[mou] State of Minnesota Owls - A New Year's Day perspective

[Alt, Mark]

I was asked by Dan Lockshaw, the editor and owner of owling.com, to
write up an article for his website explaining some of what has been
going on this year in MN. This article was my submission. I decided to
share it with everyone, there are many viewpoints represented here.
Special thanks to Tony Hertzel for proofing and editing the facts to
ensure they are, indeed, factual. What a great year to be a birder!
Happy New Year

The winter of 2004-05 is the winter of the Owls in Minnesota. The first
date for Great Gray Owl sightings called into the Minnesota
Ornithologists' Union (MOU) Rare Bird Alert was 17 August.  There were a
total of three August records, one September record and several more in
the first week of October. We cannot be sure these were not resident
birds. First report of Northern Hawk Owl was 3 October. This is not
assumed to be a resident bird. The first Boreal was banded on 17
October. Frank Nicoletti and Bill Lane were banding Boreal Owls along
Lake Superior's north shore this fall and began getting them in large
numbers, with more than 300 banded since October. The majority of netted
birds were healthy, not underweight, and female. This leads to
conjecture that this may be, at least in part, a natural dispersal of
females and not due to the result of stress from dwindling food
supplies. The male Boreal typically holds to his breeding territory
until stress induces him to move. A thick hard layer of ice or a crash
in the Red-backed Vole population - their primary food source - often
results in a Boreal Owl invasion year. Banding has been intensive this
year, so perhaps the influx of Boreals in good condition is not so
exceptional. Boreal Owls were still very hard to find away from the
banding nets as of New Year's Day. They are one of the most nocturnal of
owls, and Steve Wilson, DNR wildlife specialist, notes that Boreals not
yet found hunting in daylight suggests we do not yet have stressed
birds.=20
In November, large numbers of northern owls began hunting along roads in
central St. Louis County, especially in the Sax-Zim Bog area. Elements
contributing to stress can be different among Great Gray Owls (GGOW),
Northern Hawk Owls (NHOW), and Boreal Owls (BOOW). GGOW and NHOW use
microtine voles as the majority of their diet - primarily Meadow Voles.
When these rodent populations crash, this exerts stress on the owls. Dr.
James Duncan, of Winnipeg, has monitored small mammal populations in the
Roseau Bog area of northwestern Minnesota since 1986. The populations in
the fall of 2004 were the lowest recorded since 1992. Not
coincidentally, in the winter of 1991-92 what was then a record number
196 Great Gray Owls and a record 142 Northern Hawk Owls were reported in
Minnesota. In that same winter, only three Boreal Owls were noted. A
similar invasion appears to be happening this year. Meadow Voles breed
throughout the winter while tunneling under the snow.  They can breed at
two months of age, and with an adequate food supply and proper habitat
their numbers can explode. Red-backed Voles do not normally reproduce in
the winter, and prosper under a forest canopy which prevents the snow
from forming a hard crust.  Boreals are reported to have an affinity for
sheds and woodpiles, both great habitat for Red-backed Voles, Deer, and
White-footed Mice.=20

There have been over 1300 reports of GGOW, 200 NHOW, and 300 BOOW.  This
compares to last year's more typical numbers of 35 GGOW, 6 NHOW, and 1
BOOW.  This is indeed a banner year.  Without the banding, we may never
have known the magnitude of Boreal Owl movements this year. We are all
waiting to see what comes of this.  How far south will each species
travel?  Pine County and Aitkin County, about 70 miles south of Duluth,
each have areas where GGOW and NHOW are often seen each winter.=20

The Minnesota Ornithologists' Union (MOU) is looking for data on these
owls. It is important that as much data is collected as is possible.=20

A good record includes:
1.	A correctly identified species
2.	Date of observation
3.	A specific location. Locations are usually the weakest part of a
record. Observers might say "I saw this bird on highway 30 just past Mud
Lake". Problems with this kind of information would be, which Mud Lake?
There are more than 40 in the state. What kind of highway is "Highway
30"? The term "highway" could mean a state road, a county road, an
interstate, or a U.S. highway, and most everyone uses the term freely to
mean any one of those. If it is a county road, then they should use that
term. Simply saying "highway" is ambiguous and requires someone to take
the time to correctly interpret the information, so clarity and
certainty may be compromised. And finally, "just past Mud Lake" could be
greatly improved with exact mileage, GPS coordinates, or something more
specific.=20
4.	Observers' names and contact information

There is a data base of all known NHOW, GGOW, and BOOW records from this
season being collectively kept by the MOU. Records of sightings should
be emailed to the MOU at mou@cbs.umn.edu.

These great birds are now spread throughout the northern half of the
state of MN.  Sax-Zim was where the large numbers were first discovered,
but they have dispersed and are being seen elsewhere as well. The
numbers of birders driving and stopping on the roads, using scopes and
cameras in front of local residents' homes, has created stress on the
good people that live in this part of the state. If you get a chance to
visit, please come, but hook up with a guide or a member of the MOU to
find where to go. We need to lessen the burden of our birding soon on
this small area.=20


Mark Alt
President, Minnesota Ornithologists' Union
markfalcon@comcast.net
(Cell) 612-803-9085
Brooklyn Center, MN