Berislav Horvatic wrote:But, do you really think snakes are THAT sensitive and "delicate", not to say "spoilt"? To collectively (?) leave their favourite locality just for the reason that too many people, who happen to be around, make them too "nervous" (or "uneasy")? I don't
know, but it just seems to me a little bit too ... never mind, I can't find the right (& "politically correct") word at the moment.
To quote myself: "Of course, who am I to judge how much of that might be too much for THEM, but still..."
When it comes to people, even in a war, they don't abandon their homes and become refugees for some SLIGHT reasons,
it takes much more than a "mild disturbance" to make them leave everything they have/cherish and "relocate". OK, the
snakes might be more "sensitive" than we humans are, maybe more "sensible" in a way, more "natural", who knows - also,
they have no PROPERTY to abandon, unlike us humans - but still... I don't know.
Well, the discussion has moved on in the meantime, but I still feel I should answer this.
Honestly, I am not entirely sure what I think. Admittedly my data set is too small, my methodological rigor too lax in terms of collecting same data to draw any robust conclusions.
It does seem to me, however, that I see a pattern in the movements of adders at the locations I visit frequently that begs an explanation. The theory of disturbance by observers as the reason behind these movements seems to me the least far fetched I can come up with. This theory also seems to me a reasonable hypothesis to explain the decline in observed numbers I hear reported from some of the more popular Danish hotspots.
I concur with Jeroen in distinguishing between the levels of disturbance incurred by herpers herping and the behaviour of the general public. Of the two I believe the attention offered the snakes by herpers herping is much more likely to cause them to relocate.
I believe the question of how much might be too much for THEM is deceptively simply stated and likely has a very complex answer. Ultimately the decision to stay or go should be the result of an equation weighing in an awful lot of factors. Some of these are external factors such as availability of food, risk of predation, adequate possibilities for thermoregulation, etc. Others are internal factors, the experience embedded in the genetic makeup of the snakes enabling them to evaluate and react to external cues. This experience might even differ between separate populations.
To sum it up, I think "how much might be too much for THEM" probably varies, and potentially varies a lot, based on the snakes' environment and perhaps even to a degree on who THEY are. While I don't think we always need to worry much about stressing the animals by simply observing them, I do not find it ludicrous to believe that in some cases repeated disturbances at basking sites coupled with a perceived threat of predation could be sufficient to produce a different outcome to the equation, tip the scales and cause the snakes to relocate. I do not believe this reasoning necessarily implies attributing great "sensitivity" or "delicacy" to them.
As I am not a trained biologist I find it exceedingly difficult to express mysef about the drivers of animal behaviour without resorting to anthropomorphic language. Please do not take the above to mean I assign any form of personalities or conscious decision making to these adders.