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 -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/afec2057-ff04-4be6-85e2-3abd4729b999%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
