During the winter, my home in Centennial (just north of University and Arapahoe) can get massive flyovers of gulls at dawn and dusk. In the a.m., they move toward the eastern reservoirs. In the p.m., the come back west, usually in more concentrated flocks -- though admittedly, I'm not as often staring at the sky during the cold winter sunrises as I am at sunset.
I haven't rigorously birded these flocks, but I've picked out a few Herring and California Gulls in the past. Most of the birds are Ring-billed Gulls, of course. One day, I'll get better at this -- or more lucky -- and pick out a Lesser Black-backed Gull or a Glaucous. Maybe. One of the most remarkable sights is when the flocks catch a thermal. I've seen this several times this winter, including this evening. Hundreds of gulls will ride together and almost as soon as one portion of the flock departs, another group arrives. I don't know this for a fact, but maybe this isn't a coincidence. My home is near the intersection of two four-lane roads. There are also several strip malls at the intersection. In other words, there's a lot of concrete, which radiates heat. But all of that is surrounded by two parks -- deKoevend and Cherry Knolls -- and the thin riparian corridors along the Big Dry Creek and the High Line Canal (which themselves intersect near the intersection). Perhaps it's the mix of warming and cooling spaces that helps create the thermals? A kettle of Turkey Vultures in one of my favorite things in birding, and I've seen them ride the thermals near my home, too. But these collections of gulls -- because of the numbers of birds involved and their more energetic-seeming flights -- are equal to those. That they happen at dusk, which turns the gulls into shadowy, high, foreboding shapes, adds to it. The birds appear more a swarm than a flock. Coincidentally, I'm reading Tim Dee's slight book *Landfill* right now, which is about UK's gulls and the ways that changes in the human landscape have effected how and where gulls live there. It's a good book, and it shouldn't take more than a cold, pre-migration weekend to read, though I've managed to make the effort last longer than the Bohemian Waxwings. - Jared Del Rosso Centennial, CO -- -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/cobirds?hl=en?hl=en * All posts should be signed with the poster's full name and city. Include bird species and location in the subject line when appropriate * Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/ --- 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 view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/5812db75-2676-4c72-85ab-1dc8d923373fn%40googlegroups.com.
