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California Rotund-Resin Bee Anthidiellum notatum robertsonii Megachilidae Anthidiellum Describe your image Describe your image Describe your image Describe your image Describe your image Describe your image Description Anthidiellum notatum robertsonii are compact, yellow-and-black bees with an overlapping shelf at the back of the head, and an extended scutellum which projects over the propodeum. These overlaps, and the lack of paper-thin pronotal lobes on the thorax, help differentiate from Dianthidium . A yellow band runs along the back of the head, ending where the head curves down. Anthidium , Dianthidium and some Stelis bees can look similar. Nectar/ Pollen Plants This bee is a flower generalist. Habits Anthidiellum notatum robertsonii are known to build single-celled, pot-like, dark-brown, resin nests on pieces of wood on the ground, and have also been found to use existing beetle cavities in wood. Male bees are territorial and will bowl into perceived intruders. They are sometimes seen hovering near flowers. Season May - August

California Bumble Bee Bombus californicus Apidae Bombus Describe your image Describe your image Describe your image Describe your image Describe your image Describe your image Description Bombus californicus is a mid-sized bumble bee (large on the bee scale), mostly black in color, with black between wing bases and yellow hair in front of the wing bases. Females have a black face, whereas male bees, as shown above-right, may have some yellow facial hairs. Its 4th abdominal tergum is always yellow. Nectar/ Pollen Plants A flower generalist. On Mount Diablo, is seen on hedgenettles, Western Wallflower, thistles, lupines and Pacific Pea. Habits A dark bumble bee that lives in the West, thought by some to be a subspecies of Bombus fervidus. Eusocial, they nest primarily underground in abandoned rodent nests, or sometimes in grass just above ground. Thought to have suffered from competition with other bumbles, such as Bombus vosnesenskii . Season February - September

Wildflower Mount Diablo Skunk Bush, Skunkbush Scientific Name: Rhus aromatica Family: Anacardiaceae (Sumac Family) Blooms: Mar - Apr Color: Yellow-Orange Shrub Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

Wildflower Mount Diablo California Tea, Forest Scurfpea Scientific Name: Rupertia physodes Family: Fabaceae (Legume Family) Blooms: Apr - Jun Color: White Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Steve Beatty

Spotted Towee by Jenn Roe Marvelous Animal Adaptations May 21, 2025 by Dan Fitzgerald The Spotted Towhee is an eye-catching bird, but it takes some luck to see one. Bright white dots decorate black wings and back; rufous (reddish) sides stand out against a white belly; a jet black head holds intense red eyes. Believe it or not, this striking bird is designed to hide, which is what it does in a brushy habitat where its colorful patterns blend with the dappled shade. Chaparral and open woodlands provide the Spotted Towhee with the shrubs it needs for protective cover and a year-round food supply. An omnivore , eating from both plants and animals, the Towhee forages by hopping around and scratching the ground for insects, spiders, millipedes, and other nourishment. It also searches low limbs for food. In fall and winter, when insects disappear, Towhees dine on seeds and berries. The Spotted Towhee’s secretive life in the brush changes in spring when the male bird perches conspicuously atop shrubs to sing his raspy song either to attract a mate or declare his territory (keep out!). Why does the female have such drab feathers? The female Towhee spends most time on the ground. Her dull, ground-colored feathers help her go unnoticed by predators (such as hawks, owls, and snakes). Towhees nest on the ground or in low branches and the female is the nest builder. She also incubates (sits on) the eggs without any help from her mate. However, once eggs hatch, both parents work to feed the nestlings (baby birds). Download this article by Arnold Joe The Spotted Towhee’s black and white patterns help it blend in the shade of its habitat. The bird pictured above is male. by Arnold Joe In springtime, male Spotted Towhees can be seen singing from the tops of shrubs. by Arnold Joe The female’s dull colors help her blend with the ground, making her less visible to predators while nesting. BACK TO LIST

Wildflower Mount Diablo Fremont Bush Mallow, Diablo Mallow, White Coat Mallow Scientific Name: Malacothamnus fremontii Family: Malvaceae Blooms: Jun - Aug Color: Red-Pink Shrub Native, endemic to California Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

Wildflower Mount Diablo Mayweed, Stinking Chamomile Scientific Name: Anthemis cotula Family: Asteraceae (Sunflower Family) Blooms: May-Sep Color: White Annual herb Introduced Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Daniel Fitzgerald Daniel Fitzgerald

Wildflower Mount Diablo Common Groundsel Scientific Name: Senecio vulgaris Family: Asteraceae (Sunflower Family) Blooms: May - Jun Color: Yellow-Orange Annual herb Introduced Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Steve Beatty

Wildflower Mount Diablo Buck Lotus (Yellow) Scientific Name: Hosackia crassifolia Family: Fabaceae (Legume Family) Blooms: May-Jul Color: Yellow-Orange Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants

Orange Sulphur Colias eurytheme Pieridae Whites, Sulfurs Flies All year Host Plant Legumes, Vetches Nectar Plant Daniel Fitzgerald Female Underwing Daniel Fitzgerald Female Underwing Michael Marchiano Male Michael Marchiano White Female

Wildflower Mount Diablo Gamble Weed, Pacific Snakeroot, Pacific Sanicle Scientific Name: Sanicula crassicaulis Family: Apiaceae (Parsley-Carrot Family) Blooms: Feb - Apr Color: Yellow-Orange Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Mike Woodring

Hoverflies by Jenn Roe Marvelous Animal Adaptations June 24, 2025 The oblique streaktail hoverfly, common on Mount Diablo, visits many types of flowers. Like all true flies, it has only two wings, while bees and wasps have four (two sets). If it looks like a bee and acts like a bee, is it a bee? Look closer, because that bee or wasp-like insect you see on the flower just might be a hoverfly, a fly in disguise. Hoverflies, also called flower flies, belong to a large insect family, Syrphidae, with over 200 species in California. Many species mimic the look of a bee or wasp to defend against predators that don’t want to eat creatures with stingers. But unlike bees and wasps, the hoverfly has no stinger and is harmless to predators and humans. Same as all true flies, it has two wings (one set) compared to bees and wasps that have four (two sets of wings). Also, notice the hoverfly’s big eyes are about the width of its abdomen, much bigger than a bee’s eyes relative to its bee body. Hoverflies are often seen hovering around flowers, hence their name. Many species feed mainly on nectar and pollen. They are important pollinators that provide this essential service while nectaring (sipping nectar). Hoverflies can be beneficial in another way, as pest control. The larvae (maggots) of some species eat aphids and other soft-bodied insects that gardeners and farmers consider pests. This is true for the oblique streaktail (Allograpta obliqua) pictured on this page. The female streaktail lays her eggs on plant parts near aphids. When eggs hatch, the fly larvae’s food is within easy reach. Download this article by Jenn Roe This drone hoverfly mimics its namesake, the drone (male) bee, in color and striping. However, the fly’s large eyes are about the width of its abdomen, a feature of flies but not bees. by Dan Sandri This fuzzy fly is a bumblebee mimic. Sometimes called a bumblebee plumehorn (‘plumehorn’ for its feathery antennae) the female lays her eggs in bumblebee or wasp nests. When the fly larvae hatch, they dine on nest debris and sometimes the host’s own larvae. Not very nice guests! BACK TO LIST