Is the standard deviation in the Circular package in R correct?

Question

I'm using the circular package in R and some of the functions are pretty straightforward for my purposes. mean(vector1,na.rm = TRUE) boom, done. sd(vector1, na.rm = TRUE) boom, done.

I have 42 bearings I'm analyzing and they can be found in pretty much any direction, but I'm hoping they trend in a particular way. I thought I trusted the mean, but then when I ran the SD it gave me a result of 2.2 degrees. My understanding of SDs is that 2.2 is too small to cover the wide range in bearings I have.

Is there something different about angular SDs? Or do I have the parameters set incorrectly? Are the results I'm getting accurate?

anglecir.nest
Circular Data: 
Type = angles 
Units = degrees 
Template = geographics 
Modulo = 2pi 
Zero = 1.570796 
Rotation = clock 
 [1] 318 306 334 120  38 323 219 140 129 148  41 176 301 261 230 118 211 357 268 203 180 218 308 236 176  65  33 187  48 127  50 28 348 191 208 190 344 278  24  14 298 348

Mean 272.937784889062 SD 2.23099490661604

So, if you wanted to try this for yourself in the circular package, this is the code you could use:

anglecir.nest <- c(318, 306, 334, 120,  38, 323, 219, 140, 129, 148,  41, 
176, 301, 261, 230, 118, 211, 357, 268, 203, 180, 218, 308, 236, 176,  65,  
33, 187,  48, 127,  50, 28, 348, 191, 208, 190, 344, 278,  24,  14, 298, 348)

mean(anglecir.nest, na.rm=TRUE)
sd(anglecir.nest, na.rm=TRUE)

Answer 1

The output of sd.circular is likely in radians, even though the data is entered in degrees. Something to watch for if you use this package.