When are caecilians active (near surface)?

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jonathan
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When are caecilians active (near surface)?

Post by jonathan » February 15th, 2015, 8:04 am

Obviously, rain and high humidity, especially at night, are the main factors that bring caecilians out onto the surface.

But I was curious - are there any additional conditions, especially regarding times or temperatures, that bring caecilians close to the surface?

I'm planning on doing some caecilian survey plots - simple meter-square shallow digs - during the course of the monsoon season in Bangladesh. Is is possible that certain times of day - such as early morning, midday, late in the day, or at night - would be most likely to catch the caecilians within 15cm of the surface even if they're not actually on it? Would warm temps, or cool temps, or some sweet spot between be likely to pull them up high? Or is near-surface activity, just like surface activity, most dictated by the rain and humidity?

Answering the time of day question is the most important thing for me. I would love it if I could do all my sampling at the most efficient time of day (say, early morning, or perhaps midnight), rather than having to randomly spread my samples across the day and waste a lot of time.

I'd be great if there's anyone who could give any feedback on this little question. All my experience with caecilians has been with a single common species, and 90% of that experience was surface activity.

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yoloherper
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Re: When are caecilians active (near surface)?

Post by yoloherper » February 16th, 2015, 9:58 am

I flipped one in November in Costa Rica under an old rotting log at around 10 or 11 PM. Not sure if it was actively moving around or if it was resting in the damp leaf litter and debris but it was very quick to escape after uncovered. Unfortunately, I can't remember what the weather was like earlier in the day, but I do remember that there was a lot of moisture in the soil and under the log where it was.
Hope that was at least a little helpful,
-Elliot

Matt Cage
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Re: When are caecilians active (near surface)?

Post by Matt Cage » February 16th, 2015, 10:24 am

I've found about a dozen of them of various species in Central and South America. All of them were found at night on rainy nights. Seems to be most likely to find them on VERY rainy nights. I have found them while night hiking. I most commonly find them hiking in mud puddles in the trails that have developed as a result of the nights rain. I have found a few on the road at night on very rainy nights in Central America. I have never seen one out in the daytime. By my experience, peak activity seems to be late at night (10 PM to 2 AM).

Good luck!

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Chaitanya
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Re: When are caecilians active (near surface)?

Post by Chaitanya » February 17th, 2015, 5:02 am

In western ghats, around monsoons(late-May to mid Oct) caecilians are active near ground. you still need to turn a ton of rocks and check them in leaf litter to find them.

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jonathan
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Re: When are caecilians active (near surface)?

Post by jonathan » February 18th, 2015, 9:54 pm

Thank you!

So far the general consensus is that I should probably do my digs at night, well after dusk, and the wetter it is the more hope I should have.

Anyone have experience particularly with digging for caecilians though?

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Re: When are caecilians active (near surface)?

Post by Ruxs » February 18th, 2015, 10:12 pm

jonathan wrote:Thank you!

So far the general consensus is that I should probably do my digs at night, well after dusk, and the wetter it is the more hope I should have.

Anyone have experience particularly with digging for caecilians though?
I dig for fossorial snakes a fair bit and the caecilians tend to be found in the dampest piles of leaves. Check roadside ditches.

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Re: When are caecilians active (near surface)?

Post by Antonsrkn » February 25th, 2015, 11:32 am

I have very limited experience with caecilians but here in Ecuador I have noticed that when large earthworms are moving about its a good sign that there may be caecilians moving about on the surface as well. I have only seen the caecilians on a few occasions here but everytime its when there is also a large amount of worms moving about. I have gone out in what i thought were the exact same conditions but when theres an absence of worms i havent seen any sign of caecilians either. Maybe the same thing that drives the worms to the surface brings the caecilians up or maybe the presence of the worms themselves is a draw, not sure. I have seen caecilians at both dusk and at night so not sure which is best. Probably not overly helpful but hey a little extra info never hurts!

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