The saguaro cactus is armed with tens-of-thousands of long, sharp spines.
Yet despite this, many birds choose to nest in or on this iconic Sonoran Desert plant of the Southwestern United States and northwestern Mexico.
Birds nest in saguaro cacti using one of four methods.
1) The primary cavity nesters, Gila Woodpeckers and Gilded Flickers, bore nest holes into the living saguaro cactus.
2) Secondary cavity nesters build their nests in old woodpecker holes. Birds that use abandoned woodpecker holes in saguaro cacti include Elf Owl, Brown-crested Flycatchers, and many more.
3) Some larger birds build a large nest of sticks on the arms of saguaro cacti. Birds that build these platform nests include Harris's Hawk and Common Raven.
4) Finally, birds such as Great Horned Owls use old platform nests built by other birds in previous years.
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Saguaro cactus. Arizona. Greg Gillson. |
Why is Saguaro Cactus Important for Birds?
Birds use saguaro cacti for food, for nesting, and for perching lookouts.
White-winged Doves drink the nectar of saguaro cacti. They are important pollinators for this giant desert plant. They time their migration to bring them into the Sonoran Desert in late spring when the saguaro cacti are blooming.
Saguaro cacti are the tallest desert plants. They regularly reach over 40 feet tall, exceptionally to over 70 feet tall. As such, many birds use them as hunting lookouts.
Loggerhead Shrikes are often seen perched on top of saguaro cacti. Harris's Hawks and Crested Caracaras also use them for hunting perches. Northern Mockingbirds, Curve-billed Thrashers, and Cactus Wrens sing from perches high on this cactus.
Along with Saguaros, the Sonoran Desert does have thorny trees--acacia, palo verde, mesquite. But these have short and twisted trunks and lots of scraggly branches. They don't make a good place for woodpeckers to bore their homes.
The saguaro cactus, though, is straight and tall. The pleated sides can have a circumference of over 7 feet. This gives them plenty of room for woodpeckers to drill nest cavities. As a bonus, the long spines protect nesting birds from predators.
Every year woodpeckers bore new nest cavities.
There are many secondary cavity nesting birds that use the old woodpecker cavities for their nests.
I created this video discussing woodpecker cavities and the unique saguaro cactus in this video: What is a Saguaro Boot? My YouTube channel features birds, bird watching, and bird identification. Check it out!
Primary Cavity Nesting Birds in Saguaro Cacti
The two primary cavity nesting birds in saguaro cacti are Gila Woodpeckers and Gilded Flickers.
These birds are found only in the Sonoran Desert, and only where there are saguaro cacti.
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Gila Woodpecker. Greg Gillson. |
Gila Woodpeckers are about 10 inches long, bill tip to tail tip. They are a putty tan on the body and head. The back, wings, and tail are barred black-and-white. Males have a red cap on their head.
Gila Woodpeckers are common, active, and noisy birds of the Sonoran Desert. They are common in desert towns and visit bird feeders to eat sunflower seeds and drink nectar from hummingbird feeders.
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Gilded Flicker. Greg Gilson. |
Gilded Flickers are larger woodpeckers. They are 11 inches long, bill tip to tail tip. Their back is brown with thin black bars. The underparts are pale with small black spots. There is a black crescent across the chest. The crown is brown. The face is gray. Males have a red whisker mark that females lack. When they fly they reveal yellow wing and tail linings and a white rump.
Gilded Flickers live in southwestern deserts where they eat insects. They love ants, and are often seen feeding on the ground.
Secondary Cavity Nesting Birds in Saguaro Cacti
There are many desert birds that nest in old woodpecker cavities in saguaro cacti.
In addition, cavity nesting birds found in towns and near people also nest in saguaro cavities when these cacti are part of residential landscaping.
Both Brown-crested Flycatchers and Ash-throated Flycatchers nest in saguaro cavities. These small birds are quite common in the Sonoran Desert.
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Brown-crested Flycatcher. Greg Gillson. |
Brown-crested Flycatchers are just under 8 inches long. The upperparts are olive, brown. The chest is gray. The belly is yellow. These birds have rusty edges to the wing and tail feathers.
Brown-crested Flycatchers sit on a branch waiting for large insects to fly by. Then they chase and eat them, catching them in the air.
Ash-throated Flycatchers are slightly smaller and less colorful. They are more widespread in dry habitats across the West.
Several Owls nest in saguaro cavities. These include Ferruginous Pygmy-Owl, Western Screech-Owl, and Elf Owl.
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Elf Owl. Saguaro NP. Flickr. CC-BY-2.0. |
Elf Owls are the smallest owls in the world. They are only 5 inches long from bill to tail. They are mottled gray with yellow eyes.
Elf owls eat beetles, moths, and crickets.
Just this spring I went out into the desert at night and heard several. I did not see them, though. I'll have to try again!
Perhaps you are familiar with Purple Martins. These are large swallows found across the United States. They are usually found near water. In the East they nest in apartment style nest boxes. In the West they nest in gourd-shaped nest boxes.
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Purple Martin. Greg Gillson. |
Surprise! There is a subspecies of Purple Martin that nests in saguaro cacti in the desert! The Tucson Audubon is studying them at this web link.
Male Purple Martins appear black, with a purple sheen in good light. Females are brown above and dusky white below. They are about 8 inches long bill to tail.
The Desert Purple Martin (Progne subis heperia) times its breeding to the monsoon season. These desert rainstorms happen in August and September. There are lots of insect food for these martins then.
These birds nest in colonies where there are lots of saguaro cacti with woodpecker holes.
In town, several cavity nesting birds associated with people also nest in saguaro cavities. These include European Starlings, House Sparrows, House Finches, and American Kestrels.
Birds that Build Platform Nests on Saguaro Cactus
Several desert birds build nests in the crotch of the arms of saguaro cacti.
Harris's Hawk is a raptor found in the Saguaro desert.
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Harris's Hawk. Greg Gillson. |
Harris's Hawks are about 20 inches long. They are a bit smaller than Red-tailed Hawks but have longer tails, so their length is similar, bill tip to tail tip.
They are black with red shoulders. The rump and base of the tail is white. They have rather long yellow legs.
They eat rabbits, ground squirrels, snakes and lizards, and grasshoppers and large insects.
Harris's Hawks build large nests of twigs, sticks, and weeds. These nests are usually 12-25 feet above the ground. They breed one to three times a year. Females may have more than one mate.
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White-winged Dove. Greg Gillson. |
White-winged Doves are desert pigeons that are just a bit larger than Mourning Doves. They are 11 inches long from bill tip to tail tip.
They are graysih-brown. The tail is square-tipped. The bill is rather long compared to other pigeons and doves. The key field mark is the large white wing patch, seen in flight and perched.
These birds eat fruit and seeds of saguaro cacti. They are a primary pollinator of this cactus. Long-nosed bats also pollinate these cacti at night. The flowers open fully by midnight. They close by noon. Each flower lasts only about 18 hours.
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Crested Caracara. Greg Gillson. |
Crested Caracara is a long-legged, big-billed raptor of the Southwest deserts and Mexico. They build stick platform nests on saguaro cacti.
Crested Caracaras are 20-26 inches long. They are black with white throat, base of tail, and wing patches. The face lacks feathers and shows red skin. They are sometimes called "Mexican Eagles" but are actually related to falcons.
These birds often feed on carrion. They may chase vultures away from road kill.
Common Ravens and Red-tailed Hawks may also build platform nests on saguaro arms.
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Great Horned Owl. Greg Gillson. |
Finally, Great Horned Owls also nest on saguaro cacti. These owls do not build their own nests but use the old nests of hawks and ravens.
They are big birds. They can be 24 inches long from bill tip to tail tip. They are barred with various shades of brown. The have big yellow eyes and feathers on the top of the head that stand up like horns.
Great Horned Owls in the desert eat rabbits, packrats, snakes, and other larger prey they find at night.
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January 2023: Thank you so much for visiting! I am working on a YouTube channel on birds and bird watching. Check it out here:
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--Greg--
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