The Antimicrobial qualities of copper are well known.  Man has exploited the inherent antimicrobial properties of copper since the dawn of civilization.  It has been demonstrated clearly in many scientific studies conducted over several decades that copper has rapid, broad spectrum antimicrobial efficacy against some of the most toxic species of bacteria, fungi and viruses.

Alloys with higher copper content kill organisms faster but, as a general rule, alloys with >60% copper have good efficacy.  'Antimicrobial Copper' is shorthand for these efficacious alloys.

Erva's copper bird house portals are 99.9% pure copper and offer the highest possible antimicrobial effect.