American Crow with avian pox observed

American Crow specimen with likely case of avian pox.

American Crow with likely case of avian pox.

A concerned local resident encountered a dead American Crow (Corvus brachyrhynchos) with suspicious growths.  The images above show the warty and scaly growths that originate on the beak and skin, a likely case of avian pox.  Avian pox is a highly contagious disease that affects only birds and is caused by several known viruses.  Many birds species, ranging from wild to domestic species, can become infected by avian pox.  Disease occurrence is highest in songbirds and game birds, while occasionally observed in raptors and infrequently observed in waterfowl.  Seasonal occurrence is year-round but its prevalence corresponds with environmental factors and transmission amongst some species groups is associated with aspects of bird behavior and population abundance.  There are limited control options for this disease.  Vaccinating domestic birds is the primary method for controlling it on farms, including backyard poultry.  There are few control options for avian pox in wild bird populations.  One way it is transmitted amongst wild birds is by contaminated bird-feeders, therefore the best control method is to regularly clean bird feeders with a 10% chlorine bleach solution.  This animal was found dead on the road and collected on State Route 132 in Bethlehem and Woodbury, CT approximately 2 miles from portions of the White Memorial Foundation property. Although is likely an isolated observation, we'll be keeping a close eye on additional reports nearby in the future.  The specimen was in good condition which permitted a closer external inspection.  The animal exhibited an emaciated condition and the warty lesions likely obscured the vision of this animal.  These factors likely led to it's weakened condition which directly caused or contributed to the death of this individual.  No further tests or examinations were performed.

Further information can be found at USGS National Wildlife Health Center website, USGS NWHC Field Manual, and Michigan DNR