At the risk of sounding like a broken record, we've continued to have cold, snowy weather in Colorado for the last week. I think we had lows below zero for at least the last four nights here at my home base in Longmont, with the coldest being -14° F my low-registering thermometer marked three nights ago. Today was the first day in a while that we broke into the 20s.
So obviously, most of the water around here is now frozen, making any open water that much more valuable to birds. One interesting place to keep an eye on in Boulder County when things freeze up is the Valmont Reservoir complex, a group of three lakes that provide cooling water for a coal-fired power plant. The return water keeps at least two of the lakes perennially open, attracting hordes of birds whose other options are to leave the area or die. Birds of the big water there include thousands of gulls coming to roost in the evening (7+ species reported so far this winter), all kinds of waterfowl, grebes and cormorants that forgo migration to spend the winter there, and so on. But some water-reliant birds eschew the big lakes.
A couple of days ago, a buddy of mine (Richard Trinkner) reported an accommodating Virginia Rail at a still-open outlet of a small lake near Boulder Reservoir. I investigated yesterday and was delighted to find the bird right above the little culvert draining the otherwise completely frozen, snow covered lake. The little guy ducked into the culvert and soon came out the other side, where it began foraging in the narrow flowing watercourse. It was pretty crazy to see it probing under the overhanging snow on the edges, and to see it run over ice and across snow banks that shortcut to another section of the running water. Eventually I saw it catch a crayfish about as long as its bill, immediately followed by a retreat to the privacy and security of dense cattails to deal with its prey.
In the course of watching this bird I also noticed two companion Wilson's Snipe alternating between imitating reedy growth and probing the soft sediment flooring the waterway.
Of course, wintering Virginia Rails and Wilson's Snipe aren't unheard of around here, but seeing them in in a mid-January snowscape as cross-country skiers swished by behind me was pretty cool.
Spring Migration 2017, Part 2
2 weeks ago