Desert Tortoise

By May spring wildflowers have crisped into mere scaffoldings for seeds.  Underfoot the soil is loose and the air itself feels bone dry.  Out hiking, I descend into a dip in the Desert Classic Trail, a place where cyclists speed down and pedal madly up again. I’m startled to see a Desert Tortoise come lurching towards me.  She pitches side to side down the slick slope.  Scrape, scrape go her fin-like feet.  Once she reaches shady cover, she drops her shell to the ground and slides shiny black eyes towards me.

Hustling to safety – tortoise speed

Desert Tortoises are ancient creatures, having existed on the planet for 50 million years.  And they live long, 40 years or more.  Their reptilian features, and their awkward gait make them fascinating creatures.  These animals live underground in burrows much of the time, dormant and protected from extremes of heat and cold.  They come out in pleasant weather and cooler times of summer days to feed, to find water and to mate.  Desert Tortoise eats spring wildflowers and summer annuals that grow after monsoon rains.  She can digest dried plant material, if she has been able to find water.

Because water in the desert is rare, Desert Tortoise stores the precious liquid in her bladder, enough to get by for months.  In fact, water can make up 40 % of her body weight. This allows the tortoise to survive without drinking from winter rains until summer monsoons. 

If frightened, a tortoise will void its bladder, compromising its ability to survive.  People are urged to keep away from Desert Tortoises, and to certainly not pick them up, even if they are found on a roadway.  (I guess you stop traffic instead!) 

Arizona Department of Game and Fish handles a Desert Tortoise adoption program.  Tortoises that have been in human contact, either from illegal breeding or handling, are prevented through this program from being returned to the wild, where they may spread disease among the native populations. 

Whose Finch?

Handsome Male House Finch

Naming a bird House seems wrong.  And because it’s a commonplace urban bird, the House Finch might seem a little boring.  But consider House Finch social life.  The rather plain female keeps her colorful mate very occupied with making her happy.  At breeding season, she assesses potential partners and looks approvingly on males with the brightest coloring. 

The male has been working hard to make himself attractive. He’s in tip top shape, and has been feasting heavily on berries and fruits with strong pigmentation. These give him the brilliant red or yellow feathers that make a female sing.  She’s looking for the healthiest, best-looking guy, surely most capable of helping her raise her young.   

If her glance lingers on him, the male breaks out in fluttering flight displays and persistent song.  When she’s properly impressed, she starts right in on house hunting, touring the area for potential nests sites.  The male flutters madly after her, singing with joy.

The nest might be a remodel of an old nest, or a nest pre-owned by another species.  The couple might consider a cavity nest, or build new. 

The male can’t be complacent at this point.  He must guard his mate during egg laying and incubation and bring her the tastiest morsels of her favorite foods.  Otherwise, she may abandon the nest and look for another mate!  Both parents feed the hatchlings regurgitated seeds or vegetable matter.  These birds eat very few or no insects. 

The bright clear notes of the House Finch song string together like colorful beads.  At this time of year, it’s a beautiful backdrop to our mornings.  The House Finch is native to desert canyons of the West, where they live near water sources. Our backyard fountain is visited by a parade of the birds.

Back in 1940 some captive House Finches were put in a pet shop in New York City.  But the rascals escaped and took up urban life.  Now the clever and endearing House Finch can be found in city parks throughout the east as well as the west. 

Below see the female House Finch and various colors on males, depending on what they ate during the molt before breeding season.

Babies In Boots

Gila Woodpecker drills a cavity nest
Gila Woodpecker digs deep

This past Feburary I watched a Gila Woodpecker male, identified by the red patch on his head, creating a cavity in a saguaro.  He reared back his head and used the leverage afforded by his long tail to hammer at the green skin of the cactus, breaking through the outer layer. 

After that, things went easier.  He quickly enlarged the hole, reaching inside with his formidable beak to scrape and probe, pulling his head out to shake off the juicy bits of saguaro flesh.  Soon, the woodpecker had excavated the cavity enough that he was leaning far inside to do his work.

Once the cavity is 9-18 inches deep, the Gila Woodpecker leaves it alone to cure.  The inner parts of the saguaro callus over in a couple of months forming what is called a boot. Then the nest is ready for use.  Unless someone else moves in first, the female woodpecker lays three to four white eggs in the bottom of the bare cavity. 

Sometime in May, the eggs hatch. The parents feed their noisy hatchlings insects, berries and cactus fruit. Even after they fledge, mom and dad continue to feed and watch out for their young, sometimes caring for overlapping broods. 

Only two species of birds, Gila Woodpeckers and Gilded Flickers, make cavity nests in saguaro cacti. But many others make use of these cozy and protective hidey holes, Elf Owls, American Kestrels, Ash-throated Flycatchers, European Starlings and Screech Owls to name a few.

Desert Iguana

Desert Iguana at South Mountain Park in April

This lizard loves heat, and is out and about on even the hottest summer day.

One fast runner, the Desert Iguana bursts into explosive speed to reach the safety of its burrow when threatened.

The biggest treat for this large lizard is the yellow flower of the Creosote bush. Mmm, delicious!  The iguana crawls right up into the bush to reach the delectable treats. The leaves and flowers of the Creosote make up most of the Desert Iguana’s diet.  It also eats insects and even carrion.

The Desert Iguana digs burrows under Creosote plants, making safe hiding places.  This also helps the Creosote, as the burrows funnel water down to the plant roots when it rains. 

Desert Iguana hibernates during the chilly fall and winter months, emerging in March just as the Creosote is setting its blooms.  The iguanas breed in April or May and the clutch of 2-8 eggs hatch later in the summer. 

This Desert Iguana was soaking up the sun, and surveying its territory as I happened by. It was my lucky day as they are known to be secretive and shy.

Creosote bush stays green all summer, even with the heat. It leaves are covered with a waxy coating to keep them from drying out, and they tilt to minimize exposure to suns rays.

Saguaro and White-Winged Dove

Here’s how a cactus and bird join up to help each other out.

White-winged Doves fly to the Sonoran Desert from Southern Mexico every April.  They arrive just as the creamy blossoms of the Saguaro cactus are breaking open, releasing their sweet fragrance.  The doves replenish themselves with Saguaro nectar containing water, sugar and protein. A sports drink couldn’t be better formulated to match their needs. In return, the doves carry pollen from one tall cactus to another, ensuring the flowers will set fruit.

Saguaro flowers bloom for a single night, opening up after dark and closing when the sun is high the following day.  Nectar feeding bats get first dibs on the new blossoms.  Come dawn, White-winged Doves feast at the flowers, joined by Gila Woodpeckers and Curved-bill Thrashers.  Bees also mob the sweet blooms.

White-winged Doves mate in early May, and build their flimsy nests in the highest tree branches.  The hatching of the eggs in June coincides perfectly with the fruiting of the Saguaro. Nestlings first drink crop milk regurgitated by mom and dad, but soon transition to the pulp and seeds of the Saguaro fruits along with seeds from other desert plants.

Saguaro fruits ripen at the hottest, driest time of the summer.  The juicy fruit helps many desert animals survive until the monsoon rains arrive.  As birds feast on the fruits and fly about excreting the seeds, new baby Saguaros are planted across the desert. White-winged Dove’s digestive system is brutal on cactus seeds, but doves still help their Saguaro partners when they carry bits of dripping fruit to their nestlings.  Seeds dropped beneath nests await the promise of summer rains.

In September White-winged Doves break off the cozy relationship with their cactus cohorts and migrate back to the southern regions of Mexico.

Saguro Fruit ripening in early June
White-winged dove display
Yes, you are beautiful