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.