Nesting Birds on Seabrook Island – Part I: Cavity Nesters

Spring is in the air and the birds are busy building nests and raising their young. The post below was originally distributed three years ago, but with the upcoming Virtual Evening Event:  Nesting Birds featuring staff from Audubon South Carolina, we thought it would be fun to share this article with our members again!  And if you are interested, please register for our program. It is scheduled for Wednesday June 3, 2020 starting at 6:30 pm using Zoom.

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What is a cavity nester?  Cavity nesting birds are ones that build nests, lay eggs and raise young inside sheltered chambers or cavities. The term cavity-nesting does not typically apply to completely constructed cavities, such as birds that weave elaborate, enclosed nests, but instead is reserved for birds that rely on nesting shelter from other sources and build their nests within that shelter.  Furthermore, those cavity nesters come in two types: Primary Cavity-Nesting Birds and Secondary Cavity-Nesting Birds.  

  • Primary Cavity-Nesting Birds: These birds excavate their own holes, such as woodpeckers that drill out chambers in suitable trees or ground-nesting species that may dig out burrows in riverbanks. The labor to create a new cavity may take several days or weeks, depending on the birds’ nesting needs.
  • Secondary Cavity-Nesting Birds: These species take advantage of natural or abandoned cavities, or in some cases will usurp them from other birds through aggressive intrusion. They may make minor adjustments to the cavity, such as adding or removing nesting material or changing the entrance, but do not do substantial modifications.

In addition to these different types of nests, there are various cavities that different species will use.  The size, shape and placement of cavities varies depending on the bird species and their individual nesting needs.  

Types of chambers birds may use include:

  • Holes excavated in dead or decaying trees, stumps, logs, or poles
  • Burrows in soft, vertical riverbanks, dirt mounds, dunes or similar banks
  • Rock niches or crevices, either in natural cliffs or stone walls and structures
  • Exposed pipes, chimneys or similar artificial cavities
  • Supplemental nesting boxes and bird houses

Some birds use a bare, empty chamber, while others line the floor or interior of the chamber with grass, twigs, wood chips, feathers, fur or other materials, even creating an entire nest within the chamber.

Now that we have a better understanding of the basics, let’s go in to some of more common, specific species.

Red-headed Woodpecker – Ed Konrad

The Red-headed Woodpecker is a good example of a Primary Cavity-Nesting bird.  Red-headed woodpeckers most commonly excavate holes in the trunks of dead trees. Holes are excavated from 24 to 65 feet above the ground and the 1.8-inch diameter entrance hole often faces south or west. These woodpeckers may excavate new holes each year, or use old nest sites.  When the Eagles had their nest on the top of the dead pine on Ocean Winds, I was surprised when a Red-headed Woodpecker popped out of the trunk of that same tree.  When the Birders had a Learning Together on Crooked Oaks in early May, we were treated to this beautiful bird looking out from a tree near the green of the 10th hole.  Its mate was flying to the hole, apparently bringing food for possible babies in the cavity.

Tufted Titmouse pair nesting in a tree cavity.

The Tufted Titmouse nest site is in hole in tree, either natural cavity or old woodpecker hole.  It is a Secondary Cavity-Nester as it does not excavate its own nest hole.   It will also use nest boxes. Nest (probably built by female) has foundation of grass, moss, leaves, bark strips, lined with soft materials, especially animal hair. Birds may pluck hair from live woodchuck, dog, or other animal, even from humans. In fact, we’ve seen a video of a Tufted Titmouse doing this to one of our Seabrook Island neighbors!!!

Great-crested Flycatcher in Nesting Cavity – Charley Moore

Great Crested Flycatchers use natural cavities or excavations made by other species. Nests are found in a variety of tree species anywhere from 3 to 70 feet above the ground (mostly below 20 feet). They build a bulky nest, and therefore prefer deep cavities. Before constructing a nest, they will generally fill a deep cavity with trash to a level of 12 to 18 inches from the top. They are well known for their habit of including a snake skin in the nest or dangling it from the cavity opening.  As the Seabrook Island Birders were on a Learning Together at the fourth tee of Crooked Oaks, we saw the Great Crested Flycatcher bring nesting material to his cavity and then looking out as if to say “I’m doing well in my fixer-upper.”

Eastern Screech-owl Cavity – David Gardner

In late April, David Gardner reported an Eastern Screech-Owl had taken over the nesting cavity used last year by a Great Crested Flycatcher.  This cavity is in a tree next to the benches the children use to look at the Camp St. Christopher bird feeders.  Obviously the nearby activity did not deter the Screech-Owl from becoming a Secondary Cavity-Nester in this cavity. Eastern Screech-Owls build no nest. The female lays her eggs on whatever debris is at the bottom of her nesting cavity, be it wood-chips, twigs, or the cast-off feathers and droppings from a previous year’s nest. Settling in, she makes a body-shaped depression where her eggs lie.

Northern Rough-winged Swallow – Kiawah Island SC – Ed Konrad

A Northern Rough-Winged Swallow was recently seen excavating a hole in the steep cliffs along Bohicket Creek.  Audubon reports this species’ nest site is “usually in burrow in vertical dirt bank; may be bank along running stream, or road cut or similar bank miles from water. Birds may dig the tunnel themselves, 1-6′ long, or may use an old burrow of Bank Swallow, Belted Kingfisher, or ground squirrel. Sometimes you will find them in other kinds of cavities, such as drainpipe, culvert, crevice in bridge support, hole in side of building. It is a bulky nest at the end of a burrow made of twigs, weeds, bark fibers, lined with finer grasses, occasionally with fresh horse manure added.”  Northern Rough-Winged Swallows are frequently seen flying near the “dryer vents” on the south side of the Island House.  No nesting activity, however, has been observed.

Yes, the Eastern Bluebird is also a Cavity-Nester.  This is a good example of a bird that often uses supplemental nesting boxes and bird houses. Eastern bluebird nesting sites (snags) are often eliminated because of their unsightliness or interference with cultivation. When available, eastern bluebirds nest in old woodpecker holes, hollows of decayed trees, and crevices of rocks.  They will readily take to hollows in wooden fence posts or correctly sized and placed nest boxes.   On Seabrook Island, we have 4 Bluebird trails that have over 75 boxes that are monitored and cleaned as needed.  Bluebirds are very tolerant of the monitoring activity and their nests can be identified prior to the eggs being laid by their construction being primarily of grass and pine straw within the box. A Carolina Chickadee using the same box would build a nest of moss, pine needles and pieces of bark then line with fur, dryer lint or some other soft material.

Carolina Wren – Ed Konrad

Finally the Carolina Wren may or may not be a Cavity-Nester.  Carolina Wrens are quite universal in their choice of nesting sites. These wrens prefer nesting sites that are fairly well enclosed, but they are not totally dependent upon cavities. They are well adapted to habitat conditions provided by man, but also nest in the woods where they prefer tangles and brushy undergrowth. Nests have been found in natural cavities, mailboxes, newspaper cylinders, old hornet nests, and bird houses.

Now that I have a better understanding of the diverse nature of cavity nests, I expect to find nests I’ve never noticed in the past including for species not mentioned above.

Article submitted by:  Judy Morr
Photographs submitted by:  Various – see credit on individual photos

Join SIB for VIRTUAL Movie Matinee: Animal Homes: The Nest

Last week we had nine Seabrook Island Birder members sign up to attend our first virtual movie matinee.  We have another planned for this Tuesday afternoon on a topic we will be featuring over the next several weeks:  The Nest! Register to join us from any location with a computer, tablet or phone to join this hour long program.

We will send you a link to allow you secure access the morning of the event. We will open each event with introductions, watch the hour long show together, and finish with a short discussion to get your feedback and answer questions.

Sign up by clicking here and then plan to get comfy in your favorite chair with snacks and beverages of your choice to enjoy our gathering! And we hope you will also register to join SIB’s first Virtual Evening Program on June 3 at 6:30 pm, featuring Audubon South Carolina as they discuss the nesting habits of birds specific to Seabrook Island!

Tuesday May 19, 2:30 – 4:00 pm
Animal Homes: The Nest: Bird nests come in all shapes and sizes, crafted from a diversity of materials, including fur, grasses, leaves, mosses, sticks and twigs, bones, wool, mud and spider silk. Quite a few contain man-made materials — twine, bits of wire, even plastic bags. Each is a work of art, built with just a beak! All over the world, birds in the wild arrive at diverse nesting grounds to collect, compete for, reject, steal and begin to build with carefully selected materials, crafting homes for the task of protecting their eggs and raising their young.

Visit St. Christopher This Week!

St. Christopher Camp and Conference Center will open its campus to Seabrookers daily from 9 am to 5 pm May 18-23. Turn onto St. Christopher Lane from the camp sign at 2810 Seabrook Island Road, and the gate is straight ahead.

St. Christopher welcomes walkers, walkers with leashed pets, bicyclists, and cars. Visitors may drive through or park in a designated area to explore the grounds.

“We are not normally able to extend this open invitation because there are children all around,” said the Rev. Lawrence, executive director of St. Christopher. “But since the pandemic hit, we have had neither students nor campers in our midst. So this is the perfect time.”

Camp staff will ask for photo identification and request an optional donation. St. Christopher is a nonprofit ministry of the Anglican Diocese of South Carolina and has been affected deeply by COVID-19 restrictions.

“Please come and explore,” Lawrence said. “We may be a part of your neighborhood that you haven’t seen yet. Or if you’ve been before, please come take another look. We hope to see you soon.”

For more information about St. Christopher’s, click here.

-Submitted by The Rev. Bob Lawrence

Kiawah Conservancy Podcast: Shorebirds

Shorebirds need space! Learn how disturbances affect shorebird survival and what the Kiawah Island Shorebird Stewardship volunteer program is doing to help Kiawah’s shorebirds. This first Learning with Lee Episode features guest Bette Popillo, Kiawah Island Shorebird Stewardship program coordinator and member of Seabrook Island Birders (SIB).

To view additional podcasts and documentaries produced by the Kiawah Conservancy, click here.