Hudson Gardens, January 25 – with Chuck Aid

Great Blue Heron (c) Nona Radin

A chilly morning gradually changed over to a delightfully mild late morning, and we had a great walk going upstream from Hudson Gardens, even included a brief detour up Lee Gulch where an American Dipper had been recently reported.  We whiffed on the Dipper, but did get great views of a number of other birds.

Cackling Geese (c) Nona Radin

For starters, we had a nice mix of Cackling Geese and Canada Geese out on the South Platte.  Generally speaking, there are four main characteristics that can be used in differentiating these very similar “white-cheeked” geese.  However, complications arise because there are roughly six subspecies of Cackling Goose and eleven subspecies of Canada Goose, all of which vary slightly in size, coloration, and shape.  The first, and perhaps most import characteristic, is the bill size, its shape, and its length, as compared to the width of the side of the head.  Compared to Canada Geese the bills of Cackling Geese are shorter, closer to being an equilateral triangular shape, and their length is about 50% (or less) of the width of the side of the head.  Overall, Cacklers are smaller (3.1 – 6.6 lbs), while Canada Geese are bigger (5.7 14.3 lbs).  Cacklers tend to have shorter, thicker necks.  And, finally, there are some subtle differences in plumages, e.g. some Cackler subspecies have darker breasts, some have a white neck-ring, and some have a grayish sheen on their back.  On Saturday we got good looks at both species, and started to work towards getting a little more tuned in to all these differences.

Pied-billed Grebe (c) Bill Schmoker

Another waterbird of interest that we saw was a Pied-billed Grebe.  “Pied” means having two or more different colors, and the name derives from their bill, during breeding season, being white with a distinct black band. Grebes are not ducks, as they have lobed toes, not webbed feet, to assist them in diving.  However, for the most part they don’t have to dive to go under water; they can simply adjust their buoyancy such that they can float with differing amounts of their body above the water, or they can simply slowly submerge themselves with hardly a ripple.

Buffleheads (c) Nona Radin

We also had six species of ducks on the river, and we got to really delve into their identification – working on telling the males from the females, and what the main plumage characteristics were.  One of these challenges had to do with telling first-year male Buffleheads from adult females (get out your field guides).  In looking at the photo notice how much bigger the adult male is.  Males tend to be about 1-3″ longer than the females, and weigh about 4 ounces more, so I’m saying that what we saw were females, but I am not confident in doing so.  

Greater Scaup (c) Nona Radin

The highlight of the ducks was getting to see a small flock of twelve Greater Scaup fly in and land right in front of us on the river. This is a rare to uncommon species on the eastern plains near the foothills, and we were quite fortunate to get excellent looks.  On the males we were able to note their bright white flanks, thick neck, head sloping towards the rear and long from bill to nape and smoothly rounded (no hint of the peaky head that characterizes the Lesser Scaup – a far more common winter duck), broad black nail on the tip of bill, eye not centered in head – but higher and more forward, BIG jowls, and some green noted in the head coloring. On the females we noted the extensive white behind bills.  Also, fortunately, one of our participants, Nona Radin, took some great photos.

Greater Scaup (c) Nona Radin

Finally, some of us got good looks at a single Ruby-crowned Kinglet traveling with a little flock of Black-capped Chickadees.  This diminutive bird with its tiny bill is a common summer resident up in the mountains, but it is a rare to uncommon winter resident on the eastern plains near the foothills.

So, though we only recorded 23 species, we got great looks at some really special birds – not to mention three muskrats.  Hope you can join us on a future Hudson Gardens bird walk, or check out the walks being offered on the first Saturday of each month by the Front Range Birding Company – call 303-979-2473 for more info and to sign up for a walk.

Good birding,

Hudson Gardens, Jan 25, 2020
23 species

Cackling Goose  80
Canada Goose  300
Gadwall  11
Mallard  35
Green-winged Teal  9
Greater Scaup  12
Bufflehead  13
Common Goldeneye  6
Pied-billed Grebe  1
Killdeer  1
Ring-billed Gull  1
Great Blue Heron  1
Belted Kingfisher  1
Northern Flicker  7
Blue Jay  1
Black-billed Magpie  3
American Crow  4
Black-capped Chickadee  8
Ruby-crowned Kinglet  1
Red-breasted Nuthatch  2
House Finch  14
Dark-eyed Junco (Oregon)  1
Red-winged Blackbird  4

Milavec Reservoir, Jan 11, 2020–with Jamie Simo

Cackling Goose (left) vs Canada Goose (right) (c) Jamie Simo

Milavec Reservoir in Frederick, CO is one of the best places along the Front Range to see all the possible (read: non-rare) interior goose species. Sometimes, like last year, it even plays host to some rarities like the Colorado-record Pink-footed Goose and Barnacle Goose. As hoped for, while we didn’t see any Colorado-record geese on this frigid, but sunny, Saturday morning, we did see all the usual goose suspects. We also had some great ducks and raptors.

Nearly all Coloradans are familiar with our only breeding goose species, the Canada Goose, but winter brings migrant Cackling, Greater White-fronted, Ross’s, and Snow Geese from the arctic to our lakes, reservoirs, and fields. The most similar to the Canada Goose, the Cackling Goose was only recognized as a species in its own right in 2004. There are 4 subspecies of Cackling Goose varying in size and color, but some of the common characteristics include smaller body size than the majority of Canada Geese (there may be some overlap with the smallest subspecies of Canada Goose), a shorter neck, and a bill that looks “stubby” because of a more rounded or square head shape. Because of the difficulty of distinguishing between the smallest subspecies of Canada Goose and the largest subspecies of Cackling Goose, small white-cheeked geese are sometimes referred to as “Cackling-ish.”

Ross’s Goose (foreground) vs Snow Goose (background) (c) Jamie Simo

Like the Canada Goose, the Snow Goose also has a “mini-me” doppleganger, the Ross’s Goose, but that doppleganger is much easier to pick out than the Cackling Goose. Firstly, Snow Geese come in either the expected white plumage with black wingtips or a darker, grey-blue body plumage with white head and neck. Both have pink bills and feet as adults. The latter is sometimes referred to as a “blue goose, “blue morph,” or “blue phase” Snow Goose. There are only 2 subspecies of Snow Goose, but both have a black “grin patch” that gives them a sneering appearance, and a sloping forehead. By contrast, the Ross’s Goose, which is usually white but also occurs rarely in a blue phase, has a steep forehead leading to a rounded crown and lacks the grin patch.

The final expected goose species in Colorado is the Greater White-fronted Goose. This goose is mostly brownish-grey with darker belly bands, orange legs and bill, and white feathers around the base of the bill from which is gets its name.

Other stand-out species were 2 adult Bald Eagles, a Northern Harrier, a Red-breasted Merganser, a female Canvasback, and even a coyote. Not bad for a cold, January morning!

Female Northern Harrier (c) Chris Friedman

Frederick Lake (Milavec Reservoir) & Recreation Area, Jan 11, 2020
25 species

8 Snow Goose
3 Ross’s Goose
1 Greater White-fronted Goose
2000 Cackling Goose
4000 Canada Goose
60 Northern Shoveler
10 Mallard
1 Canvasback
7 Lesser Scaup
3 Bufflehead
20 Common Goldeneye
7 Common Merganser
1 Red-breasted Merganser
1 Ruddy Duck
3 American Coot
1 Northern Harrier
2 Bald Eagle
1 Red-tailed Hawk
1 American Kestrel
1 Blue Jay
6 European Starling
6 American Tree Sparrow
1 White-crowned Sparrow (Gambel’s)
2 Song Sparrow
1 Red-winged Blackbird

Harriman Lake, Jan 4 – with Chuck Aid

Rough-legged Hawk topography (c) Bill Schmoker

Nice mild weather prevailed on Saturday as we enjoyed a 1.6-mile stroll around Harriman Lake.  It was more than half frozen over, but that was perfect as it concentrated all the ducks a bit more and provided a nice shelf of ice for a local immature Bald Eagle.  In order to talk a bit more about plumages of Bald Eagles we need to learn a bit more about bird topography.  If you will look at the diagram, you can see that the coverts are the smaller feathers that cover the bases of the larger flight feathers – the primaries and secondaries.  There are upper-wing coverts and underwing coverts.  There are also upper and lower tail coverts that cover the bases of the main flight feathers in the tail.  I’ve labeled two other parts because they can be important terms for the identification of other raptors.  The carpal is the “wrist” of the bird, and some birds, such as the Rough-legged Hawk in this photo have a distinct carpal patch.  The patagium is the leading edge of the wing, and this can be important because to varying degrees all Red-tailed Hawks have a dark patagium.

Bald Eagle – 2nd year (c) Bill Schmoker

So, back to our Bald Eagle. It takes Bald Eagles five years to obtain their full adult plumage with the white head and tail.  During their first year they have dark brown eyes, a dark bill, and are mostly brownish overall.  During subsequent years the eyes become light brown and eventually yellow, the bill too becomes increasingly yellow.  The plumage during the intermediate years can be quite variable but tends toward a brown and white mish-mash.  For example, a first-year bird tends to have a brown belly with white underwing coverts; most second-year birds develop a white belly with extensive white underwing coverts and some white in the underwing secondaries and tail; third-year birds tend to have darker bellies than second-year birds and the underwings, while still having some white blotchiness, are darker; fourth-year birds are tending towards full adulthood with a blackish-brown belly having some white flecking, and the hood and tail are mostly white but not completely. Our bird on Saturday was a second-year Bald Eagle, much like the bird in the photo but with more white above the eye. To cut to the chase, second-year birds have more white on the body and underwings than any other year.

Best of luck with all your upcoming raptor identifications!



Harriman Lake, Jan 4, 2020
26 species

Canada Goose  125
American Wigeon  12
Mallard  7
Canvasback  2
Redhead  44
Ring-necked Duck  1
Lesser Scaup  2
Bufflehead  6
Common Goldeneye  4
Hooded Merganser  15
Common Merganser  1
Pied-billed Grebe  4
Eurasian Collared-Dove  1
American Coot  160
Ring-billed Gull  3
Bald Eagle  2 (1 adult and 1 2nd-year)
Red-tailed Hawk  2
Northern Flicker  4
Blue Jay  7
Black-billed Magpie  6
American Crow  4
Common Raven  1
Black-capped Chickadee  2
European Starling  7
Song Sparrow  3
Red-winged Blackbird  40

South Platte Park, Dec 7 – with Chuck Aid

Common Mwergansers (c) Bill Schmoker

On Saturday we visited two main destinations.  We started at South Platte Reservoir, famous in the local birding community for having a county line bisect it thus providing a potential opportunity to see whatever waterfowl are present in both Jefferson and Arapahoe Counties – that is if said waterfowl cooperate and swim from one side of the reservoir to the other. County listing has become quite the recreational sport, and instead of just “seeing” birds, the focus is to “get” them, i.e. be able to enter them on a specific list or lists (county, state, country, month, year, etc.).  A few of us don’t play this game as vigorously as others.  Our second destination was the four “lakes” (AKA old gravel pits) immediately north of C-470 along the South Platte River – Blackrock, Eaglewatch, Redtail, and Bufflehead Lakes.  This general area is a favorite destination and often has great birds.

Long-tailed Duck – female (c) Bill Schmoker

We had two uncommon sightings from the dike surrounding South Platte Reservoir.  First, a pair of Long-tailed Ducks was seen, but only at a distance so the views were not great.  This duck was formerly known as Oldsquaw in North America, but in 2000 the American Ornithologists’ Union changed the name to Long-tailed Duck, the name by which it is known in Europe.  It is primarily circumboreal in its distribution, breeding in the arctic, but with a few wandering south to the lower forty-eight each winter, primarily to New England and the Great Lakes region, but we’re fortunate to get some here in Colorado.

Harlan’s Red-tailed Hawk (c) Bill Schmoker

Our second good sighting from up on the dike was of a Harlan’s Red-tailed Hawk.  There are about 12 subspecies of Red-tails, adding a lot of fun to trying to properly identify them.  Harlan’s is among the darkest of these subspecies, being primarily black with a dusky white tail that lacks any hint of red.  They have a characteristic white streaking on the breast that can be helpful in their identification.  One of the real keys when seeing a bird in flight, as we did, is to be able to first identify it as a Red-tail, and its overall silhouette is a major key.  Red-tails, compared to other soaring hawks (the Buteos) are stocky, broad-winged even out to the tips of their wings (not pointed), and a real key is that they have bulging secondaries – that is the wing is widest where the secondary feathers are.  Once you have narrowed your soaring hawk down to it being a Red-tail, then you can start tuning in to which subspecies it might be.  One interesting aspect of Harlan’s is that about 99% of them are dark morph.  Almost all the other subspecies are only about 10% dark morph.  Get your field guides out and see if you can see what I’m talking about here.  Locally, our most common Red-tail is the light morph of the Western subspecies (Buteo jamaicensis calurus), noted for its pale breast, streaked belly band, white spotting on its scapulars, dark head, dark chin, and adults with a red tail. Finally, one last characteristic to be aware of is that ALLRed-tails have a dark patagial bar – the leading edge of the wing.  It’s less obvious in some subspecies than others, but it’s there.

Marsh Wren (c) Bill Schmoker

Our third great bird of the morning was a Marsh Wren.  These wrens breed in cattail marshes and have been recorded every month of the year in Colorado, though they are more uncommon in winter.  Their pattern of residency is a bit of a puzzle: some marshes have breeders, many evidently suitable marshes never have breeders, other marshes only have Marsh Wrens in the winter, and other sites have birds all year long.  Here’s a gross generalization – Most large marshes which tend to remain unfrozen throughout the winter generally will have some wintering populations, but there are no guarantees.

Hope you are planning on having fun participating in one of Colorado’s fifty Christmas Bird Counts!



South Platte Park, Dec 7, 2019

31 species

Canada Goose                          7
Northern Shoveler 460
Gadwall   18
Mallard   14
Green-winged Teal     4
Ring-necked Duck   18
Lesser Scaup   11
Long-tailed Duck     2
Bufflehead   38
Common Goldeneye   25
Hooded Merganser   31
Common Merganser   12
Ruddy Duck   13
Pied-billed Grebe     2
Eared Grebe     1
Rock Pigeon   18
American Coot   15
Ring-billed Gull   15
Bald Eagle     1
Red-tailed Hawk                            2
Harlan’s Red-tailed Haw     1
Belted Kingfisher     3
Downy Woodpecker     1
Northern Flicker     3
American Kestrel     1
Blue Jay     1
Black-billed Magpie     1
American Crow     2
Marsh Wren     1
European Starling     1
American Robin     1
American Goldfinch     1


Boulder Reservoir, November 9, 2019–with Aidan Coohill

Female Ruddy Duck (c) Jamie Simo

We started our walk at Boulder Reservoir with excellent sunny weather and low wind, allowing us to see the birds on the lake quite easily without many waves. Boulder Reservoir is the largest reservoir in the county in terms of both size and volume creating an excellent environment for birds but also for recreational boating, fishing, swimming, and jogging. It also provides and holds all water for the Northern Water Distinct for drinking and irrigation. We covered the area in two sections, the first on the southwestern shore of the reservoir which is extremely popular in summer for recreation, and the northern section from the West Reservoir Trailhead. 

Immediately after parking we found a large group of American coots feeding in the shallows of the swim beach. Among the flock was a lone female Ruddy duck. Belonging to the genus of “Stiff-tailed ducks”, it is a small freshwater fowl with a large range across North America. Like all in its genus, the Ruddy duck has a stiff tail (often described as looking like a bundle of Popsicle sticks), males have a bright blue bill, and a body that depending on season and sex is rusty to brown in color. These birds are currently in the process of moving to their warmer wintering grounds further south in the Unites States and into Northern Mexico. 

Bonaparte’s Gull (c) Jamie Simo

Further down the shoreline we found the Rusty blackbirds that have been seen in the area for the last several days, a rarity that drew many local birders to the reservoir. This blackbird is very similar to the Brewer’s blackbird that is common in Colorado but is an uncommon accidental migrant in this part of the west. Unlike the Brewer’s blackbird, it prefers quiet spruce forest and boreal bog and not parks, fields, pastures, lawns, and parking lots. During winter the differences between the sister species becomes most obvious with both the male and female getting buffy and ruddy patterning on their bodies. This was the state the pair we saw were in. 

On the north side of the reservoir we got another cool sighting, two Bonaparte’s gulls. This small bird is the smallest gull in North America aside from the elusive Little gull. They have dainty pink feet, a small beak, and off-white coloring. During winter plumage (what we saw) it trades its distinctive black hood for white save for a small black patch over the ear. These gulls are a real treat as they head south for the winter. 

Other highlights included a Ferruginous hawk perched in a tree on our way out, a pair of Northern harriers, and all three species of mergansers!

In all, we heard or saw 28 taxa; good for this time of year at the reservoir! 

Boulder Reservoir, November 9, 2019
27 Species (+1 additional taxa)
  • Cackling Goose 250
  • Canada Goose 100
  • Gadwall 2
  • Mallard 2
  • Lesser Scaup 1 
  • Common Goldeneye 8
  • Hooded Merganser 15
  • Common Merganser 8
  • Red-breasted Merganser 6
  • Ruddy Duck 1
  • Horned Grebe 1
  • Western Grebe 6
  • American Coot 80
  • Bonaparte’s Gull 2
  • Ring-billed Gull 200
  • Herring Gull 1
  • Great Blue Heron 1
  • Northern Harrier 2
  • Red-tailed Hawk 3
  • Red-tailed Hawk (Harlan’s) 1
  • Ferruginous Hawk 1
  • Blue Jay 1
  • Black-billed Magpie 2
  • Black-capped Chickadee 2
  • European Starling 100
  • House Finch 4
  • Red-winged Blackbird 1
  • Rusty Blackbird 2

If anyone would like me to share the eBird checklist with them please email me at

Wheat Ridge Greenbelt, Nov 2, 2019 – with Chuck Aid

Great Horned Owl (c) Jeff Jaacks

Okay, here’s the good news! Breeding season has started! Wahoo!  The probable evidence for this was seen on Saturday as we viewed a cozy pair of Great Horned Owls exhibiting some fondness for one another’s company.  Great Horned Owls can maintain their pair-bond year-round, but these two were perched so close to one another that it felt as though an even greater increased intimacy was in the air.  We also know that copulation has been observed elsewhere in Colorado as early as November (pers. com. Rob Raker), and that incubation can start in January.  December can be a great time to hear dueting males and females – the male, though about 10% smaller than the female, has the deeper hoot (listen below).  So, make sure to step outside on a brisk December night and see if you can hear anything.

Cackling and Canada Geese (c) Bill Schmoker

So, other than owls, we had some great waterbirds.  Cackling Geese, the diminutive cousin of the Canada Goose, were in abundance.  These guys breed in the far northern Arctic and then winter throughout the southern Great Plains, including eastern Colorado. They are very similar to Canada Geese, but distinguished by their smaller size (some hardly bigger than a Mallard), relatively short neck, and stubbier bill.  This is not an easy distinction to make, and I struggle with it yearly.  We, also, had eight duck species, and spent quite a bit of time working on the finer points of duck identification.

Virginia Rail (c) Bill Schmoker

A real highlight was getting to SEE both a Wilson’s Snipe and a pair of Virginia Rail.  Both of these species occur year-round in Colorado, though the rail, in particular, is uncommon in winter.  We saw the Wilson’s Snipe in flight, noting its twisting, zig-zag flight, and very long bill.  Only a few minutes later, we had two Virginia Rail pop out briefly from some dense cattails about eight feet in front of us, and then they were gone in an instant.  A third one was heard in a different spot. Pretty special to see both of these species on the same outing!

Finally, we had a good variety of songbirds.

Hope to see you on another walk soon!

Wheat Ridge Greenbelt, Nov 2, 2019
38 species

Cackling Goose  180
Canada Goose  50
Northern Shoveler  32
Gadwall  22
Mallard  35
Green-winged Teal  2
Bufflehead  14
Common Goldeneye  8
Hooded Merganser  24
Ruddy Duck  2
Rock Pigeon (Feral Pigeon)  6
Virginia Rail  3     
American Coot  14
Wilson’s Snipe  1
Ring-billed Gull  46
Cooper’s Hawk  1
Red-tailed Hawk  1
Great Horned Owl  2
Belted Kingfisher  3
Downy Woodpecker  1
Northern Flicker  7
Blue Jay  6
Black-billed Magpie  11
American Crow  8
Common Raven  2
Black-capped Chickadee  16
White-breasted Nuthatch  3
Brown Creeper  1
European Starling  7
American Robin  2
House Finch  10
American Goldfinch  12
American Tree Sparrow  6
Dark-eyed Junco  1
White-crowned Sparrow  5
Song Sparrow  10
Spotted Towhee  2
Red-winged Blackbird  9


Hudson Gardens, Oct 26, 2019 – with Chuck Aid

Hooded Merganser (c) Bill Schmoker

Well, I think we can safely say that the eclipse plumage time of the year (when males briefly have a female-type cryptic plumage) is over and that everybody is pretty much set with their fancied-up breeding plumage for next spring.  Also, our winter ducks are starting to really roll in (fly in) now. So, who did we see on Saturday? For starters we had a good number of Gadwall – the male with his black butt and puffy head, and both sexes with the white secondaries making a little white spot on the sides when not in flight.  There were also some great American Wigeons – the male with his white (or creamy) forehead, green swoosh through the eye, black butt, and big white hip patch; the female with her smeared mascara, and both with their warm coloring on their flanks. Mallards were looking glorious – the male with his green head, white collar, brown breast, and black curly tail; the female with her orange bill with a black blob on it; and both with their white tail feathers.  Next there were a few Green-winged Teal – the male with his cinnamon head, green eye swoosh and vertical white bar on his flanks; and both male and female showing some buffy, pale yellow in the tail.  Finally, we had three Hooded Mergansers – the male with his white crest bordered in black, the two vertical black stripes on his upper breast; the female with her frosty-brown punked-out crest; and both with their bright yellow eyes.

Belted Kingfisher – female (c) Bill Schmoker

I urge you newbie birders to get out your field guides and note these characteristics that I’m pointing out, so next time you can tell me what we’re seeing.  And remember that we’ll be focusing a lot on waterfowl through the winter months because we get such a great variety here in the Denver area, including a whole slew of diving ducks, loons, and grebes.

One of our real treats on Saturday was the great look we had of a Belted Kingfisher.  We could tell it was a male, because it had the single dark gray breast-band and had no rufous coloring in the breast or flanks at all. It was noted that a good spotting scope really helps discern the finer points of these incredible birds with their shaggy crest and HUGE bill.

Bushtit – female (c) Bill Schmoker

A real highlight was the good variety of songbirds that we managed to see, a great many of them at the Hudson Gardens feeders and in that vicinity.  I recommend spending some time there sitting on one of the benches and just seeing what might show up.  I think we had thirteen species there.  If you get the chance to see the little gray Bushtits note that the male has dark eyes and the female has yellow eyes.

See you on another walk soon!

Hudson Gardens, Oct 26, 2019
28 species (+1 other taxa)

Canada Goose  3
Gadwall  19
American Wigeon  5
Mallard  42
Green-winged Teal  11
Hooded Merganser  3
Killdeer  1
Ring-billed Gull  2
Double-crested Cormorant  3
Belted Kingfisher  1
Downy Woodpecker  1
Northern Flicker  5
Black-billed Magpie  9
American Crow  1
Black-capped Chickadee  11
Bushtit  9
Ruby-crowned Kinglet  1
Red-breasted Nuthatch  1
White-breasted Nuthatch  4
European Starling  2
American Robin  5
House Finch  27
American Goldfinch  3
Dark-eyed Junco  1
Dark-eyed Junco (Oregon)  2
White-crowned Sparrow  2
Spotted Towhee  1
Red-winged Blackbird  25
Yellow-rumped Warbler  1

Barr Lake, Oct 5, 2019 – with Chuck Aid

Meredith McBurney and Wilson’s Warbler (c) Heather Davis

It was a glorious morning at the Bird Conservancy of the Rockies’ banding station at Barr Lake this past Saturday!  The Conservancy has been banding fall migratory birds here for over thirty years, and each year adds additional knowledge to what we know about these birds that pass through Colorado. We hustled out there, so didn’t really look at the few birds noted along the path.  Initially, there was a bit of a breeze blowing, so only a few nets were open, but Meredith McBurney and the banding crew did have a couple of birds they had caught.  Then, in the next half-an-hour or so, the breeze let up, the birds started moving around more, and the action got pretty good.  In fact, it was so good, and Meredith so entertaining in explaining so many aspects of what she does, that we ended up spending almost two-and-a-half hours there.

Wilson’s Warbler (c) Laurel Starr



Birds that we got see in the hand, and that some of us got to briefly hold in our hands, included: a feisty Black-capped Chickadee, a Ruby-crowned Kinglet, a couple of Dark-eyed Juncos of two subspecies – Oregon and Pink-sided, a couple of White-crowned Sparrows – subspecies “Gambel’s,” a Song Sparrow, a Lincoln’s Sparrow, an Orange-crowned Warbler, several Yellow-rumped Warblers –  all in the “Audubon’s” group, and two Wilson’s Warblers.  Each individual bird got to be looked at and discussed in detail. 


Meredith McBurney at banding station (c) Laurel Starr

For starters, let’s talk about Juncos a little bit (better get your field guides out).  Here in North America we have about fifteen Junco subspecies, some of these more closely related than others.  Seven of these groupings have recognizably different plumages.  One, the Gray-headed Junco, breeds in our mountains each summer.  They, then, stick around through the winter, and six of the other groups, which have bred further north come down to also spend the winters here, and these have just started to arrive in the last couple of weeks.  The two we saw were the Oregon and the Pink-sided.  Note how the Oregon, regardless of whether it’s a male or female does not have black lores (the area between the eye and the bill), while the Pink-sided does have black lores.  This is a really key characteristic because the duller colored individuals of both groups can otherwise look quite similar.

White-crowned Sparrow – juvenile (c) Patrick Blasco

Now, let’s take a quick look at White-crowned Sparrows.  We have two predominant subspecies here in Colorado.  The oriantha ones have black lores and breed up in the highest willow carrs and krummholz – right at timberline.  They then spend winters in the southwest US and northern Mexico. The gambelii ones breed in far northern Alaska and Canada, and many pass through Colorado in the fall on their way to winter in Oklahoma and Texas.  However, we can still have good numbers of both subspecies locally in the winter out on the eastern plains.


Orange-crowned Warbler (c) Doris Huguley

And, a bit on the warblers we saw. The orange crown of the Orange-crowned Warbler is almost never seen in the field.  However, when in the hand, it’s possible to part the feathers on the head of a male and see a small patch of orange – which is exactly what we observed. We had a good variety of Audubon’s Warblers (note that the pale throat patch is confined to the throat and does not wrap around the side of the neck, as in the Myrtle Warbler). The rumps of all the ones we saw were bright yellow – this is the only part of the bird that retains that bright breeding yellow.  The yellow patches on the flanks were quite variable depending on whether we had a male, female, or juvenile.  Our two Wilson’s Warblers were bright yellow males with black caps.

White-crowned Sparrow – juvenile (c) Heather Davis

While doing all our banding station activities we spent almost no time looking at the hundreds of birds out on Barr and its surrounding mudflats.  A few notables though were the 800 or so Western Grebes, one Stilt Sandpiper, five species of gulls – including a couple of Lesser Black-backed Gulls, and a bunch of Double-crested Cormorants and American White Pelicans.




Cassin’s Vireo (c) Heather Davis

Finally, THE BIRD OF THE DAY was one more from the banding station, a Cassin’s Vireo!  These guys breed up in the Pacific Northwest and pass through Colorado when going to and from western Mexico.  They are rare during spring migration, but we do have the opportunity to possibly see a few during fall migration.  Historically, they, the Plumbeous Vireo, and the Blue-headed Vireo were considered to be one species, the Solitary Vireo, but in 1997 they gained recognition as three separate species.  The Plumbeous Vireo is the one that we know best in Colorado as they breed in our lower mountains and western canyons.  These guys have the distinctive “Solitary Vireo” white spectacles and are virtually all gray.  The Cassin’s Vireo, on the other hand, also has the white spectacles, but it has a greenish-gray back and hood with a yellow wash on the flanks, and some yellow in the wings.

A full morning at Barr Lake will keep our heads spinning for a while.  Hope to see you on another walk soon!


Barr Lake SP, Oct 5, 2019
36 species (+5 other taxa)

Canada Goose  68
Western Grebe  500
Western/Clark’s Grebe  300
Eurasian Collared-Dove  1
American Coot  6
Killdeer  44
Stilt Sandpiper  1
Franklin’s Gull  3
Ring-billed Gull  100
California Gull  60  
Herring Gull  3
Lesser Black-backed Gull  1     

gull sp.  500
Double-crested Cormorant  300
American White Pelican  200
Great Blue Heron  8
Bald Eagle  1
Red-tailed Hawk  1
Hairy Woodpecker  1
Northern Flicker  2
Cassin’s Vireo  1   
Blue Jay  7
Black-billed Magpie  1
Black-capped Chickadee  3
Barn Swallow  180
Ruby-crowned Kinglet  1
European Starling  6
American Robin  1
House Sparrow  30
House Finch  1
Dark-eyed Junco  5
Dark-eyed Junco (Oregon)  1
Dark-eyed Junco (Pink-sided)  1
White-crowned Sparrow (Gambel’s)  2
Song Sparrow  1
Lincoln’s Sparrow  1
Orange-crowned Warbler  1
Yellow-rumped Warbler  7
Yellow-rumped Warbler (Audubon’s)  7
Wilson’s Warbler  2

Hudson Gardens, Sept 28, 2019 – with Chuck Aid

Wood Duck – juvenile male (c) Bill Schmoker

We had an incredibly entertaining start to our walk on Saturday.  This year mama Wood Duck had about eight fledglings back in July.  Last month we were thrilled to see that six of them were still around, and we were able to tell that they were all males.  We could see the characteristic bright white “bridle” that the males have on their neck and cheek, even though the rest of the outrageous male plumage hadn’t quite emerged. On Saturday we were able to see, once again, all six of this year’s juvenile males.  Not too much had changed from a month ago except that they were considerably bigger (almost adult sized), there was starting to be some color definition in the bill, their eyes were getting red, and we could see some of that wonderful deep bluish turquoise in their speculums (the secondary flight feathers). However, they also still had their white eye-rings that are characteristic of juvenile birds.

Wood Duck – female (c) Bill Schmoker

Beyond the six youngsters we also had an adult female Wood Duck (mom?), and three adult males.  These latter were all in the process of emerging from their eclipse plumage phase when the males go through a sequence of molts causing them to look more drab, like their female counterparts.  It can take them awhile to regain their full male splendor, and all three of our Saturday males had different degrees of white speckling in what will become eventually a mostly burgundy-colored breast.  Part of what was so cool about this herd of Wood Ducks is that they were all tending to hang out together foraging in the grass along with some companionable female Mallards, and they were not worried about us at all.

Killdeer (c) Bill Schmoker

As we moved over to the South Platte we saw more Mallards – the males in a mix of plumages between cryptic brown and bright breeding colors, as they, too, are emerging from their eclipse plumage. We also were fortunate to see some Killdeer and a single Spotted Sandpiper which actually will have no spots until next March at the advent of breeding season. 

Cedar Waxwing (c) Bill Schmoker

We also encountered a nice flock of Cedar Waxwings, being a mix of beautiful warm-brown adults and streaky juveniles.  In the adults some of the secondary flight feathers have bright red tips from a waxy red secretion resembling sealing wax.  Historically, Cedar Waxwings were considered uncommon breeders in Colorado, being more common during spring and fall migration and throughout the winter.  However, in more recent years the number of breeders have increased dramatically along water courses in North, Middle, and South Parks and the San Luis Valley.  The resultant increase in the Colorado population may be due to a number of factors: an increase in edge habitat which promotes the growth of fruiting trees and shrubs, the planting of non-native fruiting trees and shrubs, the planting of shelter-belts, and the ongoing increase in Russian olives.

Great Blue Heron (c) Bill Schmoker

One of the topics that came up on our walk was about those species that breed in Colorado and afterwards most of them migrate south, but there are always a few individuals that stick around throughout the winter.  We were speaking primarily of Great Blue Herons, but there are quite a few others that follow this pattern such as American Kestrel, Killdeer, Mourning Dove, Say’s Phoebe, American Robin, and Spotted Towhee.

Undoubtedly the highlight of the morning was getting to watch a juvenile Red-tailed Hawk from about twenty feet away (I kid you not!) eviscerate a cottontail.  I’m thinking that as a youngster it still may have been learning the craft of capturing its own prey, and perhaps it was so darn hungry it just did not care whether we were there or not.

Hope to see you on another walk soon!


Hudson Gardens, Sept 28, 2019
27 species

Red-tailed Hawk- juvenile (c) Bill Schmoker

Canada Goose  6
Wood Duck  10
Mallard  32
Rock Pigeon (Feral Pigeon)  2
Broad-tailed Hummingbird  2
Killdeer  4
Spotted Sandpiper  1
Ring-billed Gull  1
Great Blue Heron  1
Turkey Vulture  1
Red-tailed Hawk  2
Downy Woodpecker  1
Northern Flicker  10
Say’s Phoebe  2
Blue Jay  8
Common Raven  1
Black-capped Chickadee  8
Red-breasted Nuthatch  2
White-breasted Nuthatch  3
European Starling  2
American Robin  4
Cedar Waxwing  20
House Finch  14
Lesser Goldfinch  1
Song Sparrow  3
Red-winged Blackbird  6
Yellow-rumped Warbler  2

Lagerman Agricultural Preserve, September 14, 2019–with Jamie Simo

Least Sandpiper in breeding plumage. Photo by Jamie Simo.

September is a great month to look for migrants and this past Saturday at Lagerman Agricultural Preserve didn’t disappoint on that count. We also welcomed our newest employee, Stephen Chang, to the FRBC team on this bird walk. Welcome, Stephen!

Baird’s Sandpiper in foreground and Least Sandpiper in background. Photo by Jamie Simo.

Unlike spring migration where birds are in a rush to find nesting territories, fall migration is a more leisurely affair, so we saw stopover species that breed farther north, Colorado breeders, and species that winter along the Front Range. In the stopover species category, we saw both Least and Baird’s Sandpipers. Least Sandpipers are the smallest shorebird species in the world and are long-distance migrants breeding in the arctic and wintering in Mexico and Central America. In addition to size, Least Sandpipers can be distinguished from the other small sandpipers classified as “peeps” by their yellow legs (the other four “peeps,” Western, Semipalmated, Baird’s, and White-rumped Sandpipers, have dark legs). In September, Least Sandpipers are still in breeding plumage and appear rusty with a couple of paler stripes down the back.

Baird’s Sandpipers are also long-distance migrants that breed in the arctic, although they travel even farther in winter than Least Sandpipers and fly all the way down to Chile and Argentina. Perhaps because of this they have long wings that extend slightly past their tails. They tend to look somewhat “scaly-backed,” especially juveniles, with dark-centered feathers on their backs edged with a paler tan. Their breasts are also tan with pale striping that doesn’t extend onto the clean white of their bellies and flanks.

Male Brewer’s Blackbird. Photo by Jamie Simo.

For species breeding in Colorado, we saw a number of Brewer’s Blackbirds. Brewer’s Blackbirds are often found in agricultural areas. Males are an iridescent black with a pale eye. The pale eye, lack of red shoulder patches, and thinner bill, distinguish them from the similar male Red-winged Blackbird. Female Brewer’s Blackbirds are brown with a dark eye and can be distinguished from the similar female Brown-headed Cowbird by being darker, larger, and having a thinner bill.

Finally, we were fortunate to see the first vanguard of several species that winter in our area, including the Ring-necked Duck. Despite being named for the ring around their neck, which is usually only visible at close range, Ring-necked Ducks have grey bills tipped with black and ringed with a band of white. Both males and females have peaked heads. Females are brown with a darker brown “saddle” on their backs and a white patch near the base of the bill. In non-breeding plumage, males can be picked out from females by their dark breasts, darker heads, and yellow eyes.

Male and female non-breeding Ring-necked Ducks next to American Coot. Photo by Jamie Simo.

In all, we saw 28 species. Join us next month at our Boulder location when we check out Barr Lake State Park and visit Bird Conservancy of the Rockies’ banding station.

Lagerman Agricultural Preserve, Sep 14, 2019
28 species (+1 other taxa)

Canada Goose 16
Blue-winged Teal 4
Cinnamon Teal 1
American Wigeon 24
Mallard 6
Green-winged Teal 2
Redhead 3
Ring-necked Duck 3
Ruddy Duck 3
Pied-billed Grebe 5
American Coot 12
Killdeer 6
Baird’s Sandpiper 4
Least Sandpiper 2
Short-billed/Longbilled Dowitcher 7
Ring-billed Gull 57
Double-crested Cormorant 13
American White Pelican 2
Great Blue Heron 2
Turkey Vulture 2
Osprey 1
American Kestrel 2
Say’s Phoebe 2
Barn Swallow 11
Lesser Goldfinch 3
American Goldfinch 2
Vesper Sparrow 4
Western Meadowlark 4
Brewer’s Blackbird 6