Yellow-billed Loon

Gavia adamsii


eBird Checklist S48849649
Dillon Reservoir--Blue River Inlet area
Summit, Colorado, United States
Search this location, Illustrated Checklist
Latitude and Longitude 39.5713, -106.053 Map



Observation details

Species: Yellow-billed Loon Individuals: 1 Date(s) & Times: 9/30/2018 3:00:00 AM - 9/30/2018 3:35:00 AM County: Summit Location: Dillon Reservoir Lat-Long: 39.5727406361646,-106.053268852825 Observation Details Total Amount of Time You Observed the Bird: 35 Minutes Other Observers:: Jack Bushong Age: Adult Sex: Unknown Plumage: Breeding Habitat: Seen in the Blue River Inlet. This is a high elevation mountain reservoir. Optics: (not entered) Distance: Distance was 300 ft Light Conditions: Fairly good light conditions. Description of the Bird: My brother and I first saw this bird swimming fairly close to the inlet shore, from about 150 ft away. Since the reservoir is very low at this time of the year, it is a decent walk to get to the waters edge. As I was walking along the mudflats, I immediately noticed a large loon in breeding plumage with a massive yellow bill. Loon with a large creamy yellow bill angling up slightly at the end. Overall black body, with striking white checkering patterns on the back. White ring on neck, dark red eye, and a steep forehead. White breast and below. Much larger than a Common loon, differentiated by bill color and size. Called a couple times at a distance. Diving frequently about 300 ft from shore, only staying up for 20-30 seconds between dives. Strong winds made observations a bit difficult. Similar Species Discussion: The only other species considered was a Common Loon, but size, bill size and color, and certain markings differentiated the two. Much larger loon than Red-throated, and different markings than Pacific. Resources Used: I used my binoculars and a Vortex Razor scope to view this bird at a far distance. Your Experience: I have seen this bird once before in winter plumage down at South Platte Park last winter. I have a lot of experience with the Common Loon from canoe trips to northern Minnesota and southern Canada.

Technical Information

Focal length
464.4 mm
Shutter speed
1/400 sec
Flash did not fire, auto
Original file size
320 x 240

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