Shooting small birds in cold weather is always a challenge. Today was especially hard due to bad light, and lots of disturbance. I live along a rather busy street with lots of people passing quite close to the feeders. My iPhone shut it self of and even the birds seemed a bit frozen, but the 1d Mark III didn’t miss a beat, although the view finder fogged up repeatedly. After 35 minutes I gave up because of the bad light and slow shutter speeds. At least 1/500 s is recommended when shooting birds, and if you want to capture small birds in flight you will need 1/2000 s.
Hoping for more Light and world peace!