Thursday, March 13, 2014

MYSTERY OF WINTER BIRD MORTALITY DEEPENS

Thoughts of pullorum, aspergillosus, Newcastle, avian influenza and avian cholera  filled my head as I brought four recently dead wild birds from my property to the state pathobiology lab.  Disease names like these strike fear into the hearts of poultry breeders, who can quickly lose their entire stock to such diseases.  

Observers from around the Northeast have been reporting to BCR a winter die-off of particularly cardinals. Combined with my observation of the deaths of cardinals as well as two sparrow species, it appears that the die-off has affected particularly seed-eating finch-like birds.  The question has been what is causing this die-off? Considering the cold and snow of this past winter, starvation seemed a likely culprit, but no evidence consistent with starvation has been apparent.  All seven of the birds I personally found seemed to have had adequate fat reserves.

Examination of the my birds by state veterinarians did not pinpoint a clear cause of death for any of them. One exhibited evidence of a significant head injury but, as I have already noted, all birds appeared to be in good nutritional condition.  There was also no definitive link uncovered to any specific bird disease, although all individuals showed lung congestion.  Whether the congestion was simply a post-mortem effect was uncertain, however. Hence, the possibility of disease affecting these birds has not been ruled out, although what the disease might be remains unclear.