Phillip Andrews
Great Gray Owl Surveys, Period 2 of 2
April 15-20
Delta Junction, AK
Main topics:
True sighting, repeat surveys, daytime surveys
No owls are seen or heard during the day (before sunset, after
sunrise)
Two great grays were detected during this survey period, compared
to none during the first. Each was heard, perhaps coincidentally, after the last of
about 8 broadcast calls (via playback from speakers).
The first detection was at the last
survey location on the first night (4/15), where the owl responded two minutes
after the broadcast call. The species was identified by its calls: territorial
and irritated hoots. This call was heard at 12:15 am. The owls’ location was
determined using two points and triangulating towards the owl. This area was
revisited the following day at 2:30pm after and the area was searched for two
and a half hours, with no luck in relocating the individual or finding any
signs of owl presence (nests, pellets, white-wash, etc.). Notes from the nest
search: Many squirrels, pair of grosbeaks, bald eagle flying above, raven
flying above. Possible owl flying 200ft. away. This area was great habitat. The
environment was mostly tree cover adjacent to open brushland and surrounding
pockets of meadows. Few witch’s brooms were found in the area. All of them were
large but none were determined to be occupied except by squirrels. The call was
played again at the end of the search, but received no response. This location
was 0.6 miles away from the main road (Alaska Highway 2), along a dirt path and
located within the Roughed Grouse Habitat Management Area, about 20 miles SE of
the town of Delta.
The owl was likely hunting the night
before in one of the open meadows [appendix 1 photos]. In the original written
record of this event, I noted that part of the hooting sounded “concerned,”
like the warning call of this species, with individual hoots rising slightly in
pitch.
The second
detection was at 3:40 am on 4/19. It was determined to be a great gray owl by
its large size, large head, and slow-paced hoots. It flew 10 ft. in front of
me, silently on a dark, cloudy night and I couldn’t see any color patterns in
the feathers but the silhouette was characteristic of a great gray with a large
head in comparison to its body. The hoots were single syllable and evenly
spaced but seemed too slow even for a great gray and the tone was more like
that of a great horned.
This area too,
was searched the next evening at 8:00 pm for two hours for signs of owls. None
were found. The habitat was not great for nesting and hardly looked decent for
hunting- a small patch of dense, small to medium spruce trees surrounded by
open meadow/ tussocks. This location was separated 0.17 miles from the main
road (Richardson Highway) with light spruce cover and tussock-like meadow along
the Trans-Alaska Pipeline and near a large clearing with overhead electrical
lines [appendix 2 photos].
This owl was
also likely hunting because of the low vegetation, but the only realistic
perches available were a handful of trees in the exact area the owl was
initially heard.
The call was
played again with no response. Within the small spruce trees were a substantial
amount of witch’s brooms, though all very small, and none appeared to be
occupied by any animals.
For the revisit of each of these areas, a five-minute listening
period was instigated to reduce the effects of surveyor presence on owl
detection and disturbance.
Methods:
One 4 minute broadcast call was made in Audacity (version 2.2.2)
and was composed to three types of calls: male territorial (typical “hoots”), a
female begging call, and a chick begging call. Periods of silence were
incorporated into the call to allow the observer to hear background-calling and
responding owls.
Five minute calls were composed of:
1. 120 seconds of silence
2. 70 seconds of calls
Male
territorial, female begging, chick begging
3. 30 seconds of silence
4. 20 seconds of calls
Male
territorial, female begging
5. 60 seconds of silence
A total of 142 calls were performed, with 67% overlap with
previous surveys and 47 new points this survey period, and 30 single points the
first survey period, making a total of 95 repeat-visit surveys and 77 single-visit surveys.
Single visit surveys occurred because of environmental limitations
such as wind and time of day.
One of the sightings was from a repeat-visit and one from a
single-visit survey.
Other birds detected around the time of this survey period:
In Delta Junction:
1 Bald Eagle
~5 Boreal Owls (audial)
4 Black Capped Chickadees
1 Canada Jay (i.e. Gray Jays)
2 Goshawks, different locations, both hunting
in meadows during the day.
2 Great Gray Owls (audial)
~6 Great Horned Owls (audial), one seen along
Clearwater Rd. on the top of a telephone post scarfing down a small rodent.
1 Gull (Glaucous-winged?)
2 Pine Grosbeaks (pair)
2 Swans (unknown species) in formation, three
different times and both night and day
1 Unknown small brown bird (<5 in. head to
tail)
Between Delta and Fairbanks:
1 Bald Eagle, flying 15 ft. from the highway,
in Salcha
2 swans (Trumpeter?)
2 ducks (Scaups?)
Surveyors:
Phillip Andrews, Nastasia Caole
Appendix 1:
Meadow located within the direction of detection
Appendix 2: