Mr. Few Shots, nice, I'm guessing a 600mm lens?
Here's a nuthatch of mine, done with a lowly 70-200 f/4 on my crop camera.
thanks
no i wish a 600mm 
but out of my budget
its canons 400mm f5.6L
the trick is getting closer
Is yours an American Nuthatch?
You're quite welcome. Cool, I've rented that lens, I liked it...congrats on getting stellar results with it! Alas I chose to buy a softer Sigma zoom. So far I like it considering the price (especially the color rendition), but I've only used it for an hour. Here's an admittedly compromised shot below, done today through a glass window (the storms brought wind gusts to 40 mph today!) ISO 2000, 1/200 with OS on, f/7.1, 400mm, 50% crop, then reduced from 2000 pixel width to 770.
I was told that other bird was a "brown headed nuthatch". This one is quite small, not much bigger than a hummingbird. I'm the opposite of a bird expert. I just know there aren't much variety of the small birds here...or if there are more, they don't make themselves conspicuous. I'm not much into using blinds or camping out in the mountains for a week to try to see the rarer species...especially when there are so many other people out there doing such great work already (most of them not getting paid for it).
I have never used Sigma but you got the shot with everything stacked against you by the sounds of it..nicely done
Its a bug that soon gets you. the trick is to start feeding them in your garden if you have one and get a good spot set up to photograph them without spooking them.
Here's a Blue Tit I shot in my garden which although a very common bird is striking when in the right light.
This was shot with Canon 100-400 L lens which some say isn't that sharp but I disagree if you shoot within its capabilities.
All I did was set up a perch next to the feeding area and with a bit of trial and error with the position and height of the perch they would land on it nearly every time before hopping onto the feed area.
Patience and observation are your biggest friend when trying to get wildlife shots
