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Birds and Utility Poles
South Texas Utility Pole Line
Musing about Birds and Utility Poles
Driving home from the Rio Grande Valley last week, I was on a birding high after catching some of my big wish-list finds. Among them were the Pyrrhuloxia, Golden-fronted Woodpecker, Buff-bellied Hummingbird and some clear good shot of Caracaras. I have seen and taken pictures of the Caracara before, but they always turned out blurry.
As the last day of my trip turned out to be mostly a woodpecker hunt, I was in tune to noticing woodpeckers as I drove. It was amazing how many perching woodpeckers I was seeing on the utility poles along the road. I even stopped a few times. I don’t recommend this now, even if you are the only car in a half mile radius. Woodpeckers don’t hang around when a car stops.
As I enjoyed the views, it occurred to me that from a bird’s point of view, one of our greatest wildlife support devices ever created was the utility pole. No, I’ not kidding. Think about it. It is a wooden construction approximating a tall tree. In this area, it happens to be the tallest tree. By itself, a utility pole is the perfect perch for two regular size songbirds or one large bird of prey. Birds of Prey love our utility poles. Up at the top, a hawk or eagle can have a wide unobstructed view of an area to survey for game or nest well away from threats. As we string lines between the cross bars of poles, there is room for a full flock of smaller birds to make a rest stop.
Woodpeckers especially consider our constructions prime real-estate. I swear in one stretch, there was at least one woodpecker hole in every other pole. As the woodpeckers usually don’t reuse their nest holes, other cavity nesting birds take them over, such as owls, flycatchers, chickadees, wrens others. With all those birds making nests in utility poles or resting and hunting from them, our constructions have turned into bird habitats.
Facts about Utility Poles
- There are around 180 million utility poles in use around the U.S. This means there are two poles for every person in the country.
- Poles are used to support electrical lines because earlier experiments by Samuel Morse, who first attempts at laying underground cable between Washington, D.C. and Baltimore failed. Attempts in the 1990s by modern Louisiana power companies to bury power lines also failed due to carpenter ants being attracted to the electrical fields.
- The poles in your neighborhood are usually 35 feet high, but can run from 30 to 60 feet high. The tall ones along highways run from 60 to 120 feet high.
- On a pole with two cross bars, the top tier lines carry electricity, while the lower lines are telephone and cable wires.
- Most wooden poles are made of Southern Yellow Pine, but many other species such as Douglas Fir, Jack Pine, Lodgepole Pine, Western Red Cedar and Pacific Silver Fir are used. All such trees grow tall and straight. They provide a pole that will last 40 to 60 years depending on local climate.
Well, birds may think we erected these poles just for them, but we didn’t, and bird use of power poles for perches and nesting is very dangerous for them and can become a costly problem for us.
“Woodpecker holes are a menace,” electrical companies say. Their entrance holes may only be three to four inches wide, but the cavity created can be 19 inches deep. Woodpecker damage requires poles to be replaced long before normal. A pole’s life span can drop from 40 years to just five years due to woodpecker damage. The holes weaken the poles making it a hazard for utility people to climb them. As woodpeckers will start low and build new holes progressively higher, once the first hole is made, the pole is marked for further construction every spring nesting season afterward. In other words, it’s a goner.
While the pole damage is a problem, the electrical lines on them are a major hazard for the birds. According to the Field Manual of Wildlife Disease published by USGS, Birds of Prey are especially at risk using utility poles for perches and hunting towers.
“If a bird’s appendages bridge the gap between two energized parts or between an energized and a grounded metal part, electricity flows through the “bridge” that is filling the gap and the bird is electrocuted.”
Wet or snowy weather will make the problem more dangerous as otherwise poor conducting feathers become wet, and thus, more conductive. Areas such as the Rio Grande Valley where poles are the tallest perches available are where these electrocutions occur the most.
Industry Wide Bird Safety Efforts
This is an excerpt from the Field Manual of Wildlife Disease publication, chapter 50, concerning electrocutions.
“Raptor electrocutions generally can be reduced by adopting safe electrical pole and line configurations or managing raptor perching. Safe wiring configurations separate the wires and the grounded metal parts so that raptors cannot simultaneously touch two of them at once. Existing installations that contain hazardous configurations can be modified by insulating or reconfiguring the wiring. Rather than comprehensive modifications, an economical but effective approach is to modify selected poles based on field observations of bird use and mortality. If reconfiguring or insulating the wires is not feasible, then access to the hazardous perch can be blocked and safer, alternate perches can be provided.”
Over the years, power companies have become more and more proactive about protecting both their equipment and the birds. Many participate in the Avian Power Line Interaction Committee (APLIC). Since the 1970s, this group consisting of the utility industry, wildlife resource agencies, conservation groups, and manufacturers of avian protection products have worked to understand the causes of bird/power line electrocutions and collisions and to develop ways of preventing bird mortality and associated power outages. The group first came together to address Whooping Crane collisions with power lines. Since then, they have conducted studies of power poles and lines use by birds to develop protection methods.
To protect birds, their recommendations on nest management can include trimming nest material, providing alternate nest platforms, or removing nests. When nests are removed they are generally relocated close by on a new higher perch erected for the purpose. Such a nest relocation was done in the Dallas/Fort Worth area last summer, 2014. See the below video for the story from Oncor.
Relocation Video by Oncor
Other protections for the day to day risks birds have of electrocution involve newer designs in insulators and these guards placed on poles in Baytown, Texas that were near an eagle nest.
Besides that, there are also safe perches that can be installed to keep raptors above and off power lines and cross bars.
In the next picture you see a protection that doesn’t require new equipment, just lowering the crossbar that holds the lines so they are too far away for a raptor to touch while perched on the center pole. Such arrangements have made the utility poles our bird friends have decided to call their own much safer to use and protects equipment and us from damage and power outages.
But What about the Woodpeckers?
There have been many special studies to determine a way to deal with woodpeckers too. Decoys such as mock owls and snakes have been tried, ultrasonic frequency noise has been tried; but woodpeckers get wise to decoys fairly quickly and birds as a group don’t hear in the high frequency and ultrasonic range. Nest boxes were tried, but unfortunately; North American Woodpeckers rarely if ever use nest boxes. The act of excavating a nest hole is part of the mating ritual. Wire mesh barriers have also been tried, but the effectiveness of this depends on the species of woodpecker one is dealing with. Larger woodpeckers such as Pileated Woodpeckers can peck straight through 19 gage wire mesh. They have also learned to widen the mesh holes. Wire mesh wraps also increase the conductivity of the pole. Painting poles with different colors was also tried. Believe it or not, woodpeckers like bright colored poles. They prefer them to unpainted poles.
Despite the trouble they can be, Woodpeckers are also helpful due to their ability to detect infestations in poles such as carpenter ants. Pileated Woodpeckers, for one, are partial to these ants for food and will eat both larve and adults. Some woodpecker damage repairs have been reported as insect nests, which had been cleaned out by woodpeckers. Most of the time, this damage isn’t great and can be repaired with fillers. It depends on how deep the insect infestation was and how large the nest had been. In any case, the woodpeckers end up acting as inspectors as well as exterminators. One study states that, “In essence, the woodpecker is not creating the damage, but merely pointing it out.”
When a pole does need replacing, one tactic used by linemen is to leave the old pole in place for the woodpeckers to continue using. As the birds are territorial, they will keep other woodpeckers away, which protects the new pole.
The last ditch use of chemical repellents have not proven environmentally friendly or fully effective. The problem with this was that scented and flavored chemicals didn't take into account that woodpecker senses of taste and smell are poor and the birds are chiseling away the wood, not tasting it. They even chisel into creosote soaked poles with no ill effects. New research in this area may be the only approach that will have any value.
© 2015 Sherry Thornburg