The Owls of April - 2012 edition

Last night we filled our Thermoses with hot chocolate and headed out to Ontario Nocturnal Owl Survey Route # 67, along a logging access road west of Marathon.  This particular route has been monitored for about 12 years. We've surveyed it for two of the last three years.

We were about half way to our first listening station when we spotted a Great Gray Owl perched beside the highway. The bird was very actively hunting - perching and plunging along the cut line below the hydro line - perhaps not the safest hunting territory, so close to the Trans-Canada.

We spent only a few minutes watching the owl before we headed on, eager to see in the remaining daylight how our survey route along the disused logging road had fared since we'd driven it last September.

A half an hour later we arrived at the start of the route. 'Though dry and dusty with a few holes and stretches of washboard, the road was serviceable. With 40 minutes to spare, we broke out the hacky sack and refreshments while a nearby Winter Wren sang his heart out in the gathering darkness...

Two and a half hours and twenty stops later we'd tallied six Northern Saw-whet Owls and four Great Horned Owls. We were surprised not to hear Boreal Owl, a species that's usually detected on this route. Black Bear, Beaver, Red Fox, American Woodcock, Wood Frog, Spring Peeper and the northern lights were also active. It was an excellent way to spend a Friday evening in April.

Here's an excerpt from most recent Ontario Nocturnal Owl Survey newsletter (pdf) summarizing the 2011 results:

"The most productive route in Northern Ontario this year was Melissa Mosley’s Highway 600 route near Rainy River. This route had a total of 22 owls including 16 Northern Saw-whet Owls and 6 Barred Owls. Hart Brasche’s Clear Lake Road route was the most productive in Central Ontario with 23 owls detected, including 16 Barred Owls, 5 Northern Saw-whet Owls and 2 Great Horned Owls.

Several owl species showed substantial increases across Northern Ontario in 2011. Whereas every species, except the Great Horned Owl, were detected in fewer numbers across Central Ontario in 2011. The Barred Owl was once again the most common owl detected with 448 recorded, down slightly from the 473 reported last year. Northern Saw-whet Owls showed another big increase in numbers this year with 202 reported, up from 139 in 2010. The Great Gray Owl was up again in 2011 with 37 detected, up from 28 individuals in 2010. Finally the Boreal Owl showed a slight increase of 103 individuals detected, up from 94 last year."

Because the GGOW had been sighted repeatedly at this locale over the last month, we supposed that it might have a mate and a nest nearby. A close look at this photo; however, reveals the pointed tips to the tail feathers indicating that this bird hatched in 2011 and won't breed until it matures, likely not before 2014.

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Nocturnal Owl Survey Program coordinated by Bird Studies Canada.

The owls of April

Northern Saw-whet Owl, Lappe, April 7, 2010. Photo courtesy Aarre Ertolahti (see story below).

Last Friday we filled our Thermoses with hot chocolate and headed out to Nocturnal Owl Survey Route # 67, along a logging access road west of Marathon. The route consists of 20 stops evenly spaced along 35 km of rough road. At each stop, we would spend five minutes listening for owls before and after we broadcast calls of Boreal and Great Gray Owls. We would then record the number, approximate distance, direction and duration of all owl species heard. This is a standardized protocol that enables researchers to monitor trends in owl populations across the country. This particular route has been monitored for about 10 years.

Martha, Nolan, Wayne and I met up in a clearing just north of the first stop. Conditions seemed ideal - only a slight breeze, a clear sky the temperature just above freezing. Wayne reported that he'd heard a Great Horned Owl minutes before and soon we heard the distinctive calls of both Boreal and Northern Saw-whet Owls. It was 9:10 pm; time to start the survey.

During our first eight stops we heard only a few nocturnal creatures. A male American Woodcock was displaying and calling overhead at Stop 3 and at several other stops we heard choruses of Spring Peepers and Wood Frogs, but no owls. It wasn't until 10:20 pm, at Stop 9, that we heard our first official owl of the night, a Northern Saw-whet, calling continually from the Jack Pine stand a few hundred metres to the NE. We would hear more owls - Great Horned, Northern Saw-whet and Boreal - at seven of the next ten stops. The tally for the night, including four owls heard outside of the listening intervals, was:

Northern Saw-whet Owl: 5
Boreal Owl: 3
Great Horned Owl: 4
Unidentified (perhaps Long-eared): 1

Of the nine owls we tallied during the actual monitoring & playback intervals, eight were detected during the first two "listening" minutes, before we broadcasted any recorded calls. In terms of relative abundance, our results closely match the totals from the 2009 monitoring season as reported in the annual newsletter (PDF):

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2009 Survey totals for Northern Ontario

Species	Individuals	Routes
Northern Saw-whet	72	33
Boreal	71	28
Great Horned	27	18
Great Gray	21	11
Barred	19	11
Long-eared	12	10
Northern Hawk	1	1
Short-eared	1	1
Unknown	10	10

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We had an excellent time and we all look forward to another late night of hot chocolate and owls in April of 2011.

Here are some results from the past week for other survey routes in NW Ontario:

• April 4: Gorham-Ware Twp (w. of Thunder Bay) - Northern Saw-whet: 5; Great Horned: 1; Barred: 2; Unidentified: 2.

• April 11: Hwy 627-Heron Bay - Barred: 1; Northern Saw-whet: 1.

• April 12: Hwy 11 near MacDiarmid - Northern Saw-whet: 1; Boreal: 6; Great Horned: 1.

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Lappe resident Aarre Ertolahti generously shared the above photo of a Northern Saw-whet Owl. Aarre wrote:

When I was doing surveys for the Atlas of the Breeding Birds of Ontario a few years ago, I decided to check all the tree cavities around my place by tapping on the tree trunks and then checking for any activity. I found several species of nesting birds as well as a Flying Squirrel. The best find was a Saw-whet Owl occupying an old Flicker nest cavity. I saw a juvenile NSWO at the opening a couple of weeks later. Ever since then, every spring I have tapped on a few trees with large cavities made by Flickers or Pileated Woodpeckers, to see if I could find another nesting Saw-whet. Last week I found one, very close to our house, occupying a cavity that was used by Pileated Woodpeckers last summer.

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Related:
Ontario Nocturnal Owl Survey (Bird Studies Canada).