flying north as it crosses an east-bound highway.