Wildlife Wednesday
Empty Nester
When last we checked in with the Black-capped Chickadee family, there were 4 live chicks and an egg.
About a week after hatching, the chicks were beginning to look more like birds. Feathers were growing down their backs and starting on their wings. Although their eyes wouldn’t open for another 4 or 5 days, they were already starting to preen like adult birds. Clearly this is an innate behavior in chickadees as there’s no way they could mimic what they couldn’t see either parent do.
While only the female Black-capped Chickadee incubates the chicks, both parents are active in feeding. As mentioned previously, sometimes the male will also do some mate-feeding, which the female then passes along to the chicks. The mystery of what the parents were feeding became clear as I saw the chickadee parents on my suet feeders often. Sometimes though I caught sight of them feeding a moth or a caterpillar. More and more, the female would tip herself beak down into the nest after feedings and poke around. I believe this was so she could expand the nest to accommodate her growing brood.
By week 2, the chickadee chicks were starting to look more like chickadees and were getting more vocal, clambering to be the first to get the food offered by their parents. Due to the small confines of the nest, they would often lay on top of one another seemingly without much of an issue. I thought this made sense because I thought they also roost together to keep warm in winter, but apparently unlike other birds like bluebirds, chickadees roost singly.
Most of the literature I’ve read says that Black-capped Chickadees take 16 days from hatching to fledging, but on day 15, other than exercising their wings a bit, they showed no real hurry to fly. Granted, this may be due to a late snow that occurred right around the stated fledge date, although chickadees fledged on day 19 at this nest in New York, which the author notes is the average for their yard.
May 25th, day 20, was the appointed day. The chicks were VERY busy hopping around the box and flapping their wings beforehand. Probably because they had some extra days to prepare, they fledged in quick succession. All but one chick had fledged by the time I got outside with my camera around 8am.
While the parents flitted around, calling encouragement, the chick would hop up to the hole, stretch out and look around for a few seconds, calling back, then disappear back inside. Finally, the chick decided to take the plunge and jumped out of the hole, fluttering the few feet into the nearby aspen saplings.
I haven’t seen the chicks since, but I’ve seen adult chickadees, presumably the parents, at my feeders. I can only hope the chicks are doing okay, though the fledgling period is the most dangerous for young birds. If they have survived, they’ll be just about ready to leave their parents and go off on their own; Black-capped Chickadee fledglings typically only stay with their parents for about 10 days.
And now, the mystery of the egg. When I cleaned out the box, the nest was pretty dirty and unkempt, but I didn’t initially see the infertile egg. Feeling the nest though, I definitely felt something hard. Sure enough, mama chickadee had buried the egg deep inside the nest. With their small beaks, I suppose this was more efficient than trying to pick up the egg and remove it from the nest as the Northern Flickers did.
Good luck, little chickadees! I hope I see you again even if I don’t recognize you!
Best Laid Plans
It’s only been a few days, but life moves fast when you weigh less than a slice of wheat bread! Ultimately, Mama Chickadee had 6 eggs and on May 6th, 4 tiny little Black-capped Chickadee babies hatched out.
Like with the flickers, at least one of the egg shells was eaten by the female. Birds probably eat egg shells to obtain minerals like calcium. Waste not, want not! Eating leftover egg shells also helps clean up the nest, which is important when space is at a premium, as it is in any cavity.
Both mom and dad chickadee are working hard to feed their new family with sometimes both parents in the box at the same time. At times, the male feeds the female as well. She solicits food by making a high-pitched chattering and shivering her wings. It’s hard to tell what they’re all eating, but it looks like soft-bodied insects, possibly larvae or caterpillars.
The chickadee chicks are a lot quieter than the flicker chicks. Sometimes they don’t perk up for a feeding until the parent makes a soft “dee dee” call.
Sometime late on May 6th or maybe early in the morning on May 7th, a 5th chick hatched. Sadly, the chick didn’t even last a full 24 hours. Sensing something wrong, Mama Chickadee managed to pick the chick’s body up and flew away with it somewhere. She probably dropped the body somewhere a good distance from the nest to keep predators away from her doorstep.
As of today, there’s still one unhatched egg in the nest. I suspect it’s infertile and won’t hatch. I’ll be watching to see when the parents remove it. It might take awhile though; the unhatched flicker egg stayed in the nest up until fairly close to fledging.
Return of the Black-capped Chickadees
I put up a new chickadee box this year. It’s deeper than the previous one so the camera fits inside the box rather than a hole having to be cut through the roof of the box to accommodate it. Almost immediately after putting it up, a pair of Black-capped Chickadees started checking it out, so I’m glad I got it up before April!
Like with my flicker box, I put a handful of wood shavings in the chickadee box. This simulates a natural cavity. While they’re not nearly the pecking powerhouses that woodpeckers are, chickadees can and do excavate their own cavities if the wood is soft enough. However, chickadees are considered secondary cavity nesters, moving into cavities after the original tenants have moved on.
Much smaller than Northern Flickers, and more vulnerable to competition for nests and to predators, chickadees won’t just dump wood chips right outside their front door like a flicker will. Both male and female chickadees take a beakful of chips and fly a short distance away, scattering them. This prevents rivals/predators from following the wood chips like a trail of breadcrumbs straight to the nest site.
On March 31st, after they had “excavated” the wood chips, the female chickadee went to work building her nest. Only the female Black-capped Chickadee builds a nest, which she does starting with a thick layer of cushy moss. Following the moss, she began to bring in softer material. I recognized dog fur and, I believe, some leftover fluff from when my milkweed went to seed last year. With each new addition to the nest, mama chickadee would build up the nest cup and then wriggle her body down into it, conforming it to her body.
Like I mentioned, chickadees are small and vulnerable. They have little defense against the invasive House Sparrow, a species known to kill native birds and then take over their nest cavity. To combat that possibility, I put a metal 1 1/8 inch hole guard over the 1 1/4 inch box entrance. Black-capped Chickadees are small enough to still fit through the hole, but House Sparrows aren’t.
Check out this video of mama chickadee’s “snake display” warning away a (likely) House Sparrow intruder. Without the added protection of the hole guard, this display may not have been enough to deter a persistent nest parasite.
The literature I’ve read suggests that it can take up to 2 weeks for a Black-capped Chickadee to finish building her nest, with egg laying following 1-2 days later, but this particular female seemed to take a bit longer. It wasn’t until April 18th that she laid her first egg and, even then, she was still bringing in the occasional bit of fluff to pad out the nest.
I can only assume her first egg was laid on April 18th because Black-capped Chickadees, like many other songbirds, lay an egg a day and I noticed that there were 2 eggs in the nest on April 19th. As of April 21st, there are probably 4 eggs in the nest. Why can’t I tell for certain? Black-capped Chickadees tend to cover their eggs with fur nesting material when they leave the nest so, at the moment, I can only tell for sure that there are 3 eggs in the nest. Going by the fact that they lay 1 egg a day though, that means there should be 4 today.
Black-capped Chickadees, on average, lay between 6 and 8 eggs per clutch, so we could be could be close to incubation (mama chickadee will begin incubating the day before her last egg is laid), or we could still be a few days away. Personally, I hope she goes for a smaller clutch–it’s a pretty small box and I can’t imagine how crowded 8 babies would be–but we’ll soon find out!
Front Range Birding Company in Boulder
The Front Range Birding Company (FRBC), a locally-owned bird feeding and bird-watching store located in Littleton, Colorado, is expanding to a second location in Boulder this month! The new store is located at 5360 Arapahoe Avenue Unit EÂ right next to Pica’s Taqueria.
In addition to selling bird seed and bird feeders, FRBC staff are extremely knowledgeable and helpful about all things bird (full disclosure: I may be a little biased since I just joined the Boulder crew!). They can recommend a new pair of binoculars or a spotting scope, or help you identify the bird that’s been hanging around your backyard. FRBC also hosts bird walks and talks with expert birders to birding hotspots around the Front Range.
I’m super excited to join the FRBC staff, so stop by for a visit and say hi when the store opens later this month.
Wildlife Wednesday
Wildlife Wednesday
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.
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).
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.
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.
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.
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?
Wildlife Wednesday
Wildlife Wednesday
New Colorado Naturalist 