Woodpeckers are not only interested in trees. They are also eyeing electricity and telecommunications distribution poles. The damage they cause is significant, to such an extent that it represents the second leading cause of pole replacement at Hydro-Québec. A large woodpecker stands perched at the entrance to its nest dug into an electricity distribution pole.
You may have seen or heard them banging non-stop on a pole in your neighborhood or yard. You probably smiled and wondered if those woodpeckers had fallen on your head. Why do they attack poles? For three reasons: to drum, what serves to mark their territory, it is without damage. But also, for food and nesting. And that's a whole other story. Multiple boreholes can affect the integrity of poles. A woodpecker hole at the top of a pole.
The affection of woodpeckers for poles is not new: this phenomenon was already observed in the days of the telegraph. Since then, the number of poles in Canada has multiplied, as has the number of woodpeckers. The survey of breeding birds in Canada indicates that between 1990 and 2014 the population of great woodpeckers doubled in Canada and tripled in Quebec. As a result, Hydro-Québec, which manages a fleet of 2 million poles, has seen an increase in woodpecker activity on its facilities. Dan Mastrocola is an engineer and head of pole maintenance at Hydro-Québec Distribution.
“We see places that were not affected and are now becoming more and more so. If we look at the figures from 2012 to 2021, we had more than 100,000 poles documented with damage caused by woodpeckers. About 12,000 poles need to be replaced.” — A quote from Dan Mastrocola, engineer and head of pole maintenance at Hydro-Québec Distribution A pole has a lifespan of about 60 years. It is usually at the end of this period that it is replaced. However, repeated attacks by woodpeckers can accelerate its degradation and force its premature replacement. At Hydro-Québec, woodpecker activity has become the second leading cause of pole replacement, after age. It was long believed that woodpeckers were more interested in old poles because they are more likely to be invaded by carpenter ants, the woodpecker feast. But this is not the case! Hydromega found out in 2015 in Dokis, Ontario. Hydromega's distribution line in Dokis, Ontario, some of whose poles have been attacked by woodpicks.
“It's something we've never experienced before. The plant had been in operation for about two years, and we had about fifty poles out of 500 already damaged. A 10% of the line, which is not negligible.” — A quote from Sébastien Tilmant, Environment and Asset Optimization Manager at Hydroméga This episode kicked off a joint research project that brings together Hydroméga, Hydro-Québec and the Université de Québec à Montréal, among others. UQAM researcher Pierre Drapeau has been interested in woodpeckers for several years. In this case, his gaze turns mainly to the great woodpecker and the flamboyant peak. A flamboyant woodpecker lies in wait for the surroundings from its nest dug into an electricity distribution pole.
The damage caused to poles by wood picks is of two different kinds. First, we note the feed holes, which can be multiple and shallow. They are used to reach colonies of carpenter ants. Then the birds can dig their nests inside the poles; In this case, the cavity they create is significantly larger. This nesting cavity, in the heart of a pole, has a diameter of about 15 cm and a height of about 50 cm.
“For a woodpecker, a Hydro pole is a dead snag on the ground. That's how you have to look at it. What makes it settle on a pole rather than in the middle of the forest? That is an open question at the moment.” — A quote from Pierre Drapeau, Professor in the Department of Biological Sciences at the Université du Québec à Montréal (UQAM) Pierre Drapeau and his colleague Philippe Cadieux, from UQAM, in the field for research on woodpeckers
In the field, in a natural environment and near power lines, Pierre Drapeau and his team have begun research to document woodpecker habits, their feeding radius, the state of the forest in which they live, etc Among the hypotheses being studied, is it possible that woodpeckers opt for poles when nearby trees are not large enough to dig a nest? In parallel with university research on woodpeckers, Hydro-Québec must, during frequent visual inspections of its poles, improve the description of the holes dug by the pick. Depending on their size and number, it is necessary to estimate the point at which the pole will have lost too much of its mechanical strength. On a test bench, Hydro-Québec conducted tests to measure the loss of efficiency of poles damaged by wood picks. Securely held at one end, a winch pulls on the cable attached to the head of the pole until the pole gives way. Dan Mastrocola, who supervises the tests, notes from the first tests sometimes significant losses of capacity. “We have seen from 10% to almost 40% loss of capacity. That's pretty important. Indeed, at more than 40%, in theory, the pole should be replaced.” — A quote from Dan Mastrocola, engineer in charge of pole maintenance at Hydro-Québec Distribution A pole damaged by wood picks (green mark) is subjected to a mechanical strength test on a Hydro-Québec test bench.
Replacing a pole costs $5500 or more, depending on the equipment that is installed on it or its proximity to an access road. Electric utilities try to protect some of their poles from woodpecker attacks using physical barriers, including wire mesh or rigid casings. However, their effectiveness is sometimes limited. The other option is to turn to composite poles, unassailable by woodpicks. As their cost is higher, electricity suppliers want to install them at strategic locations on the power line, likely to be frequented by woodpeckers. This is part of what the research project intends to accomplish: to identify environmental factors that would make it possible to anticipate areas at risk. But the game is not played in advance, because woodpeckers have the reputation of being tenacious!