[mou] State of the state of MN Owls version 4 - Manitoba's Steve Loch data and findings

Alt, Mark Mark.Alt@bestbuy.com
Wed, 2 Mar 2005 08:39:44 -0600


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Steve Loch puts together a lot of the pieces of the puzzle here to show
us how much an integral part of the Great Gray Owl's natural history
irruption into Minnesota is. MN born birds can be expected to travel to
the Hudson lowlands through the Canada Shield Forest within a normal
life cycle? Even our Boreal birds in MN are not just "our" birds. I hope
you enjoy this piece, Good Birding

Mark Alt

MOU President

markfalcon@comcast.net

612-803-9085

=20

Mark,

Recently, I happened to read a bit of your writing concerning Great Gray
Owls in Minnesota (the 2004-05 event, "year of the owls") and, as a
result, thought you might be interested in some selected data respecting
documented Great Gray Owl movements pertinent to our part of the
continent, i.e., northern Minnesota, Manitoba, and Ontario.  I collected
these data while working with Bob Nero of the Manitoba MNR-Wildlife
Branch and as project leader for the Manitoba Great Gray Owl radio
telemetry study, which was initiated in 1984 and designed to investigate
the significance of nesting habitats in the extreme SE portion of the
Province, roughly from Spruce Siding south into northern Roseau County,
MN.  Ultimately, our objective was to determine the lifetime habitat
requirements of the owls.

Specifically, these movements occurred after the reproduction phase of
the 'owl-vole cycle' in the southern region.  The "southern region" that
I refer to is roughly defined as those habitats that are regularly used
by Great Gray Owls in northern Minnesota and SE Manitoba for nesting and
that are south or west of the prominent Canadian Shield forests.  In the
southern region, certain types of swamp habitat (tamarack,
tamarack/black spruce, black ash, and others) are of particular
significance to the owl.  Canada bluejoint (Calamagrostis Canadensis)
meadows or other open habitats, e.g., flowage openings along streams are
also important.  Other ecological regions used by the owls are the
Shield forests, Hudson Bay lowlands, and the ecotone that exists between
the Shield forests and the lowland taiga.  All regions appear to be
important to the population and are apparently used by at least certain
individuals of the population on multiple occasions during their
lifetime.

In 1984, I radio marked 28 nesting adult Great Gray Owls and some of
their progeny in SE Manitoba during spring and summer.  During the
subsequent fall, winter, and spring, I attempted to document their
movements.  Presented here are selected records of velocity and distance
traveled.=20

Like all other radio-marked owls in the study, after the nesting season
of 1984, an adult female commenced exploratory type movements.  I
located this individual with aircraft on 12/23/84 while she was hunting
open habitats near a forest edge, 41 km south of where she had been
located on the previous day.

Like most other surviving owls in the sample, this same female
eventually emigrated from the southern region.  After an extended period
without radio contact, occurring after 3/29/85, her signal was heard
again over the Hudson Bay lowlands on 6/27/85.  On 6/30/85, an aerial
fix located her in the hinterlands of Ontario, ~ 63 miles SSE of
Shamattawa, Manitoba.  Thus, this documented a 705 km movement in 90
days or less. Based on the timing of earlier search flights conducted
for this transmitter and others, it is quite likely that most of the
movement occurred in a shorter period of time. She was fixed again near
this same location on 7/18.  (The location is roughly 135 miles south of
York Factory, which is located on the Hudson Bay coast, and 150 miles
WSW of Fort Severn, also located near the coast.) =20

Another female emigrated SE Manitoba after 2/17/85.  She was located
well northeast of the study area on 3/21/85 in Ontario north of McDowell
Lake.  This represents a movement of roughly 240 miles in just over a
month's time.  By 4/15, she was found near Muskrat Dam Lake on the
Severn River (approximately 50 miles SW of Big Trout Lake) where she
resided into the summer.  This documented a 528 km movement, which
occurred in 57 days or less.  She was fixed in this home range again on
5/23 and 6/25, and ground checked on 6/26.  Her locations as well as
visual observations indicated that if nesting occurred, it was
unsuccessful.


Documenting movements of SE Manitoba gray owls was an important aspect
of the study.  During the course of earlier work, Nero and I had
determined that the southern peatlands across northern Minnesota and in
SE Manitoba were important nesting areas for Great Gray Owls.  We were
also aware that after cyclic declines in vole populations, most nesting
Great Gray Owls and their progeny would likely emigrate to northern
locales.  This awareness is intuitive, but also existed because I had
previously observed such movement during a study conducted in Minnesota.
In that study, focused primarily in northern Aitkin County, 38 nesting
adult and juvenile gray owls were radio marked, most prior to October
1980.  Though vole abundance supported ample reproduction in a 50 km2
study area during the nesting seasons of 1979 and 1980, nearly total
emigration of the surviving radio marked population occurred after
various exploratory movements in the winter of 1980-81.  This emigration
was primarily directed northward and some individuals commenced movement
as early as mid winter after vole populations crashed, e.g., 5 owls
relocated within 60 miles of Ignace, Ontario.  The greatest movement
recorded for the 1980-81 emigrations was roughly 260 miles.  This owl
summered ~ 40 km northeast of Sioux Lookout.  However, movements of
greater distances possibly occurred, as radio contact with several
transmitters was lost.  These were not located, despite considerable
effort to search major areas in most regions of northwestern Ontario.


I have copied a few others as I think they might also be interested in
this info.


Steve Loch


PS:  Jim Duncan continued to collected data using radio telemetry in the
Manitoba GGO study on through 1991, not only in Manitoba but in
Minnesota and Ontario as well.  I believe Jim radio marked another 75
owls before that phase of the study was complete, thus 103 owls were
radio marked in the Manitoba study alone.  More than 140 radio-marked
owls have provided data for the insights that Jim, Bob Nero, myself, and
others have acquired.  As you might be aware, Jim continued his work and
now has more than 20 years of data from the Manitoba SAs. =20

Comments by Mark Alt:
=20
705 km in 90 days is 438 miles, an average movement of 5 miles. 528 km
in 28 days is 328 miles , an average movement of 11.7 miles. To move 41
km in a day equates to more than 25 miles moved in a a single day.
=20

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<DIV>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005>Steve Loch puts together a lot of the pieces =
of the=20
puzzle here to show us how much an integral part&nbsp;of the&nbsp;Great =
Gray=20
Owl's natural history irruption into Minnesota is. MN born birds can be =
expected=20
to travel to the Hudson lowlands through the Canada Shield Forest within =
a=20
normal life cycle? Even our Boreal birds in MN are not just "our" birds. =
I hope=20
you enjoy this piece, Good Birding</SPAN></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005>Mark Alt</SPAN></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005>MOU President</SPAN></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005><A=20
href=3D"mailto:markfalcon@comcast.net">markfalcon@comcast.net</A></SPAN><=
/SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005>612-803-9085</SPAN></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005></SPAN></SPAN>&nbsp;</P>
<P class=3DMsoNormal><SPAN=20
style=3D"FONT-SIZE: 11pt; FONT-FAMILY: Arial">Mark,</SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">Recently, I=20
happened to read a bit of your writing concerning Great Gray Owls in =
Minnesota=20
(the 2004-05 event, "year of the owls") and, as a result, thought you =
might be=20
interested in some selected data respecting documented Great Gray Owl =
movements=20
pertinent to our part of the continent, i.e., northern Minnesota, =
Manitoba, and=20
Ontario.<SPAN>&nbsp; </SPAN>I collected these data while working with =
Bob Nero=20
of the Manitoba MNR-Wildlife Branch and as project leader for the =
Manitoba Great=20
Gray Owl radio telemetry study, which was initiated in 1984 and designed =
to=20
investigate the significance of nesting habitats in the extreme SE =
portion of=20
the Province, roughly from Spruce Siding south into northern Roseau =
County,=20
MN.<SPAN>&nbsp; </SPAN>Ultimately, our objective was to determine the =
lifetime=20
habitat requirements of the owls.</SPAN></P>
<P class=3DMsoNormal><SPAN=20
style=3D"FONT-SIZE: 11pt; FONT-FAMILY: Arial">Specifically, these =
movements=20
occurred after the reproduction phase of the 'owl-vole cycle' in the =
southern=20
region.&nbsp; The &#8220;southern region&#8221; that I refer to is =
roughly defined as those=20
habitats that are regularly used by Great Gray Owls in northern =
Minnesota and SE=20
Manitoba for nesting and that are south or west of the prominent =
Canadian Shield=20
forests.&nbsp; In the southern region, certain types of swamp habitat =
(tamarack,=20
tamarack/black spruce, black ash, and others) are of particular =
significance to=20
the owl.<SPAN>&nbsp; </SPAN>Canada bluejoint (<I>Calamagrostis =
Canadensis</I>)=20
meadows or other open habitats, e.g., flowage openings along streams are =
also=20
important.<SPAN>&nbsp; </SPAN>Other ecological regions used by the owls =
are the=20
Shield forests, Hudson Bay lowlands, and the ecotone that exists between =
the=20
Shield forests and the lowland taiga.&nbsp; All regions appear to be =
important=20
to the population and are apparently used by at least certain =
individuals of the=20
population on multiple occasions during their lifetime.</SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">In 1984, I=20
radio marked 28 nesting adult Great Gray Owls and some of their progeny =
in SE=20
Manitoba during spring and summer.&nbsp; During the subsequent fall, =
winter, and=20
spring, I attempted to document their movements.&nbsp; Presented here =
are=20
selected records of velocity and distance traveled<SPAN=20
class=3D632251614-02032005>. </SPAN></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial"><SPAN=20
class=3D632251614-02032005></SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 11pt; FONT-FAMILY: Arial">Like all other =
radio-marked owls in=20
the study, after the nesting season of 1984, an adult female commenced=20
exploratory type movements.&nbsp; I located this individual with =
aircraft on=20
12/23/84 while she was hunting open habitats near a forest edge, 41 km =
south of=20
where she had been located on the previous day<SPAN=20
class=3D632251614-02032005>.</SPAN></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">Like most=20
other surviving owls in the sample, this same female eventually =
emigrated from=20
the southern region.&nbsp; After an extended period without radio =
contact,=20
occurring after 3/29/85, her signal was heard again over the Hudson Bay =
lowlands=20
on 6/27/85.&nbsp; On 6/30/85, an aerial fix located her in the =
hinterlands of=20
Ontario, ~ 63 miles SSE of Shamattawa, Manitoba.&nbsp; Thus, this =
documented a=20
705 km movement in 90 days or less. Based on the timing of earlier =
search=20
flights conducted for this transmitter and others, it is quite likely =
that most=20
of the movement occurred in a shorter period of time. She was fixed =
again near=20
this same location on 7/18.<SPAN>&nbsp; </SPAN>(The location is roughly =
135=20
miles south of York Factory, which is located on the Hudson Bay coast, =
and 150=20
miles WSW of Fort Severn, also located near the coast.)&nbsp; =
<?XML:NAMESPACE=20
PREFIX =3D O /><O:P></O:P></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">Another=20
female emigrated SE Manitoba after 2/17/85.&nbsp; She was located well =
northeast=20
of the study area on 3/21/85 in Ontario north of McDowell =
Lake.<SPAN>&nbsp;=20
</SPAN>This represents a movement of roughly 240 miles in just over a =
month's=20
time.&nbsp; By 4/15, she was found near Muskrat Dam Lake on the Severn =
River=20
(approximately 50 miles SW of Big Trout Lake) where she resided into the =

summer.&nbsp; This documented a 528 km movement, which occurred in 57 =
days or=20
less.&nbsp; She was fixed in this home range again on 5/23 and 6/25, and =
ground=20
checked on 6/26.&nbsp; Her locations as well as visual observations =
indicated=20
that if nesting occurred, it was unsuccessful<SPAN=20
class=3D632251614-02032005>.</SPAN><BR></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">Documenting=20
movements of SE Manitoba gray owls was an important aspect of the =
study.&nbsp;=20
During the course of earlier work, Nero and I had determined that the =
southern=20
peatlands across northern Minnesota and in SE Manitoba were important =
nesting=20
areas for Great Gray Owls.&nbsp; We were also aware that after cyclic =
declines=20
in vole populations, most nesting Great Gray Owls and their progeny =
would likely=20
emigrate to northern locales.&nbsp; This awareness is intuitive, but =
also=20
existed because I had previously observed such movement during a study =
conducted=20
in Minnesota.&nbsp; In that study, focused primarily in northern Aitkin =
County,=20
38 nesting adult and juvenile gray owls were radio marked, most prior to =
October=20
1980.&nbsp; Though vole abundance supported ample reproduction in a 50=20
km<SUP>2</SUP> study area during the nesting seasons of 1979 and 1980, =
nearly=20
total emigration of the surviving radio marked population occurred after =
various=20
exploratory movements in the winter of 1980-81.<SPAN>&nbsp; </SPAN>This=20
emigration was primarily directed northward and some individuals =
commenced=20
movement as early as mid winter after vole populations crashed, e.g., 5 =
owls=20
relocated within 60 miles of Ignace, Ontario.&nbsp; The greatest =
movement=20
recorded for the 1980-81 emigrations was roughly 260 miles.<SPAN>&nbsp;=20
</SPAN>This owl summered ~ 40 km northeast of Sioux Lookout.&nbsp; =
However,=20
movements of greater distances possibly occurred, as radio contact with =
several=20
transmitters was lost.<SPAN>&nbsp; </SPAN>These were not located, =
despite=20
considerable effort to search major areas in most regions of =
northwestern=20
Ontario.<BR></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">I have=20
copied a few others as I think they might also be interested in this=20
info.<BR></SPAN></P>
<P class=3DMsoNormal><SPAN style=3D"FONT-SIZE: 11pt; FONT-FAMILY: =
Arial">Steve=20
Loch<BR></SPAN></P><SPAN=20
style=3D"FONT-SIZE: 11pt; FONT-FAMILY: Arial">PS:<SPAN>&nbsp; </SPAN>Jim =
Duncan=20
continued to collected data using radio telemetry in the Manitoba GGO =
study on=20
through 1991, not only in Manitoba but in Minnesota and Ontario as=20
well.<SPAN>&nbsp; </SPAN>I believe Jim radio marked another 75 owls =
before that=20
phase of the study was complete, thus 103 owls were radio marked in the =
Manitoba=20
study alone.<SPAN>&nbsp; </SPAN>More than 140 radio-marked owls have =
provided=20
data for the insights that Jim, Bob Nero, myself, and others have=20
acquired.<SPAN>&nbsp; </SPAN>As you might be aware, Jim continued his =
work and=20
now has more than 20 years of data from the Manitoba SAs.<SPAN>&nbsp;=20
</SPAN></SPAN></DIV><?xml:namespace prefix =3D o ns =3D=20
"urn:schemas-microsoft-com:office:office" /><o:p><SPAN =
class=3D632251614-02032005>
<DIV><BR><FONT face=3DArial size=3D2>Comments by M<SPAN=20
class=3D632251614-02032005>a</SPAN>rk Alt:</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><SPAN class=3D632251614-02032005><FONT face=3DArial size=3D2>705 km =
in 90 days is=20
438 miles, an average movement of 5 miles. 528 km in 28 days is 328 =
miles , an=20
average movement of 11.7 miles. To move 41 km in&nbsp;a day equates to =
more than=20
25 miles moved in a a single day.</FONT></SPAN></DIV>
<DIV></SPAN></o:p>&nbsp;</DIV></BODY></HTML>

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