Reptile & Amphibian Forums

I am an independent biologist whose main interest has been field investigations of the Rubber Boa. I am also interested in conservation issues. As a graduate in Wildlife Science and believing I understand population biology, I have always been skeptical about claims that personal collecting of snakes could have a negative impact on the OVERALL population of various species.

Before one can determine if such concerns have any merit, it can help if estimates of two factors are known, those being 1) supply of the species, and 2) demand for the species.

Obtaining a ball park estimate of the supply, and the annual surplus created during reproduction, is reasonably easy for most species. However, obtaining similar estimates of demand may not be as easy. And thus I have a request to make on this forum.

Does anyone on the forum have an idea of how many individuals are involved in maintaining species of North Am. rattlesnakes? Or, do you have any suggestions as to how I might determine an estimate of the number of individuals currently maintaining native rattlesnakes in the U.S.?

I am trying to get some idea of the 'demand' that might exist on rattlesnakes here in the U.S. from collecting for personal use.

There are three, small species of rattlesnakes that have limited distributions in Arizona, all currently protected. A number of times I have heard there is 'high' demand for these species. Concerns have been expressed about illegal collecting having a negative impact on those species. To my knowledge, all of those concerns have been of an anecdotal nature, that is, simply impressions or opinions. None have been supported either by documented evidence or reasoned assessments of supply and demand for species.

If I had some idea of just how many individuals have an interest in maintaining those species, it would give a better idea if the concerns about collecting for private use have any validity.

Richard F. Hoyer

Richard,
You might get a more educated, informed answer from the AZ PARC forum. There are many folks interested in those species from AZ, but as you've mentioned, they are protected. I can say via 3rd person, that the populations aren't in danger if Arizona Fish and Game were to allow permits for limited collecting. My biggest concern would be the habitat destruction that would follow if permission was granted.
Best...
Jim

JH,
Thanks for your reply. Actually, it was a post on the AZ PARC Conservation forum that sparked my interest in two recently protected garter snakes and further restrictions on take of other species.

A gentleman by the name of Brian Hubbs asked that I review that particular post. I did and about 2-3 weeks later entered a couple of posts of my own. They were not well received as they point out flaws in the common approach used by state wildlife agencies and their biologists pertaining to the management of non-game species.

If you wish to obtain a better view of my position, you can view my response to a post by Roy M. I then posted another message dealing with common myths as they pertain to herps. As it turned out, Dr. Andy Hollycross and myself exchange about a dozen email messages each discussion population biology. The subject of rattlesnakes came up and that is why I asked about information about the demand side of those populations.

With rare exception, species can withstand some take (collecting) provided nothing is interfering with reproduction. it appears to be common practice among wildlife agencies to place species in a hands off 'protected' status when they suspect the species are having problems. Seems reasonable but it
really isn't if you truly understand population dynamics.

Richard F. Hoyer

I have studied willardi and lepidus for twenty five plus years in Arizona. It is a complicated issue for sure. I do not think that collecting has much potential to harm these species as a whole. I am not so sure, however, that it is not a potential threat to some local populations that are easy to access. They are very sensitive to disturbance. I do believe the demand is fairly high for specimens, but have no concrete evidence to support that. AZG&F has told me at times there are a lot of collectors present in the well known localities.

Luckily, most folks do not have a clue on how to hunt them. Couple that with the fact that for every canyon that is easy to access, there are many many more that are remote and relatively undisturbed.

For the populations that are easily accessed, I believe heavy collecting could possibly have an effect, but in the long run, the data is not in. The big one is habitat destruction, which of course, is not news.

HKM,
Just by chance do you know my son Rich Hoyer Jr. of Tucson? He works as a birding guide for Wings. He has mentioned that he has met someone that has conducted long term field research on rattlesnakes in the mts. of S. Arizona. A couple of years ago we traveled with Rich to the Huachucas and Santa Rita Mts. observing mostly birds but also were on the lookout for herps.

At any rate, by the nature of your remarks, I get the distinct impression that you are objective and thus credible, something I appreciated when I find such attributes in other biologists.

Concerning your remarks about collecting having a "potential threat to some local populations----." This is the case with all species in which there is moderate demand and where there is ready access. Here is what I mentioned in one of my posts on the AZ PARC Conservation forum.
"To be sure, small local populations can be negatively impacted by excessive collecting as was the case in the Garber study. Over the years, I have had 7 - 8 of my mark / recapture Rubber Boas study sites 'trashed'. In some instances, it was as if the individual(s) had a vacuum cleaner as not only were the boas taken but garter snakes, racers, gopher snakes, etc. were also removed. Of course I was terribly upset. But I can be objective enough to realize that such instances could not possibly impact the overall Rubber Boa population here in Northwestern Oregon nor the state as a whole. Nor are such impacts lasting as recovery took place in a relatively short period of time at all sites with one exception, a small, isolated parcel of land of about 1.5 hectares."

Dr. Holycross at ASU and others took some exception to some of the assertions I made in my posts, one of which dealt with two widely held myths, that species of herps are rare, and that collecting for personal use can have serious negative impacts on the overall populations of species. Rather than trouble the forum with a broad array of this and that, I provided Andy with my email address. As it turned out, over a 2 - 3 week span we exchanged about a dozen email message each in which we mainly discussed population biology but touching on other subjects as well. One subject that we briefly covered with that of C. lepidus. If you are inclined to explore more on this subject, my email address is charinabottae@earthlink.net.

Richard F. Hoyer

HKM,
I was contemplating deleting messages on my computer, I came across one in which I tried to come up with some estimate of the overall C. lepidus population in AZ. Dr. Holycross gave me two pieces of information with which to work on. He mentioned that the species occurs in 8 isolated mt. ranges in S. Arizona with three of those ranges being reasonable large. Just as a guess, he put out the figure of about 10,000 specimens for each of those ranges, the Huachucas, Santa Ritas, and one other.

Thus if those three ranges had a total of 30,000 specimens, I theorized that perhaps the other 5 smaller ranges might have a total of 30,000 specimens for a total population of about 60,000. I have been to the two mt. ranges mentioned above and they seemed to be rather extensive. So the other way in which I tried to produce a ball-park figure was to estimate the occupied habitat for the species in those 8 mt. ranges and multiply by a reasonably conservative density. If the mean area of occupied habitat for each of the 8 mt. ranges was 40 sq. miles and I used a mean density of 0.75 lepidus / hectare, I came up with an estimate of about 62,000.

If these figures are anywhere close, that told me that it was highly unlikely that personal collecting could realistically have any negative impact on the over all population of the species.

Of course, these estimates are using very questionable input. I had asked if the Natural Heritage organization in AZ has figures on percent distribution of the species in AZ compared to the overall area of the state much like that organization has for many herp species in Calif. That would be a bit better route to go in order to obtain a more reasonable idea of the area of occupied habitat.

At any rate, from the above figures I then estimated a mean, annual reproductive output. To try and be conservative, I estimated that at the low end of the population cycle in August of each year, 20% of the overall population was subadults and juveniles, 80% adults. I then used an adult males to adult females ratio of 55% to 45%, a mean female litter frequency of 1/four years and mean litter size at 4 neonates / litter. You can tell me if these figures are not conservative enough. Came up with an annual reproductive output of around 21,600 as I recall.

I even went beyond that point by trying to determine the number of surviving neonate need after one year in order to maintain a stable adult poplation of 48,000 with a mean sexual maturity occuring at about three years of age. At any rate, I never transmitted that information to Dr. Holycross.

I did notice on this forum that at least one individual is producing captive breed progeny.

Richard F. Hoyer

Forgot to mention I used an estimated 10% mean annual mortality rate for the adult segment of the population.

RFH

Thanks for the posts. I do not believe I have met your son. I do most of my work in the Huachucas and Patagonias, but spend a lot of time in the Santa Rita's and other moutain ranges south of Tucson too. And I bird when herps aren't moving so we may have met!!

I have not yet crunched any number that we have. Our tagging lepidus and willardi goes back to 1991. I will say that lepidus is very common and would label it as dense in many areas. I do not think as a whole it is vulnerable to much besides habitat destruction. As you mentioned, there is considerable available habitat for them in several ranges in Arizona alone.

I will venture over to the PARC site soon and check out the posts.

Happy holidays.

Hi,
I contacted my son Rich Jr. He indicated the individual he has met doing field work on the rattlesnakes in those mts. was a gentleman by the name of John Porter.

You mention that tagging began in 1991. Do you find any of the specimens originally tagged the first few years? I have been doing the same for Charina bottae here in Oregon and elsewhere. It is not uncommon to find specimens tagged 6-10 years earlier.

In May of 2003, I found the first boa I had captured on Mt. Pinos
(west of I-5 and Frazier Park, Calif.) that I had first found in May, 1998. Then this past April I found Tehachapi female #3 that I had originally captured in those Mts. SE of Bakersfield in the spring of 1997 although I had observed her 2-3 other times since 1997. I always get a nice feeling when encountering such 'old friends'.

Richard F. Hoyer

Hi Dad,

Those aren't John Porter's initials. I'd think too that he'd be a bit
more rabid anti-collecting that this post indicates. I would agree that
local populations would be easily affected by intense collecting. I
wonder how long it would take for snakes to disperse from one canyon to
the next. But he's right that there are plenty of more remote canyons
that have secure populations.

Rich

Hi Richard,

John Porter has studied willardi for years in the Huachucas. I have only met him once. I understand he does high quality work.

Without going to the book, I believe we got a 91 tagged lepidus in 2003, and fairly regularly get 5-8 year recaptures. I know what you mean when you see an old timer. It makes me happy too.

Mr. Hoyer;

First of, let me say that I find your discussion on this thread to be fascinating. Interesting stuff!

Just a little input. The population dynamics/management issues can get a bit sticky. I have a few things to consider. First let me say that my experience in working with crotalids is limited to predominantly C. v. viridis, and C. horridus and S. catenatus to a very small degree. These species are distinct from C. lepidus, to be sure. However, there are some patterns of interest.

First, as far as a population model goes, your ballpark figures are an interesting starting point. The most important information, however, is neonate suvivorship. There may be some research available for the species, but for crotalids in general, first year mortality is extremely high. Without collection pressures, the high mortality can generally be overcome by the population to a certain extent (though the population cannot overcome habitat destruction), based on high female reproductive output (i.e. large "clutches" of small neonates, or small clutches of large neonates).

Now, how does all this relate to the issue of limited collection? I believe that the collection limitations would have to be very strongly defined. One would hope that collected specimens would be taken at random from the population. Would this, in fact, be the case? The most heavily affected populations would be those easily accessible to people. In addition, one might venture to assume that there would be a collection bias. I suggest that, in absence of explicit collection guidelines, reproductive (and perhaps even gravid) females would be highly selected. This could potentially influence the population structure resulting in a male/juvenile bias. In the short term, it may not appear to impact the population. But over time, it may sufficiently depress the reproductive success of these easily accessible populations.

Finally, we must consider the subject of genetics and evolutionary significant units (ESUs). Genetic analyses of the Georgian Bay (Ontario) population of S. catenatus has shown that sub populations separated by a relatively short geographic distance are genetically distinct. Is this also the case for these populations of C. lepidus? I haven't looked for any research, but it would be interesting to know. If these several populations are, in fact, genetically distinct, what would be the best plan for management, if collection was to be made legal? Do we sacrifice certian populations to collection based on accessibility, and thus eliminate a genetically unique population? Or is it possible to limit AND monitor collection so as to benefit both the collector and the population? I certainly don't know, but it is interesting to think about!

Also, much more research needs to be conducted. I think that there is a general lack of information regarding much of the basic biology and population attributes of many of the crotalid species. This information would help to pin down actual population attributes, and allow for population modeling analyses that would be useful in setting possible collection guidelines.

One final note...you said "If these figures are anywhere close, that told me that it was highly unlikely that personal collecting could realistically have any negative impact on the over all population of the species." Remember, this was once said about the passenger pigeon. Estimates of the passenger pigeon ranged between 1 and 4 billion individuals in the mid to late 19th century. The last passenger pigeon died in Cincinnati in 1914, within a few decades of the previous population estimates.

Interesting stuff, regardless!

Your response to Mr. Hoyer is similarly interesting.

I am very interested to see the remark about S. catenatus having distinct genetic subpopulations despite short distance separation. There are many interesting possibilities to consider. I believe that rattlesnakes may be socializied and possibly live in family groups or something structured like that in some way. I have not done the genetic work to back those assertions up, but, where lepidus is concerned, my data supports very limited movement patterns within and between adjacent canyons. We have numerous observations of what could be considered pair bonding. Coupling that with captive observations, there are some very interesting parental care (teaching?) behaviors taking place by both male and female parents. I jokingly call lepidus rattlefinches?? Do you have more on the S. catenatus work (citations etc.)?

Your other remarks on collection pressure etc are also interesting. Where lepidus and willardi are concerned, the great majority of collectors seem to concentrate on the early monsoon season. This is when gravid females are up (I mean nearer the surface) thermoregulating just before having babies. They make easy pickings even for novice collectors. For secretive saxicolous or fossorial species like these, if they do live in relatively closed sub-populations, that could cause problems for the easily accessed populations we have been discussing. Recruitment data is very important, and so far lacking in my study (i.e., we are still trying to figure out IF snakes are moving between populations, who is it?).

Thanks for an interesting post.

HKM;

Most of the Eastern massasauga work I'm familiar with was done by P.J. Weatherhead. This link may provide the pertinent information.

http://www.life.uiuc.edu/pjw/snake.htm

With regard to your opinion on socialized family groups, I tend to agree with you. Having worked with geographically isolated populations of C. v. viridis, I've seen a degree of hibernacula fidelity, based on mark/recapture data. This suggests a limit to the ammount of movement between these demes. As we all know, snakes in general are not able to move great distances (unlike migratory birds). I think that this has a great impact on limiting gene flow of a species among isolated demes. Regardless, I agree that there is certainly some structure involved in some crotalid species, resultant from the limitations to dispersal.

For this reason, I have to admit that I'm a bit leery of proposing less restricted collection. Here's why. First, with management of non-game species as it is, there are few resources devoted to enforcement. I've never ran into a USFWS or DNR officer enforcing herp related collecting policy. Secondly, I again assert (going along with the points that you made) that reproductive age (and/or gravid) females would suffer the brunt of collecting pressure, thus leaving a population heavily biased towards adult males and juveniles.
Finally, I think that it is important to have good data on basic population parameters (i.e. fecundity, immigration, emmigration, mortality, etc.) before making any management descisions. Without this information, it's difficult to make any reccommendations for instituting collection.

I'm interested to hear any more thoughts on these issues. I find this stuff fascinating!

Gordon Schuett took DNA samples from snakes at several of my cerb dens. Groups with enough distance between denning areas were all genetically distinct. Of couse I don't really know how much bearing this really has considering the family units some crotalids species form, my family is no doubt genetically distinct from my next door nieghbor but we are still the same species. One thing that was interesting with Gordons results were the effects of a major highway. Groups with denning areas on one side of the highway showed distinction but yet were still fairly close despite some of the dens being a couple of miles apart. Yet the groups on the other side of the busy highway, a mere four hundred yards or less, were very distinct from their brethren across the lanes.

I also fully believe HKM is right about family groups. I have witnessed this many times over at my cerb dens. I have also been amazed at what I have observed in my captive molossus, parental care/teaching, intentionally mischievious babies and an observation of what I am sure was newborns actually playing at combat(I'll get some pics up later). It's amazing how much of their body language you pick up when you have had certain snakes for 15-20 years. I was thinking I was nuts for a while but then my wife started making the same observations out of the blue. One time I fed my molossus pair together in the same cage. They have very strong feeding reactions so I usually separate them but this day I was in a hurry. The female grabbed her mouse and swallowed it quickly. The males mouse was still wandering around. They saw it at the same time but the female was closer and grabbed it first. The male was only a split second later in striking, I thought he was going to accidentally bite her in the head but he changed his direction mid strike and slammed his head into a rock. The female dropped the mouse, turned on him, and started rattling, obviously angry. The male then did something I had never seen before, he started rubbing her head with his and twisting it like a dog begging for attention. I was dumbfounded at what I was seeing and starting to think I was nuts when my wife excaimed "he's apologizing for almost biting her!" I had arrived at the exact same conclusion. We have a LOT to learn about these guys. BTW, he also let her eat the mouse.

RGC,
Neat, interesting observations as are those mentioned by others dealing with rattlesnakes.

Richard F. Hoyer

Great stuff Richard. I have seen very similar things and my wife and son have corroborated a lot. I love your thought of the male "apologizing" to the female. SO IT'S THE SAME IN SNAKES TOO!!! LOL!!!!!

I have observations of what I consider parents teaching neonates and more.

I have said this for years:

"We don't speak snake. That doesn't mean snakes don't."

If 95% of communication is body language, we really have our work cut out for us. Snakes can not shrug their shoulders, change their facial expressions or do most of the other body language behaviors that we use unconsciously. Then, they are more subtle in everything they do. On top of that, the skeptics think we are nuts to think this exists at all. BUT as you said, you see things after time, captive or otherwise.

It is up to us to open the door to understanding what has been going on right under our noses for years. It is up to us to open our minds along with our eyes. I believe those that honestly do this will see a whole new world of social and communication behaviors.

This is great stuff!!!

Would a more simple answer be that it was a case of dominance? The male missed the mouse, challenged the female (thus the pseudo-combat posturing), backed down (was the female bigger?), and then became submissive. I've seen male C. aquilus that were being housed together start "combatting" in the presence of food (and in the absence of females). These same snakes were otherwise passive and co-existed without a problem. One of my pairs of C. pricei miquihuanus also "combatted" once when I was trying to feed them.

I agree that snakes, and rattlesnakes in particular, are more complex than we think. Just wanted to present a different interpretation based on my observations...

While the terminology is different, and yes we are anthropomorhizing, isn't it a case of dominance either way? However, the question is dominance by size / strength OR dominance because of strength of relationship. Feeding responses bring out all sorts of behaviors, no question there. What I think is important for us to do is to start looking at things differently, more openly to the idea that we don't have the behaviors mapped already. If we continue to try to explain everything we see through old school terminology and behavior concepts preached for years, we will continue to see snakes as simplistic instinct acting creatures. While we shouldn't TRY to say things exist that don't, we need to also make sure we aren't saying things ARE a certain way when we don't really know.

In this case, it could be simple dominance as you suggest, or it could be a more complex set of events between two pair bonded individuals. We don't know. I will strive to find the way to see the difference, and then test it.

Thanks for bringing up a good point!!! Cheers.

Hey Rob,

While you have a very valid point I don't think it was case here. I have have made many observations of competing for food between cagemates in my 30 years of keeping rattlesnakes and I have never seen anything like this. I have had my female molossus for over 15 years(raised her from a newborn) and the male for over 11 years. I have come to know both very well. The male is larger than the female. He doesn't miss when he strikes and neither does she. Both grab and retain their mice and both have become very adept at grabbing them by the neck so they can't turn and bite. There is no doubt in my mind that the male deliberately changed direction in mid strike but his momentum didn't allow him to stop before slamming face first into the rock. And the behaviour that ensued looked to be male groveling at it's finest. It was nothing like combat posturing, nor was it at all like the nudging/chin pressing exhibited during courtship. He came up along side of her and started rubing his head against the side of hers. He would twist his head so that it always ended up underneath hers. It looked exctly like when a dog keeps shoving his head under your hands to be petted. I was skeptical about what I was seeing with my molossus and at cerb dens for many years but after seeing things repeated time and again, and having my wife and others confirm what I am seeing, I am convinced there is a lot more to it. And since there was no easy way to scientifically prove my theories I usually just kept my mouth shut. But in the last several years many others have been making the same types of observations amongst various rattlesnake species and I feel a little less looney LOL. The more I learn the less I know. Nowdays I keep a very open mind.

One thing I thought I would mention is that it seems to me that it's always the older forms that have the more complex social behaviour. More recently drived forms seem to have little to no social structure. A good example would be the former viridis complex. In the two oldest forms (viridis and cerberus) I have observed very complex family structures that center mainly around the females. But in abyssus, which is the most recently derived of the group, there appears to be no social strucure whatsoever. They will use a communal denning area for convenience sake but yet even at the densites they keep to them selves. They will be individually scattered around the ledges with at least ten feet(and usually much more) between individuals. My captive abyssus pretty much ignore each other except at breeding time.

Rich

"The more I learn the less I know. Nowdays I keep a very open mind."

My point exactly Rich.

You have done a good job illustrating your point. In regards to your above quote, I often say that for all the years I have done this, the only thing I have learned is to ask better questions!

Seems we all share like minds! The tag line of my e-mails actually reads:

"Knowledge has two extremes. The first is the pure natural ignorance in which all men find themselves at birth. The other extreme is that reached by great minds, who, having run through all that men can know, find they know nothing, and come back again to that same natural ignorance from which they set out; this is a learned ignorance which is conscious of itself."

-Blaise Pascal (1623–1662)

Yes indeed.

Another Pascal quote:

"Nature is an infinite sphere of which the center is everywhere and the circumference nowhere."

BigSur08,
You touched on a good number of interesting points but I will limit my comment to three issues, all related. You certainly hit the nail on the head when you mentioned, "The population dynamics/management issues can get a bit sticky."

1) Since 1997, I have become increasingly critical of wildlife agencies after I discovered that such agencies are managing non-game species using personal opinions and other non-professional, anecdotal processes. How can a state wildlife agency manage species when it has no idea of the numerical abundance (supply) nor any idea of the demand for the species? Yet without such information, it is common practice for state wildlife agencies to set bag and possession limits on non-game species and list species in some category of concern.

2) My initial inquiry on this forum was an effort (weak at best) to try and get some idea of the demand for rattlesnakes by hobbyist. As far as my attempt at trying to estimate numerical abundance, I did not have sufficiently solid information to obtain a realistic, ball park estimate for lepidus. The purpose for using the simple 'area X density' model is only for gaining some perspective of the size of populations. Such a perspective of numerical abundance should (but doesn't) alleviate the fears about personal collecting having a negative impact on the overall population of species.

I find it puzzling that many individuals treat non-game species as somehow being different from game species when considering the removal of individual specimens from the wild. How is it that year after year humans harvest elk, bear, and cougars that have far lower densities, lower annual reproductive output, and lower overall numerical abundance than most species of herps yet concerns are expressed that personal collecting of herps could have a potential negative impact on this or that species? Likewise, certain states have commercial take on many species of herps and have done so for decades. Harvest data that may be available for such species should be a solid clue towards how to view personal take on non-commercial species of herps.

A current example of how non-game and game species are viewed differently: Utah has the Milksnake and Sonoran Mt. Kingsnake in a protected, hands off status. Both species have reasonably large distributions in that state. The reason given by wildlife biologists for the protected status is that collecting could potentially harm those species. Yet for two recent consecutive years, over 440 Mt. Lions were harvested in Utah.

3) On the main PARC site, the subject of low recruitment surfaced. Someone cited an unpublished report to the USF&WS concerning a species of turtle. Based on published levels of juvenile mortality / recruitment, the authors concluded that any harvest of adults of the species would lead to its decline. I chimed in to indicate that the authors were making a mistake in their use of such data. This point was again mentioned during my exchange of e-mail messages with Dr. Holycross and you touch the same subject when you mention, "The most important information, however, is neonate survivorship. There may be some research available for the species, but for crotalids in general, first year mortality is extremely high. Without collection pressures, the high mortality can generally be overcome by the population to a certain extent----".

I concur with your statement about high mortality of neonates during the first year (or two) as that scenario undoubtedly applies to all relatively long lived species. Below I have copied an edited version of the response I gave to Dr. Holycross when this subject was mentioned during our exchange of email messages.

When assessing the impact of take on species, the data on 1st. year mortality of the juvenile segment is derived from studies of populations which are basically undisturbed and thus reasonable stable with all age classes pretty much in balance. Therefore, most if not all available niches are essentially filled by the adult and subadult segment of those populations. Therefore, the survival rate of juveniles within 1 - 2 years after birth (hatching) is quite low. This is particularly true for predators with longer mean life expectancies. Depending on the species, juvenile mortality for the first year or two is most likely a result of the competition for prey and space between the juveniles and the established adult / subadult segment of the population.

As soon as some extra mortality (including take) occurs within the established adult / subadult segment, it is unreasonable to assume that the survival of neonates remains static. In reality, such survival must increase as there are now available niches left unoccupied. Yet in a recent turtle study, the authors used the low recruitment data of yearling turtles in a stable (un-harvested) population to argue that NO take could occur amongst the adult turtle population without resulting in harm to the overall population. Again, I am may not be conveying this in an understandable fashion so let me give an example in which about 30 years ago, after thinking about this very issue, I preformed field tests with my species of interest, the Rubber Boa.

Originally, when I obtained litters from females that were gravid when captured or captive breed females, I would release the neonates where the parent female had been found. I did this for about 4 years. Recaptures of such released neonates were very rare during subsequent years. In each instance, I was releasing those neonates in areas that in all probability, had stable and well established adult populations. Whether those juveniles died and/or dispersed is not known. I only know that recovery was almost nil in subsequent years whereas in comparison, adult recaptures were the norm and far more common than finding new specimens.

At a burnt out lumber mill of several hectares in the coast range near Summit, Oregon, in late Sept., 1974, I made my first mass release of 69 neonate boas. The area had recovered with grasses, forbs along with some brush and alder trees. Douglas fir had not yet invaded the area to any great extent. The Northwestern and Common Garter Snakes along with the N. All. Lizard were the reptiles that had re-colonized the burnt mill site in good numbers. In the three years prior to 1974, no Rubber Boas had been observed. Thus, without competition from an established adult boa population, I theorized that unlike my previous experience of not finding neonates in years following their release, there was a far better chance at recovery at this Summit site.

That is exactly what occurred. I have not reviewed that data for some time but off the top of my head, in the next three years, I ended up with recapturing over 50 percent of the original released neonates. In contrast to the relatively slow growth observed with recaptured subadults from other sites, without competition from adults for the prey base, these little devils grew at an accelerated rate.

Even though I cannot establish mortality rates for either group of released boas, a comparison of the recaptures from where an adult component is present vs. where an adult component is absent is pretty striking. The point I am trying to make is that it stands to reason that the survival of 1st year snakes would not be the same in these two different situations. It makes no difference whether it be fire or harvesting by humans that reduces the adult component. The results should be an increase in the survival rate for the juvenile component of a population. Where no take occurs, survival for the first year snakes will be lower than where take occurs. Yet some authors have incorporated data from the former situation and applied it to the latter situation and thus have reached erroneous conclusions as it pertains to the potential affects of harvest or take of a species.

I have repeated these experiments a number of times with similar result although not quite as dramatic as the first Summit experiment. I have also accomplished the opposite situation, that is, mass release of neonates at sites with well established boa populations. And as with the release of single litters, recovery in subsequent year was virtually nil.

Richard F. Hoyer

Since your post includes rattlesnakes in general, I may as well put in my thoughts.

My concern is not with the casual collector or the collector that goes out looking for stock animals intended for reproduction. I can only invision more animals, not less, due to captive reproduction.

The areas that do concern me when it comes to needless pressure on a population comes from the following.

1. The collector that collects for selling;

2. Rattlesnake roundups;

3. Road kills.

Lichanura,
You mention, "My concern is not with the casual collector or the collector that goes out looking for stock animals intended for reproduction."
We are in complete agreement as this was the major thrust of my original post on the AZ PARC Conservation forum.

With respect to your point #1, I assume you are referring to illegal trafficking. Just like poaching deer, it is something that needs to be addressed by law enforcement. But at least here in the west, the activities of a few poachers should not have any impact on most, if not all species of herps with the exception of some turtles / tortoises. It would be my guess that such illegal commercial activities have negligible impact on species with relatively large distributions and numerical abundance. Localized populations of species might be depressed by over collecting. But if surrounding habitat is occupied by the species, such reduction in populations are temporary due emigration form adjoining habitat and increased survival of neonates.

Concerning your point #2, a number of states allow commercial harvests for a variety of herps. The populations of those species have been harvested for decades and like game species, have maintained sustainable populations throughout. As much as I have a distaste for the rattlesnake roundup scene, I can put my bias aside and look objectively at what has transpired. If you haven't obtained a reprint of the paper by Fitzgerald and Painter, I urge that you do so. The title of the paper is, 'Rattlesnake Commercialization: Long-term trends, issues, and implications for conservation.' Wildlife Society Bulletin, Vol. 28. #1. Spring 2000. I would make that paper required reading for all non-game wildlife biologists, wildlife agency leadership, and wildlife agency commissioners. It should be read by everyone that has concerns about the possible effects of sport take on herp populations.

Concerning point #3, road kill. My view is that the concerns are unwarranted. Where migration paths to and from breeding ponds, hibernation sites, etc. are intersected by roads, it is feasible that road kill can have a significant, negative impact depending on individual circumstances such at volume of traffic, etc. Also, where habitat is fragmented into small parcels, I can foresee that road kill may have some negative impact as well on certain species.

There is one paper by Rosen and Lowe in AZ that I believe many in herpetology cite as proof that road kill can be detrimental to snakes. I would suggest that an objective critique of that paper does not support that conclusion. I have a reprint and in fact, I will contend that the data provides support for just the opposite conclusion.

I have always looked at road kill differently. Finding many DOR deer, barn owls, opossums, skunks, rabbits, raccoons, etc, along roads indicates to me that the populations of those species are healthy in nearby habitat. I view road kill of snakes the same way, that finding a number of DORs of a species is an indication that the species is doing fine in adjacent habitat. Just my point of view.

Richard F. Hoyer

Another interesting approach to roadkills is that if, as you say, it may be more of an indicator that the adjacent populations are in good standing (assuming this means one is seeing a large number of roadkills), roadkill numbers may support the theory that collecting won't hurt the local populations. Wouldn't you bet that far more snakes get run over in these populations than are collected?

HKM,
It has been my assumption that not all species tend to cross roads with the same frequency. Some species may rarely if ever cross roads. Just a few of years ago, research at the Savannah Nat. Hist. Reserve was initiated investigating that very point with preliminary indications that seems to be the case. I do not know the final outcome or if that study had been concluded. At any rate, any statement about road kill having a significant impact on snake populations needs to be qualified to take the above into account.

I have not conducted field efforts in desert type habitats. However a second point that seems to be at odds with the proposition that road kill has a significant adverse affect on populations of snakes is that everywhere I have conducted searched, I commonly find snakes right up to the busiest of roads and highways. I have even found snake populations on small islands created during freeway construction and in the median strip between north and south bound lanes along I-5 in Oregon. One of my minor mark / recapture sites for the Rubber Boa is such an island between north and south bound freeway lanes at the south end of Salem, Oregon. The area of that totally isolated parcel of land is probably not more than 4 - 5 hectares and the boa population has been there for decades.

None of the above however removes the possibility that for some species inclined to cross, or use roads for thermoregulation, that their populations in the immediate vicinity of the road could be negatively impacted. I don't think anyone including myself really knows the answer but from my understanding of populations, I tend to believe that any decline in snake densities near most roads would be slight to small at the most.

After all, snakes have home ranges and thus populations would not be affected in which the road is beyond the radius of home territories. So the snake habitat in proximity to roads in relation to the amount of all snake habitat would suggest that road kill could not impact the overall populations of snakes in any significant manner.

There are many other factors that enter this issue but I won't go into them. But let me say that to my way of thinking, the amount of road kill is likely to be quite small in relation to both the numerical abundance of species and in relation to the annual surpluses produced by snake populations during reproduction. Thus, neither road kill nor collecting is likely to have any reak impact on the overall populations of snakes and such losses are only temporary. You might visit the AZ PARC Conservation forum in which I spelled out, as best as possible, why I consider personal collected to be a non-issue.

With respect to your question, I don't have enough information to hazard a guess.

Richard F. Hoyer

Maybe I wasn't clear in what I tried to say.

I do not know if roadkill has much of an impact on populations. It is sort of like a random transect with the additional variables of a snake has to crawl across the line, and then get hit when it does. For most populations adjacent to roads, I do think that more snakes get run over then get collected. I live by, and haved lived right on, some of the most famous roadhunting roads in the American SW. I regularly road hunt. Most nights, I am the only one hunting (obviously hunting) on these roads. There are always roadkills (the US Border patrol gets a lot!!!). There are not that many getting collected by virtue of the fact that there are not that many hunters. There are always snakes getting run over whether we are out collecting them, taking data or sitting at home. Even right now in chilly ol desert December we see roadkills. For most desert species, it is far easier to encounter numbers via the roadways than by field collecting, particularly so in pristine habitat. Of course the opposite may be said for non-vagile species that don't move across roads that are easily field. In that case, however, roadkill isn't really a factor.

All I am saying is that I THINK that for most species that do cross roads, I bet more get run over than collected from the adjacent populations. I didn't say that either was hurting those populations. That one I don't know either.

HKM,
It wasn't that you were not clear. It was my over-kill (pun intended) of dealing with the subject. My remarks were in part aimed as addressing the original post in which road kill was mentioned as a concern.

And I suspect you are correct about road kill being greater than collecting in that many species killed on roads in the SW are not highly sought after by collectors.

Richard F. Hoyer