Birds

Both land based and offshore windfarms have an impact on bird populations. There are three major ways offshore windfarms impact birds.

1. Barrier effects

2. Habitat loss

3. Strikes and kills

Many bird species avoid wind turbines by circumnavigate them when they get in their flight path. This will cause energy loss for the bird from a longer way to fly. For daily migrations this loss of energy may have a significant impact on the population. Some species of birds avoid getting close to the turbines altogether that may hinder them to access important habitats such as mussel beds.

Many large birds, such as eagles, are vulnerable for strikes by the turbine blades that move through the air at high speeds. Bird strikes may be mitigated by radar detection of approaching birds and reducing the speed of the turbine.

Learning outcome.

After having watched this video, you should know:

• There are three major ways OWE can impact bird populations negatively.
• Habitat exclusion such as important wintering or breeding sites. Can be mitigated through marine spatial planning and siting.
• Barrier effects when OWE are place in areas that impact regular and frequent (e.g. daily) migration. Can be mitigated through marine spatial planning and siting.
• Strikes from the turbine blades. Strikes can be mitigated using adaptive control mechanisms turning the turbine off during situations with high strike risk.

Reflections

Many birds are electrocuted or killed by collisions with electricity lines.

In what way could a more distributed electricity production have a positive impact on bird by reducing these collisions?

Suggested literature

Some references may require a user account for the journal.

Remote techniques for counting and estimating the number of bird-wind turbine collisions at sea: a review: Remote techniques for wind farm bird studies. Ibis 148, 76–89.

Avian collision risk at an offshore wind farm. Biol. Lett. 1, 296–298.

Barriers to movement: impacts of wind farms on migrating birds. ICES Journal of Marine Science 66, 746–753.

Reduced breeding success in white-tailed eagles at Smøla windfarm, western Norway, is caused by mortality and displacement. Biological Conservation 145, 79–85.