Considerations for estimating diurnal vs. nocturnal home ranges

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Maina

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Jun 17, 2022, 4:28:04 PMJun 17
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Hi Chris,

I am new to using ctmm but have been watching some of your recorded webinars and reading several of your publications to try to get my bearings. I am hoping to estimate AKDE home ranges for diurnal foraging territories of a shorebird population that uses the same nocturnal roost each night. This means each individual returns to the same shared nocturnal roost site each night, and at dawn each day departs to their own foraging territory. 

In order to estimate AKDEs for just daytime foraging areas, would it be robust to simply remove all nocturnal roost points from the analysis? How would ctmm handle the time lag that creates between the last point in a foraging area each evening and the first point back in that area the following morning? 

Thank you for any tips on the most sound way to separate nocturnal vs. diurnal data points for AKDE estimation in ctmm -- and thank you for all the helpful resources you have made available for learning how to use this package!

Maina

Christen Fleming

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Jun 17, 2022, 10:19:33 PMJun 17
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Hi  Maina,

That would be a good idea and there is an annotate() function that you can use to determine local day/night conditions from the latitude and timestamp.

I have some code mostly working that can model a day/night activity cycle, but for the moment you need to segment the data like this and the current stationary models in ctmm just assume that the same behavior persists between the gaps.

Best,
Chris

Maina

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Jun 21, 2022, 9:48:41 AMJun 21
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HI Chris,

Thank you for confirming that this would be a sound method! I will try this for now and stay tuned for future updates of other ways to model a day/night activity cycle.

Thanks again,
Maina

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