A new withdrawal crisis in Philadelphia is driven by the veterinary sedative medetomidine mixed with fentanyl, causing severe health emergencies and beginning to spread to other cities.

• A Powerful New Drug Is Creating a ‘Withdrawal Crisis’ in Philadelphia — The New York Times Health -

The COVID-19 pandemic lockdowns presented a unique natural experiment, revealing significant ecological changes such as alterations in songbird beaks due to reduced human activity.

• How the Pandemic Lockdowns Changed a Songbird’s Beak — The New York Times Health -