MUSKEGON, Mich. (WOOD) — Snowy white visitors from the high Arctic have been spotted in West Michigan this week, and scientists say there is a good chance we will see more than usual this year.
Worldwide, there are thought to be between 15,000 and 30,000 snowy owls. Each year, some owls choose to leave their homes in the Arctic and travel south. Unlike many migratory birds, snowy owls do not have a set migration pattern or destination. These owls are nomadic and mysterious.
WHERE TO SEE SNOWY OWLS
Each year, a few snowy owls decide to spend the winter in West Michigan. Muskegon is typically a popular resting place for snowy owls, according to local birders. Experts say snowy owls are most prone to finding wide open spaces that best resemble their breeding grounds to the north.
Scott Weidensaul, who works with a group called Project SNOWstorm, said it is usually young owls that make the journey south. Some have never before seen trees, buildings or roads. They often land near the Michigan lakeshore, near airports or in farmland. Snowy owls are used to the tundra, so they will choose to perch on the ground or a fence post rather than a tree.
John Ball Zoo Area Curator Dan Hemmann said snowy owls can be spotted hunting during the daylight hours.
“When you consider owls, you think of them hunting at night but when they are up in the Arctic circle, it’s daylight for 24 hours,” Hemmann said.
Weidensaul said snowy owls are like “little sunflowers,” constantly turning to face the sun as it rises and falls on the horizon.
WHY MORE OWLS ARE EXPECTED SOUTH THIS YEAR
Weidensaul said years that feature a big migration of snowy owls are called “irruption” years. The last irruption was in 2013-2014 and was the biggest in a century. The map below shows snowy owl sightings from that winter, courtesy of eBird.
Irruptions are difficult to predict, but according to Weidensaul are directly dependent on lemming populations in the Arctic. Snowy owls eat lemmings. Years with more lemmings typically lead to healthy, fat owls and a boom in breeding. This boost in owl populations usually leads to more young owls making the trek south into the States during the winter. In fact, most of the owls we see in Michigan are very young. Older owls tend to stay in the Arctic year-round since they are more experienced hunters.
Lemming populations usually follow predictable cycles, but recently have started to change or lengthen in some Arctic regions. Scientists say these shifts will likely change what we see during winter migrations since snowy owl breeding is so dependent on changes in lemming populations.
Project SNOWstorm is constantly uncovering new information on snowy owls. The group is comprised of volunteers and completely funded by public contributions.
Scientists work to tag snowy owls with a transmitter that records the bird’s movement. There have been about 50 birds tagged so far. Small, solar-powered sensors are placed on birds’ backs between the wings. Every time a tagged snowy owl flies south from the Arctic within range of a cellphone tower, there is a data download, sending scientists a day-to-day account of what that owl did while away in the Arctic.
Scientists who volunteer with Project SNOWstorm have also worked with airports to think of ways to deter the birds from landing near runways, like antiperch equipment on taxiway lights.
WHAT TO UNCOVER NEXT
Project SNOWstorm is hoping to uncover new secrets about the snowy owl’s diet and whether toxins are being ingested when flying south into the States.
Other birds of prey have been known to have rat poison in their bloodstream because of their diet of small mammals. Typically, birds with poison in their blood stream have sublethal levels. However, Weidensaul says the poison can lead to the birds bleeding to death.
Snowy owls that have been tested have shown that very few have rat poison in their bloodstream. However, they have come back as having high levels of mercury. This can lead to trouble with reproduction and impact bird behavior. The higher levels of mercury are theorized to be due to air pollutants. In other studies, freshwater locations have been known to have higher mercury air pollutant levels than saltwater environments.
This upcoming winter, Project SNOWstorm is hoping to figure out how a bird’s diet and location changes the amount of mercury found in its bloodstream.