Non-insect Pollinators of Saguaro Cactus

Backyard Saguaros

Saguaro Flowers, Watercolor, M. Brummermann 1994

 In May, Saguaro Cacti form crowns of flower buds on the ends of arms and the main stem. The crown is actually a spiral of more mature buds on the outside, and smaller ones closer to the apical growth spot. The flowers open up a few at a time, so the bloom can go on for several weeks. Any individual flower opens during the night and rarely lasts longer than until noon of the next day. By then the waxy flower starts to wilt. It has almost certainly been visited by several pollinators since Saguaro flowers attract scores of very different animals with great amounts of pollen and nectar,

Lesser Long-nosed Bat visiting Saguaro flower at night. Photo:  Merlin D. Tuttle, Bat Conservation International

Famously, Lesser long-nosed bats, migrating through our area just when the Saguaros bloom, are considered a  main Saguaro pollinator. But I've yet to see them in our backyard, and our humming bird feeders are never raided by night, so I'm not sure whether they are indeed visiting our 20 or so mature Saguaros.

White-winged Doves seem to time their return from southern wintering grounds and their breeding to enjoy both the nectar and soon after the juicy fruits of our Saguaros.

Gila Woodpeckers don't just love the nectar and can often be seen with their faces smeared with pollen, they move right in with the Saguaro, hammering out a nest cavity.  The cactus stabilizes it with hard scar tissue, forming a 'saguaro boot'.

The Gilded Flicker, our local form of the Northern Flicker, is another woodpecker that is drawn to blooming saguaros. This photo shows how strong those flowers are, probably a necessary adaptation to bird pollination, especially when other landing options are so very prickly.

Noisy, raucous Cactus Wren families drop in from their nest in a nearby Cholla. Their youngsters often sit begging among the flowers, impatiently demanding to be fed by both parents. This year we have very few nests. I hope they recover soon...

Our breeding pairs of  Northern Cardinals and Pyrrhuloxias are unusual visitors, but love an opportunistic slurp of nectar.

Female Northern Cardinal

 Male House Finch

House Finches spend a lot of time at the nectar source, but then they are also great hummingbird feeder connoisseurs.

Aggressive Curve-billed Trashers love the sweets and also the dominating height that the saguaro offers, so the males alternate feeding with territorial singing.

But over the last years the Thrashers got powerful competition as our local Ravens learned to appreciate saguaro nectar. The social Ravens can often be heard telling each other when the sweets are served. Under their assaults, even some of the sturdy Saguaro blossom break off and tumble to the ground.

Saguaro fruit, Photo by Ned Harris

 Most flowers, pollinated by so many willing helpers, will develop into fruit within a couple of weeks. When the fruits ripen they stay on the cactus and burst open, forming  bright red stars. This is an announcement to all the sugar-lovers to come back, this time to help spreading thousands of tiny saguaro seeds.

Local Birds, Exotic Plants

When we bought our desert property in August of 2002, there were areas around the house where nothing was growing but a spreading, raggedy little aloes. Our first instinct was to remove them and replace them with native plants. But we had 10 acres to take care of and didn't get around to it until winter. Flower stalks were pushing up by then. Coral red and delicate, but braving night freezes and drought. The hummingbirds loved them...so did we.

Our neighbor Thea brought us a trunk-full of plants from her garden, mostly cactus clippings and agave pups, but also a different species of aloes. These were taller, not spreading, and in March, they produced long lasting yellow flower stands. The Gila Woodpeckers delicately extracted nectar ... and we were getting hooked on aloes.

 At the Boyce Thompson Arboretum and at Tohonochul Park we discovered larger species like Aloe ferox. The friendly owner of Bach's nursery gave me a free six-pack of rather overgrown, root-bound Aloes that would become some kind of tree-aloe if they survived. Two got eaten by bunnies, one was too far gone when I got them, one froze during another cold winter, but two did get so big that Randy started calling them Audrey. Right now, they are about 5.5 feet high, including the flower spike.

Aloe marlothii

The botanical name is Aloe marlothii, or Flat Flowered Aloe. According to an online source  they are hardy to 20 degrees F. This winter severely  tested that, but they both survived several nights of 18 degrees. While most of the fleshy leafs lost their tips to frost burn, the rapidly growing flower spike never even seemed to slow down. 

Bullock's Oriole

The flowers open slowly, starting at the bottom, and for the next two weeks, there will be new ones every day. Traveling Bullock's Orioles can use the refreshment on their trip north.

Hooded Oriole

They have to fight the just returning  Hooded Orioles for it, and these usually win. Here's a link to  our resident male enjoying his treat.

Gila Woodpeckers also like the tree aloes

 Aloes are natives of Africa. They may look similar and are adapted to similar arid, hot, sandy habitats as our local agaves,  but the two genera are only very distantly related. Aloes bloom every year and not just once in a lifetime like their American counterparts which makes them great for a desert garden with little color in early spring. (but we do have great penstemons also)

Since birds and insects don't seem to discriminate against the transplants, we enjoy seeing them blooming in our yard when little else does. But we keep them confined to the 'gardeny' part of our land close to the house. We collected some seeds from each blooming cycle. The seedlings are now 3 (right) and 2 years old and still in pots on the window sill.

On the outlying parts of out property, we preserve and plant strictly native vegetation, even avoiding Mexican and South American succulents and cacti. As a result, we got through the cold spell of the last winter with minimal losses and it is great to see how everything is getting ready to bloom now.
                                           All we need is MORE RAIN!!

Sunbathing Gila Woodpecker

One of our Hummingbird feeders is hanging right in front of the window above my desk. Talk about distraction! Verdins, House Finches, Hooded Orioles, Red Admirals, Gilded Flickers, and an occasional Costa's, Ana's or Black-chinned Hummer are constantly coming and going. I think in our hot and arid climate, the fluid is just as appreciated as the sugar.

Gila Woodpecker and Gilded Flicker


When the traffic is high, birds will wait for their turn on the cloth line right next to the feeder.
One young Gila male uses this time to bask in the sun. The wings spread open, contour feathers fluffed up, pupils dilated...

Just like mammals, birds are regulating their body temperature very efficiently by shivering and panting. (Swifts and Hummingbirds and probably many nestlings undergo periods of torpor during which their body temperature plummets). In addition to this autonomous thermoregulation, birds also use behavioral means to control their body temperature.

But today, even at 10 am it's already 84 degrees Fahrenheit in the shade. So the guy is probably not cold. When I had a tame Jackdaw who loved to do his basking on my shoulder, I found him quite unresponsive to outside stimuli during basking, so wild birds are taking a considerable risque...

My Woodpecker sits still for not more than a couple of minutes, then flies off, but he's right back to turn his other side towards the sun.

Scientists have speculated that basking may drive out skin parasites, but I don't think anybody has the answer yet. My Jackdaw as well as this Gila Woodpecker leave me with the impression that this is pure ecstatic pleasure to them....as good a reason as any, isn't it?