[mou] 2-5-05 Aitkin County Owl Field (Long)

[Alt, Mark]

February 9th found me headed for Aitkin County with Peter Neubeck to
videograph Owls and capture some behaviors.  What a day! We saw 2
Rough-Legged Hawks, a Northern Shrike, and 6 Red-Tailed Hawks on the way
to Aitkin County. No Owls until we were 1 mile inside Aitkin County on
Hwy 65, then they came regularly. It was not our mission to see how many
Owls, but I GPS'd all sightings. We saw between 60 and 70 Great Gray
Owls this day.=20
Our destination was a field Bonnie Mulligan and Charlie Greenman had
surveyed Saturday; where they and Peter had counted 9 Great Grays Owls
in it at one time. We headed up Hwy 65 past McGrath, past the Hwy 27
turnoff, then turned left on County Road 4. We had seen 12 Great Gray
Owls by then. We drove 4.3 miles to the field, which lies directly south
of Rice Lake. It stretches a mile along the road and is about a half
mile deep, I estimate it to be about 300 acres in size. It stretches
along the Southern Side of Cty Rd 4, its openness broken in two spots by
a windbreak and a house surrounded with large trees and a barn. Owls
were perched everywhere.  Peter and I estimate 21 Great Gray Owls in
this field alone. We could see 12 at one time west of the windbreak, and
had just counted 9 east of the windbreak a moment before. Owls were seen
flying deep into the woods and others would suddenly appear from the
woods. There could easily be many more than we counted. We stayed at
this field to videograph for 50 minutes. Owls were in the air nearly
constantly in that timeframe. We witnessed 5 plunges into the snow, we
saw Owls standing on the ground, perched on the barn, multiples in a
single tree, on telephone poles, on fence posts, atop a birch or spruce,
midway up a large spruce, etc., etc. They were visible around the entire
perimeter of the 300 acres and were rather regular in their spacing.
Bring a scope, this is not the pull up and look at a roadside Owl, you
can only see 6 or 7 that way here. A scope is in order to see how many
are around further out. The closest two we saw was a pair in the same
tree, 15 feet apart, others seems to maintain a 50 yard distance pretty
regularly.=20
It was cold out - 20 degrees, yet we bundled up and filmed in one spot
for a long time, panning the field, when we heard an Owl on a telephone
pole 80 feet away give a "whulp" call, the muffled low hoot of a Great
Gray Owl, delivered in a hushed conversational tone, so we barely heard
it. At least one other Owl answered from, the windbreak area, my
impression is I heard 3 separate Owls from this spot. I wouldn't call it
a duet; it was more of a conversation, but of single, disparate hoots.
It lasted less than 30 seconds and it was only after standing still for
more than half an hour that we heard it. The 4:00PM traffic picked up
and it made things hard to hear, so we moved on, and found more owls
awaiting us as we moved west. We came upon a Great Gray perched at eye
level at one point, where the road goes down to a valley on the right.
Peter's big camera started rolling, and from 50 feet away, with Peter's
car as a blind, we watched as this bird started vocalizing.  The bird
looked about, stared at another Owl 75 yards away, rocked forward
slightly, raised its tail an inch, its abdominal/chest area heaved
slightly, and out came a "whulp", the low breathy hoot of a great Gray
Owl. How to describe it? You know I had to try!  Its tone had
breathiness and a lack of volume reminding me of a tenor trying to sing
bass cleft lower register. At this close range, there was a glottal
quality to its start and finish similar to calls I have heard from
Turkeys as they strut or a really close Whippoorwill before it calls. I
do not know the exact physics of the calling, but I presume the bird
builds pressure, releases and closure its air path, eliciting a single
toned note of less than 1 second, the stopping and starting creating the
glottal noises. Cool to see and hear in daylight; really good to see on
tape, as well, especially when Peter tapes it. Tony Hertzel believes
these are "contact calls", possibly solicitation for a prospective mate,
to show interest, to try and inspire a response.=20
Other behaviors, observations, questions and thoughts:
*	Birds changed position, but when they did, they keep their
distance as they traversed the field. Only one observation where a Great
Gray gave a start and lifted all it feathers on edge. I could not see
anything it was defending, but it was clearly making a statement to
something. Peter and I both remarked on how peaceful the sharing was in
this field with Owls everywhere.
*	With so many Owls coming in and going and moving about, it led
Peter and me to wonder if this was not the greatest density on feeding
grounds a single area could support. The birds had less than 15 acres
apiece, on average, and if, as Dr. Jim Duncan reports, a Great Gray Owl
needs 7 voles a day to maintain good health, which is around 150 voles
per day from this field every day.  Talk about predator pressure!
*	Owls had two types of flights - Type 1 - a slow glide from a
perch in a straight line, with head turned down, locked and loaded; we
saw 3 plunges from this type of flight. In these instances the bird
traveled from its perch more than 50 yard, in one case 200 yards, then
lifted its wings, flapped to raise elevation, wheeled to one side,
closed its wings and dropped from a height of about 10 feet into the
snow. 2 of these were successful hunts. Type 2 - the slow ponderous
slow-motion line flapping, where it seems the bird was traveling from
point to point.
*	Twice we saw Owls that after plunging, actively dug in to the
snow or crust under them to extract prey. The motion they did was
reminiscent of a Fox Sparrow or Towhee scratching for food. The bird's
body would be thrust forward forcefully, and then the Owl would peer
downward by moving into a very upright stance, elevating its long neck
and pulling its facial disks in parallel to the ground. The vole, when
found, is grabbed by the scruff of the neck and the Owl flies to a
nearby perch to consume its meal.=20
*	We saw no evidence of prey stealing or birds approaching other
as they fed
*	We saw 4 Great Grays that were defecating, in each case, rather
large splashes of whitewash. This seems to me to be a sign of a healthy
bird, with an active digestive tract. All birds we saw were actively
hunting, alert, and we got the overall impression that they were faring
well. Have any banders been capturing these birds, can this be
confirmed?
*	How loud is the territorial call, as opposed to what we heard? =20

It was a great day, the best yet in a winter full of superlatives. The
GPS location of the Owl Field is N 46 Degrees.28.592'; W 093
degrees.22.484'.
There is a mile of good shouldered roads to pull off on, dress warm and
listen carefully and you may be as lucky as I, to hear that mournful
call of wildness, the call of the Great Gray Owl.


Mark Alt=20
Brooklyn Center, MN=20
mark.alt@bestbuy.com=20
"I recalled that I had read somewhere that in the Middle Ages Hell was
envisioned as a place without birds." Jim Harrison=20