Metabolic bone disease can occur in a wild bird, if for example, a young, rapidly growing bird sustains multiple fractures through some type of trauma. The combination of needing calcium to grow healthy bones, repair fractures and for metabolism cannot be met through a normal diet. 

In wildlife rehabilitation the admission of a bird with metabolic bone disease is generally caused by inappropriate care by a human. If someone finds a nestling raptor they usually know it is a carnivore. They might assume that since hamburger is meat it can be substituted for the normal diet. Sadly, this can be a fatal mistake for the bird. Not only does hamburger not have any calcium in it because it does not contain bone, it does contain a high level of phosphorous. The body needs approximately a 2 to 1 Calcium-phosphorous ratio in the diet for healthy metabolism and growth. If the diet contains more phosphorous than calcium, the body sees that as a calcium deficiency and will pull calcium out of bones to correct the deficiency. 

The radiograph below is of Swainson’s Hawk 24-359. The hawk was found in a road and the initial assumption was that he had been hit be a vehicle. An exam found no bruising and multiple fractures in various states of healing. It is a classic example of metabolic bone disease resulting in multiple fractures throughout the bird’s body.

The second admission this past week was a Little Brown Bat that had been caught by a cat. The bat had fractures of the left and right radius and damage to it’s pelvis. The injuries were too extensive to repair and the bat was euthanized.

Below is a photo of Swainson’s Hawk 24-359