[mou] Great Gray Owls, remarks on 2005-2006

[Holly Peirson]

Jim:

Thanks so much for asking these questions! The responses are very
interesting, both from the standpoint of owl breeding biology, and from the
aspet that we might enjoy their company this winter also. I hope they can
find enough to eat here, and that we don't see as high a mortality rate as
we did last year...

BTW: last night and this AM, I had at least two, possibly more Great Horned
Owls calling near my house. I usually only hear them a couple of times
during the year, usually at breeding season. This seems early for that,
maybe they were just establishing territories... Fun to hear them, though!!

Holly Peirson
Forest Lake, Anoka Co.

-----Original Message-----
From: mou-net-admin@cbs.umn.edu [mailto:mou-net-admin@cbs.umn.edu]On Behalf
Of Jim Williams
Sent: Wednesday, November 09, 2005 8:49 PM
To: MOU-net
Cc: MnBird
Subject: [mou] Great Gray Owls, remarks on 2005-2006

Today, I posed some Great Gray Owl questions to Dr. James Duncan, the
Winnipeg owl researcher who also does work in Roseau County. Here is
the exchange.
Jim Williams
Wayzata

====

Hi Jim,

Good to hear from you.  I attempted to answer your questions below in
CAPS the best I can, recognizing that the information I am providing is
not from the main MN owl invasion area. Things could be quite different
there regarding great grays and meadow voles compared to Roseau County
and southern Manitoba!

Cheers, Jim
________________________________________
Dr. James R. Duncan, Manager
Biodiversity Conservation Section
Wildlife and Ecosystem Protection Branch
Manitoba Conservation
Box 24, 200 Saulteaux Crescent
Winnipeg, MB R3J 3W3
Wildlife Web Site  www.manitoba.ca/conservation/wildlife
CDC Web Site  http://web2.gov.mb.ca/conservation/cdc/


Can we expect the owls to return in numbers this winter?
YES - OUR LONG-TERM WINTER DATA SUPPORT WHAT I CALL AN "ECHO EFFECT",
IN WHICH THE ONLY SIGNIFICANT TIME SERIES CORRELATION IN WINTER NUMBERS
OF GREAT GRAY OWLS FROM YEAR TO YEAR IS THAT IN THE YEAR IMMEDIATELY
AFTER AN INVASION/IRRUPTION YEAR, THERE IS TYPICALLY HALF AS MANY GREAT
GRAY OWLS AS THE INVASION/IRRUPTION YEAR.

How did the owls fair on the breeding territories this spring and
summer? Was their a normal pattern of breeding? Did the birds enjoy
breeding success?
NO GREAT GRAY OWLS NESTING IN THE NEST STRUCTURES I MONITOR IN MB AND
ROSEAU COUNTY, MN, IN SUMMER 2005.

How is the prey population for these birds, spring, summer, and present?
I ONLY MONITOR SMALL MAMMALS ONCE A YEAR (OCTOBER) IN MY MB AND MN
(ROSEAU COUNTY) STUDY AREAS, AND ONLY IN HABITATS WHERE GREAT GRAY OWLS
ARE KNOWN TO HUNT.  THE GREAT GRAYS IN MY STUDY AREA  EAT >90% MEADOW
VOLES, THEREFORE I AM COMMENTING ON NUMBERS OF THAT PREY SPECIES ONLY.
THIS YEAR THE NUMBER OF MEADOW VOLES ON MY STUDY AREAS WERE STILL VERY
LOW, BUT APPEAR TO INCREASING SLOWLY, A NORMAL PATTERN.  I EXPECT
MEADOW NUMBERS IN MY STUDY AREA TO BE MORE NUMEROUS NEXT YEAR, AND
COINCIDENTALLY TO HAVE OWLS NESTING IN 2006.

What other comments might you offer?
THE RESULTS OBSERVED ON OUR STUDY AREAS SHOW A NORMAL CYCLIC PATTERN OF
THE FLUCTUATIONS IN THE NUMBER OF BREEDING GREAT GRAY OWLS AND THEIR
TYPICAL PREY, THE MEADOW VOLE.

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