|The Poweshiek Skipper Project|
|Butterfly Forecasts for
|October 1 to year end, 2013
October in Iowa often brings pleasant weather and spectacular scenery. If you like Iowa even a little you will love the state this month.
Butterflies can be common when the weather cooperates. But the weather can turn cool and rainy easily, and make the butterflies disappear. Soon they will be gone for the year. In some years the last butterfly of the year will be seen in the middle of October. In other years butterflies hang around until the end of November. These are the last weeks of a far from spectacular year for butterflies, but if you get out on the good days and watch you might still see some pretty good ones.
Fiery skippers are often among the last few stragglers each year. They hang on even after the first frost, and can often be seen on the warm sunny days right before winter hits. Even though you might be tempted to move the photo to the left ninety degrees counterclockwise, the fiery skipper in the picture is in its original orientation as were the Spanish needles.
In addition to fiery skippers, you might see sachems, Peck's skippers, tawny-edged skippers, and common checkered skippers.
Some of the migratory butterflies might still be seen in the early part of October. Species we normally think of as being part of this group in Iowa include the monarch, red admiral, painted lady (shown below and to the right), and buckeye. One we may not think of so much is the cloudless sulfur. This is a large yellow butterfly, significantly larger than our more common orange and clouded sulfurs. They make their way into Iowa late in the year from areas to the south, and usually do not reach significant numbers here. They do reach as far north as southern Canada. We normally do not see it, but cloudless sulfurs have a southward migration as well, reaching good concentrations in areas like South Carolina and Georgia on their way to southern Florida. Since they are such a large and noticeable butterfly the migrations are frequently observed in those states. When we see them here, we usually consider ourselves lucky to see one, let alone a handful. You might be lucky enough to run across one in the next week or two, and if you do watch to see if it is flying in a particular direction.
Dainty sulfurs have been unusually common this year, and they will probably hang on until they are killed by the cold weather. Cabbage whites can usually be seen late in the year as well. Orange sulfurs usually hang on until first frost, and they have been somewhat common lately. Clouded sulfurs normally become common this time of year, and usually can be seen on sunny days until we get a hard frost. Clouded sulfurs have been almost non-existent in Iowa this year, however, so I don't think we will see many.
Black swallowtails can hang around for a while also. When their caterpillars pupate, a certain number go into a diapause to overwinter and emerge in the spring. Some do not, and emerge in conditions that are usually not well suited for their survival.
A group of Iowa's butterflies spend the winter as adults, squeezing tightly into cracks in the bark of trees or down in leaf litter. These include the mourning cloak, the eastern comma, and the tortoiseshells. They might still be encountered late into the fall as they search for suitable hiding spots.
Saying that the butterflies are gone during the winter is really not correct. Some, like the monarch and other migratory butterflies really are. But most are present in some other stage of life than the adult. Some are in the chrysalis stage, some are in one of the larval stages, and some are present as eggs. I recently finished my copy of Mariposa Road by Robert Michael Pyle, and was entertained by his descriptions of searching for eggs of particular butterflies in the middle of winter.
So the butterflies are still here, we just have to search to see them.
I have done this butterfly forecast for a number of years and have enjoyed doing them. I don't know what the future will bring, but I appreciate having an audience to my little obsession, and thank you all for your interest.
Signing off for this year...
September 16-30, 2013
The end is near. The end of the butterfly season, that is. This year has been a little disappointing as far as the butterflies go. The season started later than normal, and just when the numbers started to increase we got an extended dry period. Normal population sizes just never materialized. Late September is usually a great time to find lots of butterflies. This year you will see some, but you sort of have to look for them harder than normal. There are some things you can look for, though.
Since this year was so dry, I suspect you will have the best luck looking in areas that have water--stream beds, lakes, etc.
Some species have been especially uncommon this year. I would include the clouded and orange sulfurs in that group because they are normally very common in September. This year I am only seeing a few per day. I have not seen any silver-spotted skippers, although a few other people have reported seeing them. The one that is most surprising to me seems to be the silvery checkerspot--most years they can be quite common, but I have not seen one this year nor do I remember anyone reporting a sighting.
This is a good time to look for seasonal morphs. Many butterflies exhibit dramatically different coloration or size differences, depending on photoperiod, temperature, or rainfall. The dainty sulfur shown to the right is identified as a "dry season/winter form" by Glassberg's Swift guide. Compare it to the summer forms shown below this forecast. Common buckeyes have a very beautiful reddish winter form if you are lucky enough to see it. Many other species have forms that are not quite so distinctive, but still recognizable if you look closely.
In general populations of individual species of butterflies increase throughout the summer all across the nation. As those populations increase, they disperse outward from their home ranges. Sometimes the best chance to see a butterfly that is not normally found in Iowa can be late in the season before the first frost. A few years ago I downloaded range maps from the precursor to the Butterflies and Moths of North America website for a number of species. Based on those range maps, I believe there are around 50 species of butterfly that have not been documented in Iowa yet but could possibly show up as occasional strays. Tom Jantser and Chris Edwards documented a red-banded hairstreak in Keokuk just a few days ago, that was apparently a first sighting of the species for Iowa. So there can still be some butterfly action yet this year.
Some butterflies are possible all year long but seem to show up in fairly high numbers in late summer and early fall. Among them are the gray hairstreak, the little yellow, the dainty sulfur, the fiery skipper, the American snout, and the sachem (shown below and to the left).
These butterflies are thought to have one-way immigrations each year, and overwinter in areas to the south, but rapidly expand northward until winter kills them off.
Watch for butterflies making southward migrations. The monarch is the most well-known of butterflies that regularly migrate, but you might also see painted ladies, red admirals, American ladies, and red admirals. There has been a noticeable migration of painted ladies noted on the east coast, and there is at least a small possibility that we will see one here.
We still should see some cabbage whites, possibly checkered whites, and little yellows. Black swallowtails will continue to hang around, but they will be very ragged. Common checkered skippers and tawny-edged skippers will continue to make appearances, as will Peck's skippers.
The populations of butterflies are low this year, compared to recent years, primarily because of weather events. However, another reason the populations are low is because of our steady encroachment into butterfly habitats. Row-crop fields produce no butterflies at all, nor do paved roads and parking lots. Urban and suburban lawns produce very poor habitat for butterflies. Maybe the only good habitats left are weedy waste places (few and far between), river and creek greenbelts, and parks and preserves. The numbers of butterflies we see now are a tiny fraction of what the original habitat supported.
I think there are things we can do, however, to reclaim some of the habitat for butterflies. Integrated Roadside Management is one program that works--planting the ditches that have become monocultures for alien grasses with a selection of native prairie plants. Can we get people to spend less time mowing or cutting vegetation in areas where it doesn't hurt to have the weeds a little longer? Can we get people to think about butterflies when they do landscape design or when they maintain that landscape? Can we get businesses to plant some prairie plants rather than maintain acres of turf grass around their properties?
Can we convert stormwater management structures to butterfly habitat?
Imagine your back yard with ten times as many butterflies as you have now. Imagine it with one hundred times as many. That would probably be close to the original, pre-settlement populations. Wouldn't that be nice to have?
I don't know. Maybe I'm too much of a dreamer. But I think with small steps we can get closer.
Until next time....
|September 1-15, 2013
If you enjoy watching butterflies, you understand that numbers matter. It is fun following one or two butterflies across a flower-filled meadow, but it is more fun to see clouds of butterflies flitting across that same meadow.
Butterfly numbers fluctuate throughout the year, but in most years they steadily increase from about mid-June through the end of September. Some things will slow the population growth--extended cold or rainy weather, for example, or thunderstorms with massive amounts of rain. Short periods of hot weather and drought don't slow them down too much, but extended dry periods do.
In most years September is a magic time for butterflies. It probably won't be this year, though. With the extended drought and extremely hot weather at the end of August the butterflies will go through their short lives faster than normally and may not find enough moisture to survive.
Butterflies should still be present and have a high degree of diversity, but you may have to look a little longer to find them.
Black swallowtails have been pretty common this year and will likely continue to be so until first frost. Giant and eastern tiger swallowtails may also be present, but not so common.
Cabbage whites have been showing up in good numbers recently. Orange sulfurs have also been around, but not in the great numbers that they usually have this time of year. Clouded sulfurs may be present later, but have not been common recently. There seem to be very few little yellows or checkered whites. Look for dainty sulfurs in areas with sandy or bare soils and sparse vegetation--Saylorville Reservoir is pretty good spot to find them.
Gray hairstreaks, like the individual to the left, are never all that common but can often be seen this month, obtaining nectar from goldenrods and asters.
Eastern tailed-blues have been common in places, but are fairly small and easy to miss.
Pearl crescents will maintain good numbers until about the end of the month. Silvery checkerspots can usually be found in fair numbers in September but are very uncommon this year. Buckeyes have had pretty good numbers and are usually fairly easy to find. Painted ladies often make an appearance in some numbers in September but I don't really expect them this year. Viceroys and question mark butterflies will be occasionally seen in small numbers as well.
Skippers often make a good showing in September. Peck's skipper and the tawny-edge skipper have been making appearances. I have seen a few Sachems and fiery skippers as well. Others have reported seeing silver-spotted skippers but I have missed them this year. Least skippers can also probably be found in tall grasses around water, but have been rare this year in my experience.
Of course, the big star of September is the monarch. Monarchs have a spectacular migration every year which is loved by kids of all ages. Events have been planned around the migration of the monarchs. There have been some worrying reports about populations of monarchs lately, however. There are suggestions that the nation-wide migration of monarchs might be in danger. Monarchs would not likely go extinct, but might not have enough numbers to maintain the migrations.
There is some pretty scary data that supports the fear, unfortunately. The area of the forests in Mexico that hold the over-wintering population has decreased drastically since 1994-1995, and almost certainly had decreased prior to that time. For the period monitored, the smallest area measured was 1.19 hectares and the largest was 20.97 ha, with the smallest area recorded last winter and a clear downward trend. For comparison, two football fields laid side-by-side would measure just about 1.19 ha.
In 1868, Mr. J.A. Allen collected butterflies in Iowa, and wrote about monarchs (which he called Danais Erippus) that he saw in Iowa. To quote him:
"This extremely abundant butterfly seems to prefer open prairie, but is driven to the groves by the winds which sweep furiously over the prairies in the summer months, and especially in September; here the butterflies are collected in such vast numbers, on the lee sides of trees, and particularly on the lower branches, as almost to hide the foliage, and give to the trees their own peculiar color. This was not seen in one grove alone, but in all of those which were visited about the middle of September. If unmolested, they remained quietly on the trees; if disturbed by blows upon the trunk or branches of the tree, they would rise like a flock of birds, but immediately settle again, either on a contiguous tree or upon higher branches of the same. At New Jefferson, a little later in the year, when the gales had abated, they were seen leaving the groves in vast flocks, and scattering through the air almost beyond reach of the eye. They were observed as early as the middle of July, became common by the last of August, and increased in abundance until the end of September."
Can you picture that? Groves of trees, covered with monarchs. Not just the trees, but the groves themselves. And the sky filling with monarchs near Jefferson, Iowa.
When you picture that, are the groves larger than two football fields adjoining each other? Did the populations of butterflies in isolated groves of 1867 Iowa approach the entire population of monarchs in North America last winter?
We have lost so much of the magic....
Reference: Samuel H. Scudder, 1869. A Preliminary List of the Butterflies of Iowa. Chicago Academy of Science, Vol 1 Part 2, pp. 362-337.
August 16-31, 2013
The last half of August used to be the end of summer. Now it is the first part of the school year. All the experts seem to agree that children need to be prepared so they can better compete in the global economy. Missing that last chance to be outside must not be so important. So the kids can compete. But can they name ten common butterflies? Can they name ten local wildflowers? Can they name ten birds that are not sports mascots or hunted? They can compete, but does the contest really matter?
The end of August is a period of maturity in the butterfly season. Butterfly numbers are high. The diversity is also high. But maybe there are not so many new butterflies--the ones you see now have been present earlier in the season but in smaller numbers. Some you see now, particularly the large ones, may be the individuals that emerged a few weeks ago, and are now tattered and ragged. Others are the newly emerged from a second or third generation. Some are still dispersing north from areas to the south--they may have emerged in Texas and arrived here on the winds of a summer storm.
The common checkered skipper shown to the left was visiting a clump of semi-dry algae at the edge of a nearly dry pond. Checkered skippers become common in the late summer, and can often be found visiting goldenrod.
Many of the small skippers become common near the end of summer. You may be able to find Peck's skipper, fiery skippers, and sachems. Silver spotted skippers are normally fairly common in late August, but I haven't seen any yet this year. Least skippers are normally common as well, particularly in the tall grasses near ponds. I have seen a few of them, but they aren't so common this year.
Some of the whites and sulfurs do not overwinter in Iowa, but often become common late in the summer. Little yellows, dainty sulfurs, and common checkered whites can usually be found late in the summer, and I have seen all three this year. However, they do not seem as common as they have been in some years. A number of southern dogface were seen near Iowa City earlier this year, but I have not heard of them being sighted elsewhere.
Black swallowtails have been more common this year than in recent years. Giant swallowtails and eastern tiger swallowtails have been spotted reliably as well.
Summer azures and eastern tailed-blues have been the most common small blue butterflies this year, but watch for some of the others. Reakirt's blue can sometimes be found, especially in areas with leadplant. I have stumbled across the marine blue a few times as well. The melissa blue is found in prairies in the Loess hills.
Gray hairstreaks are making an appearance now, and can usually be found until the first frost.
Sometimes it is easy to concentrate on the rare and to forget about the common. Three of the most common of Iowa's butterflies are the cabbage white, the clouded sulfur, and the orange sulfur.
Orange sulfurs, like the butterfly below and to the right, are yellow below and yellow-orange above. Clouded sulfurs are slightly smaller and have a lighter yellow color above. They are two distinct species that interbreed, resulting in intermediate forms. You will see some that are clearly orange sulfurs, some that are clearly clouded sulfurs, and some that are somewhere in between. The white forms only add to the confusion, and can be confused with cabbage whites. In many years half of the butterflies you see in Iowa will either be clouded or orange sulfurs.
Pearl crescents have been pretty common this year, which is not unusual. Silvery checkerspots have been strangely absent. I have seen one gorgone checkerspot this year--I usually consider myself lucky to see one of them every two or three years.
Red admirals are making a pretty good appearance now--their numbers seem about normal for this time of year. Viceroys and red spotted-purples have been present recently--they seem to have shown up later than normal this year.
Buckeyes have been pretty steady this year--most times I have been out taking photos or doing a survey I have run across at least two or three.
There have been widespread reports that monarch numbers have been significantly down nationwide. I have seen a few--maybe some fewer than in other years, but my impression is that their numbers are not significantly reduced in Iowa, at least for this time of year. But it is really hard to say, and so many people are reporting greatly reduced numbers that there is probably something to it.
This time of year lots of things are competing for your time--school events, athletic events, and work. Take some time out to look for butterflies. Skip the competition over the global economy. Watch the butterflies in their competition over the hostplant economy.
Butterflies add a little bit of magic to our lives. Don't let that magic slip away.
August 1-15, 2013
We are well into the 2013 butterfly season. Numbers are lower than average this year, and some species have been conspicuously absent. However, as with every season, the numbers pick up late in the summer so there are at least some to observe.
We did have a long dry and hot spell that threatened to have a significant impact on the butterflies, but we probably avoided a crash with the recent rains and cool weather.
There is a set of butterfly species that do not spend the winter in Iowa, and do not have a two-way migration, but which populate the state on a reliable basis. Some, like the little yellow (shown to the left), American snout, and fiery skipper can have significant populations in the state almost every year. Others, like the cloudless sulfur and checkered white will show up in small numbers most years. Some are occasional strays--showing up once every five or ten years.
I have seen a few little yellows this year, and normally I would expect their numbers to increase significantly over the next few weeks. However, their caterpillar host plant, partridge pea, seems to be doing poorly this year compared to recent years. That may decrease the expected population boom.
Chris Edwards posted the results of a butterfly count near Lake McBride and Iowa City. They found 33 species, and among them were seven individuals of the southern dogface. Southern dogface butterflies among the occasional immigrants from the south, and are rare in Iowa outside of the Loess Hills region.
Shane Peterson posted results of a three and a half hour count in Monroe County on the Recent Sightings section of the North American Butterfly Association (NABA) web site. He found 42 species and 632 individuals. That is really good for Iowa, especially this year.
The casual surveys I have been doing in the suburb-like areas of the Camp Dodge Cantonment area have had near-normal numbers, but most of the butterflies I have counted there have been eastern tailed-blues. The normally common clouded and orange sulfurs have been present, but much less common than for most years. However, it seems to me that the butterflies that have had the worst problems with the drought and the late spring are those normally found in the understory of the woodlands. Question marks, northern pearly eyes, silvery checkerspots, viceroys, red-spotted purples, and hackberry emperors are in that group. I have seen a few individuals of the question mark and viceroy, but have yet to see any of the others this year.
The summer generation of red admirals has emerged. They are significantly larger than the red admirals you see in the spring. There is some really good information about red admirals and other Vanessa species on the website the red admiral research site created by Dr. Royce Bitzer.
I have seen only one or two individuals of the giant swallowtail and the eastern tiger swallowtail this year. There have been really good numbers of black swallowtails, however. Pipevine and spicebush swallowtails are both possible in Iowa, but are at the very edge of their ranges here and you probably will not see them here. If you want to see zebra swallowtails you need to go to the extreme southeast or southwest corners of the state. If you want to increase your chances, you probably need to go to the part of Iowa we call "Missouri."
Great spangled fritillaries have been pretty common this year, as have pearl crescents. Summer azures have emerged in good numbers, although their peak was about two weeks later than normal.
Buckeyes have been present in small but reliable numbers. They seem to prefer areas of closely mowed grass near areas with taller vegetation.
I have seen a few monarchs. Monarch numbers seem to be on the low end of normal for the year.
There were a few skippers around in the first part of July. I would expect to see some of the late summer species soon--fiery skippers and sachems normally become quite common.
Gray hairstreaks should be showing up soon as well.
Bull and tall thistles will start blooming soon, and they become a magnet for many of the large showy butterflies, as well as skippers. I have yet to see silver-spotted skippers, which are among my favorite butterflies, but they have been seen in some numbers in southern Iowa. They may just be late showing up--after all, this is the year we had a big snowstorm in May.
This time of year is always a good time to look for the occasional strays that only show up every few years or have not been recorded in the state yet. One that I think is very possible is the phaon crescent--it supposedly uses fogfruit as a host plant, and we have fogfruit in many locations in Iowa. This butterfly has been reported in more than one location close to Iowa, but not yet in Iowa.
The bordered patch was reportedly found in Jasper County, Iowa--see the Butterflies and Moths of North America website. I have my doubts about that sighting, however. It was identified by the caterpillar and not the adult. There seems at least one species (gorgone) that could easily be confused with it. But it was verified by an acknowledged expert.
The butterfly season is moving quickly. Soon it will be over. So get outside and chase butterflies. The window of opportunity will soon be closed.
July 16-31, 2013
When I wrote the last forecast, I was frustrated from spending hours looking for butterflies that just weren't there. I thought we were well into a pretty poor year for butterflies. The first few days of July made me change my mind, however. The butterflies are back. It took a while for them to show up again, but they are present in some numbers now.
Great spangled fritillaries had been reported in greater than the usual numbers from observations in southern Iowa, but I did not see my first until the third of July. Since then I have seen many. I have seen a number of species in the last few days that were absent earlier. This is still a slower than normal year for butterflies, but it is not a disaster.
I was able to visit a couple of prairies in southern Iowa recently--Rolling Thunder and Medora Prairies. When I visited them last year, in late July or early August, the vegetation was dry and crunched under foot, and there were no butterflies. This year the prairies are green and lush. Common wood nymphs are everywhere. So are pearl crescents. I saw several coral hairstreaks and one gray copper. A few little yellows were present, and several black swallowtails. But the stars of the show were the regal fritillaries.
Regal fritillaries are the showiest of the prairie obligate butterflies. Their caterpillar host plants are two species of violets found in Iowa prairies--Viola pedatifida and V. pedata.
Regal fritillaries are large dark brown butterflies with silver or white markings that are roughly triangular or diamond-shaped. They have a single generation per year in Iowa, but have relatively long lives, so they should be around for another month or so. Regals can be found on a number of prairies in Iowa, and it is worth your time to try to see them.
I spent time try photograph them at those two prairies, and had mixed success. I did get a number of good views of the regals, but they were quite restless and I never got close to one that was sitting down. The photograph below and to the right shows a regal in flight. They are quite easy to recognize, even if you only get a brief glimpse of one.
Large butterflies, like the eastern tiger swallowtail (shown above) and the giant swallowtail should be present in small numbers, but since they are large they will be easily spotted. Black swallowtails seem pretty common this year, more so than last year.
If you see a white butterfly, it will most likely be a white form of either the orange or the clouded sulfur. Cabbage whites can also be present though--they seem to like berms or banks of soil near water. Watch for checkered whites this time of year as well, too. I have not seen any yet but they should show up soon.
Migratory butterflies--red admiral, buckeye, monarch, and American lady all seem to be present in respectible numbers. Painted ladies seem to be absent this year, however.
Butterflies that immigrate here annually, like the cloudless sulfur, fiery skipper, little yellow, and dainty sulfur should be showing up any time soon. A huge irruption of American snouts was recently noted in Texas, so we might see some of them soon as well.
I noted a method to watch for some of the hairstreaks that show up for short periods annually in my June 16 forecast, which was to observe common milkweeds from a distance for a change in the circular form of the flowers that can indicate the presence of those butterflies. I find that method not to work so well now because we have a heavy infestation of Japanese beetles that gives lots of false positives.
Some butterflies have been notibly absent from areas they can usually be found. Viceroys, red-spotted purples, silver spotted skipper, and northern pearly eyes may show up soon, although normally they would have been seen by now. Of the skippers, I have seen a few Delawares, a few least skippers, and one crossline. Others may or may not show up soon.
Of course, eastern tailed blues will be present in good numbers, but they are small and easily ignored. Pearl crescents are common and will continue to be common most of the summer. Silvery checkerspots should show up in numbers in wooded areas (but that is another species which has been strangely absent this summer). If you are lucky, you may run across a gorgone checkerspot--they look like pearl crescents from above, but can be a little larger and are distinctively patterned below.
So do get outside and watch the butterflies. You will be glad you did.
July 1-15, 2013
We are well into the butterfly season--a time when butterflies normally become quite common. That has not been the case this year. No butterfly seems particularly common this year, and some that I usually see in some numbers I have not seen at all yet. A butterfly count in south east Iowa, at Shimek State Forest, reported fairly high numbers of great spangled fritillaries. I haven't seen any yet this year, however.
The great spangled fritillary is usually quite a treat to see. In the photo to the right, the darker female is on the left and the male is the lighter individual. The photograph was taken during a bioblitz for the Iowa Wildlife Center near the Ledges State Park. This was the first time I had observed this particular behavior in this species--presumably a pre-mating display. Both butterflies were hanging under the bergamot flower, and were trembling or shaking vigorously. They hung there for a while, then both took off at about the same time, and flew out of sight.
Last year we had a pretty serious drought. This year we had a late spring, and I think the combination of the two is causing the low numbers of butterflies. Is it being too optimistic to suggest that the butterflies will show up soon? I am not sure.
Clouded and orange sulfurs have been present in small numbers. Pearl crescents have been present--they are usually quite common, and can be seen now, but in somewhat reduced numbers. Eastern tailed-blues are fairly small and inconspicuous, but are at about normal population numbers.
Red admirals have shown up predictably in the evenings. I have seen small numbers of monarchs--probably about normal numbers for this time of year. I have also seen fairly good numbers of Delaware skippers lately. The rest of the butterflies have been sparse or completely absent.
Common milkweed is just starting to bloom here. I have not seen butterfly milkweed in bloom yet, nor swamp milkweed. Those flowers, as well as some of Iowa's dozen or so other milkweeds are magnificant flowers for attracting butterflies--watch them especially for the small hairstreaks.
This year has been notable for what butterflies have not shown up, or at least have not been common yet. I have not seen a single red-spotted purple, question mark, hackberry emperor, silver-spotted skipper, meadow fritillary, or a number of other butterflies that would normally have shown up by now. Perhaps they are just late, or mayby they did emerge but in greatly reduced numbers.
One butterfly that I think will show up within the next few weeks is the common wood nymph. It is a large butterfly that has subdued colors, but is quite variable in appearance. A number of years ago I trained some volunteers to conduct butterfly surveys, and collected the results for a number of prairie areas in the central part of Iowa. I was somewhat surprised to find that the numbers of common wood nymphs were higher than for any other species in those habitats in the middle of July.
The common wood nymph frequents areas with tall grasses or forbs. It will visit flowers for nectar, but it has a tendency to be somewhat secretive, hiding under leaves or deep within the vegetation. That can make it difficult to photograph, but sometimes you just get lucky.
It seems that this year observing butterflies may require more active searching on the part of the observer than other years have. You might have to visit some areas with natural habitat instead of just waiting for them to show up in your back yard. But butterflies are worth the effort. Go outside and look for them.
June 16-30, 2013
The extended cool, rainy weather has not been good for butterfly viewing. There was a streak of several days in which I have not seen any butterflies at all. Lately I have been seeing two or three per day with extensive searching. I expect that to change fairly soon, however, as the weather warms up and some of the mid-summer single generation butterflies emerge, and the second generation of butterflies with multiple generations per year join them. The numbers will pick up.
Over the next few weeks there may be opportunities to see some of Iowa's seldom-seen species, and the key to finding them is knowing where to look. Keep a close eye on the different species of milkweed, because they are very attractive to some of the smaller hairstreaks--banded, coral, gray, and Edwards hairstreak. If you visit prairies or savannas much you will be familiar with butterfly milkweed. Hairstreaks are especially attracted to this flower and stay on it for long periods of time. You may find several hairstreaks on the same flower cluster.
Common milkweed forms flower clusters that are roughly ball shaped. When hairstreaks are on them they can often be seen from great distances because there appears to be a dark triangle on the perimeter of the ball. You may have to inspect fifty or a hundred common milkweed clusters to find a hairstreak, but it is fairly easy to do from a distance, especially if you have butterfly binoculars. Usually the butterfly will stay on the flower cluster for an extended period of time, so you should be able to get to them. The butterfly to the right is a banded hairstreak, and it is on a common milkweed flower. The photo shows how the tiny tails on hairstreaks could easily distract a potential predator, and may seem to be the head end of the animal.
This website is dedicated to the Poweshiek skipper, Oarisma poweshiek. It was originally discovered on June 17, 1870. In recent years, its presence in Iowa was only in the northernmost counties in Iowa, and the initial emergence probably a week or so later. Look for it in prairie areas, especially prairies with minimal disturbance. I don't think it can be found in Iowa anymore, or in Minnesota. But it still might be found here, and now is the time to look for it. Keep your eyes open.
The three most common swallowtails in this area are the eastern tiger swallowtail, the giant swallowtail, and the black swallowtail. I have seen all three this summer, but in very small numbers. In addition, a number of pipevine swallowtails were seen in Shimek State Forest, in the south-east part of Iowa a few days ago. The pipevine swallowtail is normally very rare here.
Monarchs will be present, but will also be rare for a while.
As is usually the case, the orange sulfur should become common. I have seen a few so far, and expect them to become more numerous as the summer progresses.
Some of the nymphalids will start showing up in good numbers--the northern pearly eye, the question mark, the little wood-satyr, and the common wood nymph could all make their presence felt soon. As always, mourning cloaks can be present at anytime during the summer, but are usually not very common.
The normal emergence of summer azures seems to be a little delayed this year, but they will probably show up in the next few weeks. Summer azures are light blue butterflies which have a tendency to fly at high levels, which makes them easy to differentiate from eastern tailed-blues that fly nearer ground level.
I did not realize until recently that a butterfly I have run into was an Iowa butterfly. The gray copper was described by Samuel H. Scudder from specimens found in Iowa. In 1867 Mr. J. A. Allen collected butterflies in Dallas, Greene, and Audubon counties in Iowa, and some areas in Illinois. He sent his collection to S.H. Scudder, who published the results, along with descriptions of four new species. Two of those are recognized today--the Iowa skipper, now called Atrytone arogos iowa, and the gray copper, Lycaena (formerly Chrysophanus) dione. The other two were some kind of duskywing and an emperor, neither of which held up as new species.
Gray coppers seem to be pretty selective about habitat, preferring wetlands and prairies, but where they are found they are easy to see. They are pretty large for gossamer-winged butterflies, and are usually present in good numbers. The smaller bronze copper may be present in the same habitat.
Pearl crescents should be encountered in significant numbers in open field areas, and silvery checkerspots will be present in the more wooded areas. Gorgone checkerspots may also be encountered, but they are typically a lot rarer.
I have not seen a skipper yet this year, but there should be a number of them coming out shortly. The least skipper will be found around tall grasses near water. Peck's, Delaware, hobomok, tawny-edge, and dun skippers can be found in the typical old-field habitats found around Iowa. Silver spotted skippers, common sooty-wing, and some of the dusky-wing skippers, especially the wild indigo dusky wing could be encountered. Look for common checkered skippers as well.
If you happen along a gravel road in the morning while dew is still in the grass, or especially when the air is heating up right after a thunderstorm, look for butterflies in the gravel near the edge of the road. Concrete culverts can be another good place to look, especially where the concrete holds moisture for a while. Look for moisture loving butterflies near the edges of ponds and mud puddles.
Now that the weather is hot, butterflies can be seen at almost any time of day. So get out and enjoy them. Butterflies are a lot of fun.
June 1-15, 2013
Summer is here, and with it the summer butterflies. The variety of butterflies that can be seen is really starting to pick up, although the numbers are still low. As of May 29, 2013 I have seen 40 butterflies on my surveys. By way of comparison, I had seen 741 by the same time last year, and 17 by that date in 2011. Most years would have had some, but not a lot, more butterfly observations by this time. It is certainly not uncommon to be in the triple digits by now. Much depends on the weather.
This forecast features two butterflies that are very similar--in the same genus even, but are very different in appearance. Limenitis arthemis astyanax is the red-spotted purple (some people call it the red-spotted admiral). It is generally considered a subspecies of the white admiral, Limenitis arethemis arethemis. Both subspecies, as well as intergrades between them, are found in Iowa but the red-spotted purple (shown to the left) is by far the most common here.
Limenitis archippus, the viceroy, is shown below and to the right.
Both of our Limenitis species are mimics of butterflies that are toxic or distasteful to birds. The viceroy is a mimic of the monarch. The red-spotted purple is generally considered to be a mimic of the pipevine swallowtail, a poisonous butterfly that is common throughout most of the purple's range. In Iowa, however, the pipevine swallowtail is very rare, and the red-spotted purple might gain some protection by looking like the black swallowtail, which is not so rare.
Caterpillar host plants for both butterflies are tree species, notably willows and poplars, but other trees as well. The red-spotted purple and the viceroy are easily drawn to baits of rotten fruit, beer, and a variety of other sugary liquids. They can both be found drinking sap from trees. Both are magnificently beautiful butterflies and can often be found around the edges of wetlands or river banks.
In early June the variety of butterflies that can be seen picks up pretty well.
Three swallowtails and can be seen now in central Iowa. The black swallowtail is fairly common and is the most likely to be seen. The eastern tiger swallowtail and the giant swallowtail are not so common, but are large and very conspicuous, so if they are flying you will see them. You have to go to the extreme southeast or southwest corners of Iowa to be likely to see the zebra swallowtail.
The clouded and orange sulfurs are the most common midsize butterflies in Iowa, and you should not have to look very hard to find them. The eastern tailed-blue may continue to be common in the first part of June, then will disappear for a few weeks. The summer azure should become fairly common towards the middle of June.
Look for red admirals on tree trunks that are well lit by the sun just before sunset. They will be hard to miss as they bask up high and chase other butterflies that happen by. Question mark butterflies may also be seen basking in similar locations, but usually earlier in the day.
I have seen monarchs, but do not expect them to be common this early in the summer.
Pearl crescents will be very active, chasing each other in groups of two or three near some of the larger flowers. Wooded areas will have the slightly larger silvery checkerspot, and can put on a similar show.
Fritillaries of various kinds will start to show up. Great spangled fritillaries are large and readily visit garden flowers. Meadow fritillaries are smaller and can be common some years and absent in others. If there is a good prairie nearby you might want to look for the regal fritillary. Most prairie butterflies have been doing poorly in Iowa, but the regal has been doing better, being consistantly seen in some prairies in recent years.
Skippers should start showing up in some numbers soon--the large silver-spotted skipper, common sootwing, Delaware, Peck's, hobomok, and least skippers will be common at least in some habitats.
With the heavy rains we have been having you might find the window for observing butterflies to be small. They can often be seen in large concentrations within an hour after a thunderstorm, especially if the sun comes out and heats up the air. Watch for them along gravel roads or driveways at these times.
So be sure to get out and enjoy the summer. I know I will.
May 16-31, 2013
This spring has been unusual. I can remember several times when we have had frost in Iowa in the month of May, but I can't remember getting significant amounts of snow in May before this year. And I'm kind of an old guy.
Snow is not really good for viewing the butterflies--at least for most of them. I did notice that on the Wisconsin Butterflies site, Scott Swengel reported seeing three Compton tortoiseshells when the air temperature was around 50 degrees or slightly lower, and there was an average of eight inches of snow on the ground. Our snow went along with cooler temperatures and precipitation--not good for butterfly watching.
It seems to me that if you were to graph the numbers of butterflies over the season, most years would show two peaks--one that starts as early as March and then peaks in late May or early June, then another peak starting in mid to late June and going the rest of the summer. That is not a hard and fast rule--weather patterns have a great effect on the numbers, but it seems to hold true most years. This year I think we are still on the early, uphill part of that first peak. We are still seeing mostly the early spring butterflies--mourning cloaks, eastern commas, cabbage whites, red admirals, American ladies, and black swallowtails. We are starting to see some that typically come out a little later--pearly crescents and eastern tailed-blues (like the butterfly shown to the left), for example. The numbers that have been seen are still very low, but I think they will pick up fairly well by the end of this week (the week of May 12) if the weather forecast holds. By the end of the month, hopefully, we will be seeing a lot of butterflies, including some of the butterflies that are more typical of summer than early spring. I am (finally) starting to see a few myself.
One of the butterflies that shows for the first time in late May also happens to be one of my favorites. It is a large, fat skipper that typically lands on the edge of a flower and sticks its proboscis over the flower to get nectar. It is the lovely silver-spotted skipper, as shown below and to the right.
Clouded sulfurs should be showing up any day now--they are a fairly common species, and can constitute a large percentage of the total number of butterflies seen at any one time. Orange sulfurs will be showing up as well--in my experience they come out a little later than the clouded. Eastern tiger swallowtails and giant swallowtails should be present in small numbers, the they are so showy and conspicious that if one is present you will be likely to see it. Great spangled fritillaries are also large, showy butterflies, and I would expect to see them by the last week of May at least, and possibly sooner.
Monarchs should start showing up by the last couple of weeks of May, and buckeyes as well.
One of the treats of this time of year is the appearance of some of the smaller skippers. The hobomok skipper can be found in domestic gardens, as can Peck's skipper, the tawney-edged, and the Delaware skippers. The common sootywing and the common checkered skipper are not rare, and both can show up now.
It is a lot of fun to walk out in the wild when butterflies are everywhere. Sometimes they are not so common, however. Then you have to search a little more. But when you do see the butterflies, the effort is worth it.
Be sure to get outside. You will be glad you did.
Until next time...
May 1-15, 2013
The seasons seem to be a couple of weeks later than normal this year. Maybe if I just repeat the butterfly forecast from last time it will be pretty close. But I really hate to do that.
As of April 29 of this year I have seen exactly zero butterflies. Nada. Zilch point nothing. And that is unusual for any year.
But we haven't exactly been having days that are good for butterflies. And other things have come up for me in the good days that we have had. The closest I came to seeing a butterfly was that I found the wing of a red admiral on a woodland floor--it looked to be fresh enough to be from this year, but how can you be sure?
There have been reports from others who have seen some butterflies, although the reports have proven to be less than what would normally be seen this time of year. The most I have seen reported was seven species and 24 individuals by Thomas Jantscher and Frank Olsen. They saw a Henry's elfin and a Juvenal's duskywing, in addition to the more common black swallowtails, red admirals, spring azures, cabbage whites, and mourning cloaks. Twenty four butterflies might seem like a lot, but it took them five and a half hours to see them. That is an average of about one butterfly every 15 minutes. That is a pretty slow rate for this time of year, especially for two of the top butterfliers in Iowa.
The butterflies are pretty sparse now because of the cool wet weather we have had, but the drought of last year might have reduced this year's crop as well.
Butterflies are pretty resiliant, and their numbers should rebound pretty well this season, given good weather, but it may take a while. Of course, if you look at the land use patterns in Iowa, it becomes apparent that the numbers we are accustomed to seeing are only a tiny fraction of what we would see if the vegetation patterns prior to European settlement persisted.
In addition to the seven species mentioned, we should see painted and American ladies, eastern tiger swallowtails, and eastern commas.
The clouded and orange sulfurs should start showing up--in my experience, the clouded sulfur appears before the orange. We should be seeing pearl crescents soon as well.
The most common of our blue butterflies, the eastern tailed-blue, will have a generation emerge. Usually they are not particularly common in the spring. Males, with their dark blue upper wings will appear first, followed within a day or two by the females with their brown upper wings. Then, depending on the weather, eastern tailed blues will disappear for a while and reemerge in significant numbers later in the summer.
It is still a little early for many of the small skippers, although you might see the dark black common sooty wing flitting around your yard. If the color black can be thought of as brilliant, it surely is on this butterfly. Though small, the black coupled with the white spots make this a very beautiful insect.
Other skippers that you might see include the tawney edge skipper and Peck's skipper.
Viceroys and red spotted purples can often be seen in the first part of May, but my guess is that they will be a little later than that this year. Meadow fritillaries are common some years and rare in others. If this is a good year for them they might show up now. Also, look for question mark butterflies.
Bronze coppers are typically not too common, but they might start showing up in mid-May. Even though they are small, if they are around you will probably notice them because they are spectacularly beautiful.
Already we will be losing windows to see some of the butterflies. If you don't see a Henry's elfin or an Olympia marble in the next couple of weeks you will probably have to wait until next year to see them.
So make a point of getting out in nature to enjoy the scenery. You should see some butterflies. But if you don't, enjoy the birds and the wildflowers. Listen to the frogs sing.
You owe it to yourself.
Until next time...
April 16-30, 2013
I saw three reports of butterflies seen in Iowa in March, and a few in the first part of April while we had some warmer weather. Then it turned cold again and none were reported.
The Wisconsin Butterflies website had no butterflies reported for March, but had a number reported for early April. Those butterflies were mostly mourning cloaks with a single cabbage white as well.
The last half of April will show a steady increase in the number of common butterflies that might be seen, and there are a small number of rare or seldom-seen species that add to the excitement of the hunt.
We should be seeing mourning cloaks, eastern commas, and question mark butterflies. Less common butterflies within the guild of those that over-winter as adults could include Milbert's and compton tortoiseshells--not common in central Iowa, but more so as you go east and north of the state.
The butterflies that may be common enough to be seen in the middle of this month include the spring azure, the cabbage white, black swallowtail, and eastern tiger swallowtail. By the last week in April and the first of May, we might see clouded sulfurs and pearl crescents (like the one shown just to the right).
There are a number of butterflies that migrate or immigrate into the state each year. Their numbers can fluctuate wildly, as they depend on summer winds associated with storms to bring them north. Red admirals, painted ladies, and American ladies might show up in fairly significant numbers. The American lady, shown below and to the left, has two large eyespots on the underside of its hind wings. The painted lady usually has four or five smaller eyespots.
Last year I saw dainty sulfurs in late April--I saw them first on a trip to The Ledges State Park, and later it seemed they were everywhere. I think, however, that 2012 will prove to have been a highly unusual year for that species and we won't see this species in Iowa until late in the summer this year.
There are some rare species to look for now, as well. I have seen and photographed most of Iowa's butterflies, and recently photographed some which are occasional or rare in Iowa in other states, but there are still some which I have yet to see.
The Olympia marble is a small white butterfly with beautiful green markings on its underside. It has one generation in Iowa. It can be found from late April through May. It is mostly found on the western tier of counties in Iowa, although I have reports of it being seen in The Ledges and even in Ames along the railroad tracks near North Dakota avenue. I have yet to see this one, and I hope to soon. Look for it low to the ground, in areas that have wild mustards growing. Rock cress is reported to be a host plant.
Henry's elfin is a small, brownish colored hairstreak which has one generation per year in Iowa. It has been found mostly in the southern part of the state, and its caterpillars feed on redbud. This butterfly can also be found from late April through May, mostly on its host plant. I have yet to find this one for myself--maybe I will get lucky this year.
The juniper hairstreak seems to have two generations per year in Iowa. Its host plant is eastern red cedar, and that can be found everywhere in Iowa. However, the butterfly does not seem to be all that common, or all that easy to locate. This butterfly seems to use the upper branches of tall cedars as a roosting point, and others have reported success by beating those branches with a net or a stick to get the butterflies to fly. I have tried that myself with no luck. I have seen this butterfly and photographed it, but I also want to get better pictures--this is one of our most beautiful butterflies. I have searched long hours for it, and I have not figured out a way to locate it reliably. The only times I have had success with this butterfly have been with the early brood--late April or early May.
Perhaps one of Iowa's most enigmatic butterflies is the white M hairstreak. This butterfly looks similar to the gray hairstreak below, although there is a distinctive white dash near the leading edge of its forewings. The dorsal surface of the wings of this butterfly are a brilliant blue, unlike the subtle shades of the gray hairstreak. The white M hairstreak may have three generations in Iowa, although it is only rarely seen. Perhaps Iowa is the extreme northern edge of the range of this butterfly, and it really is rare here. There has been some speculation that the white M hairstreak is a butterfly of the canopies, particularly of oak forests or savannahs, and is possibly more common than its sightings would indicate. There have been a handful of sightings in Iowa, and seeing this butterfly is a pretty big deal.
So get out and enjoy nature. Watch for the common butterflies and search closely for the rare ones. Enjoy.
|April 1-15, 2013|
So much of March was almost warm enough for flowers to start bursting out, and almost warm enough for butterflies. But the rest of it was cold and snowy. I may have been overly optimistic, thinking we might see butterflies in March. We will see if there are any last minute entries, but as of now I have not heard of any sightings of butterflies in Iowa yet.
The first of April usually has similar episodes--warm sunny days mixed in with the cool and rainy. Hopefully, the winter weather is behind us and the flowers and butterflies will soon be seen. I have seen crocus blooming, and that's a good sign.
We will see the butterflies which over-winter as adults when the weather is warm enough to encourage them out--mourning cloaks, eastern commas, and question marks. Other butterflies within this group are rarer, and less likely to be seen in central Iowa. They include the gray comma and Milbert's and Compton tortoiseshells.
Another group which should start making an appearance now are the butterflies that spend the winter as pupae. The first of this group that you are likely to see is the alien import cabbage white, shown here to the right. It is still about a month too early to see the equally alien dame's rocket that this butterfly is drinking nectar from, but the cabbage whites will be seen in sunny areas.
Spring azures will be seen flying several feet up in the trees of wooded areas. Black swallowtails and eastern tiger swallowtails may also be seen in this time frame.
Migratory butterflies may show up, carried by warm southern winds associated with thunderstorms. This group includes the red admiral, painted lady, and American lady. Red admirals are showy, conspicuous butterflies but they are also capable of disappearing on the forest floor, especially when they close up their wings like the red admiral shown below and to the left.
Some of the spreadwing skippers may show up in early April. The sleepy duskywing seems to have one generation in Iowa, and it can be found in oak forests in the early spring. Juvenal's duskywing is similar, and might be found in the same habitats.
This year seems to be warming up a week or two later than normal, and the difference is especially noticeable because last year was so far ahead of normal. It does have a tendency to balance out, however--hopefully this year will not be as dry or as hot as last year.
Warm weather should bring with it good numbers of butterflies, and a walk in a wooded area with good spring ephemerals will also have a nice population of butterflies.
I was fortunate enough to attend a conference at the Minnesota Zoo on the conservation of rare tallgrass prairie butterflies earlier this year. The Poweshiek skipper was featured prominently at this conference, as were other rare prairie butterflies. There were many people in attendance who have pretty good experience in conservation efforts for rare butterflies, and I was encouraged to see the effort and talent expended in the cause.
I think we need to look into conserving the butterflies that we consider common as well. We humans greatly modify our environment. We have been modifying the environment in small, incremental ways over a long period of time, and now those changes are seen as the normal state of things.
When we grow monocultures of crops, there is very little habitat left for butterflies, so that land produces few or none. When we grow monocultures of closely cropped grass, there is little to no butterfly habitat there as well. We are slowly getting wiser with our roadside ditches--planting prairie plants as part of an integrated roadside management program, rather than grasses or alien plants like birds foot trefoil.
So the challenge is this--rather than only conserving butterflies by setting aside and managing pristine habitats (which are increasingly rare), can we manage the existing modified landscape in such a way as to increase the quantity and diversity of butterflies?
One type of highly modified "habitat" that seems ripe for this approach is the storm water detention and retention structures that are increasingly mandated by regulations and green building management practices. Some of these structures seem to be obviously good butterfly habitat, (and I have surveys on some that show it) and others seem pretty poor in that regard. Perhaps with some attention to detail the poor habitats can become good. My impression is that new construction results in a lot of these structures and that typically the people who own them do have not given a lot of thought as to how to manage them.
We also see the brave individuals who buck the status quo and plant prairie or woodland plants in areas that others would only have mowed grass. They can have yards that are full of butterflies. Perhaps in a few years the idea will catch on with more people will do it.
If we could compare the numbers of butterflies we have now to what would have been present in the past, what would we find? I feel fairly comfortable with saying we may only have a tenth of what we would have had in the past, but the number could easily be an order of magnitude two less.
Conservation is a long term task. Enjoying butterflies is a short-term pleasure. When the sun comes out and heats the woodlands (and it will soon), get out there and enjoy them. Look at the spring ephemeral wildflowers--hepatica and snow trillium should bloom with the next sunny day, and the host of others which follow. Smell the smells of the forest. It will do your heart good.
|March 1-31, 2013|
| The butterfly season in Iowa usually starts
in March. Since the first butterflies that are seen each year
spend the winter as adults, it is possible for butterflies appear
outside on an especially warm February day, or even in January, but I
have never seen it (yet).
The weather does have to warm up a little bit. But once it does, you owe it to yourself to take a walk in the woods. Hopefully the frost will be gone, leaving the ground soft but not soggy. Mosses will be bright green. Some trees will have started to leaf out, and the first of the spring flowers will be blooming.
Every year it seems the first flowers to bloom are the same species. In the woodlands they are hepatica, snow trilliums, and pussytoes. In the prairie they are pasque flowers. In my yard I watch for crocus. Same spot, same purple crocus. But it is always exciting to see the first one.
The situation is the same with butterflies. The first butterfly you see each year is likely to be one of the same seen first every year. In Iowa, that is usually either a mourning cloak or an eastern comma. Maybe you can add the compton and Milbert's tortoiseshells to that list, but in my experience the tortoiseshells are not common in the areas I can get to.
The questionmark butterfly should, in theory, be part of that list--it also spends the winter in the adult stage, wedged into some crack in the bark of a tree or under the leaf litter. However, the question mark always seems to come out later than the others.
The sighting of the first butterfly is associated with the weather at this time of year as well. Recent first sightings have occurred as early as the first week of March, and as late as the last week.
Watch the sides of tree trunks for a little bit of moisture--sometimes sap leaking from a wound in a tree attracts the butterflies.
You might see little holes in the bark, usually several holes in a row that almost look like a human must have put them there with an electric drill. These are not the work of humans, however--they are the work of a small woodpecker called a sapsucker. Sapsuckers make the holes, and then come back to collect the insects that are attracted to the sap. How many times the first butterfly of the year has ended up as a sapsucker meal is not known.
The good butterfly days can be few and far between in March. I have to admit that some days when I am busy at work and the sun is out my mind is not really on the work. In my mind's eye I am walking through the woodland and I am feeling the sun on my face. I am watching high up in the tree trunks for the little flash of orange that shows the eastern comma.
If spring arrives early enough we might see other butterflies in March. The butterflies that overwinter in the pupal stage, especially cabbage whites, black swallowtails, and spring azures could make an appearance. More likely, they will not show up until April. Last year we had a very early spring and had red admirals in March. Other migratory butterflies, like painted and American ladies could also be possible, but I think they would be unlikely so early in a normal year.
There is something magical about the change of seasons. I know here in Iowa we complain about the winter a lot (and we generally have a good reason). But going out during the first warm weather week of the year is a magical experience, especialy if you can make it to a good woodland. The air gets a fresher smell to it, the colors start to brighten, and the birds sing a different song. Maybe the chorus frogs will be singing.
So bring on the spring and the butterfly season. I can hardly wait.