Using Motus to determine length of foraging time on tidal flats

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Mar 24, 2016, 3:18:35 PM3/24/16
to Motus Wildlife Tracking System
I'm a graduate student using Motus to track red knots in the Delaware Bay.  My goal is to track tide-dependent movements over tidal flats.  I plan to use 1-tower with 1-antenna focused over a tidal flat area to detect tagged individuals, then compare the number of detections recorded to mean water level, allowing correlations to be analyzed regarding tide-dependent behavior. 

I would like to not only use this technology to track tide-dependent movements, but to also determine if the tagged red knots are stopping on the flats at low tide.  My thought is that this could presumably show red knots utilize these flats at low tide. 

Any information, literature, or insight regarding this topic will be much appreciated.

Sjoerd Duijns

Mar 29, 2016, 1:32:10 PM3/29/16
to jbarth1235, Motus Wildlife Tracking System

Hi there,


I’ve been a PhD student at Theunis Piersma’s lab in the Netherlands and as you probably know there’s a wealth of papers and ideas about it. The difficulty I see at the moment is the question you want to address… How they utilize the mudflat is dependent on so many factors, but most importantly is the food (availability and quality). If birds stay put at given location, do they stay there because there is ample food, or are they just digesting or evading predation danger (i.e. not foraging)? This is dependent on the time of year as well. I’d be curious to see how well their movements are detected by Motus, as many small scale movements are likely undetected, but very important for the birds.


Have a look at these papers:

Bijleveld, A. I., S. Twietmeyer, J. Piechocki, J. A. van Gils, and T. Piersma. 2015. Natural selection by pulsed predation: survival of the thickest. Ecology 96:1943-1956.

van Gils, J. A., A. Dekinga, B. Spaans, W. K. Vahl, and T. Piersma. 2005. Digestive bottleneck affects foraging decisions in red knots Calidris canutus. II. Patch choice and length of working day. Journal of Animal Ecology 74:120-130.

van Gils, J. A., B. Spaans, A. Dekinga, and T. Piersma. 2006. Foraging in a tidally structured environment by red knots (Calidris canutus): ideal, but not free. Ecology 87:1189-1202.


Anyways, I’d be happy to discuss this a bit further of the motus-wts mailing list and feel free to contact me.


Best wishes,





Sjoerd Duijns

Postdoctoral Fellow
Carleton University | National Wildlife Research Centre

209 Nesbitt Bldg
1125 Colonel By Drive
Ottawa ON K1S 5B7




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