The federally Endangered California dandelion, Taraxacum californicum | Photo: USFWS

May 16 is Endangered Species Day, on which we're all supposed to reflect on and appreciate those species that are faring poorly in an increasingly human-altered world.

While other websites celebrating the occasion are understandably concentrating on the big and dramatic, the sea turtles and condors and pandas and rhinos, every day is Endangered Species Day here at ReWild and we've been there and done that. As an attempt to get into the spirit of the occasion we thought we'd celebrate by mentioning a few Endangered Species that aren't big and flashy and glamorous. They're beautiful, but they don't flaunt it.

And we'll start with a species that no one but a Southern California botanist might ever guess could possibly be endangered: a dandelion.

Not just any dandelion, of course. The Eurasian import that dots our overwatered lawns, Taraxacum officinale, might well be one of the least endangered plants there is. But that common dandelion has a cousin, Taraxacum californicum, that's found only in the San Bernardino Mountains between Big Bear and San Gorgonio Peak. Nearly visually identical to its weedy relative, the California dandelion grows in wet mountain meadows that are vulnerable to a few human activities, including alteration of streamflows for residential and resort development, as well as destructive off-road vehicle use. Cross-breeding with imported weedy dandelions is another threat.

Listed as Endangered in 1998, the California dandelion was the subject of a recent five-year-review of its status, published by the U.S. Fish and Wildlife Service in September. USFWS found that though three new occurrences of the flower have been found since listing, bringing the total to 23, the species' total numbers seem to be declining and threats to its long-term survival mounting. Given our own species habit of building superfluous second houses in the wet meadows around Big Bear and then riding ORVs through the mud, those threats probably aren't going away any time soon.

I have a personal connection to the Endangered Mission blue butterfly: I saved one from being eaten by a dog once. Of course, it was my dog, and I'd brought it for a hike in the butterfly's habitat (legal at the time), so my contribution to the species' welfare is probably a wash.

The Mission blue (Aricia icarioides missionensis) is not a uniformly conspicuous or showy butterfly: a monarch or painted lady this is not. The tops of the male butterflies wings can be bright blue in the right light, so we're not really talking drab little moths either, but the insects' small size -- wingspans of less than an inch and a half -- and hairy gray overall aspect mean they don't really grab your attention unless you're looking for them. Or, I suppose, unless you're a curious dog.

Restricted to just five known locations in the hills surrounding San Francisco, Mission blues depend on native lupines as a larval food plant, and the habitat of those lupines has been severely depleted by urban and suburban development. Pressure from developers to build more housing in the San Bruno Mountain stronghold of the butterfly resulted in the first-ever Habitat Conservation Plan, a compromise that allowed some butterfly habitat to be developed as long as a landscape-level protection strategy was worked out for the lupines and the butterfly. Widely seen by environmental activists as a major weakening of the Endangered Species Act when it was drafted for the Mission blue, the Habitat Conservation Plan model has been adopted widely for other protected species in the decades since.

One interesting natural history note: Mission blues seem to have a partnership with local native ants, who -- to oversimplify the arrangement -- protect them from parasitic wasps in exchange for a sweet, sugary secretion the caterpillars exude. The ants don't provide bulletproof security: about a third of Mission blue larvae seem to fall prey to wasps, which lay their eggs inside the poor caterpillars. When the eggs hatch, the wasp larvae consume the caterpillar from the inside. It's a grisly fate that's astoundingly common in the insect world.

The desert slender salamander | Photo: USFWS

I've written about the desert slender salamander before here, but it definitely belongs on this list: it's about as inconspicuous an Endangered species as you're likely to find, or more likely not find. Listed as Endangered in 1969 almost immediately after it was discovered, Batrachoseps major aridus is so hard to spot that it hasn't actually been seen in the wild since the late 1990s. For all we know, it could be extinct.

With just two known populations barely scraping by in two canyons in the Santa Rosa Mountains, the desert slender salamander is an unlikely desert native animal. It's closely related to the far more common garden slender salamander of coastal Southern California, and to about 20 other species of slender salamanders in the state, and like its relatives the desert slender possesses no lungs. That means that its skin needs constant moisture to allow oxygen to diffuse into its bloodstream (and carbon dioxide out), which means that surviving in hot desert canyons is at best a tenuous proposition.

Even if you happened to walk past a desert slender salamander in full view, you might not notice it. Desert slenders max out at about three inches long if you include the tail, and their legs are so small as to be essentially unnoticeable from a short distance. (When I first encountered the desert slender's cousin the California slender salamander, Batrachoseps attenuatus, up in the Bay Area in the late 1980s, I realized I'd been seeing them for years and assuming they were shortish earthworms.)

Possibly extinct, hard to find if they aren't and hard to notice even if you look right at them? Now that's inconspicuous.

Can you see the least Bell's vireo in the photo above? No? Try this hint: there are two branches that cross in mid-image, one vertical, one horizontal, and the vireo is in the upper right corner of that intersection. Still no? Now you know how I feel when I go hiking with my birder friends.

The least Bell's vireo (Vireo bellii pusillus) is one of that huge tribe of well-camouflaged birds that avid bird lovers sometimes refer to as "LBJs," short for "little brown jobs." The least Bell's vireo is more gray than brown, but you get the picture.

The USFWS's species page for the least Bell's puts it as well as anything I've read on the bird:

Feathers are mostly gray above and pale below. This is a common protective marking in birds. Seen from below, the bird blends into the clouds. From above, it blends into the landcover.

Yep.

Here's a photo that shows the bird more clearly:

I feel compelled to point out that the above is a color photo.

The least Bell's vireo was once very common throughout Southern California and the Central Valley, but destruction of the riparian habitat the bird requires has done severe damage to its numbers. So has brood parasitism by the brown-headed cowbird: cowbirds lay eggs in vireo nests (as well as those of at least 200 other species), and when their young hatch out, the high-maintenance cowbird chick diverts parental care from the baby vireos, which can languish and die. The cowbird chicks sometimes go so far as to kill their adoptive siblings.

The least Bell's vireo is a subspecies of the more widespread Bell's vireo, a migratory bird that ranges from the Great Lakes to Central America. They make their living as "branch gleaners," hopping around in trees and shrubs looking for insects to eat. The least Bell's is far more restricted in range. At listing in 1986, the bird had lost all its former habitat in the Central Valley and the Central Coast Ranges. Right now, the subspecies main summer breeding range seems to be limited to Ventura and Los Angeles counties, with a growing population in protected riparian forest along the Santa Clara River. That link will take you to the citizen science site eBird, with a range map indicating reports of least Bell's as far north as Sacramento, but those reports haven't necessarily been confirmed.

About half the subspecies uses Camp Pendleton as its summer (breeding) habitat. The birds migrate to Baja for the winter, where they're not nearly as picky about the places they choose to hang out: deserty mesquite scrub and similar landscapes find themselves visited by the tiny birds.

When the subspecies was listed as Endangered in 1986, there were only about 300 nesting pairs of least Bell's vireos in the world. ESA protection has been good for this bird; by 1998, when USFS issued a draft recovery plan for the subspecies, there were more than 2,000 such pairs.

Which just goes to show you don't have to be big and flashy to mate successfully.