Raptors and Overhead Devices...

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(To repeat our introduction, in case you've read the section on raptors, poles, and conductors first)... Utilities face two problems when it's suspected raptors are interacting (usually fatally) with utility equipment. First, raptor electrocutions don't always cause outages; often the event is a temporary fault and cleared by the up-line recloser. These types of events are usually not investigated and it may be some time (if ever) that the carcass is found. Even if an outage occurs, more than likely it's in a fairly remote rural area since this where raptors normally live. By the time the crew arrives, other predators may have already removed the carcass.

Second, because of the raptor's protected status, utilities are obligated to place their focus on reducing or preventing electrocutions. Reducing or preventing outages, recloser operations ("blinks"), or equipment damage are secondary priorities.

It has long been suspected that raptor electrocutions on overhead devices, specifically transformers, occur far more frequently that anyone realizes. A recent study by wildlife biologist Richard E. Harness provides documented data that appears to confirm that suspicion. However, Mr. Harness reminds us that transformers are usually located near places where people live and work and these electrocutions may simply be reported more often. Even with that in mind, the evidence presented by Mr. Harness certainly shows that the majority of raptor electrocutions (in his study) occurred on transformer poles. This is somewhat surprising since transformer poles in rural areas are, so to speak, few and far between. One possible explanation for this is:

A transformer supplies an irrigation pump that waters a crop field. The growing crops attract insects and small animals (mice, ground squirrels, rabbits, etc.) that, in turn, attract predators (foxes, coyotes, and... raptors). Since the crops are artificially watered (won't die when the weather is dry), the field will support a large population of small animals that will support a larger than normal population of raptors. (Assuming, of course, that there are raptors in the area) With a larger than normal raptor population and acres of treeless fields, prime perching sites become the scarce resource. It shouldn't be surprising, then, that transformer poles would be very attractive to raptors.

That is not to say that other utility poles in the area wouldn't also be used as perching sites. But, depending on the construction, it is possible for raptors to perch safely on some types of "wires only" poles. Transformer poles are a different matter. Bare energized jumpers in close proximity to grounded equipment are a lethal combination.

It is quick, simple, and relatively inexpensive to prevent raptor electrocutions on transformer poles; install bushing covers and stinger covers or insulated jumpers. There are even a number of bushing and stinger covers that can be installed hot. Why, then, are raptors still electrocuted on transformer poles?

Two reasons come to mind. First, it can be difficult for utilities to identify what transformers are at risk until after an event occurs. Retro-fitting all the transformers on the system is both unnecessary and too costly. Mr. Harness, in his study, states that many utility personnel are unaware that hawks, owls, and vultures are raptors and these electrocutions are not reported. It is likely that no efforts are made to mitigate these types of electrocution unless outages are involved.

Second, utilities may be unaware that there are raptors in their service territory and, therefore, take no preventative measures. We don't understand why, but the United States Fish and Wildlife Service (USFWS) does not notify electric utilities of existing or new populations of raptors in the utility's service territory. Considering the fines, penalties, and liabilities that can be imposed on utilities involved in raptor electrocutions, and the lack of notification by the USFWS, it is in the utility's best interest to identify any protected species within its' territory. And, needless to say, take appropriate preventative measures.

We have more suggestions that might help for both existing equipment and new construction. So if you need some help with engineering design and/or planning, let us know. Don't forget to check the Bulletin Board. If you don't see anything there, leave a question. Check the Product Catalog to see what commercial products are available.

Raptors and Overhead Devices...

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