Bird Flight Diverters: What Are They and Why Do They Matter?

Introduction to Bird Flight Diverters


Birds fly. Yes. Duh. Common knowledge. The fact of flight is an obvious distinguishment of our feathery-winged friends.


And while it’s true that not all birds fly, ostriches and penguins are perhaps the most popular flight-less birds, the vast majority of birds rely on their flight for survival. From above, birds can hunt and sustain themselves and their families, evade predators, protect their territory, and, importantly, migrate. Migration is undoubtedly the most harrowing of these, especially when you look at the numbers.


It is estimated that “70% of bird species migrate” (Audubon), meaning 70% of birds travel long distances to “find the best ecological conditions and habitats for feeding, breeding, and raising their young.” Of those, “80% migrate at night” (Audubon).


So, with such a great portion of the bird population flying so far and so consistently, the topic of their safety is often a matter of discussion.


With migration comes several risks. Natural risks like predation and inclement weather exist but there are also many unnatural risks that are caused by human activity. From the suburban house cat to industry-related avian electrocutions and collisions, a significant number of birds are killed each year due to human activity.


This is where Power Line Sentry Bird Flight Diverters come into the picture.

Bird Flight Diverter History


Here’s some background:


  1. Collisions take place in low light conditions when birds are ascending or descending.
  2. Birds do not fly straight into lines in lovely sunny conditions on purpose – they are caught off guard because they DO NOT SEE the line during flight.


So, according to ornithologist ophthalmologists (aka bird eye doctors), here’s what is most important:


  1. Contrast, so a solid surface area from all angles
  2. Light reflecting abilities

Power Line Sentry Bird Flight Diverters Features


So, let’s start at the top. The more surface area from all angles, the more visible the marker is.


The more visible a marker is, the more time a bird can react and change its flight path.


The more time a bird has to increase altitude or alter its course, the more likely it can avoid colliding with the electrical wires.


It makes total sense, but it only works if there is enough surface area in play – which is why the patented Power Line Sentry Bird Flight Diverter has a solid A-frame tent-like shape that gives the appearance of a rectangular shape from all angles.

1A BFD 050 1
1B BFD 050 2
1C BFD 050 3

While the barrel at the top cradles the wire, the two wings provide maximum visibility from all angles. From straight on, from below, or from any angle at all, it looks like a solid rectangle.


The more surface area available for viewing from those fatal ascending (taking off) and descending views (landing), the better.


Next, high visibility means the diverter needs to be visible in the first place. While the shape is vital, if the diverter were a solid dark color it may blend into the background. A good visible marker needs to stand out, not blend in. The Power Line Sentry Bird Flight Diverter uses both black to contrast with the sky, reflective yellow to contrast with trees and the ground during the day, and 24-hour glow-in-the-dark white to identify the line in low light conditions or darkness.


And speaking of glow in the dark – did you know that reflecting light in low light is how you see light in low light?

2A BFD close up

The Power Line Sentry Bird Flight Diverter has prismatic yellow stripes set against the black body for this exact reason. This is not some cheap attempt at reflection here – there are reflective mirror particles that refract, aka angle, fragments of light. Yes, even in low light.


Plus, the Power Line Sentry Bird Flight Diverter has a white stripe that features phosphor additives that absorb and emit light radiation for 24-hour rated glow-in-the-dark.

Power Line Sentry Bird Flight Diverter Attachment Methods

3A BFD hose
3B finger trap

While most other line markers are clamped to the line or physically wrapped around it, the Power Line Sentry Bird Flight Diverter has a durable rubber hose inside the barrel that cradles the power line.


Not only does this prevent any wear or tear on the wire – the plastic marker never touches the line, only its rubber does – but it also provides an incredibly secure fit. Once installed, the Power Line Sentry Bird Flight Diverter will not move down the line or fall off – it is held in its place by the hose.


The hose acts like those finger trap gag toys. If the wind tries to push it sideways along the line the rubber hose just tightens up – it does not move. Security is obviously vital here; the line marker is only effective if it says on the line!


Now, in the case that the wind blows perpendicularly, the line marker does have the flexibility to swing back and forth. This is completely fine due to the design’s two wings. Eventually gravity will settle it into the original position but until then it will still be visible from every angle.

Power Line Sentry Bird Flight Diverter Installation Methods


Power Line Sentry Bird Flight Diverters are easily installed by hand, with a hot-stick, or even robotically with the Fulcrum Air LineFly.


For a hand applied install, you simply place it over the wire and pull down until it snaps into place. Easy.


For a hot stick install, we have a hot stick attachment tool. Once the tool is loaded into the hot stick you simply slide the Power Line Sentry Bird Flight Diverter into the tool, place it over the wire, and pull down until it snaps into place. Easy.

For robotic installations, we have partnered with FulcrumAir, Inc.

5A LineFly CAD
5B FulcrumAIR Logo

FulcrumAir has developed a line of aerial robots known as the LineFlys. LineFlys install up to 24 Power Line Sentry Bird Flight Diverters autonomously, in sequence, along a span of conductors. The Linefly can either be lowered onto the conductor via a bucket truck or the FulcrumAir E7500 UAV. Once the Linefly is on the wire, the LineFly will autonomously install the Power Line Sentry Bird Flight Diverters to an accuracy of 2 cm – or .7 in – all at a placement defined by the utility.

The LineFly aerial robot eliminates the need for a helicopter install and, obviously, dramatically increases safety by removing the potential dangers associated with helicopter installations. It also provides a much more cost effective, and much less labor intensive option.

Why Are Power Line Sentry Bird Flight Diverters Different from Other Bird Flight Diverters?


Not only does our ability to provide a completely autonomous installation of 24 Power Line Sentry Bird Flight Diverters set us apart, but truly every feature we mentioned provides superior visibility and a more effective collision prevention.


Yes, the aerial robot install is very cool indeed, no arguing there, but from the rubber hose that does not abrade the wire, to the incredible reflecting abilities we achieve with the prismatic yellow and the glow-in-the-dark white, to the A-frame double-winged shape, every aspect of the Power Line Sentry Bird Flight Diverter provides superior visibility.

Regions Where Bird Flight Diverters Are Most Important


Bird Flight Diverters are important everywhere there are birds and wires. We know it is a deadly combination and that every species of bird can be fatally impacted.


In the past, the utility industry focus has been on eliminating wildlife electrocutions on live lines and equipment because that is where the evidence of a kill is visible. However, research has shown that 3 to 5 times as many birds die from collisions with the wires. The main reason is that usually only larger birds, such a raptors, have the wing span necessary for an electrocution event. However, any bird large or small can collide with the suspended wires they do not see.

7A flyways infographic

The migratory flyways shown here can be thought of as bird super-highways across the sky. Birds are not choosing a random path, they follow set routes that include suitable habitats along the way.


Many organizations, including the USFW and Birdlife International, address the areas that need protection most.


Power Line Sentry Bird Flight Diverters Conclusion


It makes logical sense that birds don’t see suspended objects like power lines in low light conditions. But when you consider that most avian collisions take place at dawn, dusk and at night, it is vital that our attempt at marking the lines to avoid these collisions take all our scientific understanding into account.


We may not have invented in the original bird flight diverter, but we changed just about every aspect of it.