|Papilio polyxenes coloro
||Thamnosma montana (Rutaceae)
||The host, Turpentine Broom, is common along the trail and the butterfly is a regular here.
||Possibly Prunus ilicifolia (Rosaceae), and/or Fraxinus velutina (Oleaceae) - Arizona ash tree.
||The largest butterfly on the trail, with a powerful flight.
||A citrus feeder, but I don't believe this is breeding on trail.
||I saw one fly by in the spring of 2020. No doubt a stray.
||I've seen females oviposit on Sisymbrium orientale and Descurainea pinnata here; there is no bladderpod, Peritoma arborea (Capparaceae), on this trail.
||Not uncommon in the spring. May use other mustards as well.
||They use a variety of mustards (Brassicaceae).
||Probably Descurainia pinnata ssp. glabra, as one that appeared to be ovipositing 4/5/15. Sisymbrium orientale also a good candidate.
|Pontia s. sisymbrii
||Descurainea pinnata ssp. glabra
||Early flyer. Found a larva on this plant in late April, 2017, and adults in March that year and the next. Common in April, 2019.
|Anthocharis s. sara
||I've seen the larvae on Descurainia pinnata ssp. glabra (Brassicaceae) not far from the trailhead. Watched one oviposit on Thysanocarpus laciniatus (narrow leaved lacepod) as well (4/23/17), and found several larvae on lacepod in April 2019.
||These typically fly from February into May, peaking Mar/April. In 2016, the Descurainia was senescent by mid-May, and the flight was nearly over.
|Anthocharis c. cethura
||Mustards, but time will tell which.
||First and only sightings by me were in early April, 2019.
|Anthocharis lanceolata desertolimbus
||Boechera perennans (Brassicaceae)
||This is a great trail to see this recently-described butterfly. My sightings have been late March and early April, usually with the adult taking nectar on Acmispon rigidus.
||Mainly Astragalus (Fabaceae), but rarely Acmispon glaber
||Astragalus douglasii (not on the trail) is the classic host, but the Monroes also list A. palmeri, which is the most common of the three rattlepod species here.
||Deerweed, rattlepod, poss. lupines.
||The Emmels (1973) have deerweed, and "possibly several Astragalus species". The Monroes list Astragalus crotalariae, Acmispon strigosus, A. glaber, and Lupinus bicolor. So there are many candidates on this trail.
||Saw one April 22, 2017. I think this was my only sighting of this butterfly on this particular trail to date. But not too surprising.
||Amorpha fruticosa (Fabaceae), a common plant on this trail.
||The abundant host, especially at drainages along the trail, is the reason there are so many of these flying here practically all year.
|Zerene c. cesonia
||Amorpha fruticosa (Fabaceae) mostly.
||Not at all common, but apparently on the trail. This species hybridizes with eurydice, and I've seen the yellow female with dark dorsal markings, just to confuse things. But I'm reasonably sure it is on the trail and Gordon Pratt sees it regularly in Anza.
||Many hosts. On this trail, probably Adenophyllum prophylloides (Asteraceae)(San Felipe Dyssodia).
||A very common butterfly most of the year. This is a beautiful, tiny sulphur with darker and lighter seasonal forms. Often patrols the trial, stopping on the dirt regularly. The Monroe's Anza-Borrego book has three hosts: San Felipe Dyssodia, Spanish Needles (Palfoxia arida), and Cinchweed (Pectis papposa). The latter two are not on the Chester list. I've searched in vain for larvae on the Dyssodia so far.
Hairstreaks and Blues
|Atlides halesus corcorani
||Uses mistletoe (Viscaceae), and there are three here: Phordendron villosum, densum and califoricum, with the first two common on juniper and ceanothus. Found an egg on densum on juniper on May 27, 2016.
||Not easily seen here, but it is present. An absolutely stunning large hairstreak with neon-like colors set against black. Always a treat to see, especially when fresh.
|Callophrys augustinus iroides
||Many hosts; I've recently seen them on Rhus ovata but they probably use Ceanothus perplexans (Rhamnaceae) as host here.
||Not as common here as they can be elsewhere. A spring flyer.
|Callophrys dumetorum perplexa
||Many, inc. buckwheats, deerweed, Ceanothus.
||They can be fairly common earlier in the spring around patches of Eriogonum fasciculatum not far from the trailhead parking area.
||Juniperus californica (Cupressaceae) is a dominant plant here.
||A featured flyer on this trail, it can be found conveniently right at the parking lot among the junipers to the north, as well as along the trail wherever there are junipers. The colors of this population on the ventral side can vary a bit, but typically (when fresh) they have plenty of blue and/or pink, while subspecies juniperaria, on the desert side of the San Gabriels, has more olive green. That said, I saw a very green one this spring (2016).
|Satyrium c. californica
||An Oak and Ceanothus feeder.
||Early summer flyer.
|Satyrium auretorum spadix
||Also early summer as an adult.
|Satyrium saepium chalcis
||Probably Ceanothus perplexans (Rhamnaceae)
||More common along the Santa Rosa Truck Trail a few miles to the west, but also usually present here if not common.
||Cercocarpus betuloides var. betuloides (Rosaceae)
||I've seen these in June and July along the Santa Rosa Truck Trail, but the host also is present on Cactus Spring Trail.
|Strymon istapa clenchi
||Hibiscus denudatus (Malvaceae), which isn't on the trail.
||Uncommon, but flying late March, 2014 and early April 2015.
|Strymon melinus pudicus
||Too many to list, but California Buckwheat is one.
||Not surprising to find them anywhere.
||Several hosts, including Senegalia greggii and Amorpha fruticosa (Fabaceae), and I see it commonly around these.
||A common garden butterfly that also thrives in the desert.
||One expects saltbush, but no Atriplex grows on this trail. Instead, it may use Salsola tragus (Chenopodiaceae) and/or Amaranthus albus (Amaranthaceae).
||Uncommon here, but this handsome and diminutive butterfly may appear almost any time of the year on the trail. Not sure it breeds here, but it's possible. I have an April record and a few from autumn.
|Celastrina e. echo
||Uses many common trees and shrubs, inc. Ceanothus, Oaks.
||I have only a couple of confirmed sightings of this butterfly here: in late April and May of 2017.
|Glaucopsyche lygdamis australis
||I've seen one oviposit on Acmispon rigidus (3/24/12), and it no doubt uses deerweed - A. glaber (Fabaceae) on this trail. Both are common right from the trailhead.
||An early spring flyer which can be common some years.
|Philotes s. sonorensis
||Host here must be Dudleya saxosa ssp. aloides (Crassulaceae)
||Another stunning and sought-after butterfly that can be found here in the spring, though perhaps not reliably. My records are from early March through April.
|Euphilotes b. bernardino
||Eriogonum fasciculatum (Polygonaceae)
||Common butterfly that uses a common host. A spring flyer that can become abundant some years.
|Euphilotes dammersi dammersi
||Eriogonum wrightii vars membranaceum and nodosum (Polygonaceae)
||Fall only around the host buckwheat, which blooms at that time. Pratt and Emmel (1998, p.211) divide dammersi into three populations, one of which is a low desert group extending from the San Bernardino Mountains south into Mexico. (There is also a spring-flyer on the northeast side of the San Bernardinos on E. kennedyi or E. davidsonii, and a population in the Mojave.) A good place to see this blue in autumn is to check the patches of wrightii two-tenths of a mile from the trailhead, just before the trail signs at the road junction. Another is just short of the creek before the so-called "dolomite mine". The black spots on the underside have a characteristic "smudging" that is easy to see.
|Hemiargus ceraunus gyas
||Senegalia greggii, Prosopis glandulosa and locoweeds such as Astragalus palmeri (Fabaceae).
||I saw a female ovipositing on Senegalia greggii buds on May 27, 2016.
|Plebejus a. acmon
||Many in several families
||Found a larva on Eriogonum davidsonii on May 27, 2016.
|Plebejus m. monticola
||Eriogonum fasciculatum (Polygonaceae)
||This and the above taxon are part of an interesting complex. Both fly on this trail. I label many of them "acmon complex" if it isn't clear what's what. John Emmel considers monticola a full species (separate from lupini) and says they are "atypical" in this area.
||Bebbia juncea (Asteraceae)
||Not common at all here
|Apodemia v. virgulti
||Eriogonum fasciculatum (Polygonaceae)
||Common, and found most of the year. On this trail, look for individuals lacking orange on the hind wing. Some resemble deserti, but they apparently are virgulti (G. Pratt, pers. comm.). Some seem intermediate as well, with just traces of orange on the hind wing. Females are a noticably lighter color and larger than the males. (The host E. inflatum and sometimes the metalmark itself can be found at a big pullout along the road at 1525' as you begin winding up the mountain up the 74 out of Palm Desert, but I haven't found it near this trail. That colony is 6 air miles from Cactus Spring Trailhead.)
||Milkweed, but probably doesn't breed here. See next entry.
|Danaus gilippus thersippus
||Sarcostemma crispum was found on the right at the small drainage just before one comes to Sawmill Road; it is in the Asclepiadaceae, as is Matelea parvifolia (Spearleaf), which was found a tenth of a mile shy of Horsethief Creek. But the paucity of these plants (one of each) suggests neither Monarchs nor Queens are breeding here.
||A desert butterfly sometimes seen taking nectar here as at Horsethief Creek on the goldenrod.
|Chlosyne acastus neumoegeni
||An aster other than Mojave Aster - its preferred food plant in the Joshua Tree area - which isn't in the area.
||Two seen patrolling approx. 2 miles down the trail on March 3, 2020. I'd never encountered this butterfly here before this year.
|Chlosyne leanira wrighti
||Castilleja foliolosa (Scrophulariaceae)
||Late spring flyer that may have a fall brood if conditions are right (saw one Sept. 20, 2014 after not seeing them that spring). I've seen larvae in mid-April as flight began, with adults through May. They are usually well down the trail where the host is more common. But this striking butterfly may be - or seem to be - absent many years. I first saw them in Spring 2011 here, and they were easily found the next spring as well. Since then, I've had a single fall 2014 sighting. In 2016, I saw neither a larva nor an adult, though the plants were healthy at the usual locations.
||Bahiopsis parishii (Asteraceae)
||Tom Chester's plant guide has the host beginning at 2.37 miles from the trailhead. The population of this butterfly seems to fluctuate, but it can be fairly common at Horsethief Creek some years on the Goldenrod there, and individuals can show up anywhere. In 2017, I was seeing it even in town in Palm Desert.
||I thought it was a stray, but I saw one ovipositing on Cordylanthus rigidus ssp. setiger on June 7, 2020 down the trail. I'll need to return to check for larvae. Also on the trail is Plantago patagonica, or perhaps the local paintbrush spp.
||A brief sighting on June 3, 2017, and the one mentioned ovipositing three years later almost to the day.
|Dymasia dymas imperialis
||The host, Justicia californica (Acanthaceae), isn't on the trail.
||I saw one September 20, 2013, and another April 5, 2015, but this trail is (probably) quite a ways from where the host Chuperosa is known to grow (online records have it several miles to the north and east). So add to the list of unexpected sightings.
|Phyciodes m. mylitta
||Various thistles, monkeyflower, others, but not established here apparently.
||A single sighting for me on this trail: May 18, 2012. Can be common elsewhere.
|Euphydryas chalcedona hennei
||Keckiella antirrhinoides var. microphylla (Scrophulariaceae) confirmed on this trail.
||Probably "near hennei" is a better description. Common, sometimes abundant, with a fall flight some years, possibly most. These will, at times, be your regular companion on a hike all the way down the trail to Horsethief Creek, where they congregate on Goldenrod if it's in bloom. The larvae can be found easily on the yellow-flowered host, with early instars in nests until the plant begins to dry out in the early summer. They go to ground, and resume feeding when the plants are again edible, as after summer/fall rains or in the spring.
||Too many to list.
||Probably just passing through for the most part.
|Limenitis lorquini powelli
||Willows (Salicaceae). This trail has Salix exigua, laevigata, and lasiolepis.
||Males patrol some of the places down the trail where willows grow.
||Three oaks are listed in Chester's plant guide: Quercus cornelius-mulleri; Q. wislizeni var. frutescens; and Q. acutidens (Fagaceae). Of the three, only Q. wislizeni is listed as a host for californica in my various books.
||Can be common on the trail, particularly in tree-lined canyons. Quercus wislizeni var. frutescens first appears on the trail near the junked car at the "Dolomite Mine". Overwinters as a larva.
|Nymphalis c. californica
||I hadn't really noticed this one before the spring of 2017 (late April), but as I write this now, in October, 2019, they seem to be a regular part of the mix. Ceanothus perplexans - cupped-leaf ceanothus - is the host on this trail.
|Epargyreus clarus californicus
||Probably Amorpha fruticosa (Fabaceae) here.
||Uncommon, but sometimes seen well down the trail, inc. at Horsethief Creek.
|Thorybes phylades indistinctus
||Amorpha fruticosa, possibly others in the Fabaceae family.
||Not common here.
|Pholisora c. catullus
||Chenopodium fremontii; Amaranthus species albus, fimbriatus, palmeri, torreyi; Ambrosia acanthicarpa (bur ragweed) possible here.
||May 12, 2018 is the only time I've encountered one here.
||I found larvae Oct. 18, 2015 on Abutilon palmeri (Malvaceae) at Moeller’s nursery in Palm Desert; but that's not on the trail.
||A rare sighting here, but it turned up March 26, 2016, and since then a few times in the fall, most recently in October, 2019.
|Erynnis brizo lacustra
||Quercus cornelius-mulleri (Fagaceae)
||The host is plentiful, but this butterfly can be scarce. I haven't seen it the last few years. I watched it oviposit once on the host oak shrub, so it may at least be an occassional resident.
||Probably Acmispon glaber and/or A. rigidus (Fabaceae)
||A regular. Males may patrol areas inexhaustibly.
|Erynnis t. tristis
||Gordon Pratt says these can't be separated from funeralis without genital dissection. I assume some of the duskywings with white fringe on the hind wings are these as there is abundant oak here.
||Oaks, which on this trail means either Quercus cornelius-mulleri, which is relatively abundant here; Q. acutidens, which was counted just five times by Tom Chester and his helpers in his field guide visits; and Q. wislizeni var. frutescens, even rarer with just two seen along the entire trail.
||Saw one on June 7, 2020 taking nectar on Eriogonum fasciculatum; that's my only sighting of this species on this trail. There is a June 9. 2019 record for the Santa Rosa truck trail on iNaturalist.
||Acmispon americanus (Fabaceae) - check after first “creek”
||Noticably smaller than funeralis, and with hyaline spots, unlike brizo. E. pacuvius may fly here as well.
|Pyrgus scriptura apertorum
||Sphaeralcea ambigua (Malvaceae)
||Another small but sought-after butterfly. A fairly reliable spot on the trail is at the Sawmill Rd. junction just to the north, where the host is common and males patrol.
||Sphaeralcea ambigua (Malvaceae)
||Fairly common around the host at times.
||Sphaeralcea ambigua (Malvaceae)
||Becomes common as spring turns to summer, esp. around patches of the host. There are three white skippers in the mallow patches here.
||Cynodon dactylon (Poaceae)
||Bromus madritensis ssp. rubens (Poaceae)
||More common in spring, but does fly late summer into fall as well.
||Agave deserti (Liliaceae)
||Always great to see these powerful flyers. Larvae burrow into the roots of the host, which is plentiful on this trail. Stephensi flies ca. September-October. Can sometimes be found zipping around the hosts on the first leg of the trail not far from the trailhead, and at various places further down trail. A good flight in October 2019.