Audubon’s Pewee

It’s a day in late May and already the nests of our eastern phoebes are bursting with nestlings preparing to fledge. Over the 47 years we have lived on our mountain, our buildings have hosted many eastern phoebe nests.

A phoebe in Plummer’s Hollow

A phoebe in Plummer’s Hollow (Photo by Dave Bonta in Flickr)

Some buildings, such as the guesthouse portico and the old outhouse, contained nests for several decades, but the outhouse finally collapsed and the phoebes deserted the guesthouse portico after years of successful fledgings. They continue to use either the outside or inside of the small springhouse, while the barn overhang has become a more recent popular nesting place.

Still, there has never been a year when phoebes have not used the top of a veranda column and one of the garage beams to raise families, even though we tried to discourage the veranda column nest sites when we had it repaired and painted by blocking in the flattened tops of the columns. Undeterred, phoebes molded their nests around the obstructions.

Eastern phoebes have been building their nests on human homes and outbuildings for centuries and were known in the 19th century as “barn pewees” as well as “bridge pewees” because they also favor the undersides of bridges. Before the advent of human dwellings and even today, they will build nests in natural rock outcroppings. All such choices protect their nestlings from the weather and often predators as well.

The Eastern phoebe (Sayornis phoebe)

The Eastern phoebe (Sayornis phoebe) (Photo by Soerfm in Wikimedia, Creative Commons license)

Members of the Tyrant Flycatcher family, eastern phoebes follow the first flush of insects north from their winter homes in the southern United States, Texas, and Mexico, often arriving in Pennsylvania in early March and leaving in late October. Sometimes they must survive late spring snow storms and are able to subsist on small fruits instead of insects until the weather improves.

These gray-brown birds with off-white throats and bellies are the first songbirds to arrive on our mountain around March 15. When I hear the raspy “fee-bee” of a male phoebe and see this tail-flicking flycatcher on a wire near the barn catching insects from the sunny side of the building, I know that spring is here.

In scientific circles, eastern phoebes are known as “suboscine” birds because their songs are innate instead of learned like those of “oscine” birds such as wood thrushes. But lately bioacoustic studies of their songs detected variations among male song characteristics that are not obvious to our ears but are to those of the birds.

John James Audubon’s house at Mill Grove

John James Audubon’s house at Mill Grove (Photo by Dennis on Flickr, Creative Commons license)

Eastern phoebes should be credited with first arousing bird artist John James Audubon’s interest in birds. When he was a youth, he lived at Mill Grove on the Perkiomen Creek in Chester County. Early in the spring of 1804, he found the empty nest of the bird he called “Pewee” or “Pewit flycatchier,” fastened to a rock in a cave on his property.

When the cave phoebes returned, he spent many hours watching them as they went about their phoebe business. “Before a week had elapsed,” he wrote in his Ornithological Biography, “the Pewees and myself were quite on terms of intimacy.”

Beginning on the tenth of April, he watched them repair their old nest as “they brought fresh materials, lined the nest anew, and made it warm by adding a few soft feathers of the Common Goose which were strewn along the edge of the creek water.”

Four eastern phoebe chicks in their nest

Four eastern phoebe chicks in their nest (Photo by jeffreyw on Flickr, Creative Commons license)

Even today, eastern phoebes often refurbish old nests instead of building new ones, since building a new nest takes five to 14 days and refurbishing an old one four days or less. One recent study found that new nest builders finished their first clutches later, were less likely to raise a second family, and lost their nesting attempts more often because of fallen nest structures, all of which led to “lower seasonal reproductive effort,” the scientists concluded.

Audubon’s close observations of phoebes’ family life reminded me of the time I spent watching a guesthouse portico family back in the early 1980s. The female refurbished an old nest and she then laid five white eggs.

The Guest House portico where I watched a phoebe nest; the arrow points to the location of a bat which also chose to nest under the roof another time

The Guest House portico where I watched a phoebe nest; the arrow points to the location of a bat which also chose to hide under the roof another time (Photo by Dave Bonta on Flickr

I sat inside the front door of the guesthouse and watched the family through the portico window, but I also climbed up on a chair outside and held a mirror above the nest to check the eggs. The female is the sole incubator, even sleeping in the nest overnight. It takes 16 days until the eggs hatch, and most eggs in a single nest, including the ones I watched, hatch within 24 hours.

Audubon’s eggs hatched on the thirteenth day and in his nest of six eggs one did not hatch just as in the nest of five that I watched one never hatched. In both cases a parent removed the egg. Audubon opened the rejected egg and “found the embryo of a bird partly dried up, with its vertebrae attached to the shell…”

Since the hatchlings are helpless, almost naked, and in need of nearly constant brooding, I waited until they were 11 days old, fully feathered, and active before spending an hour every day watching the nest and recording the number of feedings. For four days they averaged 25 feedings, but when they reached 16 days of age, the feedings diminished to 15 an hour. A recent study showed that parents adjust their feeding rates according to the begging rates of their nestlings.

By then the nestlings were flexing their wings or standing on the edge of the nest and beating them. When they were 17 days old, the female parent appeared with nesting materials in her beak and, despite screams of hunger from the nestlings, proceeded to build a second nest beside the first one, yanking nesting materials from the side and top of the first nest as the youngsters watched.

While she worked on construction, the male fed the nestlings. But sometimes when they begged, she tried to push construction materials down their throats which they promptly spat out. They even jumped back and forth between the old and new nests but settled into the old nest by nightfall. The following morning, at 9:30 a.m., they all fledged at once. Usually though phoebes fledge one at a time over an hour or so as the veranda column nestlings do.

Audubon’s painting of the eastern phoebe, the “pewit flycatcher” as he called it

Audubon’s painting of the eastern phoebe, the “pewit flycatcher” as he called it (Image in the Wikimedia, in the public domain)

While I kept a “hands off” approach to the young, Audubon spent his time gaining the trust of both parents and nestlings so that they tolerated the light silver thread he fastened to the leg of each nestling before they fledged. This was the first time that birds had been banded in North America.

His banding proved the following year that phoebes return to their same nesting site and even nest, writing, “When the Pewees returned to Pennsylvania I had the satisfaction of observing them again, in and about the cave. There again in the very same nest two broods were raised…Several of these birds which I caught on the nest had the little banding ring on the leg…”

He assumed many of the pairs he observed, not only in the cave, but on farm buildings and his mill nearby remained faithful during one breeding season and from year to year. Recently, two studies found that most pairs were both socially and genetically monogamous within a breeding season. In one case in Indiana only 15 of 87 families had extra-pair young in at least one brood, most commonly the second brood.

Those researchers followed up with a second study in which they captured and color-banded 198 males and 237 females, studied them for three seasons, and discovered that they were faithful to their territories, nest sites, and mates within and between years with 85.5% of males and 92% of females mating with the same mate during multiple breeding attempts. But mates were replaced following their disappearance and probable deaths.

A study of infanticide in Kentucky by an unrelated male phoebe even while the female continued feeding her nestlings, resulted in the death of all the nestlings. The researchers hypothesized that the male parent of the nestlings had died or disappeared and that it was a way for a non-breeding male to obtain a mate and start his own family.

A phoebe nest with a brown-headed cowbird egg

A phoebe nest with a brown-headed cowbird egg (Photo by Galawebdesign in Wikimedia, Creative Commons license)

A greater threat to breeding phoebes has been repeated brood parasitism by brown-headed cowbirds. I’ve occasionally observed cowbird parasitism in our nests over the years, but never in the veranda column nests. A study of cowbird parasitism in New York State concluded that even over generations of birds, cowbirds prefer particular eastern phoebe sites, such as our old outhouse.

Other threats to phoebe eggs and nestlings are black rat snakes, raccoons, coyotes, blue jays, American crows, chipmunks, and house wrens, but not one of those predators has climbed or flown into the veranda column nests.

Overall, phoebes are incredibly successful throughout their range including Pennsylvania where they live everywhere except for the urban cores of Philadelphia and Pittsburgh. Although our songbird population has dwindled since the 1970s, it is comforting to know that eastern phoebes continue to thrive and are able to quickly adapt manmade structures for their own purposes.

 

Cavity-Nesting Birds

tufted titmouse at nest hole by The Natural Capital on Flicker

tufted titmouse at nest hole by The Natural Capital on Flicker (Creative Commons licence)

I’ve never thought of myself as a female Dr. Doolittle, but last June a bird “talked” to me and I understood her.

My tale began last April when our son, Dave, decided not to remove a dead oriental cherry tree trunk in his front yard. It was an eyesore, but, on the other hand, he thought it might attract cavity-nesting birds.

And so it did. Almost immediately a pair of black-capped chickadees started excavating a hole facing the woods and then deserted it and began another hole facing the guesthouse porch five feet away. Unlike most chickadees, which are secretive during the nesting period, they were exhibitionists. As Dave and I sat on the porch, they continued to dig out their nest, carrying beaks full of wood chips and dropping them nearby. Not only were they unafraid of us, but they also weren’t fazed on April 20 when several members of our Juniata Valley Audubon Society stood on the porch watching them.

Dave spent far more time on his front porch than I did and kept me informed about the chickadees’ work. Once they hollowed out an area deep in the trunk, the female started gathering material for her nest. Chickadees are supposed to use natural materials such as moss, pine needles, and possibly bark to provide a firm foundation to their nests and then they line them with finer material such as rabbit fur.

But at 2:00 p.m. on April 23, as I sat on our veranda reading several hundred feet away from and out of sight of Dave’s porch, a chickadee, presumable the female, flew in and landed on my book. By doing this, she grabbed my attention, and I watched her fly over to a piece of unraveling beige twine attached to the handle of a covered plastic bucket. She clung to the twine and pulled out strands of this material until she had crammed her beak full, and off she flew. She returned several minutes later and yanked off more, but this time her beak was only half full. She didn’t come back so I assumed she had enough lining for her nest.

 

One of the chickadee parents at the nest hole in the cherry snag

One of the chickadee parents at the nest hole in the cherry snag

The next time I saw her pulling out twine fibers was the afternoon of the Pennsylvania Migratory Bird Count on May 11. No doubt she had been back numerous times when I hadn’t seen her. According to chickadee researchers, nest-building by females can take as little as two days and as long as two weeks so this female was several days over the limit. Or maybe she was freshening her nest lining.

On the 21st, Dave and I sat and watched the chickadee male feeding the female sitting down in the nest. Neither paid any attention to us. But we were worried. Several days earlier Dave had discovered a six-and-a half-foot-long, shed black rat snake skin not far from the nest. And the previous spring he had observed a black rat snake climb up a tree at the edge of the woods and wipe out a northern flicker nest he had been watching form his porch. We hoped the chickadees would survive and raise their young, but their nest hole was much closer to the ground and the trunk much easier to climb than the mature live tree that had held the flickers.

a black rat snake in a flicker hole, just after eating the nestlings

a black rat snake in a flicker hole, just after eating the nestlings

Four days later, when I went down to check on the chickadees, one parent held a caterpillar in its beak and kept calling “dee-dee-dee” as it perched on a cherry stub above the hole, while a second chickadee flew down into the nest. Finally, it emerged and the calling bird zipped down and reappeared a few seconds later without the caterpillar. Then both parents flew off.

It looked as if they were feeding young. She must have begun incubating her eggs the day after I saw her gathering more twine because it takes 12 to 13 days for the eggs to hatch. But after the eggs hatch, according to ornithologists, the male is supposed to feed both the young and the female for several days since she is brooding the nestlings. Not only was this pair unusually bold, but they didn’t seem to be following the “rule book” either.

Day after day they continued feeding their young, most often caterpillars, which was the most common fare for chickadee nestlings, according to the work of one ornithologist in Massachusetts back in 1961. He constricted the throats of nestlings when they were fed and altogether counted 35 caterpillars, 11 spiders, 10 unidentified larvae, six termites, one white Lepidoptera, one pupa, and one fly.

On June 2 I did some more chickadee watching as they fed both caterpillars and insects to their young. Twice a parent emerged with a fecal sac and flew away with it. Sometimes parents eat these sacs, but usually they drop them far from the nest so they don’t attract predators.

After a short wait, a parent arrived with a green caterpillar, paused at the nest hole for several minutes, and finally ate the caterpillar. It flew into the nest entrance and stayed there for more than ten minutes, and I could see the nestlings below. Then the second parent arrived with another green caterpillar which it fed to a begging nestling.

Right on time, on June 8, 16 days after hatching, the chickadees fledged, but both Dave and I missed it. However, the black rat snake never found them, much to our relief, because we had gotten fond of the plucky birds. Perhaps, by building their nest close to the porch, they had gained some measure of protection from our constant surveillance.

In the meantime, the twine story developed another twist. On May 26, my husband Bruce and I sat on the veranda in the afternoon and watched a tufted titmouse fly in twice and pull out a beak full of twine strands, the second time mixing it with a little freshly cut grass. Titmice are also cavity nest builders and titmice females construct the nest, but I had no idea where her nest was. Still, I couldn’t believe how popular the twine was as nest-building material.

More than three weeks later, on June 19, as I sat on the veranda reading in early afternoon, a tufted titmouse flew in and landed on a round white table. Then she flew toward my face and over to the rim of a white chair across from me. Next she flew back to the table, then to me where she landed on my foot, which was propped on a stool, and looked up at me. This titmouse was trying even harder than the chickadee had to get my attention.

She returned to the table, hopped underneath it, and pecked a few times on the cement floor beneath her spread legs. It was then I realized that she was “asking” me to move the two large containers of potting soil I had recently placed in front of the covered bucket with the treasured twine.

“Alright,” I said to her. “I understand what you want.”

She flew off, and I moved the larger containers so the twine would be accessible. A couple minutes later, the titmouse returned and spent five minutes shredding the end of the twine and filling her beak. She looked over at me several times as if to say thank you. At least that’s how I interpreted it. Then she chirped to me as she flew away.

For the first time in my life, I felt as if I had had actual communication from a wild creature. To me it was a transcendent experience I will never forget.

A short film of the chickadees at work excavating the den hole.


Video and photos by Dave Bonta except where indicated.