They are a slate gray on the top and white underneath. I thought of a titmouse, but these birds don't have the tuft on their heads. They are agressive, fighting off other birds and even sometimes their own species. Maybe all birds are this way, but these little gray ones seem more agressive than others at the feeders.
Figure 3.6 An independent BSS (IBSS) is the most basic type of 802.11 wireless LAN. Figure 3.7 An Extended Service Set (ESS) 802.11 wireless LAN consists of multiple cells interconnected by access points and a distribution system, such as ethernet.
ESS became a European Research Infrastructure Consortium, or ERIC, on 1 October 2015. The European Spallation Source ERIC is a joint European organisation committed to constructing and operating the world's leading facility for research using neutrons.. ESS will use spallation, a process in which fragments of material (spall) are ejected from a body due to impact or stress.