Possible Arctic Tern, Chatfield Douglas, Co.

[Glenn Walbek, Castle Rock, CO]

Folks,

I spent some time studying an interesting sterna tern on the Chatfield sandspit this morning.  The bird is small, with a small dark bill, except a reddish center and inner bill.  In flight, the primaries were fairly uniform gray with white secondaries and secondary covert tips.  The tips of the primaries are dark.  There was no hint of a dark secondary bar.  Resting, the primaries look a tad darker than the mantle with pale outlines, but gray not black. I suspect the bird is a juvenile (see worn juvenile in Sibley's guide).  I will upload some photos later.

Glenn Walbek

Castle Rock, CO

Sent from my Verizon Wireless 4G LTE DROID

[Glenn and Laurie]

Here are some pictures of the juvenile plumage, Arctic Tern from Chatfield. 

 

http://www.pbase.com/gwalbek/2015_birds

 

He has been sitting on the end of the sandspit, taking off to fill up on gizzard shad and returning to the sandspit.  At first glance he could be overlooked as a Common Tern, but aging the bird helps determine it’s ID.  The white secondaries with white-tipped, secondary coverts should not appear in any plumage Common Tern.  Additionally, Common Tern should show a dark secondary bar in all plumages except Alternate, which this bird clearly is not.

[Scott Somershoe]

I didn't see any terns at the sandpit or elsewhere around chatfield between 345-440. 

Scott Somershoe 

Littleton CO. 

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[Tom Behnfield]

At around 5:30 this evening, I spotted this Tern that looks quite a bit like that seen by Glenn today. What leads me to believe this is the same Arctic Tern is the rounded head, lighter carpal bar and pale gray primaries. I've attached a picture, which as usual is nowhere as good as Glenn's fine shots.

I can only hope..........

www.flickr.com/photos/behnfield/21874197016

Good birding!

Tom Behnfield
Lakewood, CO
behn...@q.com
www.flickr.com/photos/behnfield

[Tom Behnfield]

Forgot to mention that this was also at the end of the Chatfield Marina Sandspit (Douglas County.