Category Archives: ID Challenge

The Wrens of Colorado

Quick! What’s that dull-colored little bird with the Napoleon complex? Is it holding its tail upright? Is it giving you the side-eye and scolding you with some truly acrobatic vocals? Well, my friend, you probably have the Joe Pesci of the bird world on your hands: the wren.

There are over 80 species of wrens world-wide, with most of them occurring in the western hemisphere. In Colorado, there are 5 that can be regularly found and several rarities that show up on occasion, but here I’ll concentrate on the more common ones.

House Wren at Sylvan Lake State Park in Eagle, CO building a nest near one of the cabins. Photo by Jamie Simo.

The most common wren to most people along the Front Range is probably the House Wren (Troglodytes aedon), which is a summer resident in Colorado and is named for its tendency to nest in proximity to houses. House Wrens are one of the smallest wrens in Colorado at about 4.5 to 5 inches. They are also the drabbest. They love to hang out low in brushy areas where their plain, faintly barred, brown coloring blends in well.

House Wrens are an interesting species with a mixed reputation. The males have a beautiful song they use to attract mates and defend their territory. They’re also industrious. Once he has an interested lady, a male House Wren will bring her around to a number of cavities where he has built up a nest base of sticks. She’ll then pick one to complete a nest with grasses, fur, and other soft materials. House Wrens are particularly aggressive during the nesting season. They will pierce the eggs of other birds nesting nearby (including bluebirds).

Marsh Wren at Jim Hamm Natural Area in Longmont, CO. Photo by Jamie Simo.

About the same size as the House Wren is the Marsh Wren (Cistothorus palustris), also a summer resident throughout most of Colorado. Like its name, the Marsh Wren is found in wetland areas where it slinks around among cattails and reeds, flying only short distances with its diminutive wings. The male’s song sounds to me a lot like a VHS being rewound or fast-forwarded. Marsh Wrens are brown, but with a more visible pale eyebrow and paler underparts than the House Wren. They also have a black and white striped patch on their back.

Like the House Wren, the Marsh Wren male builds multiple “dummy” nests that he will show his mate for her to choose between. Unlike House Wrens, however, Marsh Wrens don’t nest in cavities. Their nests are dome-shaped and formed from grasses, reeds, and other marsh plants. Marsh Wren males will mate with multiple females in an area and both parents will defend the resources of that area by destroying other birds’ eggs and killing nestlings.

Bewick’s Wren at Lake Pueblo State Park in Pueblo, CO. Photo by Jamie Simo.

In the southern and western portions of Colorado lives the Bewick’s Wren (Thryomanes bewickii) whose body is only slightly bigger than a House or Marsh Wren’s, but whose tail is much longer and white-edged. Bewick’s Wrens have a very prominent white eyebrow, pale underparts, and a decurved (down-curving) bill. The Bewick’s Wren prefers dry, scrubby areas in woodlands or grasslands.

As with the House Wren, Bewick’s Wrens nest in cavities, which unfortunately has put them in direct competition with the House Wren as the House Wren’s range has expanded with human settlement. Though smaller, the House Wren is fiercer and out-competes the Bewick’s Wren, which has all but been eradicated from the eastern United States and is in decline in the west.

Canyon Wren at Golden Gate Canyon State Park in Golden, CO. Photo by Jamie Simo.

If you’re in a rocky area with cliffs, you may encounter the chubby little Canyon Wren (Catherpes mexicanus) with its long, decurved bill. Quite flashy for a wren, it has a rust-colored body with black and white speckles and a stark white throat. You’re more likely to hear this wren than see it, however. The male’s song descends as if he’s falling down a cliff. There’s some speculation within the birding community that the female also sings, though a raspier, more ascending song.

Canyon Wrens nest in rock crevices where they build their cup nests. Because they’re able to pick insects out from between rocks with their long beaks, they are mostly year-round residents in Colorado rather than migratory. Due to the steepness and rockiness of their habitat, Canyon Wrens haven’t been studied as much as some of their cousins. They are the only species in their genus.

Rock Wren at Barr Lake State Park in Brighton, CO. Photo by Jamie Simo.

Last, but not least, the Rock Wren (Salpinctes obsoletus) is the largest wren in Colorado, though it’s only slightly larger than the Canyon Wren. It’s also probably my favorite wren in Colorado because it’s just so charismatic with its deep knee bends and curious mien. This bird is greyish-brown with faint speckling on its upper parts, buffy belly, and pale, buffy eyebrow.

Like the Canyon Wren, Rock Wrens are mostly found in rocky areas like canyons. This comes in handy in the nesting season because they incorporate the rocks into their nest site. The cup nest of the Rock Wren is built in a crevice by the female and then both sexes will seek out and lay a series of flat stones in front of the nest crevice to form what scientists often refer to as a “front porch.” What the purpose of this “porch” is though isn’t known.

So, that’s it! Which wren are you watching right now? Or maybe the question should be: which wren is watching you?

ID Challenge: American vs Lesser Goldfinch

Male American Goldfinch in breeding plumage. Photo by Jamie Simo.

When I was a kid, my mom always put up a lot of bird feeders and it was a treat when a certain little yellow bird showed up. We lived in a pretty suburban area so the only little yellow bird we ever saw was the goldfinch. My mom used to call them “wild canaries.” Living in Virginia, our goldfinch was the American Goldfinch, but in Colorado there are 2 types of goldfinch.

American Goldfinches (Spinus tristis) are in Colorado all year long, but in the fall and winter, they molt out of their bright colors and become more drab and brown while the Lesser Goldfinch (Spinus psaltria) is only in Colorado during the breeding season. Since you won’t confuse the two here except in the breeding season, I’ll focus on what they look like then.

The American Goldfinch is widespread across North America, which is probably the reason it received the common name “American.” It tends to be found in riparian areas and suburbs. Breeding males of the American Goldfinch have bright yellow bodies with pinkish or orangeish bills and feet, black caps, and black wings with white bars.

Male Lesser Goldfinch. Photo by Jamie Simo.

Lesser Goldfinch males are fairly easily distinguished from American Goldfinch males. The name “lesser” probably came about because it has less yellow on it than its more widespread relative. While a Lesser Goldfinch’s plumage varies based on location, in Colorado, males tend to have olive green backs and faces, yellow underparts, dusky beaks, and big white wing patches that are highly visible in flight. They are a southwestern bird living in drier, shrubbier habitats typically than American Goldfinches.

Female American Goldfinch in breeding plumage. Photo by Jamie Simo.

During breeding, female American Goldfinches are a little more subdued than the males. Their yellow isn’t quite as bright and they lack the black cap and deep black wings of the male. They also have the pink or orange bill and feet, however.

Female Lesser Goldfinches look somewhat similar to non-breeding female American Goldfinches. They have dusky bills and tend to be a brownish or olive-y yellow. They lack the white wingbars of their American counterpart, but have a white smear on their primaries that’s visible when the bird perches or flies.

Female Lesser Goldfinch. Photo by Jamie Simo.

The 2 species also sound distinctly different. The American Goldfinch has a very sweet, fast song. It also has a distinctive flight call usually rendered as “potato-chip” or “perchickity.” The Lesser Goldfinch is much hoarser with a slower song and a somewhat whiny call.

So, now that you know the difference between the two goldfinches in Colorado, which little yellow goldfinch do you see?

ID Challenge: Mountain vs Black-capped vs Carolina Chickadee

Mountain Chickadee. Photo by Jamie Simo.

It’s a cold, grey, windy day today and my yard is awash in activity. My bird feeders especially are getting a workout with several new visitors this year, including a Mountain Chickadee. Mountain Chickadees aren’t uncommon along the Front Range, but they’re usually found in the foothills and mountains where there are an abundance of conifers rather than in my lower elevation deciduous-tree-dominated suburban neighborhood.

I was first alerted to my new guest by its scratchy “chicka-dee-dee” call, like a Black-capped Chickadee (a year-round resident in my neighborhood) with a sore throat. For comparison, here’s the Black-capped Chickadee’s call.

Black-capped Chickadee. Photo by Jamie Simo.

Other than their calls, Mountain Chickadees are fairly easy to differentiate from Black-capped Chickadees. The most obvious visual difference is the Mountain’s bold white eyebrow, which makes it a little angry-looking. The Mountain is also usually a lot greyer, with very little if any buffiness on the underparts and less white edging on the wings.

Although my area of Colorado is only home to Black-capped and Mountain Chickadees, the true ID challenge is between Black-capped and Carolina Chickadees. Carolina Chickadees are slightly smaller than Black-capped Chickadees and are more of a southeastern US bird. They were my backyard chickadee in Virginia.

Carolina Chickadee. Photo by Jamie Simo.

Like the Mountain Chickadee, Carolinas are greyer than the Black-capped with little white wing-edging and not as much buffy coloring on their underparts. Their white cheek patch is greyer toward the back of the head and their black “bib” is smaller than the Black-capped with well-defined edges. There is also much less white edging on the outer tail feathers in Carolina Chickadees.

Probably the easiest way to distinguish between the Carolina Chickadee and the Black-capped Chickadee, however, is by voice. The song of the Black-capped Chickadee is usually a 3-note “Hey sweet-ie” whereas the Carolina’s song is usually a a 4-note song: “Fee bee fee bay.” The Carolina Chickadee also tends to have a faster call. But don’t worry, the two look-alikes only share territory in a small band roughly shown on the map below.

Map showing zone of overlap (black line) between Black-capped and Carolina Chickadees.

ID Challenge: Cattle Egret vs. Great Egret vs. Snowy Egret

Cattle Egret in breeding plumage. Photo by Jamie Simo.

Ah, the egret. One of the most majestic and graceful of birds. Fashionistas of the past agreed: thousands of egrets were slaughtered for their long, silky plumes, which used to adorn ladies’ hats.

There are 3 egret species that regularly visit Colorado: the Cattle Egret, the Great Egret, and the Snowy Egret. All 3 are only found in Colorado in the breeding season and are generally white birds. So how’s a birder supposed to know which one they’re looking at?

Size comparison between the Great Egret (left) and the Snowy Egret. Photo by Jamie Simo.

One way is to look at where the bird is. Is it wading in ankle-deep water in a marsh or is it poking around in a (perhaps wet) pasture or agricultural field? If it’s in a field, sometimes surrounded by cows, you’re almost certainly looking at a Cattle Egret. Cattle Egrets, which somehow became established in North America in the 1950’s, are shorter and stockier than our native egrets with either dark legs in non-breeding plumage or orange legs in breeding plumage, and thick, orange beaks. In breeding season, their plumes are a rusty color on their crowns, backs, and breasts that immediately give them away. Neither the Snowy nor the Great Egret have colorful

Snowy Egret in breeding plumage. Note the plumes on the chest. Photo by Jamie Simo.


The next biggest egret in Colorado is the Snowy Egret. Next to the Cattle Egret, the Snowy is taller and more slender with a longer, more pointed bill. As mentioned, the Snowy Egret has white plumes so it’s more difficult to tell it apart from the Great Egret than the Cattle Egret.

The Great Egret is about twice the size of the Snowy Egret, towering over the smaller bird. It’s roughly the same size as a Great Blue Heron. It can be hard to judge size if you are only looking at a single bird, however. The Snowy Egret has black legs with yellow feet, while the Great Egret has both black legs and feet, but if the bird’s feet are submerged in water, that’s not a helpful characteristic either.

Great Egret. Photo by Jamie Simo.

The best way to distinguish between the two birds then, is by bill color. The Snowy Egret has a black bill with a yellow patch of skin on its face while the Great Egret has an orange bill with a yellow patch of skin on its face that turns a bright green in the breeding season.

So head to your nearest wetland or cow pasture and look for some egrets to test out your newfound ID skills. I guarantee you won’t be disappointed by these birds.

ID Challenge: Sharp-shinned vs. Cooper’s Hawk

Winter is a great time for viewing raptors, especially in Colorado. For instance, it’s the only time of year you can see some species, like the Rough-legged Hawk or Merlin. And  with the leaves off the trees, it’s much easier to see birds of prey. I’ve been seeing tons of raptors myself over the last few months, but I wanted to talk about two of them that get a lot of people (including me!) confused: the Sharp-shinned Hawk and the Cooper’s Hawk.

Immature Sharp-shinned Hawk. Note the small head and thick streaking. Photo by Jamie Simo.
Immature Cooper’s Hawk. Note the bigger head and more diffuse breast streaking. Photo by Jamie Simo.

The Sharp-shinned Hawk and Cooper’s Hawk are both members of a group of hawks called the Accipiters. Accipiters, also known as forest hawks, are much smaller than soaring hawks like the Red-tailed Hawk. They have long tails and broad wings to help them maneuver quickly and easily through trees. In addition to forests, though, you can often find Sharp-shinned and Cooper’s Hawks in your backyard because they primarily feed on birds and small rodents.

Both the Sharp-shinned and the Cooper’s Hawks are slate grey on the back as adults, with rusty, barred breasts and grey and black striped tails. When fully mature, they also both have red eyes. Juveniles are also difficult to distinguish since they’re both brown with streaked breasts. The Sharp-shinned Hawk is the smallest Accipiter in North America, but while it’s easy to tell size differences between it and the Cooper’s Hawk if the two are sitting side by side, it’s much harder to judge size otherwise. So what other information can we use?

One often-cited id clue is to look at the hawk’s tail from the back. If the tail is rounded, you’re looking at a Cooper’s Hawk. If it’s squared off, it’s a Sharp-shinned Hawk. This is a helpful diagnostic characteristic, but not always reliable depending on molt, how the hawk is holding its tail, etc. So I’d use this as a secondary key.

Adult Cooper’s Hawk. Note the “capped” look of the head and the rounded tail. Photo by Jamie Simo.

I’d say the most important characters to look for in all plumage stages are the size and shape of the head and the shape of the body. The Sharp-shinned Hawk has been called “pigeon-headed” because it has a small (relative to its body), rounded head like a dove or pigeon. In flight, its head barely sticks out past the crook of its wing. By contrast, the Cooper’s hawk has a more proportionally-sized head that’s maybe a little squarish, and a longer neck. The nape of the neck on the adult Sharp-shinned Hawk is also the same color as the top of the head, making it look like it’s wearing a hood, while the adult Cooper’s Hawk has a paler nape making it look like it’s wearing a cap.

The Sharp-shinned Hawk, true to its name, also has much thinner legs than the Cooper’s Hawk and looks “squashier.” Its shorter neck makes it look noticeably broad-chested. The Cooper’s Hawk, however, is much slimmer, with a barrel shape (the same width all the way down). If you’re looking at a young hawk, you can also use the streaking on the breast as a field mark. The Sharp-shinned has much thicker streaking than the Cooper’s.

So, given what you now know, which hawk do you think this is?

Photo by Jamie Simo



ID Challenge: Williamson’s Sapsucker vs. Northern Flicker

You’re up in the mountains of Colorado in a Douglas fir forest on the look out for the Williamson’s Sapsucker (Sphyrapicus thyroideus) when all of a sudden a woodpecker flashes past you and lands on a nearby tree. Your first glimpse is of a barred back and you immediately say to yourself “Northern Flicker” and start to turn away. But wait, you could still have a Williamson’s on your hands.

A male Northern Flicker feeding young. Photo by Jamie Simo.
Male Williamson’s Sapsucker. Photo by Bob Gunderson, CA, Sierra County, June 2013.

Did you know that the male and female Williamson’s Sapsucker look so remarkably different that 19th century scientists thought they were 2 different species for almost a decade? Let’s look closer.

The male Williamson’s Sapsucker is distinctive and probably not likely to cause many identification problems. It has a glossy black back and chest with a red chin, prominent white wing patch, barred flanks, and a yellow belly; truly a striking bird. The female, by contrast, is mostly black, white, and grey.

Like the Northern Flicker, the female Williamson’s Sapsucker does have a barred back and a black “collar”, but the Flicker’s back is more brownish and it has spotting on the breast and belly instead of more barring. It is more colorful overall with red or yellow wing and tail linings, a red or black mustache (male), and, in the Eastern

A female Williamson’s Sapsucker drinks sap from a recent tree cut at Meyer’s Ranch Open Space. Photo by Jamie Simo.

subspecies, a red nape patch. The female Williamson’s Sapsucker’s single point of color, meanwhile, is a yellow belly, which is often not visible due to its typical posture climbing the trunks of trees where it drills wells from which it eats sap and the insects that get stuck in it. While the Flicker also climbs trees, it spends a great deal of time eating ants off the ground, catching them with its sticky tongue. It is also a bigger bird at 11 to 12 inches versus 8 to almost 10 inches for the Sapsucker.

The sounds the two birds make is also different. Rather than the “wicka wicka” and “clear” calls of the Northern Flicker, the Williamson’s Sapsucker makes a “churring” sound. They appear to be less vocal than the Flicker, however, so you may not even hear them call at all.

So, the next time you spot a fairly large woodpecker with a barred back here in the Colorado mountains, take a second look instead of dismissing it as another Northern Flicker.




ID Challenge: White-tailed vs Mule Deer

Let’s turn now from the difficulties of distinguishing similar species of birds to a large mammal conundrum. Living on the east coast for most of my life, there was no doubt that the deer eating the flowers in my neighbor’s backyard was a white-tailed deer (Odocoileus virginianus). There simply are no other deer in Virginia. It wasn’t until I visited Yosemite National Park when I was already an adult that I saw a different type of deer for the first time, the mule deer (Odocoiileus hemionus).

A mule deer during rutting season at Rocky Mountain Arsenal National Wildlife Refuge. Photo by Jamie Simo.

While the mule deer is typically a western species and the white-tailed deer typically an eastern species, the westward expansion of the white-tailed deer due to the replacement of grassland communities with agriculture and trees, has led to areas where the two commingle. At some point, perhaps, the white-tail, due to its greater adaptability (e.g. tendency toward twins rather than single fawns) may eventually out-compete the mule deer entirely, but, for now, both are present in eastern Colorado.

So, you’re hiking in a state park and you’ve come across a small herd of deer. They stare at you. You stare back. Who are you looking at? Is it a white-tail or a mule?

White-tailed deer. Photo by Jamie Simo.

One way people say to tell is by looking at the size of the ears. The mule deer has enormous ears, like its namesake, while the white-tail’s are smaller. I’ve never found this particularly useful though because, unless they’re right next to each other, I can’t tell whether that’s a really big or just an average-sized ear.

A better way of distinguishing the two species is by their tails. The mule deer has a rather short, white tail with a black tip and its backside is also pretty white. The white-tailed deer, however, has a longer, bushier, browner tail. Its name comes from the way it raises its tail like a flag to expose the white underneath when alarmed.

White-tailed deer unnerved by my presence in Fort Collins, CO. Photo by Jamie Simo.
A mule deer chows down on roses near an office building. Photo by Jamie Simo.

Another way to distinguish if you don’t have a good look at the back of the animal, is by the facial pattern. The mule deer has a fairly even-toned pale brown face. This often sets off a darker forehead (sometimes this looks to me like a unibrow or a toupee). The white-tailed deer, however, has a face the same tone as the rest of its coat with white rings around the muzzle and eyes.

White-tailed deer buck. Photo by Scott Bauer.

If you’re looking at a buck during antler season, you can also tell what species you have by checking to see whether the the points branch off continuously like a tree (mule) or whether they all split off a main “trunk” (white-tailed). Obviously, this only works for males and only during a part of the year though.

After learning this, I’m now confident I know who I’m looking at when I come across any deer while hiking. Hopefully you will be too!