BC-Yukon Nocturnal Owl Survey 2005

The BC-Yukon Nocturnal Owl Survey 2005

Boreal Owls continue to decline, Inside... Northern Saw-whets bounce back

Thanks to the owlers...... 2 Owl populations are difficult to monitor Playback results...... 3 because they often fluctuate from year to year Summary chart ...... 4 depending on the availability of their prey. These prey Lots of Saw-whets!...... 5 cycles can range from about 4 years in length for Trends in owl numbers...... 6 lemmings and voles to 10 years in length for snowshoe News and Notes...... 7 hares. Great Horned Owls, which depend on Snowies come south ...... 8 snowshoe hares over most of their range in Canada, hit rock bottom in northern BC and the Yukon about 2001, the second year of this survey, so we have a long way to go before we see what the top of the cycle looks like. Boreal Owls, on the other hand, are more of a vole specialist so have shorter cycles. We caught the boom of this cycle in 2002 and 2003 and are now getting to know what the bust part of the Boreal Owl cycle looks like (see page 6). Northern Saw-whet Owls specialize more in woodland species such as the deer mouse, which doesn’t cycle like its vole and lemming cousins, so population ups and downs are harder to predict. They do eat a lot of voles when they’re available (see page 5), but can survive handily on deer mice when the voles crash. This year 124 owlers carried out 118 surveys on 103 routes, stopping 1613 times in the darkness to listen for owls (see p. 4 for details). They detected 269 owls, an average of 1.67 owls per 10 stops, up nicely from last year’s figures of 238 and 1.35 respectively. These totals are still well below those in the banner year we had in 2003, however (383 owls, 1.67 per 10 stops). Most of the increase this year was in numbers of Northern Saw-whet Owls, which bounced back to 127 after a low of 84 last year. Twenty Boreal Owls were reported, down from 33 last year and the lowest total since the first year of this survey. Almost all of them were from the Cariboo region, where 10 were seen on the Skulow Lake route alone. ----Dick Cannings, survey coordinator

FLAMMULATED OWL SURVEY IN THE OKANAGAN-SIMILKAMEEN This year a special survey was organized for Flammulated Owls in the Okanagan-Similkameen, funded by the regional office of the BC Ministry of Environment. Eleven observers listened for the soft “boo-boot” of this tiny owl at 211 sites. While the nights are warmer in June than in March, the long days meant the participants had to stay out much Flammulated Owl; ph: Dick Cannings later at night than during the regular survey. The survey tallied 25 Flammulated Owls as well as nine Northern Saw-whet and three Great Horned Owls. Also of interest were 22 Common Poorwills, a species that is not monitored effectively by other means and listed as “Data Deficient” by COSEWIC. The Ministry of Environment will use the data to develop more accurate habitat models that will be used in recovery efforts.

Thanks to 124 owlers:

Kris Andrews, Cathy Antoniazzi, Libby Avis, Rick Avis, Ron Barre, Darren Bennett, Michael Bezener, Derek Bonin, Jack Bowling, Tom Brighouse, Doug Brown, Richard Cannings, Danielle Chalmers, Bob Chapman, Dan Clements, George Clulow, John Coffey, Paul Colton, Larry Cowan, Linnea Cross-Tallman, Loyd Csizmadia, Ed Dahl, Monica Dahl, Jonathan Darbyshire, Gary Davidson, Peter Davidson, Rick Dawson, Boris Dobrowolsky, Frank Doyle, Dan Dunlop, Helen Dunlop, Eva Durance, Lloyd Esralson, Carol Fairhurst, Uwe Finger, Dustin Ford, Brent Forder, Trevor Forder, Julie Frisch, Mark Gardiner, Steve Gartside, Dolly Gehlen, Phil Gehlen, Wayne Giles, Mike Gill, Sue Gower, Helmut Grunberg, Les Gyug, Larry Halverson, Willie Haras, Todd Heakes, Tony Heal, Daniel Helm, Dr. Charles Helm, Phil Henderson, Scott Herron, Neil Hughes, Steve Hunter, Andy Karassowitch, Gerald Kerr, Joan Kerr, Sandra Kinsey, Nancy Krueger, John Lambie, Vi Lambie, Laird Law, Maria Ledergerber, Wendy Marshall, Rachelle Martin, Sue McDonald, Sue McDonald, Darrel McEachern, Kathleen McEachern, Bob McKay, Roger Meyer, Michelle Mico, Bruce Morgenstern, Pearl Morgenstern, Bob Murkett, Gordon Neish, Laure Neish, Heather Neville, John Neville, Ann Nightingale, Mark O'Donoghue, Molly O'Donoghue, Ken Otter, Georgia Patterson, Larry Prosser, Basha Rahn, Anne Redfearn, David Reid, Trish Reid, Louise Richard, Gillian Richardson, Keith Riding, Margaret Riding, Laurie Rockwell, Marj Rodwell, Greg Ross, Madelon Schouten, Brian Scott, Roger Simms, Jessica Speed, Gail Spitler, Elsie Stanley, Glen Stanley, Alf Tallman, John Theberge, Mary Theberge, Russell Tkachuk, Irene Twiss, Helga Vrabac, Alan Vyse, Frances Vyse, Margaret Waring, Michaela Waterhouse, Wayne C. Weber, Rita Wege, Eve Whitehead, Doug Wilson, Chris Withers, Stuart Withers, Chris Wood

This juvenile Long-eared Owl was found by owl surveyor Bob McKay near Road 22, Oliver.

AN UPDATE ON THE PLAYBACK PROTOCOL FOR COASTAL OWL SURVEYORS

We’ve now used a playback protocol on the coast for two years. The protocol still has the two minutes of silent listening that all owl surveys across Canada employ, but this is followed by two bouts of Western Screech-Owl song with listening periods after each. We hoped that this playback would increase detection of screech-owls for obvious reasons, but also thought that Barred Owls might be attracted by the promise of food and other species such as Northern Saw-whet may simply get excited and call back to the sound of the screech-owl song. The chart below summarizes two years of data. It is clear that the playback (or at the very least the simple fact that owlers are at the stop for five minutes instead of two minutes) has increased detections, particularly of Western Screech-Owl and Barred Owl. Eleven of 12 screech-owls and 7 out of 10 Barred Owls were first heard after the playback started. However, most (14/17) Northern Saw-whet Owls were first heard before the playback started, typical of this species that tends to either call steadily through the night or be rather unresponsive. Barn Owls were first detected just as much after the playback as before, as is expected with a species that is usually seen or heard calling almost randomly as it forages over fields. It is disappointing to note that, while the protocol has apparently doubled the number of owls reported on the coast, detection rates there are still far below those in the interior.

Effect of Playback on Owl Response 30

25 before playback

after playback 20

10 Total Owls Detected Owls Total

0 BNOW WESO GHOW NPOW BDOW NSWO UNOW TOTAL

Barn Western Screech Great Horned N. Pygmy Barred Gr. Gray Long- eared Boreal N. Saw- whet TOTAL COAST 27 surveys Total Owls 3 9 1 1 4 0 0 0 5 23 Owls per 10 23 routes stops 0.11 0.32 0.04 0.04 0.14 0.00 0.00 0.18 0.81 # routes with species 2 6 1 1 4 0 0 0 4 SOUTH INTERIOR Total Owls 0 5 20 1 12 0 8 1 42 89 44 Owls per 10 surveys stops 0.00 0.08 0.32 0.02 0.19 0.00 0.13 0.02 0.67 1.42 # routes with 44 routes species 0 4 13 1 8 0 6 1 21 0 NORTH INTERIOR Total Owls 0 0 36 14 5 1 19 7 157 35 Owls per 10 surveys stops 0.00 0.00 0.51 0.20 0.07 0.01 0.27 1.14 2.23 # routes with 36 routes species 0 0 20 5 3 1 6 4

TOTAL Total Owls 3 14 57 1 14 5 8 20 127 269 118 Owls per 10 surveys stops 0.02 0.09 0.35 0.01 0.19 0.03 0.05 0.12 0.79 1.67 # routes with 103 routes species 2 10 34 2 17 3 6 7 43

Table 1. Owls reported on the survey in 2005. Species totals are given as birds per 10 stops so that direct comparison can be made among regions and years. Coastal routes are those west of the Coast-Cascade crest; Southern Interior counts are those from the Thompson, Nicola, Okanagan, Columbia and Kootenay valleys and adjacent plateaus; Northern Interior routes include those from the Cariboo-Chilcotin, Prince George, Mackenzie and Fort Nelson areas, the Bulkley Valley, and the Yukon. The number of surveys includes routes that were done more than once. Not shown in this table are singles of Northern Hawk Owl and Short-eared Owl reported from the Northern Interior.

LOTS OF SAW-WHETS!! In late November I went owling around my neighbourhood with Peter Davidson, Bird Studies Canada’s new Coastal Waterbird Survey Coordinator. Peter had never been owling in North America and was keen to see any of the local species. We tried going uphill for Boreal Owls, but an icy hill turned us around (literally), so we kept to lower elevations and whistled for Northern Saw-whet Owls. I was surprised to hear one or two at every place we stopped—and most of these sites I’d never heard an owl at before. So when it came to Christmas Bird Count (CBC) season I decided to do some serious owling on the Vaseux Lake count—I felt the Canadian CBC record of 26 saw-whets was reachable. The Vaseux Lake count circle has quite a few suitable owling roads—quiet, forested and plowed. I took the east side of the valley and my son Russell took the west side of the valley— he was helped initially by Chris Dale and Bill Sampson. We started at 7 p.m. and I quickly found two saw-whets up Irrigation Creek and three more along Shuttleworth Creek. I was happily surprised to hear a Western Screech-Owl calling along Shuttleworth Creek at a site we haven’t heard them at for years. At 11:30 p.m. I called Russell to see how had done—I had done my bit, with a total of 13 saw-whets, a screech and a Great Horned. Russell calmly commiserated with me on my bad luck—his group had a total of 38 saw-whets, four screech and 10 Great Horneds! With the addition of one saw-whet found during the day, the Vaseux count ended with an amazing total of 52, double the old record. Unfortunately we discovered that it was still short of the North American record of 61 reported from Massachussetts. Photo: Laure W. Neish W. Neish Laure Photo: So why were there so many owls out there? I noticed as I hiked the grasslands and pine forests on various Christmas counts in the southern interior that vole numbers were very high as well—their runways were everywhere and I was seeing several voles each day. So I suspect that as the saw-whets migrated south through the southern Interior they encountered all those mice and decided to stick around for the winter. Whether this will translate into increased numbers on the 2006 owl survey remains to be seen—but I’m looking forward to my routes!

5 Western Screech-Owl Trends in owl numbers 0.35

0.3 Here are the trends for the numbers Southern Interior of five common owl species reported since Coast 0.25 the survey began, presented in owls per 10

0.2 stops. Please note that the effect of playback has not been factored out of the 0.15

owls per 10 stops results from the coast for the past two years.

0.1 Boreal Owl

0.05 1.40

1.20 0 2000 2001 2002 2003 2004 2005 Northern Interior Year 1.00 Southern Interior 0.80

Great Horned Owl 0.60 Northern Interior owls per 10 stops 0.40 0.9 Southern Interior 0.20 0.8 Coast

0.00 0.7 2000 2001 2002 2003 2004 2005 0.6

0.5

0.4 Northern Saw-whet Owl Owls per 10 stops 0.3 2 Northern Interior 0.2 Southern Interior 1.8 Coast 0.1 1.6

0 1.4 2000 2001 2002 2003 2004 2005 1.2 1

0.8

0.6 Owls per 10 stops Owls per 10 Barred Owl 0.4 Southern Interior 0.2 Southern Interior 0.35 0 Coast

0.3 2000 2001 2002 2003 2004 2005

0.25

0.2

0.15

Owls per 10 Stops 0.1

0.05

0 2000 2001 2002 2003 2004 2005

This Great Horned Owl was roosting in a thick plantation of trees near Vernon. Photo: Don Cecile

6 NEWS AND NOTES

Western Screech-Owls studied along Shuswap River The Interior subspecies of the Western Screech-Owl, Megascops kennicottii macfarlanei, is listed as Endangered in Canada because of habitat loss. This owl is known to be strongly tied to riparian habitats such as cottonwood, birch and aspen stands, woodlands that have suffered as much as 80% loss in the core of the subspecies Canadian range in the Okanagan Valley. But while the birds clearly prefer to nest in riparian habitats, almost nothing is known about what habitats they use for hunting. This information is essential to recovery planning for the species, since if only riparian habitats are secured and restored, the screech-owl population may still decline if adjacent pine-fir woodlands are critical foraging habitat. To answer this question, biologists Helen Davis and Rich Weir of Artemis Wildlife Consultants are studying screech-owls along the Shuswap River using radio telemetry techniques. Initial results show the birds do use adjacent Photo: Dick Cannings conifer forests to a considerable extent.

Flammulated Owl found near Chilliwack in December An intriguing report has surfaced of a Flammulated Owl found injured in Sardis on December 1, 2005. The bird apparently hit a window and was taken to the O.W.L. rehab centre in Delta where unfortunately died. This is the latest fall record for a Flammulated Owl in Canada and the first record for the British Columbia coast.

In Memoriam: Phil Gehlen and Mary Collins The British Columbia birding community, and naturalists in Vernon in particular, lost two of their most active members in 2005 with the passing of Mary Collins in January and Phil Gehlen in December. Both Mary and Phil were mentors to all members of the North Okanagan Naturalists Club and had compiled the Vernon Christmas Bird Count for many years. Mary and Phil set up two routes for this owl survey and carried them out every year since its inception. They also partnered each May on a team in the Okanagan Big Day Challenge; failing health in recent years kept them to a Little Big day (4 a.m. to noon), but they were always enthusiastic about the event. . We will all miss them both.

7 SNOWY OWLS COME SOUTH AGAIN

Snowy Owls have come south in good numbers this winter, with birds scattered along the coast and even a few in the Interior (there was even one seen in downtown Penticton!). Snowy Owl expert Denver Holt of the Owl Research Institute thinks that this push southward is due to a good breeding year on the Alaskan tundra. Denver has studied the birds for many years at Barrow, and claims this year was the best year for breeding he’s seen, and lemming numbers were at record highs as well. So he suggests that the high

Photo: Ralph Hocken production of young has forced many of the immature birds south to seek out winter foraging grounds. They concentrate on the BC coast, where there are abundant ducks and other waterbirds that wintering Snowy Owls prefer. Nonetheless, some of these young birds have a hard time surviving their first winter as they must hone their hunting skills by themselves. You can read more about the Owl Research Institute at their website: http://www.owlinstitute.org/research.html. It’s already 2006… Participants will be getting their 2006 BC Nocturnal Owl Survey packets by email before the end of January. I plan to post the proper datasheets on the Bird Studies Canada website, so check there if you accidentally delete my email message! Surveyors without internet access will be getting paper forms as usual. Many thanks for your work on this survey over the years! --Dick Cannings

BC-Yukon Nocturnal Owl Survey Bird Studies Canada 1330 Debeck Road S11, C96, RR#1 Naramata, BC V0H 1N0 1-250-496-4049 [email protected] www.bsc-eoc.org