Half of all birds are cavity nesters. Woodpeckers, owls, chickadees, nuthatches, and parrots are among the species that do. Cavity nests are safer than open nests.
Cavity nesters can be divided into several categories:
- those who excavate their own nests and don’t use abandoned holes (primary excavators)
- those who excavate and use natural or abandoned cavities
- those who don’t excavate but use natural or abandoned cavities – snags (secondary cavity nesters)
These are the bird species which will use a birdhouse. See our post on Birdhouses: Choosing, Maintaining, and Attracting the Birds.
Remember: Good birders don’t disturb nesting birds. Observing nesting birds should be only done from inside a blind (like your house), with a video camera installed in a birdhouse or not at all.
Do-It-Yourselfers: Birds that Excavate Their Own Cavity Nests
Woodpeckers are the primary excavators of nest holes. Where the Northern Flicker is the primary nest cavity excavators, the Flicker’s nest holes provide homes to over thirteen species of mammal and bird species.
On average, it takes a woodpecker two weeks to excavate a cavity.
Most birds that nest and excavate in living trees choose softwoods such as aspens. Some woodpecker species will choose to live trees with hardwood softened by fungal disease to drill new nests. The woodpeckers spread the fungal infections by carrying the spores on their bills. This creates future potential nest sites.
Other species will choose trees with wood softened by disease and fungal infestations. These primary nest hole builders include:
- Northern Flicker
- Pileated Woodpecker
- Red-bellied Woodpecker
- Red-headed Woodpecker
- Yellow-bellied Sapsucker
- Hairy Woodpecker
- Downy Woodpecker
Species that nest in living trees often make new holes in the same tree over several years.
Eastern Woodpeckers that use Living or Dying and Dead Trees
- Red-cockaded Woodpecker – living pines; taking up to two years to excavate the cavity
- Yellow-bellied Sapsucker – living poplar or birch tree with heart rot
- Downy Woodpecker – dying or decaying tree
- Hairy Woodpecker – living or decaying tree trunk or limb
- Flicker – dead or dying deciduous tree
The Red-cockaded Woodpecker (Picodes borealis) nests in living pines. It is a rare and local bird of the southeastern U.S. It lives in mature Longleaf Pine savannas. It spends on average two years excavating the cavity because of the living trees relatively hard wood.
Western Woodpeckers that Excavate Nest Holes in Living Trees
- Golden-fronted Woodpecker – live trunk or large tree; usually mesquite, pecan, oak or in a dead limb
- Yellow-bellied Sapsucker – live tree with rotting heartwood caused by fungus
- Red-napped Sapsucker – dead or living tree with rotting heartwood caused by fungus
- Ladder-backed Woodpecker – live saguaro cactus
- White-headed Woodpecker – live tree or dead shrub of pine
- Black-backed Woodpecker – live tree with rotting heartwood
Both male and female woodpeckers build nest holes. Most woodpecker species will excavate a new nest cavity every year. This provides plenty of abandoned cavities for other animals to use. Woodpeckers are supremely important to ecosystems for their excavation activities. Many woodpecker species are poorly studied. This means citizen scientists can help to fill in the gaps in research by collecting data.
Woodpecker nest holes can be identified by shape. The large Pileated Woodpecker makes a large squarish, oblong hole. The wood chips beneath the hole will be oblong, too. Wood chips are often used to line the nesting cavity. Hairy Woodpeckers make round holes.
Birds Who Excavate their Own Cavity Nest or Use Natural or Abandoned Cavities
Secondary nesters will build their nest on top of the old nests left in the hole. Snags (standing dead trees) with natural cavities are important to secondary cavity nesters. Secondary cavity nesters are the birds that will use human-made birdhouses.
Chickadees and nuthatch don’t have the powerhouse drilling bills of woodpeckers. But these little birds drill their own nest cavities in the rotten wood of old trees.
- Black-capped Chickadee
- Carolina Chickadee
- Red-breasted Nuthatch
- Brown-headed Nuthatch
Birds who can’t excavate and only use natural or abandoned cavities
Some birds can’t excavate their own nests. These species will locate and occupy abandoned woodpecker holes. The competition is fierce among these secondary cavity nesters to find and keep their nest holes. These birds will often use birdhouses.
- Bluebirds
- Brown Creeper
- Carolina Wren
- European Starlings
- Wood Ducks
- Common Goldeneye Duck
- Bufflehead Duck
- Barrow’s Goldeneye Duck
- Barn Owls
- Eastern Screech-Owl
- Great Horned Owl
- Northern Hawk Owl
- Elf Owl
- Barred Owl
- Long-eared Owl
- Boreal Owl
- Saw-whet Owl
- American Kestrel
- Purple Martin (in Western North America)
- Tree Swallow
- Tufted Titmouse
- White-breasted Nuthatch
- House Wren
- Winter Wren
- Prothonotary Warbler
On really cold nights, some birds have been known to seek the shelter of abandoned nest holes to survive the cold. Many birds will even gather in holes for warmth.
Cavity Nest Photos Submitted by readers
Winter Nature Journal Activity Ideas
Find abandoned nest cavities in trees
- search for abandoned bird nests and holes
- sketch the holes
- note whether the wood is living, rotten or diseased
- guess who made the hole
- guess the age of the hole
- guess who might live in the hole
- keep up those birdhouses, birds will use them during severe weather
I’d be careful looking into the hole. You don’t want to startle a Great Horned Owl with sharp talons.
And if you upload your sketch to the Internet, let me know. I would like to share it with your fellow naturalists. We would love to see it.
Further Information
Birdhouses: Choosing, Maintaining, and Attracting Birds
Forest Forensics: A Wolf Tree Tells a Tale
Nesting Boxes: National Wildlife Federation
Put Out Nesting Materials and Nest Boxes, March 1
LoveNest Birdhouses with WiFi Cameras
Tiffany Gailey, a blog reader shared these great photos of a cavity nest. https://donnallong.com/wp-content/uploads/2023/04/IMG20230331114948.heic
https://donnallong.com/wp-content/uploads/2023/04/IMG_20230331_115505.jpg
What year was this article published in ?
Hi Suhotra – This post was first published in February 2018, and updated numerous times. The last update was July 2022.
[…] Nguồn: … […]
Donna – very interesting article and site. I searched for this because I found 3 new holes in a tree in a tree (we have many). So naturally I’m curious – the top one is squarish and now I’ll check the chips per your article. Maybe stick a camera down there to see who did the work. We’ve been hearing an owl early in the mornings lately but your article told us their home is elsewhere.. Thanks again
Hi Bob, I glad you found the information useful. I’ll be publishing a question and answer interview with a maker of bird houses that feature video cameras in the near future. If you have any questions please add you questions to my contact form. 🙂 https://donnallong.com/contact/
Have a bird that looks like a sparrow, grey, with brown maybe black that is excavating my dead tree. What is it
Hi, Jan – Thanks for your question. The little birds that have the strength and strong bills to drill holes are Black-capped Chickadees, Carolina CHickadee, Red-breasted NUthatch, and Brown-headed Nuthatch. Try the Brown-headed Nuthatch first – https://www.audubon.org/field-guide/bird/brown-headed-nuthatch. If that isn’t it then maybe it’s one of the other ones.
Enjoyed reading this info. Thanks for your work!
Can I erect some larger logs for potential woodpecker housing? I live in a suburban habitat and would like to attract them and be beneficial to them.
Again thanks!
Hi, Phil
You’re welcome and thanks for contacting me.
Sure, you can erect larger logs for the woodpeckers to make cavities. I checked on woodpecker cavity-making behavior in The Sibley Guide to Bird Life and Behavior (pages 380-381). David Sibley writes:
woodpeckers excavate their nests in living or dead wood
the tree must be wide enough so the hole does cut into the sap layer and cause the sap to run and fill the hole
Woodpeckers won’t keep using a nest once shrubbery or other objects grow and provide a snake or predator easy access to climb into the nesting cavity.
I would do some research to find out if the woodpeckers in your area nest in live or dead wood, and what trees they often choose. You can also go to a area where woodpeckers nest and see what tree species, size of trunks, etc. You would have the best chance of having a woodpecker nest in your logs. Good luck.
We had to take part of a tree down but have a stump left about 8-9 ft tall and approx. 32-36 inches across. We’d like to leave it for the birds…do we drill any holes in it or let the birds take care of making their own home? Thank you for your help
Hi, Mary
Woodpeckers usually drill the holes in trees. After the woodpecker finishes using the nesting hole, then other birds are free to move in.
If you want to create holes for the birds I would use the standard sizes for making birdhouses and their openings. I have a downloadable pdf on my website that includes a page with hole sizes for various birds. Find it here https://donnallong.com/wp-content/uploads/2011/12/building-nest-structures2.pdf. See page 23.
When building a wooden nesting box or birdhouse, you create a box/cavity for the nest. If you want to create a hole in a tree you would have to create the cavity for the actual nest to rest in. You also need to place the hole a safe height from the ground. The height is probably in the pdf also. It is doable.
Or you can let the woodpeckers to it for free. It would be great to watch them and see how long they take to excavate a hole and nest.
Regards,
Donna
Hello Donna,
The Great Crested Flycatcher is a cavity nest borrower here in South Carolina.
Enjoyed your article,
George
Hi, George – Thanks for contacting me. Thank you for the addition. I’ll add it to the list.
Donna,
I was so happy to see this article! I live in Ohio and work as a naturalist for our local park system. I knew chickadees were secondary cavity nesters, but didn’t realize that they would use a human made bird box until this spring. Last summer, my husband painted a bird house and put it out in our tree off the front porch. I thought it was too small to attract any birds, but this past month chickadees starting checking it out and in the last week have been flying in and out of it with nesting material! If we can get a picture, I will send it to you!
Amy Roell
Hi, Amy – Thanks for contacting me. It is great to hear you are providing free room and board to a family of chickadees. They are one of my favorite birds. Many people find the cavity nesting article helpful. I’m glad you did, too. I look forward to the pictures.
I enjoyed your article about cavity nesters. One of your statements caught my eye:
“Some woodpecker species will choose living trees with solid hardwood to drill new nests.”
I remember reading a couple of years ago that a woodpecker made its cavity in a ‘healthy’ tree and took 2 or 3 years to do so. I have been unable to find that reference again.
Can you please provide me what woodpecker species make their cavity in a healthy tree?
Inquiring minds want to know!
Many thanks.
Jim Wilson
Hi, Jim
Thanks for contacting me. I’ll get back to you on the woodpecker species. I don’t recall which one off the top of me head.
Hi, Jim
Here is an answer to your question. I focused on the key idea of taking 2 or 3 years to excavate a nest cavity. The only bird that I found that takes that long is the Red-cockaded Woodpecker (Picodes borealis) that nest in living pines. It is a rare and local bird of the southeastern U.S. It lives in mature Longleaf Pine savannas. It spends on average two years excavating the cavity because of the living trees relatively hard wood. I found this information in – wait for it – The Sibley Guide to Bird Life and Behavior, 1st edition, p. 381 by David Allen Sibley.
I am also updating the “Cavity nesters” post with all the other info I found. Thanks for an absorbing mystery to solve. Peace, Donna
Donna
Thank you! I have the Sibley’s book on my shelf but I never thought to look thru it for an answer.
I am enjoying reading your articles now that I have discovered them.
Jim Wilson