IBRC 58-B-09
Idaho Bird Records Committee Rarities Report Form
(this
form is available on www.idahobirds.net)
Species: RED-THROATED
LOON
Reporter: (include
address, phone, e-mail)
Lisa Hardy
819 W. Park Ave.
Kellogg, ID 83837
basalt@earthlink.net
Other Observers: none
Date Report
Prepared: 22 October 2009
Date Sighting
Occurred: 16 October 2009
Locality of
Observation: Hayden Lake,
Kootenai County, Idaho
Habitat: freshwater
Conditions: Partly sunny, light breeze. Between 1:30 and 4 PM.
Did you take notes…
during the observation? ____________
after the observation? ______________
the same day? _______X_____________
another day?______________________
not at all? ________________________
Did you consult a field
guide or other reference work?
during the observation?_____X_______
later the same day? _______________
another day? _____________________
not at all? ________________________
What guide(s) or
reference(s) did you consult? National Geographic 2nd ed.
Description: A diving bird that, at a distance of about a half
mile, appeared to be fairly similar in size and general coloring to Western
Grebe (present nearby on the lake): dark on top of head and continuously down
nape, gray body. The front of the neck was white, narrowed by dark notches at
the base. White patches showed along its sides at and just above the waterline.
Differed from the WEGR by having a thicker neck and the white at the waterline.
After relocating the bird at a closer distance, I could see a dark eye in the
white/light area below the dark crown. There was no sign of a chin strap. The
breast, front of the neck, throat and lower sides of the face were clean white.
There was no sign of a chin strap. There appeared to be a dark vertical mark on
the throat, though it was possibly due to shadow. The bill was light gray and
much more diminuitive than the clunky bill of a Common Loon (present at similar
range at this time).
Behavior: "Loafing", but seemed quite alert, turning
its head back and forth, with the bill held tilted upward at a slight angle
(like a cormorant). Also seen swimming and looking underwater as other diving
birds do, and diving. The dives lasted 45 to 50 seconds and the bird stayed on
surface for 10 to 15 seconds between dives.
How and when did you
positively identify the bird, and what clinched the identification for you? After
relocating the bird, I had several closer looks and could see the dark eye in
the light colored area of the face, and the light gray bill.
How did you
eliminate similar species, and what were they? I first
thought this was a distant Western Grebe, but after more study, I could see
that the neck was too stocky. Also, the contrast on the head and neck was not
as great, and the loon showed white patches on the sides which the grebes did
not. After determining that this was a loon, I thought it was probably a
Pacific (or Arctic), though I could not determine the bill color or make out a
chin strap. At this point, I lost the bird as it started to forage. I checked
my field guide and saw that the RTLO typically carries its bill tilted upwards
and I realized I needed to get another look before I could determine if this
was a PALO or a RTLO, but I was not able to find the bird then.
I returned an hour later
and relocated the bird at closer range.
A Common Loon in mostly
alternate plumage was nearby on the lake and available for comparison. The COLO
was a markedly bulkier bird with a clearly heavier bill. This comparison
allowed me to comfortably eliminate both COLO and YBLO.
Pacific (and Arctic) Loon
were eliminated by the white/light area of the face extending upwards above the
eye. In PALO and ARLO, the eye is within, or mostly within the dark. On this
individual, the area around the eye was not clean white, but rather a dirty
white. However, the upper boundary of this dirty white area was abrupt, not
gradational as might be expected in a PALO. The lower face was clean white, indicating
this was an adult.
During these looks at
closer range, I was concentrating on distinguishing the facial pattern and bill
structure, and did not note the body plumage.
Experience with this
species (and similar species):
Very little experience with Red-throated
Loon and Yellow-billed Loon. Some experience with Pacific Loon, fairly familiar
with Common Loon.
General birding
experience: intermediate
Were photo(s),
video, and/or audio obtained by you? (If yes, please include or attach) No usable
photos.
Below is a transcript of field notes taken by Doug Ward:
Idaho Rare Bird Report – 23 October 2009
(field notes written at time of observation)
Species: Red-throated Loon (Gavia stellata)
Sex/Age: Adult (?); full basic plumage
Dates: 22 October 2009
Location: Hayden Lake; Kootenai County, Idaho
Observation: Bird was swimming and feeding (diving) between 50-100m off shore and observed for an aggregate of ~2 minutes using both 8X40 binoculars and a 15-40X spotting scope (primarily on 15X) – lost it as I was writing my notes. Lighting was bright overcast with midday sun at my back.
Description: Small, light weight loon; winter plumage; bill consistently held at an upward angle (~20º).
Plumage: Light grey dorsally. Even coloration on back, up nape and across crown to bill. Face, throat, breast and belly white. [Dark] eye isolated in white face (similar to Clark’s Grebe (Aechmophorus clarkia)).
Bill / Eye Color: Bill primarily horn colored with dark culman. Eye appeared red.
Structure: [Bill] structurally light weight, ~ ¾ head length with a straight culman and an upwardly curved lower mandible. Combination of coloration and structure gave appearance of upturned bill; accentuated by its behavior of holding head with an upward tilt.
Behavior: Low riding bird which dove consistently to feed; dive was a gentle rolling motion. As mentioned above, consistently held head / bill tilted up at about 20º.
Similar Species: Medium sized, low riding water bird with moderately long neck, rounded head, and long, sharp pointed bill eliminates most waterfowl besides grebes and loons.
Common (Gavia immer) and Yellow-billed (G. adamsii) Loons eliminated by this bird’s relatively small size (only slightly larger than nearby Western Grebe (Aechmophorus occidentalis)) and light weight build.
Pacific (G. pacifica) and Artic (G. artica) Loons eliminated by pale grey, not well demarcated plumage, as well as by bill structure (straight culman, upward curved lower mandible vs. the curved culman of these species) and this bird’s behavior of tilting head up.
Western (A. occidentalis) and Clark’s (A. clarkia) Grebes eliminated by this bird’s comparatively shorter and thicker neck as well as its pale grey coloration. Western Grebe nearby for direct comparison.
Red-necked Grebe (Podiceps grisegena) eliminated again by this bird’s pale grey coloration, dark (red) eye surrounded by its white face, and the head / bill posture described above.
References (referred to later the same day after notes written):
1) “The Sibley Guide to Birds”; Sibley; 2000
2) “Complete Birds of North America”; National Geographic; 2005
3) “Advanced Birding”; Ken Kauffman; 1990