immature Common Gallinule?

[Flyingbass]

Hello,

I was out checking for a very small pond for reptiles and amphibians for a citizen science project when I stumbled upon a bird I had never seen before.  It was walking slowly through some thick cattail along the edge of this very small pond.  My first reaction was why is there a chicken in those cattail?   I had my binoculars with me so I got a brief but good look at it.

It was mostly a darkish brown black mix on top with some white underneath and a clear white patch under its tail.  The beak had a slightly yellow colour to it, I didn't notice any other markings or colours.  During the 30 seconds I observed it before it went back into the cattail it was continuously flicking its tail with the white underparts.  

I tried to make a mental note of everything I saw and now that I am back at a computer my best guess is an immature Common Gallinule.  Does this make sense for this time of year?   This bird is on ebird but is not very common, are there any other birds that I should be thinking of?  Also I need to buy a camera, a picture would be so useful right now!

[Rotarran]

Common Galinule is probably the most likely...especially based on the sizing profile you gave (comparison to chicken).  I don't think it was a Sora because Soras are too small to match your description.  Virginia Rails are also quite small and are more reddish overall with a longer beak.

[Flyingbass]

It wasn't a Virginia rail, the other one I was thinking about was an American Coot but I am fairly confident it wasn't an American Coot because of the colour discrepancy.  I am curious if anyone knows of the Common Gallinule flicking its tail as persistently as the bird that i saw?   It was almost like a spotted sandpiper in terms of frequency.  I will try and go back today and have another look, hopefully I can get a picture!