37-B-2018 Black Scoter

STATUS
In 1st Round
HOW MANY OBSERVED?
1, juvenile/1st winter or adult female
DATE SIGHTING OCCURRED
DATE REPORT PREPARED
REPORTER
JON CURD
OTHER OBSERVERS
Alice Cantelow reported the bird on eBird the evening before (10/17). I'm not familiar with her, nor do I know the name. She reported the "party size" as 2 on her checklist. The local eBird reviewer may be able to contact her as well, or provide her email/contact info. After seeing the eBird report, I thought there was a reasonable chance that it was an erroneous report, since I didn't know the name, but figured I lived close enough to check the area at first light the following morning.
LOCALITY OF OBSERVATION
Julius M Kleiner Memorial Park. Not positive if the park is actually located in Meridian or Boise - very close to the city borders. Ada County
HABITAT WHERE THE BIRD WAS OBSERVED
Man-made ponds bordering grassy park-like areas, common in municipal parks. Big water feature in the middle of the northern 2 ponds, where I observed the bird, spraying continuously in a big fountain display.
SIGHTING DURATION, CONDITIONS, and EQUIPMENT USED
Binocular: Vortex Talon, 10 X 42
Camera: Digital Panasonic Lumix, 25-400 lens
I observed the bird for about 20 minutes. First seen just a very short distance away (15 yards?), almost directly below me. I was on a concrete pathway, with a fence separating the path from an immediate drop-off into the deeper water of the pond. I observed the bird from shortly after first light and lasted until just prior to sunrise, when the lighting was much better. Clear, cold morning (34 degrees upon arrival) no wind. For most of the sighting time, the bird was between 30-50 yards away.
DID YOU TAKE NOTES?
No, not at all
DID YOU CONSULT A FIELD GUIDE OR OTHER REFERENCE WORK?
Yes, during the observation
Yes, later the same day
WHICH GUIDE(S) OR REFERENCE(S): DID YOU CONSULT?
Sibley's "Guide to Birds"
iBird Pro (electronic bird app)
DESCRIPTION OF THE BIRD(s)
Obviously in the duck family, I initially thought it was a female ruddy duck when I saw it with the naked eye. A smaller duck, but larger than coots in the general vicinity and smaller than mallards also in the vicinity. The body was very dusky overall. Very clean demarcation between the dark top of it's head/back of neck to the white of the cheeks that extended down to the upper front of neck. Much more white on the face/neck than would be present on a ruddy duck. The part of the breast that was exposed above the waterline also seemed to be a lighter shade than the rest of the body, which would seem to point more toward a juvenile bird.
BEHAVIOR OF THE BIRD(s)
The bird swam away from me when I surprised it almost directly below me, but never seemed panicky or afraid. It stayed to itself and swam a slow circle completely around the northern pond (maybe 2-3 acres or so??). I never saw it dive until just prior to walking away at the end of 20 minutes when it dove several times, and stayed down for 20-30 seconds each time, apparently feeding.
HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU?
I was 95% certain after I got my binos on the bird that it was indeed a female or juvenile BLSC when I saw the size, dark body, and white cheeks. The light wasn't strong enough to easily see the scoter-type bill shape, but the silhouette seemed consistent with a scoter bill as well. After capturing some photos, I did double-check my iBird Pro app on my iPhone just to be 100% positive it wasn't a female or non-breeding male Ruddy Duck, but the photos convinced me 100%.
HOW DID YOU ELIMINATE SIMILAR SPECIES? WHAT WERE THEY?
The other 2 scoter species and scaup species don't have the clean, pale to white, cheeks of this bird. Ruddy duck has a noticeably cocked tail (unlike this bird), the female ruddy has a dark line through the white of the cheek and the white of the cheek on the nonbreeding male ruddy doesn't extend down onto the upper throat/neck as on this bird.
WHAT IS YOUR EXPERIENCE WITH THIS (AND SIMILAR) SPECIES?
Saw 2 similar looking BLSC's last fall on the Snake River near Hagerman. There were numerous ruddy ducks in the vicinity to compare with the scoters. Also seen on various pelagic trips over the years off the West coast.
DESCRIBE YOUR GENERAL BIRDING EXPERIENCE
~40 years of birding; much of it on a semi-to-serious level.
ADDITIONAL INFORMATION (If any)
After the initial 20 minutes of observation & photos, I returned to my vehicle to get the word out (Facebook - Rare bird & discussion group, IBLE and eBird checklist) and warm up! Afterwards I decided to walk back to the pond (1/4 mile) and try for some photos now that the sun had risen. I walked around both ponds twice and could not relocate the bird. Apparently it flew away while I was in the rig, even though it seemed content diving/feeding when I saw it last and nobody else was present to pressure the bird.
WERE PHOTO(S), VIDEO, AND/OR AUDIO OBTAINED FROM THIS SIGHTING?
Photo
SUPPORTING IMAGES