Nature Notes for November 24, 2017
“There’s a Snowy Owl on the roof of the house across the street.” said the voice on the telephone last Sunday. The caller was excited enough that I had to ask, “What street?” It was only a few blocks away, so my husband and I jumped into the car to look for it. (It’s not difficult to distract us from yard clean-up.)
We found the bird without difficulty and had a good look through binoculars. Unlike the two Snowy Owls that had turned up at Cobourg Harbour breakwater the week before, a spotting scope was not necessary to have a good look. At least one Snowy has also been reported from Presqu’ile this week.
There seems to be an irruption of Snowy Owls into southern latitudes this year.
Photo © Rob Lonsberry Photography
Why this bird had chosen to land in a built-up part of town is a mystery. There didn’t seem to be any obvious hunting area there. Perhaps the bird was just tired from bucking the wind. Because Snowy Owls nest in the Arctic, where there is no night in the summer, they are as apt to be active in the daytime as at night.
Snowy Owls are an irruptive species. That is, they sometimes move out of their regular range in search of food. In the case of the owls, a high population of lemmings on the breeding ground may lead to more young birds than usual being raised. When winter comes there may not be enough food for all these birds. Some of the Snowy Owls will irrupt south in search of food.
In the south, Snowy Owls eat rodents, rabbits and many wintering ducks and gulls. Some spend a lot of time on the edge of the ice in the Great Lakes in order to hunt ducks. Four years ago, when there was a massive irruption of Snowy Owls into the south, the Ontario Ministry of Natural Resources was collecting owl pellets to determine just what the owls were eating. Pellets are the undigested parts of the prey – bones, fur, feathers – that the owls cough up. Many pellets can often be found around favourite roosts. By dissecting the pellets, the prey can be identified. I never heard the results of the MNR study.
That same winter, 20013/14, saw an irruption of Snowy Owls to the south like no one had observed in 50 years. This led to the formation of Project SNOWstorm, a group of scientists who decided to take advantage of this event to study the birds. (SNOW is the code that bird banders use for Snowy Owl.) They teamed up with an IT team to create a small GPS transmitter which an owl could wear on a harness. These small devices are powered by a solar battery. Last winter’s cloudy weather did slow the units a bit, since they never fully charged. As long as the owl was within range of a cellphone tower, the information could be retrieved.
The transmitters have evolved since that first year to be lighter and collect more data. Many remote northern communities have been installing cellphone towers, which has helped in the retrieval of data from the north. However, these amazing machines can store data. If an owl returns to the south in a subsequent winter, the data from the previous summer can be downloaded. A number of the birds have come back south
Although some of the people involved in Project SNOWstorm are professional biologist, for this project they are volunteering their time. There are many avocational biologists involved, too. The project has been funded by crowdfunding and by donations from naturalist groups.
Just this week, I received two posts from Project SNOWstorm. Snowy Owls are returning to the south in higher than usual numbers and they are anticipating a large irruption. To follow the project, check out http://www.projectsnowstorm.org/
Remember to carry your binoculars if you go for a walk by Cobourg Harbour. You may find a Snowy yourself.
Before the December column is published, several Christmas Bird Counts will have been held. There are three in Northumberland County, dates as follows:
●Port Hope-Cobourg CBC, Sat., Dec. 16, 2017
●Presqu’ile-Brighton CBC, Sun., Dec. 17, 2017
●Rice Lake Plains CBC, Mon., Jan. 1, 2018
Christmas Bird Counts are not actually held on Christmas Day, but from December 14 to January 5. Each count covers a specific geographic area. For more information about Christmas Bird Counts, go to http://www.birdscanada.org/volunteer/cbc/.