|The Poweshiek Skipper Project|
|Butterfly Forecasts for Central Iowa|
|August 1-15, 2015|
is it August already? Where did the summer go? It's not gone
yet, of course, but don't blink. Don't put off taking vacation
days or playing hooky because if you wait too long the warm weather will
be gone, and so will the butterflies.
Clouded sulfurs and orange sulfurs are quite common right now. The two are quite similar to each other and often cannot be told apart in the field. The clouded sulfur is slightly smaller and its upper surface is usually a pale yellow. The orange sulfur is larger, and its dorsal (upper) surface has more orange in it. But it is kind of a stretch to call it orange. It is not the color in the eight crayon box called orange. It is more of an yellowish, orangish yellow. In the field, it is often fairly easy to find some butterflies that are clearly orange sulfurs, and some that are clearly clouded sulfurs. Then there are individuals that are somewhere in between. The two are known to hybridize and produce offspring that have characteristics of both. To make matters more difficult, there are white morphs of both species mixed in, and they are pretty much indistinguishable. Often the flight is mostly one or the other, but right now I am seeing them in about equal high numbers.
Meadow fritillaries have been unusually common this year--I think I have seen more this year than the last ten combined. They also seem to be disproportionately represented on flowers as the victims of ambush bugs and crab spiders.
Great spangled fritillaries have been putting in an appearance this year as well. They seem to like to work the larger flowers like purple coneflowers and can be predictably found there. Eastern tiger swallowtails and black swallowtails have been around in low numbers, but look for some fresh individuals of those species to show up soon. Field thistles and bull thistles will start blooming soon, and they are especially attractive to these species. Bull thistles are so tall this year that you may need a ladder to get close to the flowers though.
Silver spotted skippers are around and will increase in numbers soon. Least skippers can be found in and around wet areas with tall grasses. I have seen a few Peck's skippers and expect them to increase in numbers soon. Also, watch for the common checkered skippers to become more common as the season progresses. Sachems and fiery skippers will make their first appearances and will become increasingly more common until the end of the season.
Little yellows use partridge pea as a host plant, and usually become quite common anywhere that plant can be found. I have only seen a few little yellows so far this year, and I am not sure this will be a good year for them.
Pearl crescents continue to be pretty common, but watch for gorgone checkerspots mixed in with them. Silvery checkerspots can also be present in certain areas in high numbers.
There was a recent sighting on the Butterflies and Moths of North America (BAMONA) website of caterpillars, identified as bordered patch, in Polk County Iowa. The only other record of this butterfly in Iowa was also identified in the caterpillar stage, and it was in Jasper County. To my knowledge, there is not yet a record of an adult bordered patch in the state. The photo of the sighting showed a large number of caterpillars so we may know for sure soon.
Cabbage white, question mark, eastern comma, and red admiral all are fairly common right now and make can be found in all of the habitats that involve edges in Iowa. Summer azures and eastern tailed-blues will continue to be seen for a while yet.
Checkered white is a resident butterfly with a spring generation, but I have only seen it in the late summer or early fall. Perhaps it disperses from the small areas where it thrives to larger areas later in the year.
We may see some of the migrating species in good numbers soon. Painted ladies and American ladies were seen earlier in the year and we may see numbers of them later. American snout is always a thrill to see. This is usually a rare butterfly in Iowa, but can be common enough to form large swarms in the south, particularly Texas. Cloudless sulfurs can also be very common in the south, but are a rare treat to see here.
This year seems to be a good one for monarchs in Iowa, although some of the states to the east of us are reporting few to no sightings.
Common buckeyes have not been so common to date, but may start showing up in larger numbers soon. Another butterfly that often becomes common late in the year is the gray hairstreak.
As the summer progresses butterfly populations generally increase, particularly in those species that have more than one generation per year. As the numbers get high, the butterflies disperse. There are a number of southern species that have multiple generations and ranges that come close to Iowa but have not yet been observed here. Now is a good time to look for those species. Look particularly for species that might be similar to some we have here but are subtly different. Areas along good river corridors or in the loess hills might be better places to look for some of these species that have yet to be seen here. If you find something new try to get a photo to document it.
The summertime air of Iowa is full of life and evidence of life. Go outside near a wetland, especially in the evening, and you are likely to see swarms of insects, often tiny flies. You will also see dragonflies and damselflies chasing those small insects. Sometimes you will see little balls of fluff falling from the sky--seeds of the cottonwood trees. You may also see little balls of fluff that seems to fall, but then move with a particular direction.
Flying fluff? No, not really. The fluff is a waxy coating and underneath is a plant-sucking insect, a woolly aphid.
There are many species of aphids that have the waxy coating and can be called woolly aphids. Aphids are usually somewhat host-specific, but these also generally have two or more specific host plants at different times of the year. Aphids are interesting in their own right. They have complex life cycles, switching between egg-laying stages and parthenogenetic, live-bearing females. You can often find clusters of aphids on leaves and stems along with predators and parasitoids, and sometimes ants which protect them. The primary strategy aphids use to survive is to out-reproduce anything that consumes them.
The woolly aphid shown here was at the Ledges State Park, and it and a number of others were attracted to greenbrier plants. I searched the plants for evidence of harvester butterflies, but did not find any. Harvesters are known to inhabit woolly aphid colonies, and are usually reported on alder trees in the northeast. Reports of harvesters in Florida almost always have them on greenbrier, however, and I suspect that may be where they can be found here.
Watch for woolly aphids, and look for any stage of harvester. Happy hunting.
|July 16-31, 2015|
|Butterflies are out in full
Populations should continue to increase, although some of the very heavy
rains we have had lately can temporarily knock them out of the air.
There is a gravel road adjacent to our house and after a heavy rain the
edges of the
road are thick with butterflies--pearl crescents and red admirals
mainly, but a host of others as well. These butterflies are
generally males, and have been engaged in "mudding" or "mud puddling"
activities. The butterflies drink fluids from between the spaces
in the sand or soil, and are generally thought to concentrate minerals
that are passed on to the females and/or offspring during mating.
This is a common activity of butterflies and it can be observed in a
large number of species. Other insects drink from mud as well, but
possibly for different reasons.
Pearl crescents are quite common in the constructed prairie area on our property, chasing each other around in groups of three or four. Pearl crescents can be quite variable in coloration, and I always inspect them closely in the hopes of finding some similar looking stray from somewhere else. One butterfly I find occasionally during such searches is not a stray but a fairly rare resident. The gorgone checkerspot ranges from about the same size as a pearl crescent to quite a bit larger. It can be easily confused with the pearl crescent from above, and also with the silvery checkerspot. From below it is very distinctive, especially on a fresh individual.
Skippers are a group of butterflies that in general have fatter bodies and less colorful wings than the group called "true butterflies." A subgroup of the skippers are the "grass skippers," which can be distinguished by a characteristic habit of resting with the forewings at about a 45 degree angle and the hind wings horizontal. This gives them the general look of a jet fighter. Several grass skippers have only one generation per year, and they can be found from mid June until late July. The most common of these include crossline, northern broken dash, Delaware, and possibly dun. Tawny-edged skipper, least skipper, and Peck's skipper have multiple generations and can be found now but also throughout the season. Also watch for the silver-spotted skipper, common sootywing, and common checkered skipper, which are all in the "spread-wing skipper" group.
Gray coppers and banded, Edwards, and coral hairstreaks are nearing the end of their flight period. They can often still be found--look for them on butterfly milkweed and other milkweeds, and flying around their host trees (oaks, cherries, and hickories.) Gray hairstreak may show up and last until the end of summer. There is a second flight of juniper hairstreak that emerges in July, so look for this species on eastern red cedar.
We encountered some "angle wing" butterflies very early in the season, most notably the eastern and gray commas. Question marks are also early angle wings, although not as early as the other two. The ones we see in the early spring and also late in the fall are the forms (morphs) that overwinter as adults. Typically they are lighter than the ones we see now, particularly the upper part of the hindwing. The summer forms of these butterflies can be spectacularly beautiful, especially when newly emerged, and can have subtle shades of brown, purple, orange, blue, and black.
Orange sulfurs will continue to be numerous, as will cabbage whites. Clouded sulfurs are also in the mix, but are usually less common in the heat of the summer than orange sulfurs. Little yellows often start becoming common late, but I haven't seen any this year. Most years we get a healthy population, but sometimes we have none.
Great spangled fritillaries are still around but are starting to get ragged. If you visit a prairie that has them you can see regal fritillaries, also starting to age. Meadow fritillaries have multiple generations so you should be able to find some fresh ones.
Swallowtails will have a mix of fresh and aging individuals. Watch for eastern tiger swallowtails, black swallowtails, and giant swallowtails towards the end of the month as the liatris and the tall thistles start to bloom.
Monarchs have had a steady presence, and are slowly building up numbers. Viceroys and red-spotted purples will show up in slightly higher numbers than earlier in the year. Hackberry emperors and tawny emperors will be present in woodlands and urban areas.
There are a number of late-season migratory butterflies that we might start seeing. These butterflies typically (but not always) spend the winters to the south of us, then rapidly build up populations and have a one-way dispersal to the north. In addition to the previously mentioned little yellows we often get dainty sulfurs, American snouts, fiery skippers, and gray hairstreaks. Cloudless sulfurs are magnificently large yellow butterflies, easily distinguished by size alone from our clouded and orange sulfurs. They are not seen that often in Iowa, and probably only have a one-way migration into the state. Further to the south they are two-way migrants, similar to painted ladies, red admirals, and others.
We will continue to see summer azures for a few more weeks. In most years eastern tailed-blues will take over as the most common blue butterfly late in the summer. I have seen a few this year, but the numbers seem lower than normal so I think we might not see so many this year.
Flies are a very diverse group of organisms, with more than 150,000 described species. Robber flies are a diverse group within the flies, with over a thousand species in the United States and Canada. That makes this small group more diverse than the butterflies. Robber flies usually have predatory larva, and the adults are predators as well. Robber flies often catch other insects in flight, then eat them by sticking their pointed mouthparts into the prey, and injecting saliva to slowly digest them.
Robber flies can be large and scary looking. The gnat-ogre is very small--not much larger than a mosquito. They are easily overlooked, but once you notice them they can be quite easy to spot. Typically they roost on the tip of a stem of grass (usually one that is a few feet tall). From there they will dart out after small insects. I have seen them with tiny flies as prey.
Bugguide says there are three species in our area.
I did not know these flies existed for a long time. But then I noticed one and photographed it. Soon I was seeing them everywhere.
In my experience they are quite common some years, and impossible to find in others. You do have to look for them, though.
So get out and watch the butterflies.
Watch for robber flies, too.
Some of the larger robber flies can catch butterflies. But probably not the gnat-ogre.
|July 1-15, 2015|
fireworks can be quite a show, but so can the July butterflies.
You see spectacular moving bits of color that don't last long. But
butterflies don't make as much noise.
Most of the larger butterflies are on the wing now. Quite possibly the most spectacular of those butterflies is the regal fritillary. It is a very large dark brown butterfly with large silver spots. It is about the size of the familiar monarch butterfly, and in fact flies quite a bit like it so it can be mistaken for a monarch from a distance. But up close it is so much more spectacular (not to take anything away from the monarch). Regal fritillaries are rare butterflies, but not so rare that you should not be able to find them. But you have to go to a pretty good prairie to see one. The trip is well worth your time, however, because prairies are quite special places to visit this time of year. Watch along hilltops, especially where butterfly milkweed is blooming. Regals move rapidly and can be difficult to follow and to photograph. They will stop on and nectar on flowers, often with a strong preference for the milkweed.
If you visit a prairie in the first part of July you may find the most common butterfly to be the common wood nymph. They have sort of a hopping flight and disappear deep into the grasses where they can be difficult to photograph. The wood nymphs you see in the prairies can often appear much darker than those that are found in more wooded areas. Some can seem almost black.
You may also find smaller numbers of less common butterflies. Look for milkweeds, especially butterfly milkweed. You should find hairstreaks. Coral hairstreak as well as banded and Edwards hairstreak can often be on butterfly milkweed. Sometimes a particular clump of flowers will yield a handful of the small butterflies, while you will not find them anywhere else in the prairie. Hickory, Acadian and striped hairstreak should also be looked for, but they are rarer. You might also see gray coppers--in my experience, they can be quite common where they are found, but are totally absent from other habitats. Of course, eastern tailed-blues and pearl crescents will also be all over the butterfly milkweed.
We have some very rainy weather lately. After those rains the edges of gravel roads can be packed with butterflies. We seem to have an irruption of red admirals right now, and you will see huge numbers of those. I have also seen good numbers of question mark butterflies and eastern commas, as well as pearl crescents along the roadsides.
Great spangled fritillaries and meadow fritillaries can be seen in small numbers.
Orange sulfurs were quite numerous a few days ago but seemed to take a hit with the heavy rains. I think their numbers will rebound quickly and they once again will be the most common butterfly in Iowa.
Eastern tiger swallowtails will be seen occasionally but are large and hard to miss when present. I have seen a small number of black swallowtails and expect them to become more common as the summer progresses, unlike last year when there were almost none.
Monarchs have been present, and will continue to slowly increase in population over time.
There are a number of butterflies that immigrate into Iowa after they populate areas to the south of us. Little yellows, cloudless sulfurs, common buckeyes, American snouts, dainty sulfurs, and a number of other butterflies normally do not over winter here, but can form stable populations here in the summer months. I have not seen any of those yet this year, but would expect them to start showing up sometime soon.
The Baltimore checkerspot is a spectacular black, orange, and white butterfly that is only found near fens in Iowa. It will make its appearance in early July, and you should consider yourself quite lucky if you are able to see one.
The Poweshiek skipper is a small grass skipper which was originally discovered and described in Iowa, and was probably widespread. With habitat destruction its range was restricted to a few original prairie patches, where it would show up in fairly good numbers until recently. It had a single generation each year which would fly from late June through mid July. It seems to have been extirpated from the state sometime between 2000 and 2005. It should still be looked for, however, as it might be present somewhere that has been overlooked in the past.
Look for other skippers to be showing up soon as well. Silver-spotted skippers are large and chunky and hard to miss as they hop around. They have a habit of landing to the side of a flower instead of on top of it, then sticking their long proboscis over the top to get nectar. Also look for common checkered skippers, sooty wings, least skippers, crossline, dun, and Peck's skippers.
As you do some of your summer outdoor chores you might run across black mud dauber wasps. These insects are interesting in their own right--they are solitary wasps that construct nests out of mud, then capture spiders and provision the nests with paralyzed spiders for their larvae. There are several species, but one of the most common ones around here is a shiny metallic black or very dark blue-purple with black wings. These wasps do not normally defend their nests, and do not normally sting, but they can. And, like all stinging insects, the sting can be painful.
The wasps are marked in distinctive, easily identifiable colors (aposematic coloration) that warn other animals to stay away from them.
Some moths take advantage of that situation, and are essentially wasp mimics. The grapeleaf skeletonizer is one of those mimics, although there are moths that look even more like wasps. This moth flies and acts a little like a wasp, so might get some protection from that. It might also be somewhat toxic to predators that try to eat it as well.
The grapeleaf skeletonizer is a minor pest of vineyards and of some ornamental plants.
Enjoy the summer. It is going fast.
|June 16-30, 2015|
|Summer is here.
May and early June had very low numbers of butterflies. Then the
weather turned warmer, and within a few days there quite a few.
Leading the way were the summer azures--small blue butterflies that fly
high in the trees. Red admirals show up late in the evening and
are very active, chasing each other in little circling flights that last
half a minute or so before they tire and split up. Least skippers,
meadow fritillaries, question mark butterflies, great spangled
fritillaries, and little wood satyrs have recently shown up.
Little wood satyrs are particularly charming though difficult to
photograph. They have a little hopping flight that stays only
inches above the bare ground. When they fly over grass, they fly
slightly higher, but still almost touch the grass. When they are
in brushy areas, they fly through the brush, still fairly near the
ground. Look for little wood satyrs in clearings in woodlands.
They can usually be found anywhere there is poison ivy.
Northern pearly-eyes are medium-sized butterflies of woodland clearings. They should start showing up in late June. In some years they are quite common and in others they can be difficult to find. I don't often find them on flowers, but they will come to sap where branches have been trimmed, and also to rotten fruit.
It is possible to set up bait stations to attract butterflies. Rotten fruits such as watermelon, bananas, musk melon, and others can work, or you can mix brown sugar, molasses, beer, and mashed bananas to a thick paste and paint it on trees. Baiting can be an excellent way to see large numbers of butterflies that you might not see otherwise. Be aware, however, that other insects will be attracted to the bait as well and may present a nuisance.
As the season progresses the flowers that come into bloom change in character. Bees and flies are better able to move about in the cool, often rainy conditions of spring. Spring flowers are often simple (think hepatica or spring beauty) and are pollenated mostly by small flies or bees. Other spring flowers have a structure that requires a fairly strong insect (usually a larger bee) to enter inside in order to obtain nectar and pollen. Dutchman's breeches and foxglove beardtongue are examples. The composite flowers that mostly bloom in the summer--cone flowers, thistles, and sunflowers--have structures that mesh with needs of butterflies better than the early flowers. Butterflies can land easily on these flowers, and do not have to go through a lot of contortion in order to obtain nectar.
Perhaps we should not try to analyze the changes too much, and just enjoy the procession. Prairies in particular can be spectacular places to visit in the summer and the flowers blooming one week will be different from the flowers blooming the next. If you visit a good prairie once a week throughout the growing season you will see something different each time you visit. You will see different flowers each week, and different insects.
Iowa has about 16 species of milkweed, and several of them are great butterfly flowers. Several of the hairstreak species--coral, banded, and Edward's, for example, can most easily be found by inspecting the flowers of butterfly milkweed or common milkweed. A milkweed relative, dogbane, has small white flowers and is also good for attracting hairstreaks.
Orange sulfurs normally start showing up in high numbers about now, but I have only seen a few so far this year. It may be that their flight is just delayed, but we may see lower numbers of them this year.
Some of the small skippers have been showing up and will continue to do so. Least skipper is particularly common now, but I have also seen Peck's skipper, tawny-edge skipper, Delaware skipper, and cross line. I have only seen one silver-spotted skipper so far this year, but they should start showing up in higher numbers soon.
Some butterflies have a special charm, and the hackberry emperor is one of them. Its charm comes from its tendency to land on people. Maybe they are attracted to large sweaty mammals so they can get access to the minerals, or maybe they just like the view. In any event, it can be fun to have a butterfly land on you, and hackberry emperors are likely to do that. The one I have shown here is on my brother Carl.
If you can visit a prairie that has them, the regal fritillaries should be out, and they should be fresh. There is not a more spectacular butterfly in Iowa, and it is well worth the trip to try to locate some.
Railroads in Iowa were at one time a great place to look for small patches of prairie plants. The right-of-way was minimally disturbed and would retain prairie plants longer than roadsides did. Many of those rights-of-way have been converted to bicycle paths, and can be surprisingly good places to find butterflies. I have also taken a ride on the Boone and Scenic Valley Railroad, and was quite pleased by the number of butterflies that could be seen along the trip. The area over by Fraser was thick with giant swallowtails.
The featured creature for this forecast is what I consider Iowa's most spectacular insect. The ebony jewelwing is a large damselfly with black wings. It is a metallic green color (which can appear blue, depending on the angle of the light).
The ebony jewelwing inhabits wooded areas near clean flowing streams. It seems to seek out shady areas, then finds a beam of sunlight to perch in. The effect is sort of like a spotlight--the insect is isolated from the background. And the ebony jewelwing is shiny. This insect is shinier than your boss's new car.
Watch for the ebony jewelwing--it will take your breath away.
Enjoy yourself and get outside to chase butterflies.
|June 1-15, 2015|
is starting to get here, and so are the butterflies. Not only will
we start to see species that we haven't seen yet, but we will also start
to see a fairly dramatic increase in the numbers of individuals over the
next few weeks. Numbers have been low recently, in part because it
is still early, but also because the heavy rains have suppressed
butterfly activity. When they do suddenly show up, they could be
all around us.
Orange sulfurs may have the first population burst this summer. They are usually Iowa's most common summer butterfly, and they mix with the similar clouded sulfur which can also be quite common.
A small blue butterfly, the summer azure, will also likely show up in high numbers. As this is a smaller butterfly it may not be as noticeable as the sulfurs. They will become quite common, flying high up in the trees, however.
Pearl crescents can have high numbers, and they inhabit weedy areas, often including lawns. If you are near a prairie area you might see the similar but slightly larger gorgone checkerspot, but you have to look closely to tell the two apart. Pearls will be far more common than gorgones.
Wooded areas are more likely to have the silvery checkerspot than are prairies. This butterfly can also reach fairly high numbers.
Areas with tall grasses, particularly near ponds and wetlands can have large numbers of the very small but wonderfully perky least skipper. Since this butterfly is so small it is easily overlooked, but once noticed it can be quite charming. Other grass skippers may be present in smaller numbers. Peck's skipper and Hobomok skipper can be particularly noticeable. Common checkered skippers can often be seen, but usually only a few at a time. Silver-spotted skippers will start showing up, and they are usually hard to miss because they are large and have a distinctive method of visiting flowers, preferring to drink nectar while perched on the side of or below the flower, rather than on top of it.
Many butterflies never reach high numbers, but can usually be spotted if you look for them. Eastern tiger swallowtails are particularly noticeable when they are flying around. Giant swallowtails are usually a little rarer in this area.
Viceroys and red-spotted purples will be out. Look for them in wet brushy areas, where willows and wild cherries grow.
You should see occasional monarch butterflies, but their numbers are still pretty low. They will have higher populations later in the summer and early fall.
One fairly rare butterfly that seems worth talking about is the harvester. It is a small but distinctive brown and yellow-brown butterfly. It seems to have many overlapping generations throughout the year. The interesting thing about this butterfly is that the caterpillars are predatory, feeding on wooly aphids. Wooly aphids and the harvester are reported to favor alder trees, which are apparently fairly rare in Iowa. Some of the photos on the internet which show the caterpillars and aphids have them on greenbrier (Smilax), which is fairly common in Iowa. So look for the adult butterflies, but also look for clusters of wooly aphids that might have caterpillars on them, particularly on greenbrier.
As the seasons progress there are living things all around us that are going through changes. Most of the life around us responds to the seasonal changes. Native flowers often bloom only for a short time--one or two weeks out of the year. With good biological diversity we will see flowers throughout the growing season, but they change as the time goes by. Pay attention to the life around you, because if you miss it you may have to wait another year to see it again.
Insects can have several generations throughout the summer, or they might just have one. Sometimes when they have more than one generation, a particular generation can be much more conspicuous than others, so you only really see that insect at a particular time.
The featured creature for this forecast may fit into the group of insects that just has one generation per year, or it may have several generations. The truth is that, as far as I know, the life cycle of this creature is not really known for sure.
In fact, this creature is so little known that it does not have a scientific name. But it will look familiar if you have ever seen any of the star wars movies. It looks a lot like the storm troopers.
The insect shown here is the nymphal stage of a treehopper. I usually can find them in the first week or two of June on walnut trees in my back yard. Some years I have been able to locate them and some years I have not. Look for them on black walnut trees, often at about eye level. If they are present they can often be spotted from quite a distance--they look like a little white dot at the very base of a leaf. You will often see ants associated with them.
Just because the species is undescribed does not necessarily mean that it is uncommon. It can be hard to find at times, but there are a number of photographs of it on bugguide. If you go to the info page for the species, you will probably have access to most of the published information on this storm trooper leafhopper (I did not come up with the name myself--someone else on bugguide suggested it, and I think it fits).
So look for this species on walnut trees in the first two weeks of June this year. I don't know how rare they are, and I don't know if this will be one of the years they show up. But if you find them, be aware that you are looking at an undescribed species. And it might even be in your own back yard.
Keep watching the wildlife. You never know what you will see.
|May 16-31, 2015|
is starting to heat up and so is the butterfly action. We are
starting to see higher numbers and more diversity. With the higher
numbers we are seeing some of the behaviors that make watching
Spring rains that last all day are starting to leave us. In their place come thunderstorms that can drop a similar amount of precipitation in an hour or two, to be replaced by sun and heat later in the day. Those are perfect conditions to observe butterflies mud puddling. Walk along the edge of a gravel road about an hour after a thunderstorm, especially if the area around the road has good butterfly habitat. You will see numbers of butterflies standing on the damp ground, especially in sandy areas. Those butterflies will be sipping fluids from the spaces between the sand grains.
Most of the butterflies that you observe doing this behavior will be males, like the male pearl crescent shown to the left. The reason for this disproportionate ratio of the sexes is not really known. It is thought that the males are concentrating minerals from the water they sip, and that they can transfer those minerals to the females upon mating, thereby increasing the survival of the offspring. But maybe it is just that the males like to drink more than the females.
As the summer progresses this behavior can become quite common. It can be a real thrill to come upon a cluster of butterflies engaged in mud puddling behavior. Often there are several species at the same damp area, and when that happens you will notice that they usually segregate themselves into same-species groups. Yet they don't interact much, other than to drink. If you get too close, you will startle them and they all fly away, only to land at some similar nearby spot. Sometimes you will see road-killed butterflies, and if you put one of them in an area that looks like a good watering hole, butterflies that are exploring the area in search of the right spot will land near the corpse. So in a manner similar to using a duck decoy, you have created a butterfly decoy.
Pearl crescents can often be seen in pre-mating flights and displays. This can involve three or more individuals, a larger female and one or more pursuing males. The female drinks nectar from a flower, and her wings are usually spread out horizontally or in a "V" shape, while the pursuing males have their wings in the vertical position, but pulled back so that the hindwings mostly cover the forewings. There is a lot of vibrating, usually on the part of the males. The female takes her time getting nectar, then flies off to another flower with the males in hot pursuit. You may see many of these pre-mating dances and never see the actual mating.
Red admirals put on a similar show. They are more likely to only have two individuals involved in a chase, but I am not convinced that the two are a likely pair. Red admirals perch high on tree trunks or buildings, often head down, and chase anything that moves. There is a detailed description of their behavior on the Red Admiral and Painted Lady Research site which is run by Dr. Royce Bitzer. It is fun to know some of the science behind the behavior, but red admirals are totally entertaining on their own. The mad chases are spectacular. Pets can get involved in the action as well--cats and dogs cannot resist trying to pounce on the butterflies, only to get a paw full of air.
Other butterflies will be present during the last part of May as well. The overall numbers of butterflies will remain low, but each day can bring the promise of a first of the year butterfly for a number of different species. The common sootywing is a black skipper with white spots on the wings and the head. It is pretty distinctive and can't be easily mistaken for anything else. Juvenal's duskywing and wild indigo duskywing may be seen as well. I find the duskywings to be frustratingly difficult to differentiate from each other even with a sharp photograph of a fresh specimen.
Silver spotted skippers may be present, as may Peck's skipper and Hobomok skipper. Eastern tiger swallowtails, giant swallowtails, and black swallowtails should be present in central Iowa. Black swallowtails are pretty common in most years, but I did not see any last year. I have seen one already this spring, however. Zebra swallowtails might be flying, but only in the extreme southwest or extreme southeast corners of Iowa.
American ladies, painted ladies, and common buckeyes all could be flying, probably in smaller numbers than the red admirals. Clouded sulfurs are flying, and they will likely be outnumbered by orange sulfurs in a few weeks. Summer azures and eastern-tailed blues will start to pick up numbers soon as well.
Question mark butterflies may be seen. There is some evidence that question marks migrate, although they likely also over-winter in the adult stage in Iowa.
Viceroys and red-spotted purples can show up by the end of May, as can monarchs as well.
Spring is a great time in Iowa. It is great to see the new butterflies as they emerge, but there are a host of other life forms that can be entertaining, from the spring ephemeral wild flowers, to the mushrooms, lichens, mosses, and liverworts. Small flies can set up temporary leks in a ray of sunlight, only to disappear when a cloud crosses the sun.
Dragonflies and damselflies dance across the waters and hunt insects in the tall weeds. Birds are raising young and you can hear them at times, calling for food. Bees are busy visiting flowers on the ground and in trees.
A walk in the garden can surprise you with the pleasant odor of the flowers of lilacs, or the unpleasant dead animal odor of dogwoods.
For the featured creature this time, I am going with a member of a group of animals that has a relatively insignificant number of species--this group represents only about 3% of all animals. The group is the vertebrates. Since this is such an insignificant group, I probably won't feature another vertebrate this year.
If you are close to a shallow body of water in the spring, and you listen at night, you can hear a number of frogs calling. Chorus frogs will be the first to call in the spring, followed by leopard frogs and American toads. Gray tree frogs start calling in late April and will continue through May. Most species of frogs call only from the shallow pools or the areas next to them. Gray tree frogs will call from there, but they also call from trees and other areas far from the water.
We often find gray tree frogs on our house--they seem to like hanging out near the windows and under porch lights where they wait for insects and just munch down.
Iowa has two species of gray tree frog, the eastern gray tree frog, Hyla versicolor and Cope's gray treefrog, or Hyla chrysoscelis. They are pretty much indistinguishable and in fact, my photo could be either. The big difference between the two is genetic--one is tetraploid, having two pairs of each chromosome, rather than the usual diploid condition in which all chromosomes are paired. There is a difference in the calls of the two species--experts can tell the difference but I am not one of those experts. The Iowa frog and toad survey is a citizen science project to identify the frogs and toads in Iowa by tracking their calls. I participated in it several years ago, and I can't describe the pleasure it gives me today to still remember which call goes to which frog. Of course now you can go to various websites that have recordings of the calls and learn that way.
So watch for gray tree frogs and listen for their calls. You will be glad you did.
|May 1-May 15, 2015|
days are getting longer and warmer, and butterflies are showing up more
reliably and in greater numbers than before. It might still be
possible to see some of the early single-generation butterflies like
Henry's elfin and Olympia marble. They can be quite difficult to
find, but look for them anyway because they are worth the trouble.
Two small blue butterflies will appear during this time period--summer azures and eastern tailed blues. Summer azures fly at tree-top level, or at least often end up there, and eastern tailed-blues typically stay away from the trees.
There is a complex of several Celastrina (azure) species (or subspecies, depending on the taxonomist), and two have been identified for Iowa, although others are possible. I discussed this in this post last year, so I won't go over it again.
Summer azures and eastern tailed-blues can both be present in the first half of May, although both will show up in much higher numbers later in the year. You may also still find eastern and gray commas, mourning cloaks, and Compton and Milbert's tortoiseshells are possible, but mostly in the north-east part of the state.
Last year I found goatweed leafwing and common roadside skipper on the fourth of May, but both were in the western part of Iowa, at West Oak Forest and Folsom Point Preserve, in Mills County. Neither of those butterflies are likely to be found in central Iowa.
Clouded sulfurs and orange sulfurs should be present and could become fairly common. In the field I am never completely confident of my ability to differentiate those two species, but the clouded sulfur is generally smaller and has a light yellow upper surface. The orange sulfur is larger and has an upper surface that is more of an orangish-yellow, but still more yellow than orange. There are some butterflies that are clearly one or the other, but there are many that are sort of in between. Generally speaking, the butterflies I see earliest in the spring and the latest in the fall usually look more like clouded sulfurs than orange. In the summer ratios can vary, often with one species dominating.
Common butterflies will also include cabbage whites, red admirals, American ladies, and painted ladies, any of which could be present in fairly high numbers.
Bronze coppers can often be seen around wetlands, but usually in low numbers. Although small, they are brightly colored and leave a pretty good impression. American coppers are rarer, although they can be present in high numbers where they are found. They are very small and can be overlooked quite easily, however.
Black swallowtails and eastern tiger swallowtails will make an appearance, and while not common they are large and showy and cannot easily be missed.
Skippers were generally uncommon last year but may be more common this year. The large silver-spotted skipper is always fun to see, as it hops around, landing underneath flowers and popping its proboscis over the top to get its nectar. Peck's skipper and hobomok skipper can often be found on some of the mid spring garden flowers.
The earliest of the monarchs can be seen in early to mid May in Iowa.
Of course, this time is full of other magical creatures as well. Flowers will be full of tiny insects--bees, wasps, and especially flies, all chasing the gift of nectar. Most can be difficult to identify, although some are so distinctive as to be easily identified.
Frogs can be heard calling often now. The gray tree frog will have replaced the chorus frog by now, and American toads, bullfrogs, and cricket frogs may be calling.
I had a fairly good education while I was growing up, and majored in biology at Iowa State. I got outside fairly often--maybe more than most, but less than others. But perhaps I did not pay enough attention, because I was unaware until after I had graduated college that there were terrestrial snails in Iowa. I knew there were slugs, which are snails that have an internal shell, but for some reason I had not made the connection with snails.
The featured creature for this forecast is a snail.
Turns out there are quite a few species of snails in Iowa. I have a list, although there is still a lot of work that could be done with the snails. There are a few large snails--those with shells between half an inch to slightly over an inch in diameter, but most are quite small. There really aren't any good field guides currently in publication, but there are a few older ones.
Most snails can be difficult to identify. The key characteristics involve determining whether the undersurface of the coil (termed the umbilicus) is open or closed, and looking at the opening or aperture to the shell--some have lips, and some have projections into the aperture. Then you measure the shell, count the coils, and note the color and texture of the shell.
There is a snail that is considerably easier than most to identify than most. Anguispira alternata is found in most rich woodlands. The umbilicus is widely open. The aperture has no lip or projections into it. The snail is fairly large, with a shell diameter of about 3/4 inch. The shell often has alternating red and clear stripes, and it appears sculptured. The slime this snail gives off is often reddish in color.
This snail often climbs high in trees, and the individual shown was several feet off the ground during a sudden rain storm.
So if you see a snail in the woodlands, often partway up the tree, and it looks like this you can be fairly sure of the I.D. This is a fairly distinctive species, and no other Iowa snail looks much like this one.
So get outside and watch for butterflies and all the other creatures that make the season fun.
|April 16-April 30, 2015|
the days continue to get longer and the warmer the butterflies are
coming out in higher numbers than earlier in the spring. Still,
the weather can determine whether any butterflies are seen at all.
Long rainy days or late frosts can mean that none will be seen.
Sunny warm days can result in lots of them.
The nymphalids that spend the winter in the adult phase--mourning cloaks, eastern commas, gray commas, Milbert's tortoiseshell and Compton tortoiseshell can still be seen in wooded areas. Migratory butterflies, mostly from the same group, can also be seen. Red admirals, American ladies, painted ladies, and buckeyes can be seen, sometimes in fairly large numbers. Then there are some of the resident butterflies that come out a little later. Cabbage whites are usually among the first of these, followed by clouded and orange sulfurs.
Eastern tiger swallowtails can be conspicuous and somewhat common in the spring. Black swallowtails are often found in pretty good numbers also. However, black swallowtails were almost absent from the landscape last year, at least here in central Iowa. I hope their numbers rebound this year.
The last half of April marks the emergence of what I call "frustration butterflies." These are butterflies that are either difficult to find, either because they are rare or because they only come out for a short time in specialized habitats. The fact that I have posted this forecast for a number of years has led some people to think I am an expert. I am not--I am an enthusiast. And often times I am a frustrated enthusiast. I can spend lots of time looking for butterflies that others seem to find easily. But maybe they are frustrated also.
The juniper hairstreak is one of my frustration butterflies. I have been lucky enough to see it on a handful of occasions, and to get photographs. But the amount of time I have spent searching for this little gem is way out of proportion to the number of times I have seen it. Eastern red cedar is a hostplant for this butterfly, and is also a tree which grows like a weed around here. Juniper hairstreaks are probably more common in the western-most counties of Iowa, and also some counties in the eastern part of the state. I have seen them in my yard on two occasions, but I have gone out specifically looking for them on dozens of occasions. This butterfly seems to have two generations in Iowa, one in late April and early May, and another in late June through early August. The few times I have seen it have been in the first generation, although I have looked for it extensively in the second generation as well.
Another frustration butterfly for me is the Olympia marble. I have yet to see this one. It is rare, and when it is found it is mostly found in one of the western counties of Iowa. I did hear of a report of someone who found them in an area of Ames in in The Ledges State Park, but some other people I talked to about those reports were somewhat surprised by them.
Olympia marble uses small native mustards like rock cress as host plants. They are reported to occur only in small numbers in Iowa when they are found at all. Mike Reese (Wisconsin Butterflies) describes trying to photograph them as the fly and nectar on pasque flowers, and notes that they are skittish and very difficult to photograph.
My final frustration butterfly (at least for this time period) is Henry's elfin. I have yet to find this butterfly either. It is a small hairstreak with a short flight period that coincides with a very busy time of the year for work and school activities, and short weather windows for locating butterflies. But it is known mostly from native redbud trees, and I have finally figured out how to reliably identify redbuds. I will find this butterfly if I keep looking for it--at least that is what I tell myself. I have all the information I need. I just need some good timing and luck.
A few other species of butterflies should be seen, and will be easier to find than the frustration butterflies. Spring azures are small blue butterflies that can be found flying high in woodlands in late April. Eastern tailed-blues might also be flying, but the peak of their first flight normally comes a little later. Eastern tailed-blues usually fly closer to the ground than spring azures. Watch for pearl crescents and possibly even silver-spotted skippers.
Late April is a great time to be outside enjoying nature. The woodland floors are alive with flowers--spring ephemerals as they are called. Hepatica, bloodroot, spring beauty, Dutchman's breeches, and May-apple can be found in abundance on forest floors all over Iowa. If you are lucky you might also find squirrel corn, wood-betony, large-flowered bellwort, showy orchis, Solomon's seal, false Solomon's seal, and wild ginger. These wildflowers will be visited by small solitary bees and beeflies. Some of them have pollinators or other visitors that are specialists--they can only be found on that particular flower.
If you do not know Iowa's woodland wildflowers, and especially if you don't get out and walk the forest floor in mid to late April in Iowa you are really missing out. Try to get away from everybody, but you might run into mushroom hunters this time of year. But if you are one of the mushroom hunters, take some time to enjoy the wildflowers and small critters.
If you get to a pond or lake, you will find that the dragonflies and damselflies are still pretty uncommon this time of year. You may see a few large dragonflies cruising the perimeter of the pond, or maybe just a single individual. It is likely to be the common green darner, Anax junius.
For this butterfly forecast, my featured (non-butterfly) creature is Anax junius.
Common green darners are migratory. The exact details of where and when they migrate are still being worked out. Other dragonflies are migratory as well, but the general phenomenon is not well known. There is a citizen-science project that is gathering information, and it is called the Migratory Dragonfly Partnership. This project monitors five species that are known to migrate.
Of course, if you want to know more about Iowa's dragonflies and damselflies, don't forget about the excellent Iowa resource, www.iowaodes.org. This lists all known Iowa species and includes their flight times, biology, and excellent photographs.
So get outside and look for butterflies. Watch for common green darners. Walk in the woods and enjoy the spring ephemerals. Listen for the sound of bees flying, and the calls of frogs looking for mates. Take in the sun and the cool breeze.
You will be glad you did.
|April 1-April 15, 2015|
gave us temperatures that were twenty or thirty degrees colder than
normal. When I published my first butterfly forecast for this year, I thought we
would be well into March before we would see any butterflies. But
then it warmed up to temperatures that were about the same range above
normal. Before long, the snow was mostly gone and a few reports of
butterfly sightings started trickling in.
The first butterfly sighting in Iowa that I am aware of was from Kevin Pape in a new Iowa DNR property called Spirit Knoll, recently renamed Heendah Hills. Kevin saw an eastern comma on March 9th. Then I got a report from Lloyd Crim of a cabbage white seen on March 10th. Benjamin Hoksch reported seeing an unidentified Polygonia species on the 11th. Chris Edwards reported a gray comma on March 16th, and Armund Bartz reported a mourning cloak on March 14th.
People were reporting butterflies on the Wisconsin Butterflies site starting on the 9th of March as well. The first ones seen were all eastern commas or mourning cloaks.
Generally speaking the first butterflies we see are the ones which hibernate as adults. These include the commonly seen mourning cloak and eastern comma, and also less common (around here, at least) gray comma, Milbert's tortoiseshell and compton tortoiseshell.
The cabbage white is one of a group of butterflies that spend the winter as a pupa, and it is generally one of the first to be seen in the spring. Others we are likely to see soon include the spring azure, the clouded sulfur, and the black swallowtail.
Most of the butterflies we have here in Iowa are native to the state. The cabbage white is not. It is originally from Europe, where it has the common name "small white." In The Butterflies of North America by James A. Scott, a study is mentioned where cabbage whites were marked and followed as the moved throughout the day. It was noted that the females flew a distance of about 700 meters every day, and usually ended up about 450 meters from where they started. Each day they would fly in a preferred direction, but that preferred direction could change, apparently at random, the following day. Adults lived only about five days. So the next time you get to observe cabbage whites, see if you can detect a preferred direction of flight. If they reach the edge of their habitat do they keep going, or do they fly back?
The migratory butterflies can start showing up in the first part of April, depending on the weather. Red admirals can be very common, and usually American ladies or painted ladies can show up as well.
Henry's elfin and Olympia marble are butterflies which only fly in spring in Iowa. They might show up in early April, but they are more likely to be present in the last half of the month or even in early May. I have been frustrated in my attempts to find these species and have been unsuccessful so far. For those of you in the same boat, my best advice is to check out the website www.insectsofiowa.org for those species. The database gives lists of locations and times, and if you are lucky enough to know one of the individuals who has documented one of the specimens maybe they can help you.
Early spring brings lots of changes to the landscape. If you are able to visit one of the woodlands around Iowa with a good understory of spring ephemerals, you might be able to find something new each time you visit. There are a lot of small solitary bees flying at this time of year. All of your senses can be involved in the experience, from the smell of the nightcrawlers after a spring rain, the softness of the moss growing on the earth of the forest floor, and the sounds of the birds and frogs singing, or the bees and flies buzzing around. The flowers let you appreciate your sense of sight. I am sure there are plenty of things to taste, as well, but let me recommend morel mushrooms (just starting their season) and maple syrup (at the end of its season).
I have written this butterfly forecast for several years now, and I thought I might spice it up a little bit from time to time with other creatures you might want to look for. Butterflies are only a small part of the biological diversity of Iowa, and there are other things that can be fun to watch for.
The first featured creature is called the "golden dung fly." This is a fairly distinctive and common fly here in Iowa. They are found all over the United States and are most common in the early spring and summer, then again in the fall.
Golden dung flies are slightly larger than a house fly, and have noticably thicker and longer legs. They are golden-yellow, and covered with golden yellow hairs. The adults seem to be attracted to areas with sugars--wounds of trees that are leaking sap and flowers. When peonies first start to bud you can often find them on the sugary buds, along with ants and other species of flies.
Although the adults seem to be attracted to sugars, they are not nectar feeders--they capture and eat other insects. They seem to be quite good at it, in fact.
Eggs are deposited on decaying vegetation and on animal dung. I am no expert on Latin names, but I can tell you that the "phaga" part of the name refers to eating. I will let you fill in the rest.
So get out there and look for butterflies. Listen for the calls of frogs. Watch for other creatures as well. And see if you can find a golden dung fly.
Enjoy the outdoors.
|March 1-March 31, 2015|
is March, so it must be butterfly season. In Iowa, butterfly
season almost always starts in March. It might be the first day of
March, or it might be the last day. There is about a 98% chance
that the first butterfly seen in the Iowa each year will be seen in
March. It is also likely that it will be either a mourning cloak
or an eastern comma.
How do I know that? I don't really. But I have done this forecast for six years now, and in each of those years the first butterfly showed up in March. The first butterfly reported in Iowa for those years was either a mourning cloak or an eastern comma. I recorded reports as late as March 30 and some as early as March 16. In a couple of years I reported that butterflies had been seen in March, but did not record the actual dates. In 2012 I reported that I had seen four species by April, but did not record which species or when they were seen.
Mike Reese does a better job on his Wisconsin Butterflies site. He has records from 2005 through 2014, and the ability for others to submit records. The first butterfly sightings on his website are all in March for that time period, and include Compton tortoiseshells and Milbert's tortoiseshells in addition to eastern commas and mourning cloaks. Those tortoiseshell species are not so common in central Iowa and so are less likely to be the first butterfly seen.
Butterflies are fun to watch. It can also be fun to keep records of what you see and to share those records with others. Those records can really help your success. A number of websites out there encourage this type of citizen science, or are created by citizen scientists. Each is slightly different and can be used for different things.
Jim Durban has created a database to track Iowa's insects. His first version is still online at insectsofiowa.com. He has a greatly modified and improved version at insectsofiowa.org. Both sites are useful on a number of levels, but the last version looks to be particularly useful for people who are trying to find the rarely seen butterflies of Iowa.
When you talk about butterflies someone always asks if there are fewer now than there used to be. The answer is usually that it seems like there were more back then, but how do you know for sure?
There is an answer to that question. The British Butterfly Monitoring Scheme was developed in the 1970s and has been used successfully to monitor butterfly populations in Great Britain. The primary survey technique, the "Pollard Walk," has been adapted and used by several butterfly survey efforts in the United States. A Pollard walk involves walking at a steady pace along a set route and identifying and counting all of the butterflies seen along that route within a given distance from the observer. Usually the observer conducts similar surveys along that same route several times during the season. The data can be reduced to numbers of a particular species seen per hour, or numbers seen for a given area. It can also give valuable information about what was not seen in a given time.
Nathan Brockman and Reiman Gardens have set up an Iowa Butterfly Survey Network effort for Iowa, and it has been making steady progress. Last year they fielded a new smartphone app for surveying butterflies. Now they are coordinating with others to input information into a national database for Pollard walk-type data, and it can be found on the Butterflies and Moths of North America website.
But enough about websites and databases. What we really want is to get outside and look for butterflies. Hopefully within a few weeks we can string a couple of warm days together, and the sap will start to flow in the trees. When that happens take a walk in a woodland. Where small branches have broken or cracked , or where sapsuckers have drilled holes you may see the sap running down the trunk of a tree. Check those areas especially--they are great places to find butterflies. Mourning cloaks, eastern commas, and the tortoiseshells can be found here. They also might be seen sunning themselves on a well-lit tree trunk, or flying through the understory.
Late in the month, if we are lucky enough to have some warm weather, we might see red admirals, cabbage whites, or spring azures. So much of the early butterfly season depends on the weather. But hit a good woodland in the early spring. You will be glad you did.