Tuesday, December 30, 2014

Back from holiday in Carlsbad, NM!

On the way to Carlsbad Caverns
I've recently returned from holiday in Carlsbad, NM.  Averaging a little under 13 inches of rain annually, this region is where the the Chihuahuan Desert takes over after the last gasp of the short grass prairie fades in far eastern New Mexico. My main impression was of a thinly grassed chaparral dotted with spiky yucca-like plants I couldn't tell apart. Remarkably, it rained or snowed two of the three days I was there. This was some feat considering the area averages only 41 days of precipitation per year. I have a knack for getting rained on in deserts.

Closer view of the vegetation
I'm not totally clear on differentiating the various spiked rosettes that dominated my visual impression of the landscape. I do not think I could tell them apart without their dried floral stalks. Thanks to guidebooks, I know I saw sotol (Dasylirion leiophyllum), torrey's yucca (Yucca torreyi), mescal agave (Agave parryi), and lechuguilla (Agave lechuguilla).

I've gleaned the following: sotol and lechuguilla's leaves have hooks curved back toward the base, but sotol leaves are finer with dried, light brown fibers extending far beyond the tips of their leaves. Mescal agave looks like what we call a 'century plant' in horticulture, and torrey's yucca is raised up on a brown pedestal of its previous growth, leading me to initially call it a 'joshua tree'. Yuccas (vs. agaves and sotol) don't seem to have hooks on their leaf edges. Of course, most people go to Carlsbad to see what's underground, not to do a comparative study of spiny rosettiform succulents.

Possibly a torrey's yucca?
A giant fungus-like speleothem
One of the stories my dad tells about me is that as a small child I essentially had a 'freak out' in Luray Caverns, VA. I remember reading some Tom Sawyer-y/Little House on the Prairie-type book about children getting lost in the caverns at about that time. I imagine I was pretty concerned about the lights staying on and getting back to the surface. Supposedly we completed the tour but I begged and whined the entire time.

This family story of some early childhood cave-associated terror came to mind as I prepared to go down into the cavern. I hadn't toured a cave system since that experience, so I was curious if I would discover some forgotten fear. I am pleased to report that I enjoyed visiting the fantastic Carlsbad Caverns without incident. Some things do change.

The big room
Carlsbad Caverns is famous for its remarkable speleothems (cave formations including: stalactites, stalagmites, columns, etc). While most caves are formed by carbonic acid, the limestone of Carlsbad Caverns was dissolved by sulfuric acid.  The caverns started forming approximately 4 million years ago, and progress ceased with climate change at the end of the Ice Age. These caves might start building again, if climate changes bring the area more rain.

Despite the lull in geologic activity, you could hear dripping water echo through the caverns. It smelled like dust and wet stone. Human odors seemed sharper for some reason. Whenever I passed someone wearing cologne, it was stronger than at the the surface. I'm not sure if the human scents were being thrown into relief by the spareness of the cave, or they were more efficiently picked up by my nose because of the 90% humidity underground.

It is astonishing to me that early explorers dropped ladders in the abyss and descended into the darkness in total ignorance of what they would find. It seems likely that this need to have a finger in every pie is a characteristic human trait.

I saw more of New Mexico than the caverns, and I will write on that shortly. Until then: have a happy New Year's Eve!

Higher elevation desert slopes near visitor center

Thursday, December 11, 2014


Skunk tracks in tuff? Badlands National Park
Winter is a good time to work on your tracking. I am not especially skilled. I can generally tell canid from feline, and anything with unexpectedly burly claws on a smallish paw could be a skunk or badger. Those rascals love to dig. I learned most of the little I know from a day long class with a biologist that I took when I was in grad school in North Carolina and the rest from books.

What struck me most was the diversity of wildlife you share a space with but never see. Many creatures are either active at night or are crepuscular, so you are unlikely to stumble upon them on your hike or jog. In the semi-rural piedmont of North Carolina where I took my class, we saw sign of river otters, mink, beavers, foxes, mice, rabbits, house cats, and coyotes. You can get a feel for the lushness of North Carolina's forests from that list.

Shortly afterwards I moved to Nebraska. My regular jogging route was up and down gravel roads. I'd pat the nose of the neighbor horse, and I flushed deer and turkey most mornings. I saw plenty of their tracks, but I also saw coyote, badger, skunk, and, in the western part of the state, antelope. My impression of Nebraska was that it was a sportsman's paradise. They are drowning in game. Between the resident turkey flock (one technical term is 'rafter'; as in 'a rafter of turkeys') and the jumping deer, Nebraska seemed veritably made of meat.

What happened here? Near Paria canyon, UT
Something long dead
(fossil dino tracks)
Tracks and sign can tell you more about a place than you might otherwise sense.  In Utah I saw the marks of desert beetles, lizards, and crows. I also saw the signs of long dead creatures. I was in Utah volunteering as a range technician's assistant, and one of our monitoring locations happened to be near a fossil bed. Dinosaur tracks preserved in ancient mud had been exposed at the surface by erosion.

I was shocked that these fossils didn't have so much as a fence around them. You could walk right up and touch them, or put your feet in the tracks and mimic the dinosaur's gait if so inclined. The location was self-guided, so there wasn't even anyone to stop you from taking a pickaxe to the rock and hauling away a chunk of dino-print. It seems that the people who have trekked out so far have managed to restrain themselves. Let's hope that continues to be the case.

People! Chipped toeholds near Paria Canyon, Utah
Also in Utah, I enjoyed seeing the signs of ancient peoples. These chipped 'toe paths' were pretty common. I took the above picture next to my campsite. These lines seem too perfect to have been caused by erosion, but I'm open to someone else's interpretation.

Raccoon tracks look like children's hand prints (Old Alton Bridge)
I must admit I haven't devoted much time to tracking since I got to Texas. I've been travelling so much for work I've neglected to take all the dreamed of road trips to the western part of the state, where the bare ground shows more evidence of passing creatures. I have seen a few mud prints in the parks around town. Raccoon and fox, nothing too exceptional, but pleasing to see all the same. Raccoon prints look for all the world like a baby pressed their hands into the dirt. Fox prints are smaller and less rectangular in composition than the average canine, but they have the permanently extended claws of their family. Canids leave claw marks in their tracks and cats don't because cats have retractable claws.

I hope to tour a little of the western part of the state over the holidays. I'll certainly takes pictures to document any interesting traces of the resident wildlife that I should come across!

Canid, probably red fox (Old Alton Bridge)

Saturday, December 6, 2014

Winter Ducks at the Drying Beds

How many can you spot?
I took my bird-dog bird watching at the Village Creek Drying Beds in Arlington, Texas this morning. This was not as fool hardy as it may sound. As I have mentioned in previous posts, Colby is something of an embarrassment to her line-- she prefers butterflies to coveys. She also knows that when I have my camera out tugging and general knuckle-headed-ness is futile. I will remain un-moved until I'm done. She seems to enjoy our excursions though, and I get a kick out of watching her try to figure out what's got my attention. This morning it was ducks.

The Village Creek Drying Beds are locally renowned as an excellent place to view ducks in the winter.  Or they were renowned, I should say.  The site is in the process of decommissioning. Originally used as a solid waste treatment facility, it is now the domain of birders, dog walkers, and nature photographers. Water levels are kept much lower than they used to be, and thus the numbers of visiting waterfowl have declined.  I only saw one bed with enough water to draw ducks when I visited.

A northern pintail
I was actually visiting the drying beds to work on my duck ID. I know basically nothing about ducks, and a warm winter day where most of the other wildlife has gone cryptic seems like as good an opportunity to learn as any. In addition to the ubiquitous mallards, I saw northern pintails, green winged teals, and northern shovelers. There were many other ducks drifting and dabbling with less obvious field markers. I had to look up the term "dabbling"-- this is the word for the duck feeding behavior where they go 'bottoms up'. Ducks are described as being dabblers or divers, where divers dunk themselves entirely and the dabblers do underwater headstands leaving their rear-ends visible above water.

Green winged teal
I think my favorites were the pintails, probably because they were the easiest to spot to my untrained eye. Pintails have… an elongated pin-tail. They also have a white breast and grey head. Green winged teals were easiest to identify based on the white slash ahead of their wing. Their copper heads seemed to make their green ear patch hard to spot at a distance. Northern shovelers were distinctive because of the strong white/chestnut patterning on their bodies and their dark heads.

Northern shovelers
The origins of the names 'pintail' and 'green-winged teal' are pretty obvious, but what about 'shoveler'? Do they use their bills to shovel and pick through mud? Well, not really. I suppose their bills vaguely resemble shovels, but the term most commonly used to describe them in the literature is "spatulate". Their bills are broader at the end than at the base, and the edges are toothed like a comb. They use these crenellations to filter food from the water. This species is remarkable in that it is common to North America, Europe, Africa, and parts of the Indian subcontinent.

Another picture of a shoveler 
Supposedly the Village Creek Drying Beds are even better during the spring and fall migrations. I imagine that its usefulness as a duck pond will ebb and flow with rainfall and chance as the drying beds are totally phased out. Until that happens, I can still recommend this spot as an excellent place to see ducks.

Dry drying beds

Useful Links
visual guide to Texas ducks:

list of ducks and relative commonness:

Bird World's map of birding hotspots:

The description of Village Creek Drying Beds:

FW Audubon's list of hot spots:

Friday, November 28, 2014

Five hairstreaks of south Texas

Sweet face on a dusky blue groundstreak
Hairstreaks, of the subfamily Theclinae within the family Lycaenidae ("gossamer wings"), are small butterflies that are most diverse in the New World tropics [1]. I think they are highly underrated, as far as butterflies go. While they are certainly 'cute', telling them apart can be a challenge. Many of them are dainty gray butterflies with wing bands, eye-spots on their hindwings, and wispy tails.

I thought it might be instructive to go through key field markings. For this purpose, I searched through my back catalog and pulled images of five different species of hairstreak I've observed here in Texas. The subjects I've selected include three relatively similar-looking hairstreaks (the dusky blue groudstreak, the gray hairstreak, and the mallow scrub hairstreak) and two more distinctive hairstreaks (the great purple hairstreak and the silver banded hairstreak).

A gray hairstreak (Strymon melinus)
First, let's start with one of the most common and widespread hairstreaks in North America: the gray hairstreak. Larva tend to eat mallows and legumes, while adults are nectar generalists [2]. I would consider the gray hairstreak to be the "generic hairstreak", the hairstreak from which all others are differentiated. Note the relative cleanness and lack of clutter between the wing bands and wing edges. Also, remember the thickness, numbers, and placement of the orange markings on the hindwings. These are all traits that will vary from species to species.

Dusky blue groundstreak (Calycopis isobeon)
Now let's compare the gray hairstreak with the dusky blue groundstreak. This butterfly's larval food source matches its name ('groundstreak'): it's caterpillars feed on decaying leaf matter and other detritus [3]. At first glance these two hairstreaks look pretty similar. However, remember to check the eye-spots. The dusky has two well defined eye-spots outlined in red, versus the gray's one and a half. The dusky blue groundstreak has a third iridescent blue spot on the bottom edge of its hindwing, below the red and black eye-spots. This marking is totally missing in the gray hairstreak. The wing bands also differ- the dusky has obvious red outlining the post-medial band on its hindwings, and the thickness of this red outline is one of the field marks distinguishing it from its cousins. There's also provenance. The dusky blue groundstreak is only found in south Texas within the United States. If you anywhere but south Texas, then odds are it isn't a dusky blue groundstreak.

Mallow scrub hairstreak (Strymon istapa)
The mallow scrub hairstreak, which is actually in the same genus as the gray hairstreak, looks a bit different from the preceding two butterflies that I covered. When I saw this butterfly up in the canopy nectaring on Mexican olive (not pictured), I initially couldn't decide if it was a hairstreak or a tailed blue. I was better able to pick up on some of the identifying markers upon closer inspection.

Remember when I wrote about the uncluttered wings of the gray? The mallow scrub hairstreak is most definitely messy. There's a whole host of scribbles and bands in white and dark gray after the post-medial line. There's also minimal red on the eye-spots. Lastly, look at the front part of the hindwing and note the two dark gray spots. These two spots before the hindwing's band distinguish this hairstreak from all others. Like its con-generic the gray hairstreak, the mallow scrub hairstreak's caterpillars feed on mallows. This species is confined to the southern-most portions of the United States.

Another important thing to remember when identifying hairstreaks is that sometimes they don't have tails. The entire purpose of the eye-spotting and enticing tails on their hindwings is to encourage birds to take a nip there instead of other, more critical, areas. Many species of hairstreak even twitch and fidget their tails such that they resemble antennae.

Silver banded hairstreak (Chlorostrymon simaethis)
This silver banded hairstreak has seen better days. Either he's scrunched up, or something took a medium-sized chomp out of his right hindwing (he's scrunched up- ed.). The other side still seems to have its tail. Silver banded hairstreaks are another southern species. Their larvae are rather sly. Instead of feeding on leaves and exposing themselves to visual hunters, they hide inside the pods of balloon vines and eat the seeds [5]. This green hairstreak is pretty distinctive for a number of reasons. Its green coloration and straight silver bands are some of the easiest cues to pick up on in the field.

Great Purple Hairstreak (Altides halesus)
I'm going to end this post on the unmistakable great purple hairstreak. This butterfly has a wide distribution across southern North America. When I first saw this butterfly I was floored by its iridescent markings. The blue green markings on the edge of hindwings flashed in the sunlight whenever the butterfly re-arranged itself on the flower head. Its body is bright orange, and its wings are touched with bright blue. Their larvae eat mistletoe [6].

Obviously, this butterfly is quite distinct from most hairstreaks. However, the tells are still there. Like other hairstreaks, Great purples are petite with thin little tails, in contrast to the thick, chunkier tails on swallowtail butterflies. They also tend to sit with their wings folded, instead of spread to catch the sunlight.

In summary, many small butterflies with eye-spots and thread-like tails on their hindwings are in the Theclinae sub-family. After you have narrowed your search to this particular group, sorting through your options to get to species will probably require a combination of eye-spot characteristics,  wing band size and coloration, and location.  Good luck!

A silver-banded behind

1. http://www.butterfliesandmoths.org/taxonomy/Lycaenidae
2. http://www.butterfliesandmoths.org/species/Strymon-melinus
3. http://www.butterfliesandmoths.org/species/Calycopis-isobeon
4. http://www.butterfliesandmoths.org/species/Strymon-istapa
5. http://www.butterfliesandmoths.org/species/Chlorostrymon-simaethis
6. http://www.butterfliesandmoths.org/species/Atlides-halesus

Saturday, November 22, 2014

Palo Pinto and the Butterfly Hound

Clouds echoing the topography, Palo Pinto County
God help me, I've turned a red-blooded bird dog (my german shorthaired pointer) into a butterfly chasing hound. It wasn't planned. It just happened naturally. Ever since I adopted her, I've taken her with me on my invertebrate photo hunts. I strap her to my waist with a leash, leaving my hands free to snap away with my camera. My impressionable pup seems to have picked up on me stalking bees and butterflies with my lens. She's realized these flittery creatures are of some importance, and worthy of attention. Now it's a race to see who can reach the bug first- me with my camera or her with her snapping teeth.  Funny enough, she's somewhat indifferent to her ancestral prey. We've actually spooked coveys without her paying much mind, but butterflies- she just loses her little head. I suppose we end up with the dogs we deserve.

View from the mesa
My dog's enthusiasm for lepidoptery got us in trouble a few weeks ago when we were poking around Palo Pinto County, the home of a (relatively) soon-to-be-opened 5,000 acre state park. My dog Colby does not have what I would call "cactus-sense".  Time and again, running headlong after a butterfly (this time of year it's sulphurs, admirals, buckeyes, and southern dog-faces) she would face-plant into a prickly pear or pencil cactus. I'd pin her down, grab her little maw, and pull the spines out with the pliers on my leatherman. You'd think she'd learn to take more care, but it seems her joie de vivre simply cannot be dampened by something so insignificant as a spine between the eyes or a nopal hanging from her wet little nose.

Keeping a willful dog out of the opuntia was... tricky. 
Topo and satellite images of our trek.
Bringing my naive dog to cactus-country was just one of many poor decisions that accompanied my trip to explore this rugged landscape prior to its development as a state park. I was in search of a sheer canyon with unusual plants located in the southern section of the parcel, off a recently bull-dozed road, not yet added to maps of the area.

I should mention that I have a somewhat poor sense of direction. I am great at following trails and using maps and compasses, but if I rely on 'instinct', it generally ends poorly. I had thought to bring a borrowed GPS unit and printed out satellite photos, but somehow I forgot about the unmarked road leading more or less directly to my target. As a result, we ended up bushwhacking straight up and over a low mesa, through thick juniper and opuntia scrub, when we could've just gone around. I just about had a conniption fit up on top when it was cactus thickets in every direction. I was convinced I was going to blind my poor dog (or, rather, she would blind herself being an idiot), and I'd have to carry her back to the car and race off in search of an emergency vet.  Despite these complications, we did find what we were looking for. We ended up turning back at the cusp of the canyon because it was fringed in a wall of cactus, and I just couldn't justify blinding my dog for the sake of exploration.

View from near the road to the canyon
Despite our misadventures, I was very impressed with the landscape. It looked like a translation of my mental image for "Texas" from before I actually moved here. Low, flat topped mesas were edged in rocky drop-offs, and they were lightly covered in juniper and mesquite. It is hard to believe that something so rugged and western exists less than an hour and a half from green, treed Fort Worth. It was a world away from the hackberry and pecan groves. I could see going into full-hermit mode out there. I'm a real sucker for rocks and spare landscapes.

Migrating sand hill cranes passed overhead
Once we reached the peak of our ill-advised mesa scaling adventure, we had a moment of peace. I could see for miles down the valley, a valley that raptors funnel through in their fall migration. I stopped and ate an orange and Colby huffed quietly. Then I heard a familiar gurgling trill from overhead: sand hill cranes! They were using the same flyway on their migration south to their coastal wintering grounds. I'm not sure Colby appreciated it, but I got a lot of joy from hearing the cranes. Seeing them pass through provides something of a thread linking my year in Nebraska with my time here in Texas. I'd like to return to this undeveloped landscape to see it change with the seasons, though if I bring Colby we'll stick to the roads.

Dog tired. (Hah!)

Thursday, November 13, 2014

Three polyphenic butterflies

This question mark hasn't given up on summer. (11/2/2014, Mission TX)
In an organism that is seasonally polyphenic, also termed seasonally polymorphic, the same genetic code produces different physical traits in response to environmental conditions. In butterflies this is quite common, and it is often expressed as "summer" and "winter"/"dry season" morphs. Day length and temperature seem to trigger these changes. Butterflies are most sensitive to these seasonal cues while they pupate, and they only get to choose their morph once (see comments).

Some researchers believe that polyphenism evolved as a solution to differing needs for camouflage and thermoregulation in summer vs. winter. Perhaps summer butterflies survive better on fresh green leaves in bright coats, while fall butterflies are more comfortable with darker coloration that allows them to soak up the weak winter sun. Fall butterflies also tend to live much longer-- some late-emergent butterflies hibernate for 9 months before reproducing, instead of the brief flight window and immediate reproduction of their summer kin.

Dainty sulphur. (11/8/14, Palo Pinto Co. TX)
I've encountered at least three polyphenic butterflies in the past couple weeks. Interestingly, these three butterflies couldn't agree on the season. Two were plainly marked for winter, while one insisted on hanging onto summer.

The question mark's dark morph is its summer form. In the winter, the hind wings lighten. Question marks don't typically nectar on flowers-- like the hackberry emperor, they prefer to feed on dung and rotten fruit. That's the reason you see the question mark perched on a log in the picture above- someone had smeared the log with bait. You'll notice s/he shares the perch with flies.

Another pic of the dainty sulphur
For the dainty sulphur, the summer morph is paler with more yellow markings, while the winter morph has a mostly sooty coloration, especially on its hind wings. Dainty sulphurs are the smallest member of their family found in North America.

In white peacocks, the winter morph is larger and whiter than those which emerge in summertime. White peacock males are notable for a behavior that is somewhat unusual in the butterfly family. They defend patches of their larval host plant in hopes of monopolizing any passing females. These harmless insects perch in their small territories and engage rivals in aerial duels. I'm not sure how a 'winner' is determined. Each participant is essentially incapable of harming the other, unless it is by exhaustion.

The seasonally confused question mark looked pretty fresh, not at all like some holdover from longer days and warmer weather. I wonder if he will suffer for his poor judgement? Perhaps he pupated during  a warm snap, confusing his cues. The verdict of the dainty sulphur and white peacock, and the arrival of an arctic front, tend to suggest that cooler weather is here to stay, at least for a little while.

White peacock (11/2/2014, Mission TX)

Wiklund, C., & Tullberg, B. S. (2004). Seasonal polyphenism and leaf mimicry in the comma butterfly. Animal Behaviour68(3), 621-627.

Lederhouse, R. C., Codella, S. G., Grossmueller, D. W., & Maccarone, A. D. (1992). Host plant-based territoriality in the white peacock butterfly, Anartia jatrophae (Lepidoptera: Nymphalidae). Journal of insect behavior5(6), 721-728.

Nylin, S. (2013). Induction of diapause and seasonal morphs in butterflies and other insects: knowns, unknowns and the challenge of integration. Physiological entomology38(2), 96-104.

Karlsson, B., Stjernholm, F., & Wiklund, C. (2008). Test of a developmental trade‐off in a polyphenic butterfly: direct development favours reproductive output. Functional ecology22(1), 121-126.

Sunday, November 9, 2014

Tropicalia at the Texas Butterfly Festival 2014

The red-bordered pixie, a tropical butterfly in the metalmark family. Unique to So. TX within the US.
I saw so many 'lifers' at this year's Texas Butterfly Festival in Mission, I've honestly been putting off writing about it. It's such a huge bite to take. Some butterflies were rare, some were deceptively common on site, and others were overwhelmingly abundant. I've decided to break my sightings down into more easily digested chunks. Because many of the butterflies I saw are limited to the subtropical regions of the United States and farther south, I'm going to focus on those species today.

Zebra heliconian, of the tropical longwing family 
I was fortunate enough to spot a number of the more distinctive members of the local butterfly community. I think I most enjoyed finding the pixies and heliconians. These are two of the 'flag-ship' butterflies of the Lower Rio Grande Valley (LRGV). There they were- and in profusion. I also saw a Julia heliconian flit past, but sadly I couldn't get a picture.

Zebra and Julia heliconians are in the "longwing" family. These butterflies all feed on passionflower as larvae. The gulf fritillary is one of the more widespread representatives of this group. Gulf fritillaries were actually quite common on site-- the daft creatures were still reproducing. I even found a caterpillar climbing up a plumbago plant looking for a place to pupate. Gulf fritillaries perform a migration of sorts. They cannot survive freezing at any lifestage, so every year they must recolonize their entire northern range. The University of Florida's entomology page claims that the adults move south over the winter. For all I know the butterflies we see north of the freeze line are representatives of a giant population sink.

I'm pleased to have finally captured the full life cycle. First comes a passionflower, then a funky caterpillar, and then 'voila', a gulf fritillary.

How to make gulf fritillaries
My other tropical finds included the soldier, white peacock, the surprisingly lovely brown longtail, the sickle-winged skipper, (possibly) a silver-banded hairstreak, among others. Pictures and the full list after the jump.

Next week: the finer points of hairstreak ID.

Friday, November 7, 2014

A new savanna outside College Station, TX

This savanna made possible by heavy equipment.
College Station has a new oak savanna, thanks to a creative restoration effort by a local landowner and a TPWD biologist. Originally, the landowner had approached TPWD with the thought of putting his land back to native grasses. He was getting older, and he wanted his holdings to look like native prairie again. Most land in the area is dominated by the commonly over-seeded nonnatives: bahia grass, bermuda grass, johnson grass, and various old-world bluestems.

Great purple hairstreak nectaring on old frostweed
On this particular site, however, the problem was thick brush, especially yaupon holly, choking out the native post-oak's understory like a green wall. Inspired by the compensation offered from the frackers who owned the mineral rights and were coming in to build a new pad on-site, the landowner instead negotiated for hours with a bulldozer. After clearing the brush he over-seeded with the native grasses recommended by TPWD.

The site looked great, exceptionally so for a year '0' restoration. Many of the seeded native grasses have established, as have some pioneering flowering plants. Beautyberry and pokeweed were most abundant. I also spotted a few tendrils of maypop, frostweed, smartweed, and some other species.

closer: great purple hairstreak
Frostweed (Verbesina virginica) is a wonderful plant, an important late-season butterfly resource with a unique attribute: during the first freeze, its sap is extruded through the stem where it solidifies into curling 'ice sculptures', similar in appearance to the icy frost flowers that burst up through the ground in colder climates.

A gorgeous great purple hairstreak was investigating the few remaining blossoms on a tall frostweed in the center of the savanna. He (?) was shimmying the tails on his hindwings enticingly- evidently a behavioral adaptation to encourage birds to take a nip there instead of places where they could cause real damage. Interestingly, great purple hairstreak larvae eat only broad-leaved mistletoe. I didn't think to examine the treetops for these arboreal parasitic plants, but I can imagine that a savanna with an understory of rich nectar sources and an overstory hosting their larval food plant would be a good place to make a living as a butterfly.

I think most people find savannas quite aesthetically pleasing, and I hope this site stays lovely, propelled forward by a solid start.

Beautyberry lit by a patch of sun in the understory
Lady's tresses, Spiranthes spp.
The landowner's other sites were not so easy to restore. Simply making room for other plants in a matrix of the aggressive non-natives is no small undertaking. Repeat applications of glyphosate or imazapyr are often needed to even make a dent in the exotic grasses. This sort of broadcast chemical application makes my little heart sad, but sometimes it is a necessary evil. Notably, in the case of this landowner's other holdings, applications of herbicides had successfully suppressed the nonnative grasses and released the native grasses that had been holding out all along. I do still worry about the broadleaf plant community under these circumstances. However, a lone lady's tresses orchid had managed to put up a bloom in the middle of a sprayed patch. If an orchid, a representative of a characteristically delicate family, can push through, then maybe there is still hope for the others.

Sunday, November 2, 2014

The three milkweed butterflies of the United States

Queens (Danaus gilippus) were... not uncommon.
I have had a wonderful time exploring central and south Texas over the past few weeks. After attending the Texas Butterfly Festival, I feel it is appropriate to write a brief butterfly-centric post. I see more of the ilk in my future-- I saw so many new butterflies, including tropical species! At any rate, it's been a blast.

The controversial non-native tropical milkweed
(Asclepias curassavica). The leaves are evergreen. 
One of the highlights of my travels has been to finally see a soldier butterfly (Danaus eresimus). Soldier butterflies, like monarchs and queens, use milkweed exclusively as their larval host plant. Unlike monarchs and queens, their range barely extends into the United States. The subtropical tips of of south Texas and Florida are the only places you can really hope to find them. I was fortunate enough to see all three milkweed butterflies in the same garden on the same day (!) in Mission, Texas at the National Butterfly Center. They were really loving the betony-leaf mistflower (Conoclinium betonicifolium)

This is the best time to see butterflies down in south Texas' Rio Grande Valley. This area hits its peak butterfly density in October and November. The Rio Grande Valley is special. It marks the northern-most extent of number of largely tropical butterflies- a few of which I saw and will cover in a future post.

The monarch butterfly
Because the queens, soldiers, and monarchs (Danaus plexippus) are all very similar in appearance, I thought it would be useful to include pictures of all three to compare the various field markings. First:  the classic monarch butterfly. Flashy and readily seen, though threatened by habitat loss in much of North America, this species can be found from Texas to Canada. They are the only milkweed butterfly with a confirmed long-distance migration, and they are much larger than both the queens and soldiers. Their size and bright orange coloration make them pretty easy to distinguish. Also, their veins are a high-contrast black instead of brown or undifferentiated in color from the wing.

Mating queens
Queen butterflies (Danaus gilippus) are smaller, more brown than orange, and they don't have the same contrasting black venation visible on their dorsal (topside) as  monarchs. They also have two lines of white dots on the dorsal side of their forewing (leading wing), versus the single line observed in soldiers. Their overall color is darker and duller. Queens are quite common in the parts of south Texas I visited- they are much more frequently found than monarchs along the coast here. They are something of a southwestern species.

Soldier butterflies are definitely the most uncommon of the three milkweed-feeders. Sometimes they stray into southern Arizona, but they primarily stick to the subtropical areas of the United States. They are the veritable four-leaf clover in the field. In addition to being distinguished from queens by their single (instead of double) line of white dots on the forewing, they also have a dusky dark patch in the middle of their hindwing. Overall, they are a rich shade of brown.

The uncommon, hard to spot soldier butterfly

So that's it! The three North American milkweed butterflies. Stay tuned for a more lengthy update on the other unusual species I found down on the border...

Thursday, October 23, 2014

The Ethics of Seed Collection

Nice, unharvested seeds.
I am passionate about native plants. I’m quite serious- it has been years since I intentionally introduced a non-native plant to my yard (other than vegetables, of course). Naturally, I jumped at the chance to get involved when my work gave me the ‘go-ahead’ to help with native seed sourcing. However, seed collection is not so simple as “find, harvest, propagate”. Many native plants have suffered population declines from over-collection, so it is important to take steps to ensure an ethical harvest.

Ginseng, orchids, carnivorous plants, echinacea, black cohosh, golden seal, and galax have all suffered from over collection. What do these plants have in common? They are the medicinal, the rare, and the weird. This damage is nothing to be sniffed at. Galax is harvested for its value in floral arrangements. The majority of galax stands along the Blue Ridge Parkway in the Southern Appalachians were targeted by poachers in 2012 [2].  Even worse, plants like ginseng, echinacea, and black cohosh are entirely destroyed by harvest, as the root is the part of the plant consumed. Others, like orchids and carnivorous plants, are delicate and often do not survive transplanting in their new environs anyway.

Someone may have beat me to it.
Or was it the wind?
Declines in medicinal plants have been well studied. Ginseng is a famous example. Recently, a ranking criterion was created to estimate the vulnerability of a plant to over collection. Traits on this list included: life history (i.e., how long does it take to reach maturity, what is its reproductive rate), effect of harvest (is the plant killed when harvested), population size, habitat, and demand [1]. To avoid over collecting, one should limit the amount of seed collected from a population, and not collect from the same site year after year. There isn’t a consensus on exactly how much seed you can collect from a population without causing harm. Some sources say no more than a third, others say 10%, and others yet say 5% per year over 10 years. I am sure that the exact details of a ‘safe collection rate’ vary by species, population size, and location. Generally agreed upon exceptions to these guidelines are in the case of plant salvage—where plants are removed from a site prior to its destruction or development. In this case, 100% harvest is acceptable.

In addition to calibrating your harvest level against the possibility of causing real damage to the landscape, one must consider legality. Obviously it is illegal to collect protected species. It is also illegal to collect in most State and National Parks. Often one can collect on Forest Service or BLM land, but this typically comes with restrictions and requires the purchase of a permit for a small fee. Collecting on private land is OK with permission as long as the target plant is not protected. Roadsides are something of a toss-up—most seed collectors (including myself) believe road sides to be fair game. However, if someone requested that I stop collecting from along their property, I certainly would.

Restored crop-field prairie
Somehow, while juggling all these factors, I have managed to harvest from two sites. One was a roadway in Denton County.  The other was a private prairie north of Temple. My harvest protocol in Denton was pretty clear-cut. Unless someone stopped me, I would be able to collect seed. Additionally, the roadsides had been mowed and most of the seed heads shattered, so I wasn’t too worried about over collecting. I probably couldn’t have collected more than 5% of the seed produced even if that had been my intent.

The second site, the private prairie, was a little fuzzier. While I made sure to get permission prior to collection, once I arrived on site it became clear to me that someone had already harvested some seeds from the target species earlier in the year. A few stalks had legible cut marks on them, while others did not. So the question became: how much could I take sustainably? How much seed had there been before the previous collector came?

After doing some looking around I decided that the original collectors had not taken much, and had collected from a central location along a mown path. Most of the bare stalks outside that area had a few seeds still hanging off them, suggesting that they had been shattered and scattered by non-human means. The plants that still held their seed were lower and had not been so exposed to the wind. I fretted some, and I never did settle on an exact amount that it would be OK to collect, but I did the best I could. I am comforted that, someday, the descendants of this foundation seed will be used for prairie restoration and will support many pollinators and other wildlife.


1.     Castle, L. M., Leopold, S., Craft, R., & Kindscher, K. (2014). Ranking Tool Created for Medicinal Plants at Risk of Being Overharvested in the Wild. Ethnobiology Letters, 5, 77-88.