Update (August 22, 2021). Cornell University’s Lab of Ornithology and the College of Veterinary Medicine have advised that, although the reason for the bird mortality is still undetermined, cases are declining the infection appears to be waning.  State wildlife officials throughout the Midwest and Atlantic seaboard have rescinded their guidance to take down bird feeders. Mysterious Bird Disease – Take Down Your Feeders | The Animal Nerd

Update – although the mysterious illness that is killing songbirds in the mid-Atlantic and mid-west appears to be declining in those states (Zenkevich, 2021), the Hartford Courant is reporting that cases have now been identified in southern New England (Arnott, 2021).  We are still being asked to refrain from putting up bird feeders and bird baths.

Arnott, C. (August 6, 2021).  Bird deaths from mystery illness confirmed in Connecticut; Audubon advises ‘no birdfeeders’.  Hartford Courant.  Retrieved from Bird deaths from mystery illness confirmed in Connecticut; Audubon advises ‘no birdfeeders’ – Hartford Courant

Zenkevich, J. (August 4, 2021).  Reports Of Mysterious Bird Disease Decreasing In Pennsylvania. Retrieved from  www.sciencefriday.com/articles/bird-disease-decreasing/