According to conservation organisation Natur&ëmwelt, 371 sick or dead blue tits were reported in Luxembourg from the beginning of March to the end of May.

“The total absence of blue tits was also increasingly observed,” the not-for-profit noted on its website. “Veterinary medical examinations from Germany, where the situation was similar, identified the bacterium Suttonella ornithocola as the cause of the death.”

The pathogen reportedly causes pneumonia in infected birds and impacts not only blue tits but other birds within the tit family.

Nature&ëmwelt bird expert Elisabeth Kirsch told Delano on Wednesday that it was first detected in the UK in 1996 and in Germany there were infections in 2018. “Yet the scale of this year's wave of infections has not been seen before. It is also the first time that the infection has been observed in Luxembourg,” she said.

Public appeal

A public appeal by Natur&ëmwelt to report deaths online helped the not-for-profit to establish that the deaths were evenly distributed across the country. It acknowledged that not all deaths were related to the bacterium, some may have been killed by predators or other diseases, but said the report descriptions appeared consistent with the symptoms caused by Suttonella ornithocola.

“Looking at the chronology of suspicious cases and reports received daily, the death of blue tits began in March, peaked in mid-April, and then declined thereafter. This chronology also coincides with that in Germany,” the not-for-profit wrote.

The bacterium was first reported in the UK in 1996, but little is known about it except that there are no known infection cases among humans or any mammal, according to gardenwildlifehealth.org.

If touching dead birds, residents are urged to protect their hands with gloves or another covering. To reduce the risk of transmission, households are urged to clean feeding and drinking points and stop feeding or putting water out for the birds for four weeks.