Boyd Terns (Larimer)

[Nick Komar]

Three Forster's, four Common/Arctic. Roosting northwest shore. North end of State Park. Working on ID now.

Nick Komar
At Boyd L

Sent from my iPhone

[quet...@comcast.net]

Saturday afternoon, 4 Oct 2015, Dave Bray and I watched at least 6 different terns at the north end of Boyd Lake. They were seen sitting and flying through telescopes, but always quite distant. At least two were Forster's, with black patch on face, and dusky gray on hindcrown and nape. At least 4 were apparently Common Terns, one of which was a full gray-bellied, black-capped adult. The other 3 were young birds with white fore-crowns, There may have been a fifth bird, an adult starting to lose its gray belly and black fore-crown. Low-quality digiscoped images support the identification of Common Tern, although all of these showed various features of Arctic at one point or another, causing much confusion in the field. For example, they all had pale bills. The bill of the adult lacked a black tip. In some views, bills looked short. Legs were shorter than the legs of the Forster's Terns with them, causing them (but not the Forster's) to waddle when they walked. One of the young birds appeared to have a tail that extended longer than the wingtips. The young birds had frosty wingtips and barely visible carpal bars. Nonetheless, I am pretty sure that they were all the same species, and photos indicated longish legs when standing, and long neck in flight. Better photos might prove me wrong about the identification, so I encourage other observers to document these birds, which are rare in Larimer County. Its been a great year for terns at Boyd Lake State Park. I wonder if these could be the same pod of terns that were there 3 weeks ago. That pod included one well-documented Arctic. I would search for these roosting at the Swim Beach or roosting in the northwest corner (among duck-hunters). Lots of Franklin's, California and Ring-billed Gulls were also present, as well as two Sabine's Gulls floating just north of the Marina, and my FOS Herring Gull (an adult) at the Swim Beach.

 

Just west of Boyd, at Horseshoe Lake, the resting gull flock harbored 4 Lesser Black-backed Gulls (3 adults and 1 2nd-cycle immature) in the northwest corner. A digiscoped photo of these can be viewed at http://www.pbase.com/quetzal/image/157696530. They are hard to pick out among the densely packed California Gulls.

 

Nick Komar

Fort Collins