Archive for the 'Phenology' Category

Apr 10 2012

Out of Synch

After stunningly warm temperatures in mid-March, Nature hit the pause button and produced lower than normal temperatures for more than a week. That hasn’t been enough to halt the onward march of plant development.

Trees are leafing out four weeks early and the insects that eat them are hatching too.   Tent worms are a case in point.

Eastern tent caterpillars (Malacosoma americanum) feast on trees in the Rose family, especially wild cherry, apple and crabapple.  Last summer the female moths laid their egg masses on the branches of host trees.  The eggs remained dormant all winter and then, just as the hosts’ buds began to swell, the eggs hatched and the larvae began to spin their tents.  In the past this happened in early May.

This year I saw the first tiny tent on April 1 at Moraine State Park.  A week later I found this much larger tent crawling with activity.

Most birds won’t eat tent caterpillars because they retain cyanide from the host plants but cuckoos eat them with relish.

Black-billed and yellow-billed cuckoos spend the winter in South America and time their arrival to coincide with the emergence of eastern tent caterpillars.  A few yellow-billed cuckoos have been seen in the Gulf Coast states but the bulk of them aren’t in North America yet.  The leaves and tent caterpillars are four weeks ahead of schedule but the cuckoos are not.

What will happen to the cuckoos when the tasty caterpillars they expect to find have retreated to cocoons?  What will happen to our trees if this causes an excess of caterpillars?

Nature is out of synch.  Some things can cope, some cannot. We’ll just have to wait and see.

For more information on climate change’s effects on bird migration listen to this interview with Powdermill’s Drew Vitz on The Allegheny Front.

(photo by Kate St. John)

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Apr 09 2012

New Leaves

Published by under Phenology,Plants,Trees

Over the weekend I hiked in both Greene and Allegheny Counties where I concluded there are more leaves on the trees near Pittsburgh than in the rural areas south of us.

I suspect that’s because Allegheny County is more densely populated, has more pavement and heated buildings, and thus is slightly warmer.

Sugar maple leaves in Greene County were still in the bud on Saturday but I found these newly unfurled leaves at Barking Slopes on Sunday.  They’re four weeks ahead of schedule.

I love how red and wrinkled they look.

It won’t be long before they’re green.

(photo by Kate St. John)

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Apr 03 2012

Fire Season

Spring is fire season in Pennsylvania.

85% of Pennsylvania’s wildfires occur in March, April and May, not because it hasn’t rained but because it’s windy and the old leaf litter provides a lot of fuel before the new leaves are out.

In Pennsylvania almost all wildfires are caused by people, so from March 1 to May 25 DCNR prohibits open fires in the State Forests.  This burn ban is instituted every year.  Even so, wildfires burn 10,000 acres annually in Pennsylvania.

Spring is also the time for controlled burns to clear the fields for planting.  If you fly across the U.S. on a clear, windless day this month you’ll see the smoke of controlled burns across the country.

Fire is the “natural” solution for clearing large fields when it’s impractical to till the old plants into the soil, but it’s not welcome near residential areas because of the smoke.  In western Pennsylvania I can tell that farmers often use herbicide because I find stark brown fields in April, surrounded by bright straight lines of green plants along the edges.

I’m not wild about herbicides.  If it weren’t for the smoke I’d prefer fire except …

Sometimes controlled burns go out of control as one did last week in Colorado.

Be careful.  It’s fire season.

(photo by Richard Chambers of a controlled burn in Statesboro, Georgia via Wikimedia Commons.  Click on the photo to see the original)

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Apr 02 2012

A Little Late, A Lot Early

Pennsylvania birders were treated to a surge of ducks last weekend when Friday night’s storm forced migrants to stop in our state to wait for better weather.  The migration fallout was especially large on Saturday.

A day late, I went to Moraine State Park hoping to see a few stragglers.  There weren’t as many ducks on Sunday but I found a nice variety:  ruddy ducks, buffleheads, horned grebes and five long-tailed ducks.

My own notes indicate that long-tailed ducks usually come through our area about a week earlier, approximately March 25.  This group was a little late, but I was too, so our paths crossed.

Meanwhile, the plants and insects are still early even though our weather has moderated.

A week ago, on March 25, I found this large-flowered bellwort blooming at Barking Slopes.  It usually blooms around April 25 so it was one month ahead of schedule.

A little late.  A lot early.

What will happen next?

(photo of long-tailed ducks by Steve Gosser, photo of large-flowered bellwort by Kate St. John)


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Mar 31 2012

Blooming Early: Trailing Arbutus

Published by under Phenology,Plants

Trailing arbutus (Epigaea repens) is a rare evergreen plant that usually blooms in April in our area.  This year it’s blooming early, just like everything else.

Both of the plant’s first names — trailing and epigaea — refer to its woody, hairy stems that trail on the earth in a dense mat.  The leaves are oval and leathery, smooth on top and hairy below.

The plant is unremarkable until it blooms.  The flowers are tubular, 5-lobed, pink or white, and usually in clusters at the branch tips.  They’re quite fragrant with a spicy smell.

I’ve seen trailing arbutus on Arbutus Trail at Bear Run Nature Reserve.  Dianne Machesney photographed them last week at North Park.

(photo by Dianne Machesney)

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Mar 26 2012


Published by under Phenology,Plants

Yesterday I hiked at Barking Slopes to see what was blooming after 11 days of June-like weather.

So many flowers had opened that the ground was carpeted with them. Squirrel Corn (Dicentra canadensis), Dutchman’s Breeches (Dicentra cucullaria), Spring Beauties (Claytonia virginica) and Cut-leaved Toothwort (Cardamine concatenata) were all at their peak.

So were Bloodroot (Sanguinaria canadensis, above) that normally blooms at this time in March and Large-flowered Trillium (Trillium grandiflorum, below) that normally blooms in late April.

It was an odd juxtaposition of two flowers that never bloom at the same time.

Tonight we’ll have a killing frost. The March flowers may be able to cope but I doubt the April flowers will survive.

(photos by Kate St. John)

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Mar 23 2012

Uh Oh!

Welcome to Day 11 of June-in-March.  The heat feels nice, huh?  What could go wrong?

Yesterday I found red oaks starting to bloom in Schenley Park a month ahead of schedule (photo above).  This should be happy but something is missing.  The rose-breasted grosbeaks aren’t here to eat them.

Long ago I learned from Chuck Tague that rose-breasted grosbeaks move north as the oaks bloom, perfectly timing their arrival to coincide with their favorite migration food — oak flowers.

But right now the grosbeaks are in Central and South America, waiting to fly across the Gulf of Mexico to arrive in Pennsylvania in late April or early May.  They don’t know our oaks are blooming.  The flowers will be gone.

What will the rose-breasted grosbeaks do when they get here?

Uh oh!


(photo of oak flowers by Kate St. John. Photo of rose-breasted grosbeak by Chuck Tague)

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Mar 21 2012

The New Normal

One day does not a summer make but a week of June-like weather is mighty convincing.

Though I’m thrilled to be wearing summer clothes in mid-March it makes me very uneasy.  Our temperatures have been 20 to 30 degrees above normal.  In Minnesota the morning low in International Falls tied the previous record high on Monday!

The heat is unprecedented but the landscape is coping.  Last Sunday I found cutleaf toothwort (pictured above) blooming four weeks ahead of schedule and yellow buckeye trees leafing out in Schenley Park (below).   The weather is three months early.  The plants are one month ahead.

Insects are responding as well.  Stink bugs are everywhere and I swear I heard a cricket last night.

Most birds can’t keep up.  Those already here are moving north a bit early but the bulk of the migrants are in Central and South America and have no idea our weather is so far ahead of schedule. When they get here they may find their peak insect food sources have passed.

Meanwhile peregrines lay their eggs so that hatching will coincide with the push of northward migrants.  Dorothy’s first egg is right on time though the heat is not.  It was sad to see her panting at the nest yesterday, trying to keep her egg cool so it won’t develop out of synch.


With a warm winter here and a very cold winter in Europe, we’re on the roller coaster of climate change.  Arguing about it is pointless now.  Ready or not, we’re already coping with the new normal.


(Cutleaf toothwort photo by Dianne Machesney.  Yellow buckeye leaves by Kate St. John.  Dorothy panting at her nest on 20 March 2012 from the National Aviary falconcam at Univ of Pittsburgh)

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Mar 18 2012

Spring Last Week

Spring came fast last week, as shown by the pictures I took at Schenley Park on Wednesday and Friday, March 14 and 16.

Spring morning with dew, Wednesday March 14.


Coltsfoot starting to bloom (Wednesday).


Magnolia bud opening (Wednesday).


Female flowers on red maple (Wednesday).

And by Friday….

Spicebush flowers are open.



…and Wednesday’s magnolia bud is now a flower.


(photos by Kate St. John)

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Mar 12 2012

March Flowers Bring…

Published by under Phenology

If April showers bring May flowers, what do March flowers bring?

In this case, scavenging flies.

Yesterday I found a huge patch of skunk cabbage blooming at Raccoon Creek State Park.  They were so well camouflaged that I had to be careful where I stepped.  I tried for a picture of the flowers hidden inside the spathe but was unsuccessful.  Of course the pollinators don’t need to see the flower.  They’re attracted to the smell.   I stepped on one by accident and yes, it smelled awful.

Also found blooming in wet places are the long, yellow catkins of American hazelnut trees. Here are some from Marcy Cunkleman’s garden.


The warm weather fooled me into thinking spring had sprung, but this field at Raccoon brought me back to reality.  How brown!

Spring still has a long way to go.

(skunk cabbage and field scene photos by Kate St. John, catkins photo by Marcy Cunkelman)

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