I've seen the described tame, intent, ground-feeding behavior dozens of times this winter since November, in many different situations and conditions, cold, wet, windy, calm, sunny, morning, afternoon, late evening, and have observed the kinglets actively picking tid bits (insects?) out of the grass and off leaf litter, plus making aerial forays from the ground up for short distances. I also tend to think these small birds are benefiting from some very small, abundant food items that are an important winter food source. Is there something somewhere in research data or literature about this behavior?

Bruce Paige
Sequim