Arctic Tern, Larimer County

[David Tønnessen]

Hi all,

I was asked to post here that the bird thus far being reported as a Common Tern at Horseshoe Lake in Larimer County is in fact a (hatch-year) Arctic Tern. I am not the first to ID it as such, and I believe (correct if wrong) Josh Bruening is the original finder.

Here is a list with pics.

https://ebird.org/checklist/S96693524?view=photos

Best,

David Tonnessen

[James Bruening]

All,

Thanks David for getting the word out.  I originally found this Tern this past Thursday and based on some blurry photos that I was convinced showed dark secondaries that would have made it a Common Tern not an Arctic Tern.  It was certainly short-legged and shorter-billed but thought being a young bird and getting dark outside that I'd stick with that ID until better photos were procured.  I finally got convincing (to my birdbrain) photos that show clean, white secondaries that tipped the scales for me on the ID.  I believe the dark secondaries I was seeing was nothing more than dark, negative space between the feathers.  A lot of field marks go blurry when birds are far away!  But big shoutout to Nick Komar who just would not let up on this bird and sent what decent photos he had out to the greater birding minds amongst us to get feedback.  The bird has been most often seen on the spit in the southwest corner of the reservoir.   Horseshoe Lake is accessible on that southwest corner if you park on 41st Street and cross Monroe.  This bird has already been seen by many so hopefully it will stick for a few more days.  Moral of the story I guess is that it's ok to report Sterna sp first and get better pics.  I will add a bunch of pics but a few of them can be found on this checklist:

https://ebird.org/checklist/S96706316

Bird is the word!

Josh Bruening

Fort Collins

[Nicholas Komar]

Here are some more photos and audio of this interesting tern at Horseshoe Reservoir (southwest corner), Loveland, from earlier this evening (see link below). The two late afternoons that I have observed this bird, it has flown off at the end of the day toward Lake Loveland, where presumably it is roosting with the gull flock. Both times it was vocalizing as it flew overhead. So it is an opportunity to audio-record it. I believe the audio in the linked eBird checklist supports the ID of Arctic Tern. I might mention that I recorded this audio with the Merlin app (free from Cornell Lab of Ornithology). Merlin did not ID the vocalization. Arctic Tern is not yet in their database. Common Tern is. 

Here is the link to the eBird checklist with photos and audio. https://ebird.org/checklist/S96708828.

Nick Komar

Fort Collins CO

On Oct 25, 2021, at 5:11 PM, James Bruening <8721...@gmail.com> wrote

All,

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