Vipera latastei

[Matt Wilson]

Jeroen, from my experience and only a few others, a number of species of snake are still just as active in summer as they are in most of spring. Of course breeding is the time for greatest activity and I wouldn't compare it to that. A colleague I met this summer has been working in areas of Greece for many years, he spends half of his time living/working in the USA and the other half in Greece. He has found all of the island vipers (xanthina, schweizeri, ammodytes) in Greece throughout the summer (when he herps in Greece), even mid- August by searching at night. As far as I'm concerned a number of species remain equally active by summer in the hot, dry areas of southern Europe, they are just out crawling by night. For me this would mostly apply to vipers, Eryx, Zamenis (situla), Rhinechis, Telescopus (of course!), Natrix species and occasionally E.quatuorlineata. In recent years all of my active Z.situla (say 4-5 specimens) were found at night on roads together with a few flipped during the daytime. I had a Z.situla this summer crossing a road at 12:30am for example.

Personally, I found road cruising a better way than searching on foot. But that also depends, on small islands it can be better to search on foot, but large areas on the mainland (like Andalucía as discussed earlier) I think driving around and covering more distance would be better. Just my opinion though!

[Jeroen Speybroeck]

And thanks for that. I'd still stick with spring herping on foot though .
Now Matthijs needs to get his MSc and do a PhD on this subject .

[Matthijs Hollanders]

You know nothing, Jon Snow.

Jeroen, Doñana is so different from most of Europe that you can't possibly be as certain as you claim to be, at least not based on anything substantial. There's nothing American about my ways, also... This way is just mostly inexperienced by a lot of European herpers. In New England, nocturnal activity is hardly observed on road. But as nighttime temps get higher as you head south, the method starts to pay off, I would expect with a direct relationship with temperature. I think that if Doñana doesn't produce road cruising, it's the exception rather than the norm. You know there are some long, little traveled roads going straight through perfect habitat, and I doubt any place in the world with that climate wouldn't have snakes on the road. And activity might be lower than in spring, but this is also the case in Texas and even august produces snakes in the desert. As for what they're doing, I'm not sure. Also, even though most of Spain is warm, I didn't experience it to be largely warm enough at night, except in the deep south.

[Jeroen Speybroeck]

You are right, my herping experience is unsubstantial. You clearly know everything about herping in Europe and about what European herpers do and don't. You'll do just fine in the academic world .

I am wondering - if road cruising to find gaditana would pay off, wouldn't you guess we would have picked up on it already? Even in Doñana where naturalists have been running all over the place throughout the year across seasons, I'd guess that if it would be that great, we'd know. There are a number of seasoned local herpers you might want to talk to.

Although Matt interestingly highlighted that there may be more going on during summer nights than we think, I'm sticking to my point that motility of snakes is lower in summer in Europe, so you are less likely to come by them (integrating over 24h for a sec), relating to prey availability, thermoregulation, water content, and bla-di-bla . If I wasn't so lazy, I'd try to dig some references up to substantiate this, but maybe Mario can chime in.

There's nothing American about my ways, also...

I hope you got I was merely referring to road cruising, nothing more.

You may also be underestimating species-specific differences. Another example (unless anyone disagrees), European vipers are (from my experience and that of a number of friends and maybe also studied e,g, in the UK in comparison with smooth snake) also less often found under artificial cover than other snake species.

The highest daytime temps are in Extremadura rather than in Doñana but dunno about nocturnal temps.

As a final note - road cruising only pays off if abundance is high enough. I wouldn't underestimate the difference between US and Europe too, although I shouldn't generalise, obviously.

Now leave me alone, I'm tired.

[Jeroen Speybroeck]

you can't possibly be as certain as you claim to be, at least not based on anything substantial.

The same goes for the substantiation of your own reasoning. Otherwise we wouldn't be discussing.

[Matthijs Hollanders]

You are right, my herping experience is unsubstantial. You clearly know everything about herping in Europe and about what European herpers do and don't. You'll do just fine in the academic world .

If you wouldn't be so sensitive about your position as alpha herper you'd understand I'm not questioning your herping experience. Of course I don't know where all you've tried night driving, but all I'm saying is that Donana can't fairly be compared to MOST of mainland Europe, therefore so vividly claiming it probably wouldn't work seems unsubstantiated. If you had read what I was saying, I only suggested it might work, because most herpers don't go out there in June and July to swelter in the day and drive the roads by night. It seems that we both are expressing opinions based on limited experience and no one will know until they go give it a shot.

I wonder where your feeling comes from that I know everything about European herpers are herping... and especially linking this to academia is amusing. (Clearly I'm not the only herper on this board who suspects cruising to pay off in certain parts.)

I am wondering - if road cruising to find gaditana would pay off, wouldn't you guess we would have picked up on it already? Even in Doñana where naturalists have been running all over the place throughout the year across seasons, I'd guess that if it would be that great, we'd know. There are a number of seasoned local herpers you might want to talk to.

Maybe, maybe not. Herpers are notoriously lazy and like to be successful on their trips at tried and true locales, and like I said, I doubt many people are out there at night looking for vipers. I don't know enough seasoned local herpers (I'm not such a self acclaimed herping expert as you might think I am!) to talk to about this topic.

Although Matt interestingly highlighted that there may be more going on during summer nights than we think, I'm sticking to my point that motility of snakes is lower in summer in Europe, so you are less likely to come by them (integrating over 24h for a sec), relating to prey availability, thermoregulation, water content, and bla-di-bla . If I wasn't so lazy, I'd try to dig some references up to substantiate this, but maybe Mario can chime in.

Like I said, Europe isn't the only place where snakes are most active in the spring. Doesn't maen you don't find them on roads at night in summer, but that's probably just cocky talk.

There's nothing American about my ways, also...

I hope you got I was merely referring to road cruising, nothing more.

You may also be underestimating species-specific differences. Another example (unless anyone disagrees), European vipers are (from my experience and that of a number of friends and maybe also studied e,g, in the UK in comparison with smooth snake) also less often found under artificial cover than other snake species.

Yeah, lots of snakes are rarely road cruised and some are so often found on the roads. Typically, and this IS the rule whether you like it or not, the majority of vipers from warmer climates belong in the latter category.

I also have an anecdotal story to tell, its relevance remains to be discovered. The pygmy rattlesnake has one of the smallest home ranges I've heard of. I believe it's only a few square meters on average in Florida, and I too am too lazy to grab the reference. In Texas, there's a spot with a 3km road, which is the only reliable place found in a radius of tens of miles. Finding several on the road here in a night is unusual but not impossible. Dozens over the years have been found on the road. However, efforts with various pieces of cover and dozens of hours field herping have yet to yield a single animal. Disregarding the whole temperature issue, some common snakes might seem extremely rare in the field but are a common sight on the roads for whichever reason.

As a final note - road cruising only pays off if abundance is high enough. I wouldn't underestimate the difference between US and Europe too, although I shouldn't generalise, obviously.

Now leave me alone, I'm tired.

People always mention this intercontinental difference in snake abundance. Without risking to sound like a know-it-all academic failure, do you have any references for this? I would suspect overall density is lower but local abundance to be highly similar, although this is a GUESS, so take it for what it is. Anyway, Donana has such a huge amount of habitat that I doubt densities there have changed over the last years.

you can't possibly be as certain as you claim to be, at least not based on anything substantial.

The same goes for the substantiation of your own reasoning. Otherwise we wouldn't be discussing.

I'm not certain, and I never claimed to be. I just think it should be tried out there!

[Jeroen Speybroeck]

I understand now that I have made my doubt of cruising gaditana in fair numbers sound too resolute, apologies.

@ this IS the rule whether you like it or not
That's quite the "alpha" statement, I'd say. Bring on those references, sir. We could dwell on the comparison hiking vs. cruising in vipers in N Africa, Oman, ... as well as in the tropics. Maybe somebody else here has ideas.

However, it is my impression the percentage of vipers in DORs in S Europe does not correspond very well to the percentage of vipers you’d turn up herping the land. While this is also likely to be related to detection probabilities, this makes me think that our vipers are less likely to hit the road than other species.

@ intercontinental abundance differences
Agreed about the relevance of scale. It's largely based on travelers experiences and no, to my knowledge no one ever really tackled this. A comprehensive review paper of population studies could give hints. As far as I can tell, estimates of snake abundance are rather hard to achieve thus rare. Actually, this could also be studied for other fauna groups, although you’d have to factor in taxon-specific stuff like hunting history etc.

You can find snakes in summer on roads in the US, but clearly it's not the best time to do so. This is what I would relate to seasonal activity patterns and also what I mean with paying off less. Probably you were not actually questioning this, but here's some copy-pasted info.

Male Vipera aspis triple their movement rates during mating season (Moser et al., 1984), male Vipera berus have a home range 4x the size of that of females because of mating (Neumeyer, 1987). There's even a study for Vipera latastei, but unfortunately from N Portugal (Brito, 2003)(increased movement in September also believed to relate to mating). What I'm starting to consider is that mating may not happen in spring, so road cruising might in fact pay off more later in the year, as far as finding mate-seeking males on the road is considered. However, mating is not the only factor driving motility. Another imho relevant aspect is seasonality in habitat use, which may make roads more attractive during a certain season as well. This seasonality is also known from several viper species (e.g. Monney, 1992; Naulleau et al., 1998).

Grabbed this from references in this paper =>
Brito JC (2003) Seasonal Variation in Movements, Home Range, and Habitat Use by Male Vipera latastei in Northern Portugal. Journal of Herpetology 37(1): 155-160.

http://vipersgarden.at/PDF_files/PDF-287.pdf

[Berislav Horvatic]

However, it is my impression the percentage of vipers in DORs in S Europe does not correspond very well to the percentage of vipers you’d turn up herping the land. While this is also likely to be related to detection probabilities, this makes me think that our vipers are less likely to hit the road than other species.

Agreed.

[Frank Deschandol]

Hi all, to give you my opinion about the first posts, V. latastei at Doñana is a tough job. If you go there in March, and if you have luck, you can probably find at least one. But it's almost impossible to find them from middle of April, it's really too hot. And if you find one into the summer, better go to a Casino the same day... I've been there many times, sometimes for a month and a half, in the spring, in the summer, in the fall and in the winter, But I never found any viper DOR, though they occur everywhere.. But they don't go out so often. Even trails in the sand are scarce..

[Gabriel Martínez]

Hi Frank,

Probably you met many times with my friend Juan Pablo G de la V. He knows MANY people there and nobody finds vipers there. If anybody finds a viper, these guys will be happy to all the year!

Some of my friends there are very good herpers and found 1 viper in all his life in Doñana. One of them told me about one of the vipers found by Jeroen et al.: "Gabri, we flipped that thing thousands of times in our lives. And we never found nothing, never. But one of these guys flipped that and... viper!!". Other guys visited Doñana and found 2 vipers in trails during a single morning... but I think that is a question of luck. In Burgos, Gredos and other areas you see the habitat and know aprox where the vipers are (many rocks and bushes in middle of habitat), but in Doñana all is the same habitat. Vipers occur there with huge Malpolons and Herpestes so they must be more shy because they haven´t good hidden places, and it seems that they have small densities. Really I don´t know, but the real thing is that probably coastal Andalussia (Doñana, Cabo de Gata) are the most difficult places to find the vipers...