Even More on Rattlesnake Relocation

Even More on Rattlesnake Relocation

Dr. Erika Nowak from Northern Arizona University commented on my last rattlesnake blog on relocating rattlesnakes, and provided the following info – so I thought I would provide it as a separate blog.

In a nutshell, if you must relocate rattlesnakes (which is preferable to the alternative of killing them) – relocating them close to their original range improves their survival chances.

 “A general rule of thumb in the southwestern U.S. that I use for larger species like western diamond-backed rattlesnakes is an average of 1 square kilometer.” Erika Nowak, PhD, NAU and Colorado Plateau Research Station

From Erika Nowak:

FYI, my colleagues Brian Sullivan, Matt Kwiatkowski, and I have a paper in review right now that focuses on how to improve translocation of nuisance herps. Also look for a chapter on rattlesnake conservation (including translocation issues) in the forthcoming book Rattlesnakes of Arizona

Nowak provided the following info regarding problems with translocation of nuisance rattlesnakes:

1)  Nuisance animal translocations more problematic: Part of the problem with interpreting how successful translocation is likely to be is that people tend to confuse the results of conservation translocations for declining species, which are often well-researched and have positive outcomes, with nuisance animal translocations, which are understudied and tend to have negative outcomes.

A black-tailed rattlesnake that Gary found at their front door a couple of weeks ago "and was regretfully disposed of." However, he and his wife went to a remote area to picnic and after awhile a small rattler warned it was under her chair..."no harm to either party."

A black-tailed rattlesnake

 

2) Best to relocate within 1 square kilometer (.6 mile): Short-distance translocation is considered to be within the rattlesnake’s normal home range; a general rule of thumb in the southwestern U.S. that I use for larger species like western diamond-backed rattlesnakes is an average of 1 square kilometer.

3) Otherwise, one-half die: Long-distance translocation (outside the normal home range) is, in fact, inhumane for many adult rattlesnakes. An average of around half of these snakes will die (look for the latest numbers in that forthcoming book chapter). The reality is that in the short term, most adult rattlesnakes will try to home back to where they were moved from. This phase often results in higher than normal mortality rates from disease, predation, and being hit by cars. My research on long-distance translocation of western diamondbacks indicated that at least 57% of the translocated animals died, including two that had successfully homed.

4) Best to not use limited release sites: As Dr. Greene pointed out, dumping of hundreds of snakes per year in a few favored release sites (see chapter by  McCrystal and Ivanyi in The Biology of Rattlesnakes, 2008) may have huge impacts on survival of snakes in that area, on rattlesnake prey and predators, on disease transmission between multiple snake species, and on genetic structure of populations. However, no research that we could find has examined these kind of population-level effects.

5) Relocating breaks up family groups: New research coming out on the sociality of rattlesnakes suggests that we may be breaking up family or social groups when we move adults (again, we’re not sure what the implications are, as translocation data is lacking). Social behavior of rattlesnakes will also be summarized in a chapter in Rattlesnakes of Arizona, but you can learn more now by checking out the following blog article

6) But, (as in prior posts) translocations is better than killing them: But, on the other hand, if some translocated rattlesnakes survive being moved outside of their home ranges, and if the only other alternative is certain death (say, if their entire home range is being bladed over or someone is standing by with a shovel), than yes, we all agree that translocation may be warranted. However, keep in mind that negative consequences of poorly planned translocations are well documented for all species (yes, plants, invertebrates, fish, amphibians, reptiles, birds, mammals), so we should not start with the feel-good assumption that any rattlesnake we move will survive. Case in point- an initial translocation by Johnson et al. (1993) resulted in 100% mortality.

There are ways that rattlesnakes can be translocated which will improve their chances of survival, and the most effective thing we can do is to move them within their home range.

For more information, some links to brochures encouraging successful  living with venomous herps in the Southwest

 

Comments

  1. Harry Greene says:

    Could someone spell out why bottom line “better than killing them” please?

  2. Harry Greene says:

    Sorry, should have been more careful: could someone please spell out why, bottom line, translocation is “better than killing them” (I’m assuming that in context this was meant to include farther away than Erika’s one square kilometer)?

  3. The prior post that was based on an interview w/Dr. Hayes dealt with this issue since many people kill them without considering translocation, and since my blog involves co-existing with our wildlife, that’s the viewpoint I also take. At least it gives them a chance.

  4. Thanks for this post Linda – co-existence is such an important message, and challenging to open minds on how to do so in a way safe to both sides. The research that rattlesnakes have social and family groups is very interesting to me; wow, who knew!

  5. Harry Greene says:

    Like you I’ve long worked for coexistence with rattlesnakes and other potentially dangerous animals through research, teaching, and outreach, and as Andrew Durso responded to your earlier piece, I fervently hope to convince folks to simply accommodate these wonderful reptiles. But, as noted in our exchange on March 26th, beyond the distinct possibility some (many?) translocated snakes won’t make it, Hayes didn’t cover potentially negative effects of adding more rattlers (with potentially alien genes, novel parasites and diseases) to an existing population–populations that are likely already at carrying capacity, such that adding new ones, especially lots of new ones, reduces the survivorship of those already there. In the end this comes down to our individual values as humans faced with difficult dilemmas: do we err on the side of the individual animal right in front of us, or the overall well being of animal populations? It’s in the context of that problem that for me, translocation would not always be preferable to humanely killing some particular “problem” rattlesnake.

  6. One major aspect to relocation that is missing from any discussion is the method of release. A snake relocated poorly (over-stressed, over-heated, bad area, etc.) will die very quickly even if it’s just moved a short distance.

  7. You know, I never thought I would say it, but I’m inclined to agree with Harry that humanely killing a rattlesnake you found in your yard that you couldn’t live with (which would of course be the preferable option) is a better alternative to translocation in cases where there are likely to be negative effects on rattlesnake populations because of translocation. The risk of snakebite is probably greatest when you try to kill a snake, 2nd greatest when you translocate it, and least when you decide you can coexist with venomous snakes and become informed about them. The risk to the ecosystem is probably greatest (overall) with translocation, 2nd greatest with killing the snake, and clearly the lowest with coexistence. It would be good if someone tried to measure this.

  8. Thanks for this post; this is such a controversial topic where humans have moved into snake habitat. As for the “translocation is better than killing them” issue, I think that Steen did a great job addressing why neither of those is a sustainable solution (http://www.livingalongsidewildlife.com/2013/10/the-only-good-dog-is-dead-dog-why-it.html). Even if you don’t want snakes in your yard, if you don’t address why they’re there, you can move/kill all you want and more will show up. The Tucson Herp Society’s brochure is great for addessing the yard problem. Damn its hard to convince most people to leave them be, though!

    And thanks for referencing our blog. Although the topic comes up frequently, this is our most comprehensive article on rattlesnake sociality that you may wish to point your readers to:
    http://blog.socialsnakes.org/squamate-sociality/

  9. Hugh McCrystal says:

    I have worked with fire department translocation procedures for over 25 years. We have honed our relocation procedures down to: try to talk homeowners into letting the snake stay and move on when it does. Then if that doesn’t work, 300 yards max for venomous, 100 yards max for nonvenomous. Never move a snake out of habitat. If the snake is far away from undisturbed habitat it goes to the closest “best” habitat. We also carefully keep snakes from getting overvheated, release them onto sheltered spots from the elements, are careful to be gentle in how they are handled. We try to educate folks about what snakes really do, and for the most part, it works. The hardest part is getting the word out to firefighters such that there is consistency. Keeping release distance very short is critical to individual survival and not impacting other nearby family groups negatively.

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