Thanks for the excellent explanations of why the wires cannot keep the feet of birds warm, and for the fascinating theory that different species have different "normal spacing". 

I have seen the spacing analysis applied to people.  Different cultures of humans apparently have differing sense of "personal space" and that does make sense, but it is a an aspect of each culture. 

Do birds have "cultures?" I believe the answer is yes. Some birds seem to have local behaviors, and vocalizations can be very different in different areas even among the same species.

william gilbert