Hubbell Power Systems Blog

If you have ever driven along a river, the ocean, or a large lake and come across a massive, imposing, messy stick nest on a distribution or transmission power line, chances are you are looking at a nest of an osprey. These large raptors (birds of prey) with a global distribution are well-adapted to specialize on small to large sized fish. They nest along fish-bearing waterbodies - historically in the tops of broken tree snags, but as power poles became common across the landscape, they became valuable real estate for nesting osprey, particularly those near water.  

Birds have no doubt been interacting with power lines and substations since the latter first appeared on the landscape. Indeed, the first record of avian collision mortality from power lines dates back to the late 1800’s, and at least one record of electrocution in North America was made as early as 1922. These incidents occur when a bird simultaneously contacts two energized components of a pole that are each at different electrical potential (referred to as a phase-to-phase fault or electrocution), or they simultaneously contact one energized component on a structure and one grounded component (referred to as a phase-to-ground fault or electrocution). These incidents not only cause injury or mortality to the birds themselves, most of which are legally protected, but they also impact the integrity of the power system.

Although we are just starting out the new year and snow is covering the ground in much of the USA and Canada, tis’ already the season for romance and courtship for great horned owls, the largest owl in North America, and one of the earliest “spring” nesters. These majestic birds aren’t much for construction or renovation, and instead take over old nests of other birds such as crows and red-tailed hawks. To the frustration of many utilities, they sometimes choose old nests in electrical substations as their chosen spot to raise a family; these substations offer protection from the elements, a heat source (important when incubating eggs, sometimes in temperatures of -30C), and protection from most mammalian predators, thanks to the chain-link fencing. What they don’t realize is the high electrocution potential for themselves and their clumsy fledging young.