Tortoise Nest Temperature Data Collection

CarolM

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@CarolM Do you have a rock on top of the sensor location? If so, that would alter the temperature readings as the rock would heat more than ground and hold heat longer. We would like the sensor location as "natural" as possible as a mother tortoise would leave it.
The stones are now off. Sorry didn't think about that.
 

Olddog

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Possibly you may find this article of intrest re nest temperatures measurements in Leatherback Turtles:

The authors list the temperature data loggers utilized in thier study and details of their study setup.
Measurement of Metabolic heat during the final third of the incubation period was associated with the number of eggs per nest.


Incubation temperatures, sex ratio and hatching success of leatherback turtles (Dermochelys coriacea)
in two protected hatcheries on the central Mexican coast of the Eastern Tropical Pacific Ocean
J. García–Grajales, J. F. Meraz Hernando, J. L. Arcos García, E. Ramírez Fuentes


Animal Biodiversity and Conservation 42.1 (2019)

Abstract

Incubation temperatures, sex ratio and hatching success of leatherback turtles (Dermochelys coriacea) in two protected hatcheries on the central Mexican coast of the Eastern Tropical Pacific Ocean. Incubation temperatures, sex ratio and hatching success of leatherback turtles have received little attention in conservation programs in Mexico. This study was carried out from October 2014 to May 2017 in two enclosed hatchery sites. To determine temperature parametersin the nest chamber environment and their variation during the incubation period, we placed data loggers in the centre of the egg mass in relocated nests. We then buried other data loggers in the sand near the relocated nests, inside and outside the hatchery. A total of 46 nests were examined over three nesting seasons. Mean nest temperature showed no statistical difference between nests in either the San Juan Chacahua hatchery or in the Palmarito hatchery nests. The mean sex ratio based on average temperature during the middle third of incubation duration was 96.3% skewed to female production. Hatching success in both San Juan Chacahua and Palmarito was high. Our findings support the common pattern of a female–dominated leatherback turtle sex ratio. Furthermore, hatching success rates in the shade–cloth hatchery were higher than those in the natural nests observed in other populations.

 

Markw84

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@CarolM Have you received the data loggers yet? Last I saw they left Johannesburg on the 6th. Let me know when you get them. I sent you 3.

I also am working with the park warden for the largest Burmese Star facility in Myanmar. She has 3170 Burmese in her care right now. I am working on getting her some data loggers as well. She never thought that necessary as they just naturally hatch!, but I am trying to convince her!!
 

CarolM

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@CarolM Have you received the data loggers yet? Last I saw they left Johannesburg on the 6th. Let me know when you get them. I sent you 3.

I also am working with the park warden for the largest Burmese Star facility in Myanmar. She has 3170 Burmese in her care right now. I am working on getting her some data loggers as well. She never thought that necessary as they just naturally hatch!, but I am trying to convince her!!
Sorry Mark, just checked. Still nothing.
 

Markw84

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We got the 2 week update from Carol on the C angulata nest we are monitoring. Here is the updated chart. I have added rainfall data from her town weather station as I like to track rainfall events when I am looking at nest data. I have charts like this for the past year+ on locations in the middle of their prime natural habitats for G platynota, S p pardalis, and A radiata. I don't have in situ nest data - so hopefully as we collect data from nests we can extrapolate what nests would be with those conditions. I also graph cloud cover in all my other data set graphs, but did not here with Carol's.

Interesting to me that we are now 3 weeks past summer solstice and the nest temperature for C angulata has only briefly peaked above 80° for a few hours on a handful of days. The average nest temperature is running about 75°!

Nest temp is red. Air temp is grey. Rainfall -blue- to show graphically on chart is X100 and is for a 3 hour period. So a reading of 10 on the chart for rainfall is 0.1 " of rain in that 3 hour period. This allow rain events to be readily seen. I do this on all my weather charts when used to predict nest temps and hatch dates, etc.

C angulata nest jan 14.jpg
 

CarolM

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We got the 2 week update from Carol on the C angulata nest we are monitoring. Here is the updated chart. I have added rainfall data from her town weather station as I like to track rainfall events when I am looking at nest data. I have charts like this for the past year+ on locations in the middle of their prime natural habitats for G platynota, S p pardalis, and A radiata. I don't have in situ nest data - so hopefully as we collect data from nests we can extrapolate what nests would be with those conditions. I also graph cloud cover in all my other data set graphs, but did not here with Carol's.

Interesting to me that we are now 3 weeks past summer solstice and the nest temperature for C angulata has only briefly peaked above 80° for a few hours on a handful of days. The average nest temperature is running about 75°!

Nest temp is red. Air temp is grey. Rainfall -blue- to show graphically on chart is X100 and is for a 3 hour period. So a reading of 10 on the chart for rainfall is 0.1 " of rain in that 3 hour period. This allow rain events to be readily seen. I do this on all my weather charts when used to predict nest temps and hatch dates, etc.

View attachment 262351
Such a pity that I cannot get one in an actual nest, as it would be very interesting to see if the temps spike closer to hatching dates. Thank you Mark for putting it all together.
 

Markw84

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Such a pity that I cannot get one in an actual nest, as it would be very interesting to see if the temps spike closer to hatching dates. Thank you Mark for putting it all together.

We do have a nest within centimeters of this location. This will tell us a lot!! I am already amazed at how low mid summer temperatures are in the "nest".
 

CarolM

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Ok. I received the data loggers on Saturday, but due to my own projects I have not been able to bury them yet. I will bury them today after work. I will place one where my above ground sensor push is and one close to where I have the other sensor push as well. The third one I will also bury in the nesting area, but a bit further up on the opposite side of the cage currently protecting an existing nest. Unless you would like it placed somewhere else (the sensor push is buried between my house wall and the cage and the data logger will be further away from the wall on the opposite side of the wall). I'll post pics afterwards of the placement.
 

CarolM

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@Markw84 / @Tom
Do I need to do anything before I put these loggers into their ziplock bags and place them? In other words am I supposed to press the play button for the 4 seconds to start the recording?
 

CarolM

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Okay. I tried following how Tom did them. So I put each one into a zip lock bag. And then taped each one with duct tape and then marked them with their designated numbers on the outside. 20190204_190943.jpeg
 

CarolM

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Number one went about 5 to 10 cm away from the sensor push under the ground. I brought out my trusty paint brush and started to brush away the sand.
And just as I was afraid of I saw part of an egg. It was however to the side of the hole and about 10.5 cm down. Since I had already partly disturbed the nest [emoji85] I decided to carefully place the data logger there as planned.
I just hope that the egg still hatches. I am also not sure if this was the egg that my domestic told me about ( as I was under the impression that it was a little further to the left away from the wall) or another egg entirely. Come March / April we should find out. That is if it hatches now.20190204_192522.jpeg20190204_200120.jpeg
 

Markw84

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Great work, Carol. You are indeed awesome!

I love the placements. The important thing is to have the same amount (depth) of soil on top of the looger as there is on top of the egg. Since they are such shallow nests, an Inch makes a huge difference.

As an example, my test nests for G platynota are 6" deep - the average to mid nest for the nests my girls dig. At that depth on days with an ambient 20°f temp swing, your nest swings about 10°f. My nests swing 5°F. The amount of direct sun makes a big difference on top of that. Especially with how sandy the soil is where you are.
 

CarolM

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Great work, Carol. You are indeed awesome!

I love the placements. The important thing is to have the same amount (depth) of soil on top of the looger as there is on top of the egg. Since they are such shallow nests, an Inch makes a huge difference.

As an example, my test nests for G platynota are 6" deep - the average to mid nest for the nests my girls dig. At that depth on days with an ambient 20°f temp swing, your nest swings about 10°f. My nests swing 5°F. The amount of direct sun makes a big difference on top of that. Especially with how sandy the soil is where you are.
Oh dear. Now I am doubting if I did it right. I will have to check tomorrow to make sure.
 

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