Triturus terrestrial activity during aquatic stage

France, British isles

Triturus terrestrial activity during aquatic stage

Postby Ilian Velikov » Sun Jun 05, 2016 9:40 pm

Near my flat in Greater London there is a small forest with a couple of ponds in it. In the deeper one of the two all three species of newts (L.vulgaris, L.helveticus & T.cristatus) found in the UK could be seen (but strangely no R. temporaria). However, the pond’s surface is heavily covered by duckweed so the only way you could observe the newts is by net dipping. I don’t have the right equipment for this so I started visiting the pond at night to see if I can observe some of them on dry land. On one side of the pond is the park’s fence and a road, on the other side immediately next to the pond is a narrow dirt footpath and on the other side of the footpath there is heavy vegetation and trees. The only place where I could observe anything was on that footpath so that was the only place I looked at. Between 14 May and 12 June I went there every night (with the exception of one or two at the most) in different times of the night (but no later than midnight). The conditions were seemingly good most of the times but I only observed newts twice in that period. The first time it was 22:45h and I saw a male T.cristatus on the footpath. The newt was facing the pond but not moving. Only about a meter away from it there was a female L.helveticus lying parallel to the footpath and pond. This was only a brief encounter so I didn’t take any photos. There were some heavy rains at some point and there were puddles forming on the footpath. In the first couple of nights after the rains stopped I didn’t see any newts although it was fairly warm. Once the puddles dried out but there was still considerable amount of moisture I saw a newt again. It was at 22:00h and I saw again a male T.cristatus at almost exactly the same spot as the first time (+/- 50cm). This makes me think they have particular routs they follow when foraging on dry land. Interestingly when he was exposed to the light of my torch he didn’t flee to the water where he was seemingly going but back into the dense vegetation in the opposite direction where he was most likely foraging before I met him. On both occasions there was an abundance of invertebrates but this was not the main reason for the newt’s activity because there was plenty of invertebrates on other occasions but no newts.
Obviously my observations cover short period and a very small area so are not in any case conclusive but the conditions at which I found the newts on both occasions were very similar and were as follows:

Time: 22:00 – 22:45
Temperature: around 20 C
Moon phase: First quarter
Ground conditions: quite moist but NOT soaking wet

Does anybody know of any publications on the terrestrial activity during the aquatic stage of any European Triturus? I looked online but couldn’t find anything.

Here's a snapshot from a small video I did of the second one.

tcrst2.jpg
Ilian Velikov
 
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Re: Triturus terrestrial activity during aquatic stage

Postby Jeroen Speybroeck » Tue Jun 07, 2016 8:03 am

No one?

Ilian Velikov wrote:Between 14 May and 12 June I went there every night

So there is someone worse than me...

It's fairly common for (especially) cristatus to move about on land during humid nights in the breeding season. Especially males are supposed to move between ponds, if memory serves me well, but I'd have to check.
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Re: Triturus terrestrial activity during aquatic stage

Postby Ilian Velikov » Tue Jun 07, 2016 9:43 am

Thanks for your reply Jeroen.

Jeroen Speybroeck wrote:So there is someone worse than me...

It's only because it's 5 min walk from my home and because I can't smoke inside since my dauther was born ;)

Jeroen Speybroeck wrote:It's fairly common for (especially) cristatus to move about on land during humid nights in the breeding season. Especially males are supposed to move between ponds


Yes, that's true. However, in this case (in my area) there's only two ponds and one of them is way too shallow(about 30-40cm) to be suitable for Triturus. So I think in this case they mostly go out to forage. I'm interested in why they go out of water during the aquatic stage (food and moving to other ponds - yes, but why? There's food in the water too) and mostly what are the favored conditions under which they do it and movement patterns (as I said I suspect they use particular routs). I know there's a lot of information on terrestrial behavior during the terrestrial stage but couldn't find anything for terrestrial behavior during the aquatic stage.
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Re: Triturus terrestrial activity during aquatic stage

Postby Jeroen Speybroeck » Tue Jun 07, 2016 11:38 am

Ilian Velikov wrote:However, in this case (in my area) there's only two ponds and one of them is way too shallow(about 30-40cm) to be suitable for Triturus. So I think in this case they mostly go out to forage.

Are you assuming that they know what ponds there are, so don't bother? Local abundance may also play a role, with high levels triggering more of this type of movement. And didn't I read somewhere that feeding intensity is lower during breeding...? I should check Griffiths book but am on the train right now. Remind me if I forget (and no one else does it before then).

I also want cristatus at walking distance...
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Re: Triturus terrestrial activity during aquatic stage

Postby Ilian Velikov » Tue Jun 07, 2016 12:02 pm

Jeroen Speybroeck wrote:Are you assuming that they know what ponds there are, so don't bother? Local abundance may also play a role, with high levels triggering more of this type of movement.


It's a very small city/town park (I'd say about 500 square meters). It's a "forest" surrounded by roads and housing estates. So I'd imagine there's not a lot of them and they don't go far. There's no other pond within at least 2 km around the place and as I mentioned too many obstacles (plus badgers, foxes and cats). Also on the few occasions I've seen them they always face the pond (cm away from the water) seemingly returning to it. That's why I assume they just go out to feed on the abundant and easy to catch terrestrial invertebrates, e.g. slugs (as opposed to the harder to catch aquatic ones) and then go back to the water. And the other interesting thing is that I always see Triturus at almost exactly the same spot on the footpath (where the footpath is very narrow and the water is the closest to the dense vegetation on the other side of the footpath), so I think they know what they are doing and where it is safest to cross. Contrary to this I have seen both Lissotriton species at various spots along the footpath.
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Re: Triturus terrestrial activity during aquatic stage

Postby Ilian Velikov » Thu Jun 09, 2016 10:18 am

Jeroen Speybroeck wrote:And didn't I read somewhere that feeding intensity is lower during breeding...? I should check Griffiths book but am on the train right now. Remind me if I forget (and no one else does it before then).


So here's the reminder. It would be interesting to know if that's true. As I said (look above) I thought the main reason they come out of the water at this spot is to feed but maybe I'm wrong...
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