Saturday, August 28, 2010

Yellow Butterfly Population Explosion

It happened again this week, the second time this summer.  Hundreds of Clouded Sulphur butterflies floated over the alfalfa fields and puddled along the roadsides in west-central Wisconsin.

They frequented the goldenrod nectar bar too.

Clouded Sulphurs are one of the most common butterflies in Wisconsin.   They've been spotted as early as March and as late as the first week in November.  They have several broods in a season and overwinter here - but not as an adult. 
The last time these insects caught my attention, I wondered why haven't I seen any predators feasting on them?

I pulled to the side of the road and looked for predators and signs of predation.

I found dozens of yellow butterflies, hit by cars, dead on the road.  I also found little piles of wings (with no bodies) - but saw no predators (birds, dragonflies, frogs, rodents and mantids) in action until we were just about ready to head back home.

I stopped to take this picture of a very small and flitty, Eastern Tailed Blue. 

It was hot (87-degrees F) and the mosquitoes were merciless, so I gave up with the photography and headed back to the Prius.  As I was buckling in, my husband said:  look - there's an Eastern Phoebe, eating a sulphur!

We watched as the phoebe grabbed one of the sulphurs "puddling" just a few yards from the car.  The flycatcher whacked it on the ground and left the wings behind as it flew off to perch in a nearby tree.

Other sightings:

American Lady
Gray Comma

Red Admiral
Cabbage White
Hackberry Emperor
"Summer" Spring Azure
Question Mark

Wednesday, August 25, 2010

Abnormal Bluebird Eggs

When I took this photo a few weeks ago, I didn't notice anything out of the ordinary.  I was happy to see 5 Eastern Bluebird eggs in a nest box that had not been productive this season. 

I didn't take them out of the nest box for a close inspection.

Next time I looked, 3 had hatched.   If the other 2 eggs were going to hatch, it would happen soon.

Two days later,  I went back to check on them.  The chicks looked good, but the eggs were cold.   That's when I took them out for a closer look.

"normal" bluebird egg and 2 "runt" eggs
While I'd never seen one before, I knew right away one of the eggs was a "runt."  It was round and about half the size of a normal bluebird egg.  I didn't realize the other egg was abnormally small (by 25%) until I compared it with a "normal" bluebird egg.  Both had tiny yellow yolks - but no sign of an embryo.

What causes dwarfed eggs?

Scientists don't know for sure.

But "runt" eggs are not as unusual as I thought.  The Western Foundation of Vertebrate Zoology has more than 1,000 in their collection.  And "runt" eggs have been found in most all species - not just bluebirds.

While they may not "know" much about them, scientists have correlated the occurrence of "runts" with the age of the female (younger birds are more likely to lay them) and a temporary impairment of the reproductive tract.

They don't believe it's an inherited trait, despite the 1983 report by my old friend Larry Zeleny (founder of the North American Bluebird Society).  Larry observed a banded hen in that laid 4 runt eggs in 3 separate clutches in one season.

Next time I find an abnormal egg, I'll contact the NABS to find out who might want to study it.

Friday, August 20, 2010

Xcel Energy - Tyrone Property

Ever since I "discovered" Wisconsin's Rustic Road 107 three years ago, I've made a point of taking that route when I go to Eau Claire.  I can't resist its easy access to the wild nature of the Lower Chippewa River.

During the week, I am dazzled by the mix of prairie, farmland and floodplain forests and the rich diversity of wildlife - the colors, sounds and smells.

But I try to avoid R107 on the weekends.   Why?  Too much noise.

Apparently the word's been out that this is one of the few places in Wisconsin where there are no restrictions on public use. 

I'm put off by the ATVs tearing up the woods and wetlands, the after-market exhaust pipes that rev up motorcycle noise and the deafening howl of air-boats on the shallow Lower Chippewa River.

Most of the property that attracts ATVs is owned by Xcel Energy.  They're the big land-owner along the Lower Chippewa River.  Over the years, there's been talk that the power company will build a coal-fired power plant on the site (known as the Tyrone property). 

A couple of years ago, at the urging of a local environmental group, Xcel Energy put up signs along the road acknowledging that they are the property owner, and that they have rules for public use (which is limited to walking, hiking, hunting and snowmobiles on designated trails).

Last week, Xcel tacked a memo onto a tree (think "Robin Hood" and "Sherwood Forest") near a dirt road.  The memo clarified the rules:  horseback riding is not permitted.

Okay, there are rules.  But who's enforcing them?

I found out today.

On my way to Eau Claire this morning, I spotted a motorcycle behind me on R107.  I slowed down to let it pass, and was surprised to see the rider slow down and stop by my car window.   It was the man who enforces the rules.

Conservation Warden Wayne Flak was riding a "new" military surplus motorcycle.  I introduced myself and thanked him for patrolling my favorite Rustic Road.  He explained that Xcel and the DNR were stepping up enforcement.

Great News!

Wednesday, August 18, 2010

Eastern Bluebird Egg Color

Earlier this season a neighbor up the road near Durand called to tell me about the 3 white eggs in one of her bluebird nest boxes.

Bluebird eggs are usually blue.  Tree Swallow eggs are white.

I asked:  Could they be Tree Swallow eggs?

Tree Swallow Nest

No, she said.  It's a bluebird nest.  There are no feathers lining the nest.  I've seen bluebirds going in and out of the box.

White bluebird eggs are unusual, but not unheard of.   Curious, I went over to take a look.

White Eastern Bluebird Eggs

No doubt about it.  She had white bluebird eggs.

As it turned out, this would be the first of 4 nests with white eggs this season.

That got me thinking.

Why are bluebird eggs blue?  Don't most cavity nesting birds - songbirds, Belted Kingfishers and Wood Ducks - lay white eggs?  How do bird color their eggs?

Beyond genetics, some the explanations for egg color seem obvious.

Speckled eggs makes sense for Killdeer, who nest on the ground, or Yellow Warblers who lay their eggs in open nests.  It’s more difficult for predators to spot eggs that blend in with their surroundings.   

But why would cavity nesting House Wrens, who also lay speckled eggs, need to camouflage them?

Scientists at Oxford University recently suggested a completely different explanation for speckled eggs.   They hypothesized that the speckles might increase shell strength, compensating for thinner egg shells caused by calcium deficiencies in their diet. 

The scientists looked at eggs of the Great Tit (Parus major) and found that eggs with the thinnest shells had the most speckling.  And the thinner the shell, the darker the spots.  They concluded that chemicals in the speckle pigment may work like glue, supporting weak areas of shell, protecting them from breaking.  

But what about those plain white eggs?   

There seem to be obvious advantages:  in the low light of tree cavities and tunnels, white eggs should be easier to spot; and it takes less energy to lay a plain white egg.   

The “less energy” hypothesis has to do with anatomy and biochemistry of the hen’s oviduct.   It’s complicated, but here’s the simpliflied version.  As eggs are laid, glands along the hen’s oviduct deposit pigments on top of the basic white shell, comprised primarily of calcium carbonate - a mineral found in chalk, limestone and marble. 

The amount of pigment and the timing of pigment release determine the base color of the egg and its distinctive markings (the speckle pattern).   As the egg enters the oviduct, the first pigment released creates the base color of the egg.   Blue and green are created by pigments known as the biliverdin and the zinc chelates.
According to the North American Bluebird Society, in 5-9% of reported nest observations, bluebirds laid clutches in which the eggs were a uniform, lighter color – white, pale pink or pale blue.  

It was once believed that laying white eggs was a genetic trait – like blue eyes and brown eyes in humans.  Bluebird hens that lay white eggs, will always lay white eggs.

But now there's a new theory about egg color in bluebirds:  it  may be an indication of the health of the female that triggers a higher level of paternal care from the males.  Older females and females in better body condition lay more pigmented blue-green eggs.

Perhaps the stress brought about by cold and wet spring weather had something to do with the increased incidence of white bluebird eggs in our nest boxes this season.

Saturday, August 14, 2010

A Painted Lady

At first I thought it was just another Red Admiral butterfly.  (I've see hundreds this summer).  Same size.  Same stutter-flutter.

I pulled off the road and pushed the park button.   I hopped out of the car with my camera, and hoped the butterfly would sit still log enough for me to get a photo. 

Painted Lady - Vanessa cardui

I knew it was something else when it opened its wings.   My first thought was:  Painted Lady.  I'd never seen one before, other than in books.  So I pulled out my iPod and took a look at what Mike Reese has to say about them (on the Wisconsin Butterflies iPod app).

The Painted Lady is the most widely distributed butterfly in the world.  They're found on every continent except Antarctica and Australia (and New Zealand).  However, it's the least common  of the three Vanessa sp. in Wisconsin.  The other two are Red Admirals and the American Lady. The Painted has 4 eye spots on the hind wing, the American has two.

Like the Monarch, the Painted Lady is a migrant.  But unlike the Monarch, it's a sporadic (irruptive) migrant.  In the Western Hemisphere, Painted Lady butterflies are common in the deserts of the American southwest and northern Mexico.   Scientists believe rainy periods in the desert trigger their migration north. 

While Monarch larvae feed solely on milkweed, Painted Lady caterpillars are known to feed on more than 100 species, including thistle (cardui is Latin for "of thistle"), legumes (including soybeans), asters and mallow.  

Send your sightings of this species to the Vanessa Project at Iowa State University.  Check out their website.

If you're interested in raising Painted Lady butterflies, you can purchase a kit (insects and food).


Other butterflies spotted today:

2 Eastern Tailed-blue and a "Summer" Spring Azure
Black Swallowtail
Cabbage White

Checkered White (male)

Eastern Tiger Swallowtail
Mustard White
Clouded Sulphur
Orange Sulphur
Northern Crescent
Question Mark
Eastern Comma
Milbert's Tortoiseshell
Red Admiral
American Lady
Common Buckeye
Hackberry Emperor

Thursday, August 12, 2010

Goldenrod Soldier Beetles

Looking for a breeze and cooler temperatures, I hopped in the Prius and took a spin through the coulees east of the Lower Chippewa River.

Great Lobelia

I didn't find respite from the heat, but I did spot Great Lobelia, several species of goldenrod and a new (for me) insect on the flower of a Cup Plant Silphium perfoliatum, a very tall (6-8 ft), plant that looks like a sunflower, named for the water-catching cup created at the stems where the perfoliate leaves meet.  Look for American Goldfinches getting a drink of water from these cups.

Cup Plant flower
Cup Plant "cup"

I could identify the flower from a distance, but not the insects.

At first glance the copulating insects looked like fireflies.  When I got close enough to take a photo, I didn't see the luminous abdomens of lightning bugs.  I'd need a good photo and some time with the Peterson Field Guide to the Insects.

When I got home, I went to the insect guide and looked up lightning bugs.  My mystery insect was right there - on the same page, one beetle to the right:  a Goldenrod Soldier Beetle, Chauliognathus pennsylvanicus.

While I've never noticed them before, according to Extension entomologists they're common this time of year.

There are more than 1,000 species of Soldier Beetles world-wide, less than 200 in the US.  Also known as Pennsylvania Leatherwings, their soft wings are leather-like.  The name "soldiers" comes from their color patterns which resemble a military uniform.  Look for them on goldenrod flowers.

The adults are omnivorous, they feed on pollen, nectar, grasshopper eggs, maggots, small caterpillars and aphids. 

They overwinter as larvae.  Like Box Elder Bugs, they can be a nuisance when they end up in your basement looking for a place to over-winter.

Tuesday, August 10, 2010

A Bat in the House

My neighbor, Vicki, called this morning.   I hate to bother you, she said, but I have a problem and I need your advice.  I've had three bats in the house the past week.  I can't believe I'm the only person with this problem.  What can I do about it?

Vicki lives in a relatively new log cabin (with a sloping metal roof).   The bats, probably Big Browns (Eptesicus fuscus), found the conditions (temperature and humidity) between her metal roof and the wood beneath it - just right for raising pups.

The bats probably got in through a tiny gap in the outside soffits - and voila! - the log cabin was transformed into a bat nursery.

Having bats around is actually a very good thing.  They go out at night and eat moths and other nocturnal insects, then turn them into nitrogen-rich fertilizer (guano).

But the recent record-breaking temperatures have created a problem for the bats.  When it gets too hot for them, a juvenile bat looking for a cooler roost falls through a tiny gap between the roof and ceiling - and ends up in the living room.   From the bat's perspective - it can become a frightening "Alice in Wonderland" experience.  From the human's perspective - it can become a frightening "trapped in a room with a bat" experience.

So, what's a homeowner to do?

Recalling what little she'd heard about bats throughout her life, Vicki admitted she was afraid of the health risks (rabies).  She didn't want to kill them, but she needed some reassurance.

After I explained the facts about rabies, the statistics and the risks, she decided the best thing to do is "help" the bats find their way back outside.

Here's what to do:

Turn off the fan.
Open the interior (and exterior) doors and windows/screens - to create a draft.
Turn on the lights (so both you and the bat can see better).
Stand by a wall.
Wait for the bat to land.

Don't hit it with a broom.  Put a thick towel in your hands.

When it lands - talk to it gently (think:  dog whisperer) as you approach.

Cover it with the towel and gently scoop it up.  Take the towel (and bat) outdoors and put it on a table, fence post or tree branch.  The bat will crawl out and fly away.

Both of you can survive - unscathed.

Consider yourself fortunate to see bats in your neighborhood.  Check out this link about regional extinction of bats.

Sunday, August 8, 2010

Watching Butterflies Through Binoculars

I spent the afternoon watching butterflies.

All I needed was my close-focus  Bushnell 7x26 Custom Compacts, my iPod (with the Wisconsin Butterflies App) and cup full of ice cubes.  

With the temperature hitting a record high of 96 and unbearable humidity after last night's storm, I expected to see lots of butterflies, in all the usual places.

I spotted 15 species - sunning on the roads, nectaring on wildflowers along the roads, feeding on scat and puddling on moist sand and mud.

I spotted hundreds of Clouded Sulphurs flitting over the alfalfa fields, nectaring on roadside wildflowers and congregating at puddles.

A surprise puddle of Mustard Whites on wet sand.  (Their larval food plants are in the mustard family - Rock Cress and Toothwort).

A dozen or so Milbert's Tortoiseshells along Dunn County Road "O" east of Meridean.  Not a surprise with all the larval food (nettles) in the ditches.  The adult Milbert's nectar on thistle and goldenrods - both starting to bloom.

I spotted Monarch Butterfly eggs and larvae, a pleasant surprise in view of the recent highway mowing.  I was sad to see all the adults dead on the road.

At first glance, I thought this Common Buckeye was just another Red Admiral.  A migrant in Wisconsin, it's the first I've ever seen other than on a postage stamp.  Their favorite nectar flowers are just starting to bloom - asters, chickory and knapweed.  Their larval food plant is plantain, gerardia and toadflax.

The other species on my list include: 

Question Mark

Eastern Comma
Red Spotted Purple


Hackberry Emperors
Northern Crescents
Eastern Tiger Swallowtails
Black Swallowtails
Eastern Tailed Blues
Red Admirals

Friday, August 6, 2010


Heat and humidity, poison ivy, mosquitoes, ticks and chiggers - the challenges of going outdoors in August.

I can tolerate the heat and humidity - my Prius air conditioner puts out a good chill.
I watch where I walk - and avoid touching the three shiny leaves.
The mosquitoes are a major, but temporary annoyance.  Buzz, swat.

But when I don't put my pant cuffs inside my socks (and spray with DEET) ... sooner or later, ticks and chiggers are going to get me.

I've had a couple of ticks this summer, but it's been a long time since the chiggers had me for lunch.  And yes, I'll admit it:  I asked for it when I ignored my rule about the DEET.

I just didn't think I was at risk.   I wasn't planning to go off into the woods - just to the edge of the road.  No ticks, no chiggers there.  Right?


I woke up this morning with itchy chigger bites - on my thighs and waist.

So how do these tiny, red "mites" make those itchy red bumps that drive me insane?

Chiggers - also known as harvest mites - are 8-legged arachnids about the size of a pin head.  Unlike mosquitoes, their 6-legged microscopic larvae are not after blood - they want your skin.  Like ticks, they lie in wait for you, and when you brush by, they hop on,  find your skin and sink their mouth parts into you.  Their saliva has a chemical that liquifies your skin, allowing them to suck it up.

When they're through with you (or when you brush them off), they return to the soil and continue with their metamorphosis. 

The nymphs and adult chiggers feed on soil insects and mosquito eggs.  How's that for irony?

Meantime, I'll be itching for several torment-filled days - however long it takes my body to get rid of the chigger larvae's skin-liquefying enzymes and replace my damaged skin cells.

I read somewhere that putting nail polish on the "bite" suffocates burrowing critters.  No so.  (They don't burrow).    The best treatment is a soap and water - then an anti-itch cream (calamine lotion, hydrocortisone, etc).

The best "treatment" is precaution.  Chiggers are everywhere - even along roadsides.

Use that DEET!  Shower when you get home (don't wait).

Thursday, August 5, 2010

Early August Butterflies

I was in a roadside ditch with my little Sony Cybershot, photographing a "mystery" mint for later identification, when a black sedan stopped next to my Prius.  I thought maybe I was blocking the road, so I headed back to apologize (and move my car).

I was pleasantly surprised to see my neighbors, Andrea and her son Rocco (the field scientist), in the sedan.  She was on her way to take Rocco to "camp" in Pepin, and stopped to say hello.

Rocco said he had something to show me as he hopped out of the back seat, opened the passenger side door and pulled out a green wire mesh bucket.

Look, he said:  know what it is?

I'd never seen one before - a Black Swallowtail butterfly caterpillar.

Rocco's butterfly cage was full of parsley, this swallowtail's larval food.  They also eat Queen Anne's Lace, which had been plentiful along the roadsides until the county road department mowed this week.

That caterpillar was a harbinger of what I would see today - lots of butterflies:

Question Mark
Clouded Sulphur
Eastern Tailed-Blue
Eastern Tailed-Blue
Eastern Tailed-Blue

Milbert's Tortoiseshell
Milbert's Tortoiseshell
Red Admiral

Hackberry Emperor