Greetings All,
Just so there is no confusion, there was both an ICELAND and a GLAUCOUS-WINGED GULL today at Aurora Reservoir, with the birds mostly hanging out at the sw. corner of the reservoir, observable from the reservoir ($10 entrance fee) and surrounding neighborhoods. The Snowy Owl is likely in the area, and likely was wise, spending the day in some comfortable wind-protected spot, unlike the gull-watchers. The Iceland (Kumlien's) Gull and GW Gull are similar in overall color, and both are well patterned dorsally. Northern (AK breeding) GW Gulls tend to more patterned than more southerly breeding populations (such as those seen in WA and BC) and approach dark imm Glaucous Gulls in overall color, which is the same color as many Kumlien's Gulls. The GW Gull is a monster, almost certainly a male, towering over nearby Herring Gulls and sporting a hefty (all black) bill with a marked gonydeal angle). Its primary extension past tail is short. The Iceland Gull has a far daintier bill, was smaller than nearby Herring Gulls, and had long primary projection. Also, the GW Gulls tertials were unmarked, the Iceland Gull's heavily marbled. Gulls were coming and going all morning from this spot, probably on way to and from dump. Here is my attempt to reconstruct what was present at rough time estimates (and the times were rough in those winds!) At about 8:00: 1 ad Thayer's, 1 ad Lesser BB. At about 8:45: 1 imm GW Gull, 1 ad Lesser BB. At about 9:30: 2 ad Lesser BB At about 10:30: 1 imm Lesser BB At about 11:15: 1 imm Iceland Gull, 1 imm Thayer's. Adult LBBGs tend to stand out, there were few brown immature gulls to sort through, and the birds were not that hard to survey, so methinks this represents real, and substantial, turnover in gulls at Aurora Res today (and probably most days). Happy New Year, Steven Mlodinow Longmont, 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]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
