Hudson Gardens Bird Walk January 30, 2021
What a great morning, and great crew of folks! Wow! We saw so many cool birds today it’s hard to know where to start. However, we’ll begin with the waterfowl. Based on what we saw on Saturday it appears that some of our ducks (and Cackling Geese) may have already begun moving north out of our area. This, however, is probably not the case as April tends to be the peak of waterfowl migration. We’ll just have to keep an eye out and see how things progress. Certainly, the high point of the ducks was getting to see four male Red-breasted Mergansers – one of my favorites. The island on Tabor Lake is starting to get its spring influx of Double-crested Cormorants, and we recorded almost thirty, complete with their doofy double-crests sticking out on either side of their heads.
With regard to the raptors, we had some good ones, starting with an adult Sharp-shinned Hawk. This smallest of our accipiters was initially observed perched in a tree where we could make out its orange breast, but the tail was hidden. Then we got to watch it dive rapidly down amongst a small group of squawking American Robins that were totally thrown off their game. Sharp-shins are dramatically sexually dimorphic, the male being the smallest hawk in North America weighing 3-4 ounces and the female weighing 5-8 ounces. A male Sharpie, which I believe our bird was based on its apparent size, has a wingspread of about 20-22 inches and is about 9-10 inches long. An American Robin, therefore, is only slightly smaller than a Sharpie, the biggest difference being that a Sharpie has longer wings than a robin which can make it appear bigger.
We also got a brief look at a Merlin, our second largest falcon, zipping past us with its characteristic direct, powerful, fast flight. Our smallest falcons are American Kestrels, which, in contrast to Merlins, have a buoyant and wandering flight style. Finally, the last bird of the day (seen from the parking lot as I was leaving) was a Harlan’s Hawk. This is one of the many subspecies of Red-tailed Hawk. As with the other subspecies there are both light and dark morphs, but while for most of the subspecies, like our generic western Red-tails, the light morph is the dominant look, for Harlan’s almost 90% of them are of the dark morph variety. Overall, what you see is a very dark bodied hawk with dark underwing coverts, the flight feathers are a light gray with black tips causing the back edge of the wing to have a black border. Then, the tail is light gray with a smudgy darker gray terminal band.
At one point we ran into a pair of Brown Creepers, one of which was singing. It’s a delightful little song, and really pretty unique once you become aware of it.
Finally, among our many highlights, perhaps the best of the day was getting to watch a flock of beautiful adult Cedar Waxwings sallying out and feeding on insects directly above Clear Creek. They are gorgeous birds and we got great views.
Good birding! Chuck
Wheat Ridge Greenbelt. Mar 6, 2021
37 species (+2 other taxa)
Canada Goose 76
Cackling/Canada Goose 6
Northern Shoveler 102
Gadwall 82
Mallard 50
Green-winged Teal 36
Redhead 1
Ring-necked Duck 4
Lesser Scaup 4
Bufflehead 4
Common Goldeneye 8
Hooded Merganser 22
Red-breasted Merganser 4
Rock Pigeon (Feral Pigeon) 1
Eurasian Collared-Dove 1
Mourning Dove 2
American Coot 44
Ring-billed Gull 34
Double-crested Cormorant 28
Sharp-shinned Hawk 1
Red-tailed Hawk 2
Red-tailed Hawk (Harlan’s) 1
Downy Woodpecker 4
Hairy Woodpecker 1
Northern Flicker 14
American Kestrel 1
Merlin 1
Black-billed Magpie 3
American Crow 3
Black-capped Chickadee 32
Red-breasted Nuthatch 1
White-breasted Nuthatch 2
Brown Creeper 2
American Robin 12
Cedar Waxwing 13
House Finch 18
Song Sparrow 3
Spotted Towhee 3
Red-winged Blackbird 70
Walden Ponds, Sawhill Ponds and Boulder Creek – February 27, 2021 – with Sheridan Samano
Last Saturday morning, there was enough interest for two different bird walks at the Walden Ponds/ Sawhill Ponds Complex in Boulder. Both groups met at Cottonwood Marsh, but with different start times and routes. The avian highlights varied substantially between the two walks.
To start, the 8 am group noticed several male Red-winged Blackbirds displaying and singing in the cattails on the south side of the marsh. It won’t be long before we see an influx of even more males and females as spring progresses and breeding season is in full swing. 
From Cottonwood Marsh, we headed to the northwest corner of Duck Pond where the group started practicing their duck ID skills. In winter, ducks showcase their fine-feathered breeding plumage so this time of year offers excellent opportunities to learn how to distinguish between common species in the area. At Duck Pond, we found Hooded Mergansers, Ring-necked Ducks, Gadwalls, American Wigeon, and Mallards. As we watched the various individuals from the same species, we noticed that members of the same species tend to move together in groups. Female ducks are harder to distinguish, but they’re often traveling with male counterparts. Those observations can help birders ID ducks on future outings. 
Each pond we passed offered a different collection of waterfowl so we had several opportunities to practice telling species apart. Finding a large group of male Green-winged Teal in a large pond north of Duck Pond, the smallest dabbling duck in North America, was a highlight for everyone. Green-winged Teal are often found at shallow edges of ponds. They often walk along muddy edges, too.
By the time the second walk started at 10:15 am, the skies were clearing and it was much warmer. These conditions favored raptor activity so the focus of the second walk shifted from examining ponds to searching perches and the sky overhead.
An adult Bald Eagle perched noticeably on a tower east of Cottonwood Marsh greeted the group. This individual was likely from the pair that nests east of 75th Street. We could see the second half of the pair at the nest tree.
Instead of heading due west from Cottonwood Marsh as we did during the first walk, we headed north towards Boulder Creek. On the west side of Cottonwood Marsh, we spotted a male American Kestrel perched on a stump with his back to us. This view provided an opportunity to discuss coloration differences among the sexes of North America’s smallest falcon. Female Kestrels don’t have blue-gray wings like males. We got a second, better look at this male later in the walk.
Other raptor highlights during the second walk included multiple Red-tailed Hawks, a third year Bald Eagle, and a Golden Eagle. A member of our group mentioned she was hoping to see a Golden Eagle this morning so having one fly overhead at the end was an excellent way to end our morning of birding.
The Walden Ponds and Sawhill Ponds Complex is featured in Best Birding Hikes – Colorado’s Front Range. The Complex offers some of the best year-round birding opportunities in Boulder County. No matter the month, a birding outing here is sure to deliver. 
22 Species Observed during 8 am Bird Walk (eBird Checklist)
Canada Goose – 13
Northern Shoveler – 5
Gadwall – 24
American Wigeon – 10
Mallard – 25
Green-winged Teal – 20
Ring-necked Duck – 6
Common Goldeneye – 1
Hooded Merganser – 30
Common Merganser – 10
Great Blue Heron – 8
Red-tailed Hawk – 2
Northern Flicker – 4
Blue Jay – 5
Black-billed Magpie – 2
American Crow – 1
Black-capped Chickadee – 8
European Starling – 2
American Robin – 2
House Finch – 2
Song Sparrow – 1
Red-winged Blackbird – 30
29 Species + 1 Other Taxa During 10:15 am Bird Walk (eBird Checklist)
Cackling Goose – 2
Canada Goose – 28
Cackling/Canada Goose – 90
Northern Shoveler – 2
Gadwall – 11
American Wigeon – 8
Mallard – 40
Green-winged Teal – 1
Ring-necked Duck – 10
Common Goldeneye – 1
Hooded Merganser – 14
Common Merganser – 5
Rock Pigeon (Feral Pigeon) – 8
Great Blue Heron – 1
Golden Eagle – 1
Bald Eagle – 3
Red-tailed Hawk – 4
Northern Flicker – 1
American Kestrel – 1
Blue Jay – 4
Black-billed Magpie – 1
Common Raven – 1
Black-capped Chickadee – 4
White-breasted Nuthatch – 1
European Starling – 6
American Robin – 1
House Finch – 3
Song Sparrow – 2
Red-winged Blackbird – 46
Yellow-rumped Warbler – 1
It was an honor and a pleasure to lead my first bird walk for Front Range Birding Company this morning. Although the temperatures never quite got above 4 degrees Farenheit, our small group had a fantastic time braving the elements in search of birds at Sandstone Ranch.
A lone American tree sparrow greeted us at the bottom of the hill, and we started off scanning the mostly frozen river for waterfowl, and mostly turned up Canada and Cackling geese as well as mallards, but we did get some great views of the local muskrat going about it’s day on the ice like it was no big deal. As soon as we crossed the first bridge we dicovered a pair of American kestrels, a male and female sitting side by side, feathers puffed up for warmth, and shortly after that we had a pair of red-tailed hawks soaring
in the distance in what appeared to be early courtship behavior. An adult bald eagle sat perched next to a partially completed nest as black-billed magpies fluttered by.
Scanning the river we managed to turn up a few gadwall among the mallards, and a Northern pintail was a “lifer” for one of our participants. We also found some more bonus mammals- a small herd of white-tailed deer and a mink! A little further upstream we had a female hooded merganser ducking and diving beneath the icy water. At this point, we made a group decision to start making our way back to the parking lot, stopping occasionally for interesting waterfowl such as a common goldeneye, as well as some little brown birds that had to be left unidentified (I blame fogged-up, iced over binoculars and shivering hands!)
When we got back to the main trail we had a soul-satisfying view of an immature bald eagle that flew low and slow over our heads, and at that point my falcon senses started tingling so I started scanning the sandstone cliffs. To my delight, a prairie falcon (a lifer for ALL the partipants of this bird walk!) was perched in plain view at the edge of the cliff so we took a small detour so that everyone could get a closer look. The final bird of the day- a special bonus I might add- was a merlin that zipped by, giving us all of 3 seconds to confirm it’s identity before disappearing over the horizon. Our third falcon species and the perfect ending to a wonderful, albeit frigid, bird walk.
Here is our complete list of (confirmed) birds seen:
Canada goose-110
American crow- 17
Am. tree sparrow- 1
Mallard- 48
Cackling goose- 37
American kestrel- 2
Black-billed magpie- 3
Red-tailed hawk- 2
Gadwall- 4
Western meadowlark- 3
Northern pintail- 2
Bald eagle- 2
Hooded merganser- 1
Common goldeneye- 1
Prairie falcon- 1
Merlin- 1
We visited two main areas this morning, South Platte Reservoir and the smaller ponds just to the east of the reservoir along the South Platte River. The reservoir had very little action, but we did get to have excellent views of a pair of Long-tailed Ducks. These guys were historically known as Oldsquaws, evidently because they (the males primarily, actually) tend to be far more vocal than most other ducks and can be heard for long distances. This politically incorrect name was changed about twenty years ago, and the name from across the Atlantic for this species was adopted.
Long-tailed Ducks have several unique qualities. One is that they dive deeper than any other duck, down to almost 200 feet. Hence, we tend to see them when they show up in Colorado on only the largest reservoirs. Then, unlike any other waterfowl, they have three plumages instead of the normal two. In the non-breeding season, when we see these guys here in Colorado, the male has a white forehead and crown, a black nape and sub-auricular area (below the ear), a beige patch on the side of head, a bi-colored black-pink-and black bill, and a white chin and breast. The most distinctive feature is the two long central tail feathers that stream behind. The female has a white eyeline, neck, nape, and area where bill meets face, a dark sub-auricular area (sort of like the male), and otherwise she is mostly mottled brown (see photo at the top of the blog).
One of our morning’s highlights was getting to see a flock of 28 (more or less) Western Meadowlarks in the top of a cottonwood. We have Meadowlarks throughout the year here in Colorado, with more around in the summer than the winter. However, these wintering birds tend to hang out together in small flocks, so when we do get to see them, we tend to see more than one bird at a time. Our flock did seem to be unusually large, and it was interesting that they were all in the top of a tree.
Another great bird we saw was an Audubon’s race of the Yellow-rumped Warbler. This is the western race, while the eastern race is the Myrtle. We have both races here in the winter. These two were considered to be separate species back in the day, but because of the degree of hybridization they were lumped together as one species. The yellow rump is always bright yellow regardless of the time of year or the race. Superficially, we always talk about the Audubon’s having a yellow throat and the Myrtle having a white throat but take a look in your field guide and note that the yellow throat of an Audubon’s in first-year birds can be very washed out and almost white. A good feature to look for is whether that throat patch is restricted to the throat area (Audubon’s), or whether it wraps around back of the auricular (ear) patch (Myrtle).
I hope to see you on another walk soon!
Chuck
South Platte Park, Feb 6, 2021
32 species
Cackling Goose 20
Canada Goose 33
Northern Shoveler 30
Gadwall 72
American Wigeon 20
Mallard 38
Green-winged Teal 56
Ring-necked Duck 44
Lesser Scaup 10
Long-tailed Duck 2
Bufflehead 12
Common Goldeneye 15
Hooded Merganser 28
Common Merganser 2
Eurasian Collared-Dove 1
Killdeer 2
Ring-billed Gull 8
Great Blue Heron 1
Bald Eagle 2
Red-tailed Hawk 6
Belted Kingfisher 1
Downy Woodpecker 2
Northern Flicker 6
American Kestrel 2
Black-billed Magpie 3
American Crow 3
Black-capped Chickadee 12
White-breasted Nuthatch 2
House Finch 14
Song Sparrow 1
Western Meadowlark 28
Yellow-rumped Warbler (Audubon’s) 1
What a great morning! A bit on the chilly side, but we saw some cool birds. We started with one of the classic bird identification conundrums. Was our group of five scaup Lesser or Greater Scaup? These two members of the Aythya genus are very similar in appearance and can cause no end of headaches. There are a number of characteristics to look for, and it’s best if you can have more than one of them on which to base you ID. Let’s begin with lateral head shape. In Greater Scaup the head is higher towards the front of the crown and is gently rounded from crown to nape as it slopes back from that high point, the eye appears proportionally higher in the face, the bill is more massive, and the head tends to be green (but there are many warnings about not relying on head color). When viewing the head from the front, Greater Scaup have definite “jowls” and the nail at the tip of the bill is quite wide.
Lesser Scaup have a more pointy, taller head with an obvious corner at the rear of the crown, which is also the highest point of the head; the eye is more centered in the face from top to bottom, the bill is thinner, and the head tends to be purple (but this is not always reliable). When viewed from the front, Lessers have a narrower (less jowly) look, and the nail at the tip of the bill is just a little black spot. For more on scaup head shape check this out – https://cobirds.org/Publications/ColoradoBirds/InTheScope/21.pdf. Two other characteristics to be aware of are the degree of whiteness in the flanks – Greaters tend to be more bright white, and the amount of white in the wings – in Greaters, this white extends through both the secondary and primary flight feathers, while the white in Lessers is confined to the secondary flight feathers. Lacking a scope on Saturday, I didn’t feel as though I was getting as good a view as I needed to make a definite identification, and therefore just put these birds down as Greater/Lesser Scaup. Incidentally, these guys were seen on Blackrock Lake which, in prior years, has been a good place to see Greater Scaup. One more resource for you – https://www.audubon.org/news/greater-or-lesser-scaup-here-are-biggest-differences-between-two.
While at Blackrock we also got to spend some time on identifying a male and female Common Merganser. The male is pretty straightforward with his all-white breast and belly, dark green head (which often appears black), and red-orange bill. But let’s spend some time on the female, because we want to be able to distinguish the female Common Merganser from the superficially similar female Red-breasted Merganser. We noted on Saturday that our bird had a warm, cinnamon brown head, with slight crests at the back, and a distinct bright-white throat patch. One other feature to look for is that the bill on a Common Merg has a wide base where it meets the head and then it tapers down to a narrow point. The bill on a Red-breasted Merg is uniformly thin along its whole length, and while there can be some lightness of color in the throat area it’s more blended and not so distinct as with the Common Merg. Also, the Red-breasted has longer, wispier, ragged crests.
Heading over to the C-470 overpass we had a few more great birds, including Killdeer, Belted Kingfisher, and a Say’s Phoebe. This last is really the only flycatcher that we can see in the Denver area in the winter. In southern Colorado, in the winter, you can also find Black Phoebes. While 30-40 years ago Say’s Phoebes were considered quite rare in the winter in Colorado, we now see them with some increasing regularity, and, overall, their numbers have been on the increase. With regard to summer populations for the US and Canada, Breeding Bird Survey data over a 45-year period indicate an estimated 40% increase.
We ended the morning with a couple of more first-rate birds at a swampy beaver pond. Rusty Blackbirds occur rarely in the winter in eastern Colorado, primarily along the South Platte and Arkansas River drainages. We ran into a little group of four and got great looks at one with its brownish hood and back, buffy supercilium (eyebrow), small black patch around its bright yellow eye, and slender, slightly decurved bill. In this same area, apparently hanging out with some Song Sparrows, we had another rare winter resident, a beautiful Swamp Sparrow. And then, in that same area we got multiple views of Wilson’s Snipe. And then……., but that’s enough for now.
Hope to see you on another walk soon.
Chuck
South Platte Park, Jan 9, 2021
30 species (+1 other taxa)
Cackling Goose 12
Canada Goose 4
Northern Shoveler 11
Gadwall 39
American Wigeon 11
Mallard 26
Northern Pintail 1
Green-winged Teal 28
Greater/Lesser Scaup 5
Bufflehead 14
Common Goldeneye 11
Hooded Merganser 5
Common Merganser 2
American Coot 4
Killdeer 1
Wilson’s Snipe 3
Ring-billed Gull 4
Great Blue Heron 3
Red-tailed Hawk 2
Belted Kingfisher 1
Northern Flicker 8
Say’s Phoebe 1
Black-billed Magpie 2
American Crow 9
Black-capped Chickadee 7
Bushtit 8
White-breasted Nuthatch 1
American Pipit 2
Song Sparrow 4
Swamp Sparrow 1
Rusty Blackbird 4
Saturday at South Platte Park was a memorable one. We had great weather, a great group, and OUTSTANDING birds! We began at Blackrock Lake where we spent time working on the finer points of Greater Scaup identification. These diving ducks belong to the Aythyagenus along with Canvasback, Redhead, Tufted Duck, Ringed-neck Duck, and Lesser Scaup. A few of these are very similar and it takes some work learning the subtle differences required to differentiate them. Telling Greater Scaup from Lesser Scaup is the biggest of these challenges. They are very similar in all plumages. However, here are a few things to work on. Greater Scaup are 18” long and weigh 2.3 lbs; Lesser Scaup are only an inch shorter, but they weigh half a pound less (22% less). So, Greaters just seem heftier – bigger rounded head, big jowls, wide body; while Lessers are more attenuated – thinner body, thinner head, thinner neck, more pointy-headed. This is all pretty subtle stuff, but we wouldn’t want this bird-watching game to be too easy now, would we? One of the things that really helped us out on Saturday was that the Greater Scaup were mixed in with some Ring-necked Ducks which are roughly the same size and weight as Lesser Scaup. Our Greaters were significantly bigger than the Ring-necked Ducks.
We next moved on over to where the South Platte flows under C-470. There was a good variety of ducks here, but the real prize was a singing American Dipper that just went on and on. Beautiful! Particularly in December!
We then proceeded over to a relatively new beaver pond just south of C-470 where we had several great birds: Wood Duck, Wilson’s Snipe, Swamp Sparrow, Rusty Blackbird, and Pine Warbler. The look we had at the Swamp Sparrow was world class. The bird sat out in the open for ten minutes and we got to note every important feature – similar to a Song Sparrow but a bit smaller, more delicate, and shorter tailed – strongly streaked gray and brown crown, gray nape, clean white throat, dark rufous wings and shoulders, blurry gray-buff streaking on upper breast, and clean white belly. The best look I’ve ever had! We got a good enough look at the Rusty Blackbird in order to identify it, but it was high in a tree and a bit far away.
Finally, the real highlight of the day was the Pine Warbler. This bird breeds and winters in the eastern half of the United States, occurring rarely here in Colorado. We had several opportunities to get reasonably good looks – greenish-olive crown and back, throat and breast bright yellow with line of faint yellow extending back below and behind the darker auricular (ear) patch, with faint smudgy streaking on sides of the breast, white belly and under-tail coverts, yellow broken eye-ring creating eye arcs above and below the eye with a small yellow lore spot (between the eye and the bill), wings grayish with two strong white wing-bars. There was one disconcerting feature on this bird – it’s lower mandible was deformed, having grown out longer than normal. It seemed to be doing fine, but who knows what the impact of that may have on its survivorship.
Good birding!
Chuck
South Platte Park, Dec 5, 2020
40 species (+1 other taxa)
Canada Goose 24
Cackling/Canada Goose 80
Wood Duck 2
Northern Shoveler 38
Gadwall 30
American Wigeon 18
Mallard 37
Green-winged Teal 13
Ring-necked Duck 46
Greater Scaup 8
Bufflehead 12
Common Goldeneye 19
Hooded Merganser 18
Common Merganser 22
Pied-billed Grebe 2
Rock Pigeon (Feral Pigeon) 6
American Coot 7
Killdeer 3
Wilson’s Snipe 1
Ring-billed Gull 1
Great Blue Heron 1
Red-tailed Hawk 1
Belted Kingfisher 4
Hairy Woodpecker 1
Northern Flicker 3
American Kestrel 1
Blue Jay 1
Black-billed Magpie 2
American Crow 2
Common Raven 2
Black-capped Chickadee 16
White-breasted Nuthatch 2
Brown Creeper 1
American Dipper 1
House Finch 2
American Goldfinch 1
Song Sparrow 7
Swamp Sparrow 1
Western Meadowlark 1
Rusty Blackbird 1
Pine Warbler 1
The Saturday of March 14th, I led a group of 7 on a chilly morning to Walden Ponds wildlife habitat for our monthly birdwalk. We won’t be having another walk until, at the earliest, May 9th (maybe later), but we made the most of our last walk by observing 31 different species! Highlights included at least four different Bald Eagles (two adults and two juveniles), the area’s winter resident Harlan’s Hawk, and a very cooperative Northern Shrike.
Northern Shrikes are a winter visitor here to the front range, but they breed up in the arctic tundra/taiga. Shrikes are our only predatory songbird, and during the winter the Northern Shrike will eat mostly other small songbirds and small rodents. In arid, open habitats across the front range, the Northern Shrike is replaced by the Loggerhead Shrike in the summer. They will eat small birds, mammals, reptiles, and insects.
Our full eBird checklist can be found here: https://ebird.org/checklist/S65787632
There is still plenty of migration to be had, so be sure to get out and look at some birds. Spending time in our natural areas is a easy way to practice social distancing. Happy Spring and be well!
Best,
Stephen Chang
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.”
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!
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
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.
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!
If anyone would like me to share the eBird checklist with them please email me at aidan@coohill.com