Bear Creek, reprise

It’s a poor summer for butterflies in Bear Creek, but here’s Speyeria aphrodite, a big female, on the flowers of Monarda fistulosa.DSC03919

And one of the true rarities in El Paso County: Nymphalis californica, the California tortoiseshell butterfly, my third record in 30 years.DSC03911.jpg

Spreading dogbane (Apocynum androsaemifolium) is setting fruit.DSC03917.jpg

And I told you once before, but I’m telling you again, the wild raspberries are going fast. Get ’em while they’re ripe!DSC03914.jpg


Monarda fistulosa, or horsemint, is almost as a good a butterfly flower as dogbane. But by my records, Monarda has 787 visitors of 33 species, while dogbane still holds the record with 2868 visitors and 78 species. This butterfly is an Aphrodite silverspot. Note that the viewer can see both upper and lower surfaces, which makes this a great, if not good, photo.


Pikes Peak, July 2017

Here’s a pair of arctic blues, Agriades rustica, best friends, on a Potentilla flower.Agriades in cop.jpg

Anarta nigrolunata, a little fuzzy moth, on little blue forget-me-not flowers, and on a rock.DSC03850.jpg

Anarta melanopa.jpg

And Lasionycta dolosa, the most common species in this genus of Hadenine owlet moths on the Pikes Peak tundra. This moth is shown only from Colorado on the Moth Photographers Group, but seems to range from RMNP to the San Juans, with Pikes Peak in the middle. That long left antenna is actually a grass awn. And how about that tiny black beetle?Lasionycta.jpg

Mead’s sulfur, Colias meadii, is one of the most common butterflies of the tundra. The upper side is all dark orange.DSC03817.jpg

Boloria chariclea a lesser fritillary from the tundra, on old-man-of-the-mountain flowers, pretty much all day.Boloria chariclea.jpg

Most Abundant Butterflies: Bear Creek Canyon

Here are graphs showing the 18 most abundant species of butterflies in each summer month or half-month. These are based on 23 years of observations of tens of thousands of butterflies. The y-axis shows the numbers of butterflies noted per hour of observation time. This is a historic record, and I understand that many readers will not know the scientific names of these butterflies, but I am illustrating the three most common above each graph. Nymphalis antiopa, the mourning cloak, hibernates as an adult and flies on the warmest days in February. Celastrina lucia is the tiny spring blue that sometimes congregates at mud spots. Its taxonomy is still uncertain. It is the most common butterfly in the canyon from April through early June. In July, its numbers fall off and it is replaced by a series of brush-footed butterflies that are of medium size and generally orange and black in color. Limenitis weidemeyeri is a large black butterfly with bold white bands across the wings. In July, the silver spots (Speyeria) and a couple of skippers (Poanes and Euphyes) become common.Screen Shot 2017-05-23 at 10.51.50 PM


This amounts to about 26 butterflies per hour.

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Early May

This amounts to about 43 butterflies per hour.

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Late May

This amounts to about 60 butterflies per hour, but over half of them are the little Spring Azure Blue.

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Early June

This amounts to about 58 butterflies per hour.

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Late June.png

Now we’re at about 72 butterflies per hour. Quite a jump from June.

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Early July.png

And all the way up to 76 per hour…

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Late July

Then, rather suddenly, back to about 44 butterflies per hour. Clearly, July is butterfly month in the Colorado foothills.

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Or about 55 butterflies per hour.

By September, numbers drop to about 20 butterflies per hour in random habitats. But from late September through October and into November, butterflies can be found in large numbers on rabbitbush, Chrysothamnus nauseosus. On these bushes, I have found 145 butterflies and over 200 day-flying moths in less than a half hour. That’s an average of about 290 butterflies per hour!

More early emergence records

This spring continues to be the warmest I’ve seen, with new early emergence records rolling in each week. Today in Bear Creek I found Erynnis telemachus, the Rocky Mountain duskywing, usually not seen until the second week of April, and Celastrina lucia, the spring azure blue, which usually starts flight around April 5th. Pussy willows in full bloom draw in large numbers of butterflies if you stop and look closely. All of the following are early records in 2017.

Erynnis telemachus, a surprise, especially because another species, E. brizo, usually flies first, and it hasn’t been seen yet.


Celastrina lucia, the spring azure blue.DSC02487

Pieris rapae, the European cabbage butterfly, an import– in some parts of North America, the most abundant butterfly.DSC02468

Nymphalis milberti, Milbert’s tortoise shellDSC02475

Archiearis infans, the Infant moth, photographed in the net and released.DSC02472


Early and Late Records for El Paso County Butterflies

Here is a list of my personal records for the early and late observations of about 170 butterfly species in El Paso County. I hope that other naturalists will make notes and contact me with new records. Collected specimens are the best way to verify sightings, but photographs usually work.


Butterfly abundance indices, Bear Creek Canyon, El Paso Co., Colorado

Amblyscirtes eos

Introduction and site description:     Butterfly surveys have been used around the world for several decades to determine the ecological health of habitats and to document or measure changes over time. In El Paso County, since F. Martin Brown began his first forays into the hills to document butterfly ranges in the 1930’s, the human population has grown from about 33,000 to over 587,000. In the same time interval, the land area of Colorado Springs proper has increased from about 12 square miles to nearly 300 square miles, and the current human population density of Colorado Springs is about 2027/square mile, and that of El Paso County about 276/sq. mi. ( County-CO.html; U. S. Census Bureau 2000 Report). Although the habitat loss concomitant with development caused many local population extinctions, especially as wetlands were disturbed, the city of Colorado Springs today is bordered by abundant preserved public lands, and it is probable that most butterfly populations in the areas around the city are little changed in the wake of this extensive development. Strongly restricted species, however, may now have fewer refugia and may occur in depressed populations. Regional extinctions may have gone undetected. Continue reading “Butterfly abundance indices, Bear Creek Canyon, El Paso Co., Colorado”

Earliest Spring Butterflies

Obviously, it’s not spring yet, but with the last few warm days, the butterfly species that hibernate as adults (most butterflies hibernate as pupae, larvae or even eggs) are feeling springtime in the air. Today in Bear Creek I found two species, the earliest date ever for the anglewing, and the second earliest date for the mourning cloak (Eric Eaton saw a mourning cloak in town on the 6th!). These species emerge from the pupa in August, September, October or even November, and then find safe refuge in deep grass clumps or under bark until spring. But 75°F feels a lot like spring to us, and to butterflies as well. the top is the mourning cloak (Nymphalis antiopa) and the bottom the zephyr anglewing (Polygonia zephyrus).


Forest thinning

My goodness, I’ve been going back through my old data sets from the 2006 and 2007 season when we studied the effects of forest thinning on many aspects of the ecology, including the invertebrates, which, to me, suggests moths. Look at these graphs, for example. Each of them considers a single group, or genus, of moths as they respond to thinning across the years. The leftmost points are from the control stand–never thinned. The next point, moving right, is a collection made from a stand thinned the previous year. The highest points are collections made four years after the thinning. And the last point, way off to the right, is a collection made sixteen years after thinning. Look at the pattern.screen-shot-2017-01-09-at-8-16-10-pm




Can you see the trend in all of these groups? The upshot is that they all show reduced numbers after one year of thinning, then they all show increasing numbers after four years. Then, by sixteen years after thinning, the numbers fall to near the original set. The bottom graph shows the overall biodiversity of ALL moths in this study. But the wonder of wonders is that, while the biodiversity is about the same after sixteen years, the community has greatly changed. That is, many of the original species are gone, but have been replaced by a new set. So biodiversity is not affected, but the community structure is very, very different. All this to be published in the next year. One of my 2017 goals. Questions? Ask.