((Note: We got a SECOND interesting patient this week–a blog entry on him will come soon!)

((Note: We got a SECOND interesting patient this week–a blog entry on him will come soon!))

Lady, you aren’t from around here!

A Snowy Owl Irrupts at Carolina Raptor Center

When we posted an article from Audubon Magazine on our Facebook page about a possible Snowy Owl irruption in 2017, we had no idea that we would be telling this story just a few weeks later. 

On Monday, December 4, 2017, Rehab Associate Lauren Allen took a call from a very excited wildlife officer in Anson County, NC. He had picked up a bird off the side of the road that he was pretty sure was a Snowy Owl. Transport Volunteer Clyde Kiser brought the bird to the Jim Arthur Raptor Medical Center and all he had to say when he got there was, “this is a BIG bird. A beautiful bird.”Senior Medical Coordinator Mathias Engelmann confirmed later that day that this was indeed the first Snowy Owl admitted to the hospital in over 40 years. Certainly a milestone. One that many of us will never forget.

When she was admitted, the staff found that she was severely emaciated: about a skinny as they get. Engelmann recorded a 1 out of 5 keel score. Her initial examination was done quickly to reduce stress; stress can easily kill a bird in her state. She was put on fluids to rehydrate her, vitamin B and iron to help her create new red blood cells and restore her energy, and given liquid calories. When animals are emaciated, immediately giving them solid food can actually cause their bodies to fail, so we always rehydrate them first. She was also started on a preventative anti-fungal, since emaciated birds are very susceptible to contracting aspergillosis, an airborne fungal disease affecting the air sacs of raptors and other birds. After receiving quick and thorough treatment from the team, the Snowy Owl was put away in a warm incubator for the evening.

The next morning, she was perched but still very weak, and her wings were drooping from her weakness—not a good sign. We completed her treatments for the morning quickly and quietly returned her to her incubator. At midday, we did a more thorough exam and discovered some green bruising on one wing, though no bones felt broken. She was still too weak for a radiograph. We also switched her to a medication that treats aspergillosis, since CRC’s Staff Veterinarian Dave Scott suspected that she might already have the disease.At the same time, we drew a small amount of blood. It turned out that she had a packed cell volume of 29%–normal is around 45-50%. More alarming was that her blood albumin was nearly zero. Dr. Scott told the team that she had a 0% chance of survival without a blood transfusion, or a mere 10% chance of survival with a blood transfusion.

We do not have any resident Snowy Owls at CRC. We consider it too warm for them here to live comfortably year-round. Instead, we drew blood from one of our resident display Great Horned Owls, Harmony. We were successfully able to complete our first ever cross-species blood transfusion. Since Snowy Owls (Bubo scandiacus) and Great Horned Owls (Bubo virginianus) share a genus, we had hope that this would work, and we treated the Snowy Owl with a medication to help prevent allergic reactions just in case.Thankfully, she did not have an allergic reaction. She actually seemed to regain a little strength, and she tweezer fed a few bites of food later that evening. 

Unfortunately, things took a turn for the worse that night. We found her deceased on Wednesday morning.

The Jim Arthur Raptor Medical Center is a teaching hospital as well as a medical center. A group of vet students and their professor were visiting from NC State University and were able to complete a necropsy (autopsy) with an endoscope. We used this less invasive method to help preserve the cadaver for educational purposes—and it had the bonus of giving the students practice with an endoscope. Aspergillosis was confirmed: she had multiple lesions in her air sacs.

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More Information on Snowy Owls

Snowy Owls typically live way up north, in the Arctic tundra. They do migrate in the winter, though typically not all the way into North Carolina. Experts predicted an “irruption” of Snowy Owls this year throughout the United States, and our Snowy Owl was certainly one of those. This is not the first Snowy Owl to be seen in North Carolina, nor is it even the furthest south they’ve gone; sightings of them as far south as Florida have been reported in previous irruption years. Most of these birds are very hardy and do quite well despite the change in landscape. Some do not make the journey so well and find hunting more difficult in the unfamiliar environment of the south—such may have been the case with our Snowy Owl. It is also possible that whatever caused the bruising on her wing also damaged her ability to hunt, thereby causing her to become even weaker and more stressed, leading to her develop aspergillosis.

So why are Snowy Owls moving so far south for the winter? This is not a new phenomenon. Over 30 years ago, a Snowy Owl was seen in Columbia, SC on the day one of our staff members was born! In fact, a very large irruption was reported in the 1920s, and irruptions have been reported even before then, and as far south as Florida. Irruptions do not tend to correlate with a lack of food up north, but with an abundance of food up north. Lemmings, the Snowy Owl’s main prey source, have a population boom every four years or so. In response, the Snowy Owls lay many more eggs, leading to a population boom of their own. When this happens, we see small irruptions, with “mega” irruptions once or twice a century.

To follow this year’s irruption, click on this link.