a weekend of Dutch secrets

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Re: a weekend of Dutch secrets

Postby Jeroen Speybroeck » Sun May 31, 2015 9:14 pm

I have never and will never understand why anyone would prefer a patternless black animal over the beauty of a patterned viper. That's all. In this part of Europe, black adders, I think, are (very) rare. For example, I have no knowledge of a black adder ever been found in Belgium.

Daniel, Bero, what's the percentage of black berus in "your" populations?
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Re: a weekend of Dutch secrets

Postby Daniel Bohle » Sun May 31, 2015 10:02 pm

I have no really new and exact data (because im still working on my data from mid 2014 and my last calculation was from 2011) but for males it must be something like between 50-90% depending on the year and subpop. often I´m really happy to see a normal male - especially in breeding season :D
for females its close to 0 because they don´t get deep black, it´s more dark brown and mainly/only very old females get "black" - but you still see a difference to black males!
but also if you count all "ugly brown" females as "black" ones its not even 50% as far as I remember the numbers. but not sure :-D
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Re: a weekend of Dutch secrets

Postby Berislav Horvatic » Sun May 31, 2015 10:07 pm

Daniel, Bero, what's the percentage of black berus in "your" populations?

At our monitoring site for V. b. bosniensis in the vicinity of Zagreb, about 1/3 of males, and absolutely no females.
At the site in Gorski Kotar (V. b. berus) the situation is different, 1/3 of the (found) males (unfortunately, too few,
only 12 - which means just 4 blackies out of 12, a really poor specimen for any serious conclusions), and 28.1% of
females, which were significantly more abundant (= found). In any case, a different climate, a different subspecies.
Elsewhere, who knows... which means, there have been just sporadic finds, no systematic (re)search, but the blackies
are certainly present everywhere. (By that I count only those pitch-black, not just "very dark".)

I have never and will never understand why anyone would prefer a patternless black animal over the beauty
of a patterned viper. That's all.

I fully agree. But, mind you, in early spring, after the Rana arvalis mating frenzy, or at that time, the blackies are
the first to emerge from hibernation, for some ten days one can find only them, so they are the only joy to be seen
around...
I have never and will never understand why anyone would pay a lot of money to buy an albino snake (or any other
animal). A friend of mine, a terrarist, has a simple answer: "Because they are rare." Then I ask him whether he would
like his own child to be albinotic, or melanotic, or leucistic, or anything so "nice & rare" like that... No, he wouldn't.
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Re: a weekend of Dutch secrets

Postby Bobby Bok » Mon Jun 01, 2015 8:25 am

That sure was a great weekend in the lovely company of so many herping friends!

Russian Ratsnake (Elaphe schrenckii)
dr1.jpg


Spadefoot Toad (Pelobates fuscus)
dr6.jpg


Adder (Vipera berus)
dr7.jpg


Pool Frog (Pelophylax lessonae)
dr15.jpg
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Re: a weekend of Dutch secrets

Postby Berislav Horvatic » Tue Jun 02, 2015 10:21 pm

If anyone's still interested (Jeroen was), I've consulted the diploma work on the monitoring of V. berus
in Croatia, as well as had a "serious conversation" with its author, and refreshed my earlier posting
viewtopic.php?f=10&t=2242&p=21956#p21956 accordingly. Not much new to say, but now it's all clear
(at least to me, regarding these particular results and their understandable limitations.)
But the Germans have published quite impressive distribution maps for Germany with percentages of
melanistic adders (males, females) at different localities - lucky them, no - diligent them.
The "only" problem is that up to now noone has really understood the underlying factors and the (most
certainly complicated) reasons why in a particular region, under the particular circumstances...
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