One of the major causes of power outages is the interference of wildlife, particularly birds, squirrels, and different pests. Mitigation of ground-based animal interaction with electrical wires is relatively easier than mitigating aerial-based interaction by birds because we design wiring systems so that they are out of our way in our daily lives on the land. Placing these wires above us, where they will not be a bother to humans, helps to prevent non-human terrestrial mammals from interfering with them, but has quite the opposite effect on birds. It is fairly easy for different bird species to interact with and damage the wires that are suspended in the air.
Through flight, birds have attained a major advantage in terms of body locomotion, making larger birds such as the golden eagle the apex predators of the skies due to their ability to target prey from great heights. The ability of flight places mobility on a different plane than all terrestrial land-bound animals and allows birds to travel to destinations faster than their bipedal or quadrupedal counterparts. However, this freedom to explore the world from an aerial view is greatly impeded once there are man-made structures blocking their course and even ending their lives.
IEEE STD 1651-2010: IEEE Guide for Reducing Bird-Related Outages provides guidelines that can be followed to reduce both power outages and bird mortality.
In the United States, the Migratory Bird Treaty Act of 1918 protects all native, North American migratory birds, so almost any bird collision with electrical wires is a violation of federal law. Even if collisions are unintentional, the utility company generating the power will still have to answer for bird mortality. Aside from collisions with the power lines, birds can also lead to outages by perching on the wires and the connecting poles. Wire perching is especially dangerous for raptors, since they are much larger and can apply an amount of force to a single point on the wire that is comparable to the net force that a flock of smaller birds applies to different points on the wire.
Another issue that occurs is larger birds perch above electrical facilities on an overhead structure is that of “streaming”. Streaming refers to the act performed once birds take off from a perch and empty their bowels, which can result in a flashover and a streamer outage. This cause can be identified if the flashover kills the bird, which it occasionally does when the electric current travels up the stream of excrement to the bird. However, this is not always the case, so streamer outages can sometimes be difficult to detect. Flashovers can also occur from continuous contamination of small bird droppings on a single spot of an electrical structure. These occur after exposure to thousands of birds, and usually trigger by a light wetting event, such as a light mist.
The IEEE Guide for Reducing Bird-Related Outages lays out an Avian Protection Plan (APP) intended to bird-proof the electric power delivery system. The 12 key principles of the APP are corporate policy, design standards, risk assessment, quality control, training, nest management, mortality reduction, public awareness, permit compliance, reporting system, avian enhancement, and key resources. It is recommended by the standard that the APP be performed using a cost-benefit analysis, in which the price of upgrading the electrical structures must be justified by saving money by not having power outages and reducing avian mortality. A key change that should be performed through the APP is retrofitting the electrical structures so that they deter birds from perching on, or even flying towards, the electrical equipment.
Another important consideration that should go into the APP is why exactly birds are or would appear near certain electrical structures at particular amounts. For example, the structures could be located in a migration path or area that contains a higher concentration of a particular species. There is also the possibility that the electrical wires were placed on or too close in proximity to wetlands, which the standard strongly recommends against.
Bird interaction with power lines is only one aspect of blackout causes. According to the Edison Electric Institute, 54 percent of all outages are the result of weather and its effects. Inclement weather also contributes even more to the issue of bird-related electrical outages, since wet birds are more susceptible to electrocution. Protecting electrical structures against anticipated weather is also essential for preventing unwanted power outages for a grid. As for birds, limiting interactions with electrical cables would be very beneficial, since electrocutions kill tens of thousands of birds each year. However, there are many more anthropogenic causes of bird mortality, and some of these are much more severe. For example, window strikes are a leading cause of death amongst birds, and might be responsible for up to 976 million deaths every year. While many of these problems have solutions, such as putting in additional window dividers, they are still prevalent and efforts need to be made to preserve these air-mobile creatures.