CHICAGO (AP/WGN) — A necropsy on a beloved, endangered shorebird in Chicago named Monty the Piping Plover shows he died of a respiratory infection, experts said Tuesday.

The Lincoln Park Zoo said it partnered with the U.S. Fish and Wildlife Service and the University of Illinois Zoological Pathology Program to determine the bird’s cause of death.

The severe fungal respiratory infection included laryngitis that restricted Monty’s airway, the zoo announced.

Additional testing is being conducted to identify the fungus but it is suspected of being environmental in origin, the zoo said.

Further testing concluded Monty did not show any signs of high pathogenic avian influenza, also known as bird flu, that has been spreading in several states, the zoo said.

Monty died May 13 at Chicago’s Montrose beach.

His remains will be provided to the Field Museum’s avian department to be available for future studies that contribute to the recovery of the Great Lake piping plovers, the zoo said.

WGN News reached out for a statement regarding the cause of death for Monty the Great Lakes piping plover:

Lincoln Park Zoo, in partnership with U.S. Fish and Wildlife Service (USFWS) and University of Illinois Zoological Pathology Program, conducted a necropsy of Monty the piping plover to determine cause of death.

After this procedure, it was determined that Monty died of a severe fungal respiratory infection, including a laryngitis which restricted his airway. Additional testing is being conducted to identify the fungus but it is suspected as environmental in origin. Further testing concluded Monty did not show any signs of high pathogenic avian influenza (HPAI), also known as bird flu.

In addition, samples from the necropsy have been reserved for Dr. Francie Cuthbert and Dr. Sushma Reddy at the University of Minnesota as part of a genetic study of the Great Lakes piping plover population. Monty’s remains will be provided to the Field Museum’s avian department to be available for future studies that contribute to the recovery of the Great Lake piping plovers.

Lincoln Park Zoo, USFWS, and all those dedicated to Monty and the piping plovers are devastated by this loss but remain hopeful for the future of this species in Chicago and the Great Lakes region.