Well, Saturday was a huckleberry above a persimmon day.  You’ll have to look it up.  We’re not just all about birds here!  While we whiffed on getting any grebes, we had two species of geese, seven species of dabbling ducks, and five species of diving ducks.  That’s a lot of waterfowl, and “incredible-breeding-plumage” was the name of the game.  In particular, we had nice close looks at Gadwall, Blue-winged Teal, and Green-winged Teal.  Gadwall males get undue short shrift when it comes to assessing their incredible breeding plumage. Yes, they don’t have the bright colors of some ducks, but I encourage you to take a closer look at the accoutrements that they do have.  First, note the long, acutely pointed, silver-gray tertials (the flight feathers in the wing closest to the body, but covering the rear back when folded).  Second, note the beautiful copper-colored scapulars (the feathers that cover the top of a bird’s wing, and lying along the back when the wing is folded).  Finally, note the tweed-like fine vermiculations of black on the body plumage.  Pretty wonderful!

One quick note on Green-winged Teal.  Just as with Mallards, the angle of light influences what colors we see.  A male Mallard generally looks to have an iridescent green head, but that iridescence can cause it to appear purplish-blue in certain light.  So it is with the Green-winged Teal; the swoop behind the eye generally appears to be green, but in certain light it appears purple.

The island in Tabor Lake, despite having had one old snag fall down, had as in the past around one hundred nesting Double-crested Cormorants who barely left any room for a couple of pair of Great Blue Herons to nest beside them.  The cormorants are so committed to this location there were even about 30-35 nests amongst the branches on the ground of the old snag.

Leaving the waterfowl behind, the skies were full (or close to it) with Cooper’s Hawks.  We believe we had three pairs of Cooper’s vying to see who got what turf.  There were aerial interactions, and nest building, and regular calling going on, and the white undertail coverts seem exceptionally fluffy in breeding season sticking out well beyond the body.  Quite the display!

A major highlight of the day was getting to watch a couple of Bushtits nest-building among the smaller dangling branches of a mature cottonwood.  Bushtits can begin nest building in Colorado as early as mid-March, and I found Bushtits working on this specific nest on March 17.  At that time the nest already seemed well-along and perhaps more than half completed.  While sometimes Bushtits can complete their nest building in about two weeks some pairs have been known to work on theirs for as long as fifty-one days – the average amount of time spent doing this appears to be 33 days.  Because of the enclosed nature of the huge pendulous nest, it’s difficult to know when egg-laying has occurred (5-8 eggs) or nestlings have hatched, but there is evidence that birds continue to bring nesting material to the nest after egg-laying has commenced and until the eggs have hatched.  Interestingly, unmated adults may roost with the parents during the nest-building period, and may, after hatching, contribute by bring food to the nestlings.  For the most part, this is a highly gregarious species.

Spring migration is here!  Try and get out between snow storms and enjoy the new arrivals.

Chuck

Wheat Ridge Greenbelt, Apr 1, 2023
Number of Taxa: 45
Number of participants: 13

43 Cackling Goose
85 Canada Goose
1 Wood Duck
2 Blue-winged Teal
65 Northern Shoveler
51 Gadwall
2 American Wigeon
27 Mallard
20 Green-winged Teal
2 Ring-necked Duck
15 Lesser Scaup
2 Bufflehead
3 Common Goldeneye
6 Hooded Merganser
2 Rock Pigeon (Feral Pigeon)
3 Eurasian Collared-Dove
11 Mourning Dove
25 American Coot
2 Killdeer
1 Wilson’s Snipe
32 Ring-billed Gull
120 Double-crested Cormorant
5 Great Blue Heron
6 Cooper’s Hawk
3 Red-tailed Hawk
1 Red-tailed Hawk (Harlan’s)
3 Belted Kingfisher
5 Downy Woodpecker
14 Northern Flicker
6 Blue Jay
4 Black-billed Magpie
3 American Crow
9 Black-capped Chickadee
8 Bushtit
2 White-breasted Nuthatch
1 American Dipper
25 European Starling
1 Townsend’s Solitaire
18 American Robin
2 House Sparrow
16 House Finch
3 American Goldfinch
9 Song Sparrow
4 Spotted Towhee
80 Red-winged Blackbird