So I will start with this:
Jeroen wrote:
Do you catch any snake, even if it's the 24th ammodytes of the day?
Depends on!
I mean, is it a "just for fun" fieldtrip or are you doing some scientific research.
"just for fun" fieldtrips:
Here I mostly catch one or only some (different colors/markings, different age - juvenils are different from adults, a.s.o.) to have some pictures from the locality/area.
In most cases I make only a GPS waypoint - for my own data and maybe someone will need it for distribution maps or so.
"scientific" fieldtrips:
Here its completely different.
For example, if you want to get data on population density and homerange of a species, in many cases you have to grab each individual you spot.
Maybe not so important in vipers (but also here it might be difficult), but e.g. in Natrix tessellata (a project of us). You HAVE to grab it and look to its belly markings. Take a picture and GPS waypoint. Its the only way to know - have we seen it before, and when, has it changed its locality.
I think, its very important, how you grab a snake!
When I pick up a viper, I do it slowly and gently.
Less than 10% of all the ammodytes and aspis (but not berus) have tried to bite.
After taking pictures and releasing them, sometimes I found them basking again 15 to 20 minutes later again.
But I had a very sad and bad experience too.
In 2006 we catched an, about 130 cms long Dolichophis caspius in Montenegro in the early morning (around 8:00 a.m. CEST).
Yes it looks a bit skinny and it was very easy to grab it.
After taking some pictures and releasing it - we found it dead (without any injury) the next morning, only 10 metres from the place we released it.
Was it stress?
Or was it a sick animal?
http://www.vipersgarden.at/CG06.php
More answers and opinions later!
Mario