Today we were reminded we were in Colorado in December. Yes, we had some sunshine and pretty blue skies, but also a biting chill wind picked up as we began; our cheeks, fingers, and toes suffered. Wind makes land birding pretty tough, but our waterbirds may still be enjoyed. It was not so windy yet as we began at Prospect Lake, where hundreds of geese were the dominant theme. They were mostly Cackling Geese (short stature, near vertical forehead, short triangle bill, high barking calls) with great comparisons to the much larger but less numerous Canada Geese (sloped forehead, long bill, much bigger than Mallards). Prospect Lake also had a pair of Wood Ducks, some Lesser Scaup and a few others. The winds grew and we dropped down to follow the trail up Clear Creek where there was a bit of shelter. Green-winged Teal added some flair among handsome Mallards and Gadwalls that love the creek, and an American Dipper buzzed in to offer great views! Up at exposed and windy Tabor Lake we found many ducks had sheltered along the west side, including a wonderful assembly of over 120 Hooded Mergansers. Red-breasted Mergansers were also there, along with Pied-billed Grebe, Great Blue Heron, and lots of Shovelers. The heron flew in and flushed the crowd of shovelers from their sheltered shore. The flock flew fast over us, while flocks of Cacklers passed over higher up in other directions, blown to the side in the wind. It was a magical late fall moment. December birding brings cold and sometimes wind, but there is great beauty, too. And always some treat awaits us birders who venture out to take a look.
We began with a loud call of American Crow, in the stand of pines trees we observed flocks of Bustits, it’s a social songbird & one of the smallest passerines in North America. They were feeding on small insects & Bustits do love spiders one of their favorites. Along the South Platte, we heard many calls of American Goldfinches, Song Sparrows, House Finches singing, & Black-capped Chickadees surrounded us with their bouncy flight in & near cattails. As we continued along the river, Mourning Dove flew above with its long, pointed tail, & a sizable Buck was startled running along the other side river. Just as we headed across the bridge, we noticed a few Killdeers on the rocks in water & several Mallards, Buffleheads, & one stunning Common male Goldeneye. Passing the bridge, off to left a trail led us to a peaceful pond filled with Ducks both (dabblers & divers). We saw few Buffleheads, American Widgeons, a pair of Northern Shovelers, several Ring-necked Ducks, one Lesser Scaup, one American Coot. At the pond we watched closely 3 muskrats eating pond weeds or it looked like Cattails roots, & two Beavers swam by us. As we were getting ready to return back a few Common Mergansers flew in. These Mergansers, our only ducks that specific in eating fish & the largest of the three Mergansers we have. A delightful sunny bird trip with lots of Nature that surrounded us.
Ancestral home of the Arapahoe, the Ron Stewart Preserve at Rabbit Mountain is roughly 5,000 acres of grassland and foothills habitat. It boasts some of the most spectacular views of the Front Range and is home to a multitude of species.
Our walk on Saturday was rather quiet, but we did see a few good birds and the landscape and weather were beautiful. Despite mostly occurring in the western and southwestern portion of Colorado, a small population of Pinyon Jays can be found at Rabbit Mountain. Though the Pinyons were elusive for us, we did see a couple of their relative the Woodhouse’s Scrub-Jay right in the parking lot. Woodhouses’s Scrub-Jays differ from Pinyon Jays in having longer tails and grey as well as blue on their bodies. Pinyon Jays also have longer, sharper bills than the Scrub-Jays.
Woodhouse’s Scrub-Jay. Photo by Jamie Simo
A little farther down the trail we saw another great bird, a Prairie Falcon. Rabbit Mountain is an ideal habitat for Prairie Falcons, which nest on rocky cliff faces and feed on small mammals and grassland birds like meadowlarks. Unlike Peregrine Falcons, Prairie Falcons are brown and white rather than mostly grey with less of a helmeted look than their more famous relative. As they soar above you, look for their distinctive dark axillaries or “armpits.”
Prairie Falcon. Photo by Jamie Simo
We also saw a Ferruginous Hawk surveying the prairie dog town. This large hawk’s diet is mostly made up of prairie dogs and they can often be found on the ground in the middle of one of the rodent’s colonies, which is precisely where we found it.
Finally, we had a Clark’s Nutcracker in the pines at the beginning of the Eagle Wind Trail. These cool corvids cache thousands of pine seeds a year and is considered a keystone species for its role in the spread of whitebark pine.
Rabbit Mountain, Boulder, Colorado, US 13 species (+1 other taxa)
The quiet little town of Louviers sits off the busy corridor of Highway 85 in Douglas County, marked from afar by an impressive stand of tall pines and other trees, on a hillside along the autumn gold cottonwoods of Plum Creek. The town came to be in 1906 as a company town to support the new DuPont Dynamite Works built adjacent to the town. Now the dynamite plant is gone and the former company town is an historic point of interest that offers a lovely stroll and fun birding, too. DuPont Park Open Space neighbors the town and has trails through the riparian forest and through the grounds of the former dynamite plant, now “returning to nature.”
Our Front Range Birding Company walk enjoyed October’s mix of migrants and resident birds. Hot spots of bird action stopped us here and there as we made our way through the town. Right away our attention was captured by a party of migrant Western Bluebirds that had stopped in to forage. Flocks of migrant White-crowned Sparrows were occupying thickets and gardens, filling the air with a chorus of song and calls. White-crowned Sparrows differ from many of our fall migrants in that they love to sing when they pass through our area. Both adult and juvenile sparrows sing, tossing out lovely trills and song phrases. This is a time when young birds learn and practice their songs.
As we watched one sparrow flock we spotted a chunky, streaky bird with a large bill feeding by itself on a gravel alleyway. Surprise: a juvenile Red Crossbill! Not red at all but streaky and drab. But photos reveal areas of yellow-gold feathers molting in, showing it to be a young female crossbill. And what a bill! It was odd to see just one crossbill by itself. I had seen a lot of crossbills in town in prior weeks, so perhaps this lonely bird was left behind! Later we heard it call as it flew and could identify it as the Type 4 Red Crossbill – the Douglas-fir Red Crossbill — a form that is infrequently found in Colorado.
Our walk continued with many lovely views of fall color, chances to compare resident birds like Downy and Hairy Woodpeckers, and to enjoy our quiet walk through the big trees of DuPont Park. It is good to be out birding in the fall.
The Denver region is a “ducky” place as fall deepens into winter and waterfowl come south to make their home in our rivers and lakes. The South Platte corridor and nearby reservoirs and lakes are a key area for migrant ducks. We can see a great variety of ducks in winter, when 20 different species are present in the area, and some places have good numbers, too.
South Platte Park is a “ducky” park in Littleton. Our visit on November 4 enjoyed partly cloudy skies and mild temperatures – a beautiful fall day. There are large lakes, a reservoir, and the river. Here is our South Platte Park trip report. We were happy to see 10 different species, including a rather uncommon Long-tailed Duck at Eaglewatch Lake. Our ten species were evenly split between ducks that forage at the surface and those that dive under the water.
The grouping of “dabbling ducks” vs. “diving ducks” is a familiar one, and it reflects an important basic difference among our ducks, both in their natural history and the taxonomic relationships among species. Our dabblers on the field trip were Northern Shoveler, Gadwall, American Wigeon, Mallard and Green-winged Teal. Our divers were Lesser Scaup, Long-tailed Duck, Bufflehead, Hooded Merganser and Ruddy Duck.
We see dabblers “tipping up” to reach down into the water after food, or feeding at the surface, or along a shallow muddy margin, and sometimes up on grassy areas and in fields. We see divers diving under the water — propelled by feet and wings — to find fish, shellfish and other invertebrates in the water column and at the bottom.
Dabblers often use their bills to sift water, mud and aquatic vegetation to extract small bits of food, and they even eat vegetation. Divers catch prey in their bill, whether sessile or mobile, and bring it to the surface to prepare it for swallowing. Crayfish, which are abundant in our waters, are a popular food for some of our divers.
Dabbers are often seen walking on land, and they can take flight directly upward into the air. Divers have legs set farther back. They are seldom seen on land and cannot walk well. Most Divers must run and patter over the water to take flight.
Dabblers and divers are incredibly beautiful, bringing us joy as we identify and watch them here in the winter. Look for other opportunities to enjoy our winter ducks on upcoming Front Range Birding Co. trips. Learn more about ID of our winter ducks with David’s video BIRD BOMBS: Better Duck.
On a perfect Saturday morning (we even had an eclipse to enjoy!) we set out on a leisurely walk around Lagerman Reservoir to see what birds we could see. Lagerman is usually busy all year, but particularly shines in fall and winter when waterfowl and raptors are the highlights. Right away we spotted a juvenile light-morph Ferruginous Hawk that had staked a claim on a power pole overlooking the nearby prairie dog colony.
Ferruginous Hawks, named for the rusty or “ferrous” (iron) color of the feathers on their legs and backs, are our largest hawk and primarily feed on prairie dogs. Juvenile light-morphs are less rusty than their adult counterparts with more spotting on their underparts.
We were also treated to several other raptors out hunting, including a couple of adult Bald Eagles, an American Kestrel, and a Northern Harrier. The Northern Harrier is the only bird of its genus, Circus, in North America. They breed and hunt in grasslands and marshes where they use their disc-shaped faces to locate rodents. The disc shape helps funnel sound to their ears, a characteristic they share with owls, though they aren’t closely-related.
Male Northern Harrier. Photo by Jamie Simo
In addition to raptors, we had an abundance of waterfowl on Saturday. Of particular note were several Eared Grebes, the only grebe species we encountered. In winter, Eared Grebes are mostly varying shades of grey, retaining only the red eyes from their spectacular breeding plumage. They often are easily confused with Horned Grebes, with several minor differences. While Horned Grebes have bright white cheeks, Eared Grebes’ cheeks are a dusky color that doesn’t stand out from the color of their faces or necks. A good mnemonic to remember this characteristic is Eared=smeared. Also, while Horned Grebes’ heads are squarish, Eared Grebes have somewhat lumpy heads with a peak toward the front of the head.
Non-breeding Eared Grebe. Photo by Jamie Simo
We were also treated to great looks at many ducks including, but not limited to, Northern Pintail, Redhead, Canvasback, and American Wigeon. A very successful walk!
Lagerman Agricultural Preserve–Lagerman Reservoir, Boulder, Colorado, US 36 species
Canada Goose 26 Northern Shoveler 7 Gadwall 2 American Wigeon 15 Mallard 12 Northern Pintail 6 Green-winged Teal 8 Canvasback 5 Redhead 20 Ring-necked Duck 4 Bufflehead 5 Ruddy Duck 50 Eared Grebe 6 Rock Pigeon (Feral Pigeon) 13 American Coot 80 Killdeer 10 Least Sandpiper 1 Wilson’s Snipe 2 Ring-billed Gull 6 American White Pelican 2 Northern Harrier 1 Bald Eagle 2 Red-tailed Hawk 1 Ferruginous Hawk 1 Northern Flicker 2 American Kestrel 2 Say’s Phoebe 1 Black-billed Magpie 1 American Crow 2 European Starling 50 American Robin 1 American Pipit 12 White-crowned Sparrow 1 Western Meadowlark 12 Red-winged Blackbird 10 Brewer’s Blackbird 8
Old St. Vrain Road in Lyons is a beautiful, scenic place for a leisurely bird walk. Because it’s flat and all paved, it’s perfect for those with mobility challenges, and, as a migrant trap, it can offer up some unexpected avian delights. Our small group met at the Heil Valley Ranch Picture Rock Trail parking lot since parking is limited on Old St. Vrain Road and, as a residential area, we wanted to be respectful to the residents.
August and early September can be challenging for birders because the birds are largely quiet, more focused on bulking up for migration than establishing or maintaining territory and mates. Still, we had some great birds, including a lively little Canyon Wren that hopped up one of the canyon walls and let us admire for a few minutes. Canyon Wrens are one of the prettiest wrens with their cinnamon color and black and white speckling on head and back. Their falling song evokes the image of a stone tumbling down the canyon.
Canyon Wren. Photo by Jamie Simo
We were flummoxed by several quickly-darting yellow-colored birds before we finally were able to get good looks at a Wilson’s Warbler with his little black toupee like Moe from The Three Stooges. Wilson’s Warblers breed at higher altitude, typically in streamside willow carrs. Females and immatures lack this black cap, but share the overall green-yellow color.
Another mysterious yellow bird we saw was a female Western Tanager who was enjoying the array of berries growing along the creek. Unlike male Western Tanagers, which are unmistakable, females could be confused for a goldfinch. However, Western Tanager females are bigger and lankier than either our Lesser or American Goldfinches with a thicker, longer bill and two pale wing bars on a darker wing.
Western Tanager Female. Photo by Jamie Simo
Other species of note were Gray Catbirds, several Wild Turkeys (almost guaranteed here), White-throated Swifts, a singing (but unseen) Plumbeous Vireo, and a lone Osprey at the end of our walk. A quiet day, but always a good one on Old St. Vrain Road!
Old Saint Vrain Rd, Boulder, Colorado, US 31 species (+1 other taxa)
Wild Turkey 4 Rock Pigeon (Feral Pigeon) 9 Eurasian Collared-Dove 1 Mourning Dove 1 White-throated Swift 6 Broad-tailed Hummingbird 3 Osprey 1 Downy Woodpecker 1 Northern Flicker 1 American Kestrel 1 Plumbeous Vireo 1 Steller’s Jay (Interior) 1 Blue Jay 6 American Crow 1 Black-capped Chickadee 6 Barn Swallow 1 swallow sp. 5 Red-breasted Nuthatch 1 White-breasted Nuthatch 1 Canyon Wren 1 European Starling 1 Gray Catbird 3 American Robin 1 Cedar Waxwing 1 House Finch 8 Red Crossbill 1 Lesser Goldfinch 5 Song Sparrow 1 Spotted Towhee 2 Yellow Warbler 1 Wilson’s Warbler 1 Western Tanager 2
As it says on the tin, the Lagerman Reservoir Open Sky Loop is almost completely open and without shade so it was a blessing that the morning of our walk was cloudy and relatively cool for August. It’s still a long walk though, and my hat’s off to those doughty birders who stuck it out with me.
August is a challenging time to bird as birds are generally no longer singing and migration hasn’t really hit its peak yet. Still, we had some great birds, including a female Lark Bunting almost as soon as we started our walk. Colorado’s state bird, the Lark Bunting is a large, grassland sparrow. While the male in breeding plumage is unmistakable, being mostly black with a prominent white wing patch, the female and juvenile are more subtle with brown streaking. They do have a particularly chunky bill for a sparrow, almost more like a finch, but the creamy wing patch is a dead giveaway and was what clued us in to the bird’s identity.
Female Lark Bunting. Photo by Jamie Simo
Buoyed by our first big find, we continued on and had some fantastic views of Say’s Phoebes, which appeared to be everywhere. Say’s Phoebes are a kind of flycatcher and, as is typical of phoebes, are known for bobbing their tails. A trip highlight was watching an adult Say’s Phoebe feed a juvenile. One way to tell a juvenile from an adult bird is the very visible fleshy “gape” around the base of the bill. When altricial birds are nestlings, a prominent gape allows their parents to locate where to put the food. On Say’s Phoebes this gape is an orangey-yellow color, which stands out against the dark beak and grey head feathers.
Juvenile Say’s Phoebe. Photo by Jamie Simo
Another highlight of the trip was seeing a Loggerhead Shrike. Although the bird never came close to us, we were able to scope it with the Swarovski ATS 65mm spotting scope, which allowed us to get great looks at it. Although shrikes are considered songbirds, they hunt and kill not only insects, but also rodents, lizards, and even other songbirds. To kill vertebrate prey, they use their hooked beaks to deliver a paralyzing bite to the back of the neck then shake their victim with enough force to break its neck. Because they lack talons like a raptor, they impale their kill on thorns or even barbed wire to help hold it steady to eat or even to cache it for later.
Some other cool sights we had were two Great Horned Owls in a barn, a Bald Eagle with prey, and a Sage Thrasher. In all, we had 41 species, which is incredible for August in the grassland. Hopefully you can join us on our next walk!
Lagerman Agricultural Preserve–Open Sky Loop, Boulder, Colorado, US Aug 12, 2023 7:43 AM – 12:03 PM 7.07 mile(s) 41 species
Canada Goose 65 Mallard 11 Lesser Scaup 2 Rock Pigeon (Feral Pigeon) 1 Eurasian Collared-Dove 9 Mourning Dove 1 Broad-tailed Hummingbird 1 Killdeer 2 Ring-billed Gull 1 Double-crested Cormorant 5 Great Blue Heron 3 Black-crowned Night-Heron 1 Turkey Vulture 1 Bald Eagle 2 Red-tailed Hawk 3 Great Horned Owl 3 Downy Woodpecker 1 American Kestrel 1 Western Wood-Pewee 2 Say’s Phoebe 11 Western Kingbird 1 Eastern Kingbird 3 Loggerhead Shrike 1 Blue Jay 1 Black-billed Magpie 4 Black-capped Chickadee 1 Tree Swallow 1 Barn Swallow 11 European Starling 38 Sage Thrasher 1 House Sparrow 3 House Finch 5 Lesser Goldfinch 3 American Goldfinch 3 Lark Bunting 1 Savannah Sparrow 2 Western Meadowlark 8 Red-winged Blackbird 32 Brewer’s Blackbird 1 Common Grackle 7 Blue Grosbeak 3
Unfortunately our guest bird walk leader wasn’t able to lead this month’s bird walk, but that just meant I had the pleasure instead! Heil Valley Ranch is one of the jewels of Boulder County’s open space program with over 100 bird species recorded there.
Our group met at the main parking area at 8am to walk the Lichen Loop. It’s been interesting charting the changes to Heil since the Cal-wood Fire roared through in fall of 2020. The Lichen Loop in particular was heavily impacted by the fire, its forest canopy replaced by grasses, native wildflowers, and invasive weeds. What trees remain are mostly charred skeletons, a striking counterpoint to the lush understory and the perfect backdrop for our colorful migrants.
Along the stream running parallel to the parking lot we heard the newly renamed Western Flycatcher, formally classified as the Cordilleran Flycatcher. It’ll be hard to think of it as anything other than the Cordilleran though because its high-pitched call sounds very much like it’s saying its name: “cordi!” We also heard the melodious song of the Lazuli Bunting, though we wouldn’t get a good view of one until about halfway through our walk when a beautiful male perched long enough for us all to get a good look at his azure back, white belly, and orange breast.
Male Blue Grosbeak. Photo by Jamie Simo
We were also privileged to get great looks at several male Blue Grosbeaks, a grass and shrubland bird that didn’t frequent the Lichen Loop prior to the Cal-wood Fire. Like its relatives, the Blue Grosbeak is named for its large, seed-cracking bill, which is a silvery grey color. A deeper blue than the Lazuli Bunting with chestnut wings, the Blue Grosbeak sounds a little like a scratchy American Robin when he sings, only with fewer pauses.
Lark Sparrow. Photo by Jamie Simo
Another bird of note was the Lark Sparrow, a large sparrow with a beautiful red face pattern that makes me think of Southwestern Native American pottery. We also saw several Western Kingbirds with their contrasting grey backs and bright yellow bellies. Back in the parking lot we wrapped up our trip with a flock of 10 Wild Turkeys, a pair of Golden Eagles that perched in a tree on the hillside, and a gorgeous male Western Tanager. A perfect morning for birding!
Lichen Loop Trail, Boulder, Colorado, US 28 species
Wild Turkey 10 Mourning Dove 4 Broad-tailed Hummingbird 2 Turkey Vulture 2 Golden Eagle 2 Hairy Woodpecker 1 Northern Flicker 1 Western Wood-Pewee 5 Cordilleran Flycatcher 1 Western Kingbird 3 Eastern Kingbird 1 Steller’s Jay (Interior) 2 Black-billed Magpie 8 White-breasted Nuthatch (Interior West) 3 Rock Wren 1 House Wren 1 American Robin 1 Lesser Goldfinch 4 Chipping Sparrow 1 Lark Sparrow 1 Spotted Towhee 2 Western Meadowlark 4 Bullock’s Oriole 2 Brown-headed Cowbird 1 Brewer’s Blackbird 8 Western Tanager 1 Blue Grosbeak 5 Lazuli Bunting 5
Well, we finally made it to Walker Ranch after last month’s aborted attempt! The Meyer’s Gulch trail is one of the best places for foothills birding in Boulder County. It’s also spectacular in the spring with its wildflowers and butterflies.
This past Saturday the weather was warm and sunny, but not too hot. We couldn’t have asked for a better morning. Before we even left the parking lot we had some great birds, including a singing Green-tailed Towhee and a Pine Siskin. As we started off down the trail the number of singing Vesper Sparrows was incredible. Vesper Sparrows are a grassland bird with a prominent white eye-ring, streaked breast, and white outer tail feathers. If you can get a good view of one (which is entirely possible because they like to sing from an elevated perch), you may see the little reddish patch on their shoulder. Their song starts off with a couple of whistles followed by a trilling song.
Vesper Sparrow. Photo by Jamie Simo
As we continued along the trail, we were stopped by the sight of a couple Western Bluebirds and got great looks at our most common and least shy flycatcher, the Western Wood-Pewee. Western Wood-Pewees almost always like to sit out in the open and they can be distinguished from other flycatchers by their relatively long wings, lack of eye-ring, and still tail (many flycatchers tail bob).
Western Wood-Pewee. Photo by Jamie Simo
As mentioned previously, Walker Ranch is a great place for wildflowers. Some of the most notable were western wallflower, blue-mist penstemon, and locoweed (mistakenly identified by me on Saturday as a type of vetch). Broad-tailed Hummingbirds were abundant as they took advantage of the nectar and one even helpfully posed for several minutes so we could get a look at him and his gorgeous gorget.
Other species we saw on our walk were Chipping Sparrows, a Dark-eyed Junco, a Western Tanager, a lone male Red Crossbill, and several Plumbeous Vireos. Though remaining unseen, we also heard the songs of Macgillivray’s Warbler as well as Warbling Vireo.
Unfortunately we didn’t make it too far along the trail before having to turn around, but only because there was just so much to look at and listen to!
Walker Ranch–Meyers Gulch, Boulder, Colorado, US 29 species (+1 other taxa)
Broad-tailed Hummingbird 3 Red-tailed Hawk 1 Northern Flicker 2 Western Wood-Pewee 5 Cordilleran Flycatcher 3 Plumbeous Vireo 3 Warbling Vireo 3 Steller’s Jay 2 Black-billed Magpie 3 American Crow 4 Common Raven 2 Mountain Chickadee 3 Violet-green Swallow 3 White-breasted Nuthatch 1 Pygmy Nuthatch 2 House Wren 7 Western Bluebird 2 American Robin 7 House Finch 1 Red Crossbill 1 Pine Siskin 1 Lesser Goldfinch 3 Chipping Sparrow 2 Dark-eyed Junco 1 Dark-eyed Junco (Gray-headed) 1 Vesper Sparrow 6 Green-tailed Towhee 2 Brown-headed Cowbird 1 MacGillivray’s Warbler 1 Western Tanager 1
Fall Bird Walk at Walden PondsOctober 16, 2025 @ 5:30 pm - 7:00 pmWalden Ponds Wildlife Habitat, 3893 N 75th St, Boulder, CO 80301, USA
Let’s get out and enjoy the beautiful colors of fall!
Join naturalist and Reefs to Rockies guide Carly Crow for an evening walk at Walden Ponds. We will meet at 5:30 pm in the Walden Ponds Trailhead. From there we will walk the maintained paths until dusk looking for late migrants and early winter birds. Several species of sparrows, hawks, and ducks are likely! This will also be a wonderful time to soak in the fall colors in the golden light of sunset.
Nature doesn’t sleep when the sun goes down! After sunset, we will walk and listen to owls calling in the twilight. Great-horned owls are likely and if we’re lucky we may hear a species or two of Colorado’s more illusive mountain owls. What better way to kick off the Halloween season?
During this time of year, the temperature drops quickly after dark. We recommend you bring layers to stay comfortable throughout our walk. We also recommend you bring a small flight light to illuminate your path while we are walking after dark.
