About 1000 different species of bees live in the Sonoran Desert. Most are solitary and nest in underground burrows or the hollow stems of pithy plants. The majority of these bees are herbivores, subsisting on pollen and nectar.
Upwards of 80% of native flowering plants in the Sonoran region are pollinated by bees, as are 30% of agricultural crops. Bees are vital partners in the production of many of our foods, fabrics (cotton), beverages and medicines.
The introduced honey bees shown in these pictures live in social colonies of 30,000 or more. They nest in manmade hives, hollow trees or rock outcrops. Close examination of these bees reveals hairy eyes!
Baja Fairy Duster, Chuparosa, Lantana, Valentine Emu Bush and Arugula provide winter nectar for bees, butterflies, moths, hummingbirds, and Verdins.
A thief has been at work in the chuparosa patch! Verdin does not have a beak long enough to access the sweet nectar at the throat of the bloom, so makes a slit at the base of the flower and sips straight from the source. Feeding avidly at the chuparosa, Verdin does not contribute to pollination.
In addition to pilfering nectar, busy Verdins eat 400-500 insects every day. They also feast on seasonal fruits of desert plants, and seed pods of trees such as ironwood, paloverde and mesquite. All of this nutrition supports an active metabolism that is on display as the tiny birds flit about constantly, chittering, gleaning insects and sipping nectar, often hanging upside down from plant stems to do so.
Verdins are also energetic nest builders. Recently I watched a Verdin bring a long chain of fluffy plant material to an existing nest, apparently adding insulation for upcoming cold weather. Verdins build different types of nests for different situations. In spring, the solitary birds pair up and the male builds an outer shell of a breeding nest for his female. She completes the interior and lays her eggs. The male also constructs smaller roosting nests for nighttime use. Some of these are for the fledglings once they leave their natal nest.
Verdin nests are easy to see when you walk in a desert wash, built as they are within the outer branches of the trees. These enclosed, ball shaped nests have an opening facing out and downward. Breeding nests include an interior lip to prevent eggs and nestlings from rolling out. Clever Verdins build summertime nests with less insulation, and they position the opening facing towards prevailing breezes to provide cooling.
Northern Mockingbird is a fancy, flamboyant song bird. With a sleek silhouette, and elegant grey plumage, Mockingbird has an outsized attitude, and you’ll know if you’ve wandered into a mocker’s nesting territory. Mockingbirds defend their nest aggressively, dive- bombing people, dogs, other birds, snakes, you name it.
But Mockingbird is also impressive for his song. Clear liquid notes are combined in an amazing range of compositions. Mockingbirds mimic other birds and other sounds they hear, and mix these with their own melodies, making them into songs. The male keeps composing songs and adding them to his repertoire over his whole lifetime. He may end up with 200 songs. He sings tirelessly, all day and into the night when the moon is out. Females sing too, but more quietly, using their songs to establish winter territories rather than during breeding season.
Mockingbirds hop and run on the ground to catch insects, as well as nabbing them in the air. They also eat a wide range of fruits from native plants such as cacti, wolfberry, hackberry and mistletoe to fruits from cultivated plants in suburban yards.
Northern Mockingbird fledglings leave the nest about a week before they are able to fly, running on the ground and climbing into nearby bushes for safety. Mom and Dad keep a close eye on them, bringing them food and warding off intruders.
The male takes a break from this extended care and builds the outer shell of a new nest while the female continues with feeding duty. Then he returns to caring for the fledglings while she finishes the interior of the nest, lays 2-6 new eggs and incubates them. The pair may raise up to four broods between March and August in the desert.
On a recent trip to Desert Botanical Gardens I visited the butterfly tent. Inside butterflies fluttered about lazily or perched on flowers and leaves. Seen up close, their colors were dazzling. Butterfly wings are covered with thousands of overlapping scales, each a solid color, creating lovely hues and the distinctive patterns of each species.
Many butterfly species are found in the Sonoran Desert. Some are residents that stay in a fairly small range centered around larval food plants, others are visitors from other areas, drawn here by weather patterns or plants. Adult butterflies feed on nectar and are important pollinators, while the larval stage caterpillars eat green leaves and often become food themselves for birds and their young.
Pesticides applied to landscape plants, roadsides and agricultural fields are major threats to butterflies, as is habitat destruction, particularly in riparian areas.
In our neighborhood grows a beautiful Cascalote tree. When I walked by on a chilly morning recently I saw hundreds of showy yellow blossoms had unfolded at the ends of the branches, and that the tree was alive with tiny birds.
Usually tiny birds around flowers are hummingbirds or Verdins, both of whom eat nectar and insects, but the one that caught my eye on this day was neither. As I paused beneath the tree, it dipped its head and a slash of red gleamed on its crown.
This was a Ruby-crowned Kinglet, and he was in constant motion, hopping from bloom to bloom and flicking his wings. These birds eat insects, perhaps it was ants or aphids attracted to the sweet blooms that the kinglets and Verdins were eating. Only adult males have the red crown patch which is flashed when the bird is excited. Sometimes the ruby coloring is not visible at all.
Ruby-crowned Kinglets spend their summers in spruce and fir forests in the Northwestern United States and across Canada. In Arizona they can be found in the northern parts of the state where coniferous trees grow. In fall, Ruby-crowned Kinglets migrate to warmer areas, which is why I saw this one enjoying the feast at the Cascalote tree.
A bird with a swagger? Yes, that’s the Cactus Wren. This brash songbird makes no effort to conceal his busy occupations about the desert. Nest building is nearly a full-time job, but plenty of hunting is done as well, and Cactus Wren is always on patrol in his territory, singing from a cactus top or scolding intruders.
Cactus Wrens choose life-long partners and live in year-round territories. They build many nests, nests for raising babies, and nests for shelter from heat and safety from nighttime predators. The spherical nests are open at one end, where a tunnel leads to the inner chamber, which is cozily lined with feathers.
These nests are usually placed in cholla or prickly pear cacti, but are also found in acacia, Palo Verde or mesquite trees. The thornier the better. Working together, a Cactus Wren pair can build a nest in one to six days, working mostly in the morning. After the youngsters have fledged, the grasses and weeds woven into the abandoned nest are popular with other bird species. In a prime location, a new nest will be built right on top of the old.
When not nest building, Cactus Wrens are hunting. Omnivores, they eat insects mostly but also spiders, lizards, berries, fruit and nectar, some seeds, and occasionally a small rodent. They do not drink free standing water, obtaining moisture from cacti pads and fruits. Dust baths keep their feathers clean.
Parents raise 2-3 broods every year, feeding the 3-5 nestlings insects. Grasshoppers are a favorite food. The parents pull the wings off before feeding up to 14 grasshoppers to each nestling every day. Fledging happens in about three weeks. So strong is the nest building instinct, that the youngsters begin picking up nesting materials when they are only 12 days out of the nest.
This Red-tailed hawk perched on the rocks out back and watched Boo the cat, who was enjoying a supervised breath of fresh air. Boo was oblivious to the predator, intent instead on a wily lizard hiding in the chive patch. What a plump and juicy treat Boo would be! Red-tailed hawks eat mostly rodents, but also squirrels, and rabbits, taking prey up to 5 pounds. (Boo weighs much more!) They also hunt other birds, snakes, and lizards. A Red-tailed hawk is one of the largest of the raptors, yet weighs only about 3 pounds.
We all observed each other with great interest. I watched the hawk through my camera lens, the hawk leveled its binocular-keen eyesight on the cat, who peered into the chives for the lizard. Boo finally gave up on the little reptile, safely hidden in its herby jungle, and I put him back in the house. The Red-tailed hawk flew to find more suitable prey.
A sprawling platform nest rests on a high ledge in the canyon near here, and a pair of Red-tailed hawks performs aerial acrobatics at mating season each year. Although Red-tails mate for life, the male woos his female every spring. I see them circling together higher and higher until they disappear in the sky. At some point in the mating dance the male drops from above and touches the female on the back with his talons. Sometimes Red-tailed hawks actually grasp each other’s talons and plummet together towards the earth, gracefully pulling out of the fall with wind whooshing through feathers.
Lately I’ve noticed flocks of these striking birds foraging on the desert floor, and singing in trees. White-crowned Sparrows hop around, kicking at the soil, uncovering seeds to eat. During breeding season in spring and summer, they establish and defend territories, hunting insects, caterpillars, wasps, and beetles, for themselves and for their young.
White-crowned Sparrows are famous for their dialects, common songs that vary slightly depending on where they live. Young males learn the local songs from other males in the neighborhood when they are just 2-3 months old. Females also sing, but their songs are more limited and related to defending breeding territories and feeding grounds.
A White-crowned Sparrow’s song is key to its survival, helping to attract mates and to defend nesting territories, with a particularly vigorous song warning off other males. Dialects of White-crowns are quite distinct – imagine a Southern drawl or a Yankee twang, and the boundaries between dialect areas are sharp. Sometimes a particular White-crowned sparrow dialect is only learned by males within a several mile area, and the sparrows just on the other side of this sparrow defined boundary sing a slightly different song. Birds that live in the middle usually learn both dialects.
These distinctive dialects make the sparrows prime candidates for many types of scientific studies. Using digital recordings of White-crowned Sparrows’ songs recorded over many years, scientists report that birds in urban areas are evolving to sing at higher frequencies so as to be heard over city noise.
This sparrow can be found across the North American continent, generally breeding in the far north and wintering in southern areas. Some stay in place all year, others undertake long migrations. White-crowned Sparrows that breed in Alaska migrate 2600 miles to winter in Southern California.
To hear the song of the White-crowned Sparrow click the link below.