Denver Botanic Gardens at Chatfield, August 5, with Chuck Aid

Thirteen of us had a great Saturday morning at the Denver Botanic Gardens at Chatfield, recording 33 species (see list below).

American Goldfinch (c) Bill Schmoker

The finches were well represented and we had great looks at both American and Lesser Goldfinches. American Goldfinches are about thirty percent bigger than Lesser Goldfinches, being about half-an-inch longer and more stocky, and they are found throughout the year in Colorado. Lesser Goldfinches used to be found rarely in the winter in Colorado, generally wintering from central Arizona and New Mexico south into Central America, but they have been wintering here increasingly in recent years. Furthermore, thirty years ago Colorado Lessers had a rather brief breeding season (late June to late August), this has expanded, so that we see breeding activity now from mid-May into October. There is much debate as to what may have caused this dramatic change. An interesting aspect of Lessers is that virtually all the birds on the west coast have green backs while all the birds in Texas (the eastern extent of their range) have black backs. Here in eastern Colorado we find both, with the average amount of black increasing as one heads southeast from Colorado. The back patio of the Front Range Birding Company is an excellent place to sit down and study these guys up close.

Lesser Goldfinch (c) Bill Schmoker

While we had many great moments Saturday morning, including a fly-over Golden Eagle, the real highlight was an adult, light morph, Ferruginous Hawk. We tend to think of Ferruginous Hawks as a fairly common winter species here in eastern Colorado. However, they do occur here occasionally in the summer, breeding primarily out on the eastern plains. Generally, the young fledge by mid-July, and as they disperse so, too, do their parents. There have been almost no reports over the last couple of months of any Ferruginous Hawks in the Chatfield area, making our bird one of interest. Here is the description I submitted to eBird, as this is a rare sighting, and they requested documentation:  “Seen primarily from above. Light morph adult in flight – soaring in wide loops with slight dihedral. Rusty back and upper wing coverts. Distinctive tail, white proximally, and pale rufous distally. Long winged, with obvious white primary panels. Seen from about 800-1000 ft with both 8x binocs and 22x scope.”

Overall, it was a rather quiet morning – the calm between the end of breeding season and the advent of migration. Nonetheless, we were very entertained!

See you soon on another Front Range Birding Company bird walk!



Denver Botanic Gardens at Chatfield, Aug 5, 2017
33 species (+1 other taxa)

Double-crested Cormorant (Phalacrocorax auritus)  4
Great Blue Heron (Ardea herodias)  2
Turkey Vulture (Cathartes aura)  2
Golden Eagle (Aquila chrysaetos)  1
Swainson’s Hawk (Buteo swainsoni)  1
Red-tailed Hawk (Buteo jamaicensis)  3
Ferruginous Hawk (Buteo regalis)  1

Rock Pigeon (Feral Pigeon) (Columba livia (Feral Pigeon))  4
Mourning Dove (Zenaida macroura)  9
Broad-tailed Hummingbird (Selasphorus platycercus)  8
Downy Woodpecker (Picoides pubescens)  1
Northern Flicker (Colaptes auratus)  8
American Kestrel (Falco sparverius)  1
Say’s Phoebe (Sayornis saya)  2
Western Kingbird (Tyrannus verticalis)  4
Blue Jay (Cyanocitta cristata)  2
Black-billed Magpie (Pica hudsonia)  9
American Crow (Corvus brachyrhynchos)  12
Violet-green Swallow (Tachycineta thalassina)  2
Barn Swallow (Hirundo rustica)  3
Cliff Swallow (Petrochelidon pyrrhonota)  2
swallow sp. (Hirundinidae sp.)  6
Black-capped Chickadee (Poecile atricapillus)  4
White-breasted Nuthatch (Sitta carolinensis)  2
House Wren (Troglodytes aedon)  4
American Robin (Turdus migratorius)  1
Gray Catbird (Dumetella carolinensis)  3
Yellow Warbler (Setophaga petechia)  1
Song Sparrow (Melospiza melodia)  2
Red-winged Blackbird (Agelaius phoeniceus)  6
House Finch (Haemorhous mexicanus)  14
Lesser Goldfinch (Spinus psaltria)  13
American Goldfinch (Spinus tristis)  9
House Sparrow (Passer domesticus)  2


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