Ross's Geese at Union Reservoir (Boulder County)

[Jay Hutchins]

I braved the wind and snow this morning around 9 am and headed out to Jim Hamm Nature Area and Union Reservoir (Longmont).  Yeah....nope.  Winds were 30 mph + so didn't last too long.  About 700-800 ducks on Jim Hamm (mostly Redheads), 2 Canvasbacks, 4 Hooded Mergansers and  Great Blue Heron staying low in the reeds.  Drove the road on the north side of Union and saw 4 Green-winged Teal and surprise! 5 Ross's Geese (one dark adult) hunkered down on the mud flats.  Pretty nasty weather today.

Jay Hutchins

Longmont, CO

[Sarah Spotten]

I wonder if one of these birds was the Ross's Goose I saw over my house not far from Union Reservoir just after 5:00 PM Wednesday, after the snow stopped? It was with a mixed flock of about 30 Canada Geese and 30 Cackling Geese struggling to make their way north against the high winds (and only succeeding in going east to west for a minute or two...then swinging back west to east).

Sarah Spotten

Longmont, CO

[Jay Hutchins]

Depending on the timing of our sightings, he/she either added or lost three others. When I saw them at Union they were definitely ground bound, along with some gulls right next to them.

I am curious as to why my Ross's sighting isn't showing up on eBird?  It was marked as rare so I added a description.  Just checked a few minutes ago and it's still not showing up at Union Reservoir.  There was another sighting of a Ross's just a mile or so to the west as a flyover, and it got approved same day.  Anyone either know why that is, or experienced a similar situation - same species being approved on one checklist, but not another?

Jay Hutchins

Longmont CO

On Wednesday, March 13, 2019 at 12:37:41 PM UTC-6, Jay Hutchins wrote:

[Sarah Spotten]

Several months ago eBird started using its own crowd-sourced species frequency data based on its 20x20km grid system to determine the “expected species” list for a given area. I don’t know all the ins and outs of their algorithm, but as I understand it, over time the more observations are reported in a 20x20km grid cell, the more accurate the expected species list for a given area will become. Our Ross’s Goose observations, although close to each other in distance, are probably in different 20x20km grid cells, so it’s using different data to determine “rare” status. When I reported my Ross’s on 3/13 (which I’m guessing is the one you’re seeing on eBird not far to the west of Union Reservoir), it was not flagged as rare for me, just “unreported” for my grid cell.

The wind was really trying to scatter the small flock of geese I saw overhead on 3/13, so I wouldn’t be surprised if they had gotten separated from another group in flight, and I just could not see the rest of them from my vantage point.

Sarah Spotten
Longmont, CO