Archive for the 'Phenology' Category

Jun 07 2015

Color With Thorns

Published by under Phenology,Plants

Nodding thistle flower head (photo by Kate St. John)

Nodding thistle flower head (photo by Kate St. John)

Lots of big thistles are blooming now by the road to Duck Hollow in Pittsburgh.  At first I couldn’t identify them but my guess was that anything growing so well by the road was probably alien and invasive.  I was right.

Nodding thistle or musk thistle (Carduus nutans) is a biennial from Africa and Eurasia that came to this continent by accident, perhaps in ballast water.  It thrives in disturbed soil at roadsides and landslides and in heavily grazed pastures.  It’s a thorn in the side for cattle farmers and an alien invasive.

A view of the entire plant shows many thorns and the reason why its called “nodding.”

Nodding thistle nods (photo by Kate St. John)

Nodding thistle by Old Browns Hill Road (photo by Kate St. John)

Despite its mean reputation, I think it’s beautiful. The buds look like reddish-purple star bursts as they open.

Nodding thistle bud opening (photo by Kate St. John)

Nodding thistle bud opening (photo by Kate St. John)

And the color of the flower is outstanding. My favorite view is too wide for this blog’s narrow format so click here for a closeup of color without thorns.


(photos by Kate St. John)

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May 21 2015

What To Expect in Late May, Early June

Published by under Phenology

Chestnut-sided Warbler, female (photo by Chuck Tague)

Throw Back Thursday:  A Southwestern Pennsylvania Phenology for Late May and Early June

As we head into late May and early June the natural world is gearing up for the solstice.  Here’s a hint of what you’ll see and hear:

  • Long daylight as we approach the summer solstice. Today in Pittsburgh is 14 hours, 36 minutes long. By June 15th we’ll have 15 hours and 4 minutes of daylight.
  • Nesting! Everywhere birds are singing, courting, defending their territory, carrying nesting material, carrying food, feeding fledglings, warning of danger.  Chestnut-sided warblers like this one are nesting in the Laurel Highlands.  Canada warblers jump out of the bushes to yell at me when I hike at Quebec Run Wild Area. Not to be missed!
  • New flowers blooming, especially long-tubed flowers that feed hummingbirds and butterflies.
  • Fireflies, crickets and dragonflies.  When will you hear the first crickets?
  • Mosquitoes 🙁
  • Baby bunnies, baby birds, babies of all kinds.
  • And my personal favorite:  Fledging time for young peregrine falcons, the best time of all to watch peregrines.  Stay tuned to this blog for Fledge Watch dates which I’ll announce soon.

Now’s the best time to observe Nature and, frankly, I’d much rather be outdoors than at my computer. So I’m going out to enjoy it!


(photo of a female chestnut-sided warbler by Chuck Tague)

p.s. When I wrote this article in 2009 we didn’t have the crazy weather we’re experiencing this spring: temperatures in the 30’s, then the 90’s, then back again to the 30’s this weekend.  What a Weather Yo-yo!

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May 05 2015

Leaf Out!

Red oak leaves, 1 May 2015 (photo by Kate St.John)

Last weekend’s new leaves in Schenley Park demonstrated that the city is warmer than the suburbs.  Schenley’s leaves unfurled on May 1 while the suburbs were still brown.

Above, new red oak leaves. Below, sugar maple.

Sugar mapleleaf-out, 1 May 2015 (photo by Kate St. John)

This white ash sapling opened its leaves like a crown.  Tiny ash saplings aren’t eaten by emerald ash borer because their stems are too narrow for the bug to use.
White ash leaf-out, 1 May 2015 (photo by Kate St. John)

For dramatic leaf-out, you can’t beat a shagbark hickory.  This bud was just about to unfurl …
Shagbark hickory, leaves about to open, 1 May 2015 (photo by Kate St. John)

And … Boom!
Leaf out! Shagbark hickory (photo by Kate St. John)

Three days later the leaves now produce shade.
Shagbark hickory leaves, 4 May 2015 (photo by Kate St. John)


Take a look at tree covered hillsides as you drive north or south and you’ll notice leaf-out moving north 13 miles a day — except in the city.


(photos by Kate St. John)

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May 02 2015

What to Expect in Early May

Published by under Phenology

Scarlet Tanager in flight (photo by Chuck Tague)

The beginning of May is a birder’s paradise. Spring migration hits full stride.  Of course there are great birds at the “hotspots,” but unexpected species may stop in your backyard on their way north.

Here’s just a taste of the excitement in early May:

  • The trees leaf out and our brown, sun-filled forests become green and shady almost overnight.
  • Birds arrive in many colors:
    • Bright red, orange, black and blue:  scarlet tanagers, rose-breasted grosbeaks, Baltimore orioles, indigo buntings.
    • Shades of brown: hermit thrush, Swainsons thrush, wood thrush and veery.
    • Yellow and green:  Warblers and vireos galore!  The yellow warblers and yellow-rumped warblers we were happy to see in April will seem boring in May.
  • Nesting is happening everywhere.  Watch for the first robin fledglings.
  • More flowers bloom:  Jack-in-the-Pulpit, Fairy bells, Bellwort, Canada Mayflower and Mayapples.
  • More moths and butterflies appear.
  • And you’ll see the first baby bunnies.

Take part in some outings to see the sights of May.


(scarlet tanager in flight above new oak leaves. photo by Chuck Tague)

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Apr 22 2015

A Symbiotic Relationship

Boxelder blooming (photo by Kate St. John)

Boxelder blooming, 17 April 2015 (photo by Kate St. John)

Warbler migration is ramping up and we’re already craning our necks to see them.  Up to now it’s been easy to find birds in the leafless trees but that’s about to change.

In Schenley Park the box elders burst into flower and leaf last week (above), the Norway maples opened last weekend, and the oaks and hickories are blooming now.

Here’s a red oak twig on April 19 just before the buds burst.  Who knew they could grow so long!

Red oak buds about to burst, 19 April 2015 (photo by Kate St. John)

Red oak bud about to burst, 19 April 2015 (photo by Kate St. John)

Inevitably the warblers gravitate to the leafy trees where they’re hard to find, prompting the common complaint, “The leaves are hiding the birds.  I wish the leaves weren’t there!”

But if the leaves weren’t there, the birds wouldn’t be either.

Insects time their egg-hatch and larval growth to take advantage of leaf out.  These tentworms appeared in Schenley Park when the choke cherries opened their leaves.

Tentworms on a choke cherry branch, 18 April 2015 (photo by Kate St. John)

Tentworms on a choke cherry tree, 18 April 2015 (photo by Kate St. John)


Leaf out brings insects.  Insects bring warblers.  It’s a symbiotic relationship between birds and trees.

Blackpoll warbler gleaning insects from a boxelder (photo by Chuck Tague)

Blackpoll warbler in a boxelder, eating a caterpillar (photo by Chuck Tague)

The trees are probably happier than we are to see the warblers arrive.


(tree photos by Kate St. John.  Blackpoll warbler by Chuck Tague)


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Apr 19 2015

Now Blooming

Published by under Phenology,Plants

Sessile trillium, Boyce-Mayview Park, Allegheny County, 15April 2015 (photo by Kate St. John)

Toadshade (Trillium sessile), Boyce-Mayview Park, Allegheny County, 15 April 2015 (photo by Kate St. John)

As I mentioned yesterday, spring wildflowers are now blooming in southwestern Pennsylvania.  Here’s a sample of what Dianne Machesney, Donna Foyle, and I found in our outdoor travels last week.  Check the captions for the flower names, locations and dates.

  • Toadshade or Sessile trillium (Trillium sessile) is found in rich woods.  The dark red flower holds the petals shut.  In my photo there are two Virginia spring beauties that hadn’t opened on that cloudy day.
  • Virginia spring beauty (Claytonia virginica) is also found in rich woods.  The flowers are small with faint pink details.  They don’t open until the sun comes out.
  • Lesser celandine (Ranunculus ficaria) is an invasive import that does well in rich damp woods.  I’ve seen it in Schenley and Boyce-Mayview Parks. Dianne saw it at Enlow Fork.
  • Siberian squill (Scilla siberica) is another import, a non-invasive garden plant that’s escaped to the wild.  I’ve seen it planted in Schenley Park.  Dianne photographed it at Enlow Fork.
  • Purple deadnettle (Lamium purpureum) is an import that doesn’t care where it grows.  You’ll find it everywhere once you start to look.  Up close its flowers are intricate.  From a distance the leaves have a purplish cast.
  • Horsetail (Equisetum) is a “living fossil” plant, the last species of a class of plants that dominated the dinosaurs’ forest.  Some were as big as trees. Today they are coal.  Visit the dinosaur exhibits at the Carnegie Museum of Natural History to see what they looked like.


Virginia Spring Beauty (Claytonia virginica), Enlow Fork, Washington-Greene county line, 12 April 2015 (photo by Dianne Machesney)

Virginia Spring Beauty (Claytonia virginica), Enlow Fork, Washington-Greene county line, 12 April 2015 (photo by Dianne Machesney)


Lesser celandine (Ranunculus ficaria), Boyce-Mayview Park, Allegheny County, 15 April 2015 (photo by Kate St. John)

Lesser celandine (Ranunculus ficaria), Boyce-Mayview Park, Allegheny County, 15 April 2015 (photo by Kate St. John)


Siberian squill (Scilla siberica), Enlow Fork, Washington-Greene county line, 12 April 2015 (photo by Dianne Machesney)

Siberian squill (Scilla siberica), Enlow Fork, Washington-Greene county line, 12 April 2015 (photo by Dianne Machesney)


Purple deadnettle (Lamium purpureum), everywhere in Pittsburgh, 15 April 2015 (photo by Kate St. John)

Purple deadnettle (Lamium purpureum), everywhere in Pittsburgh, 15 April 2015 (photo by Kate St. John)


Horsetail (Equisetum), Youghiogheny Rail Trail near Buena Vista, Allegheny County, 15 April 2015 (photo by Donna Foyle)

Horsetail flower spikes (Equisetum), Youghiogheny Rail Trail, Buena Vista, Allegheny County, 15 April 2015 (photo by Donna Foyle)


(photos by Kate St. John, Dianne Machesney, and Donna Foyle)

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Apr 06 2015

Yellow Throats and Bloodroot: What to Expect in April

Published by under Phenology

Yellow-throated warbler (photo by Steve Gosser)

Yellow-throated warbler (photo by Steve Gosser)

Spring is off to a slow start this year.  Last month I predicted coltsfoot would bloom in March but it didn’t appear in Schenley Park until April 4.  Since the city is always warmer than the countryside I’m sure many of you are still waiting for coltsfoot.

Despite my poor March prediction I’m going to make one for April.  Maybe spring will “catch up” this month.  If so, you can expect to find…

  • The earliest warblers arrive in early to mid April before the leaves open.  Look for yellow-throated warblers and Louisiana waterthrushes along the streams and creeks.  Yellow-throats walk the high trunks and larger branches of sycamores.  Louisiana waterthrushes walk the stream edges bobbing their tails.  Both sing loudly to be heard over the sound of rushing water.
  • The purple martin scouts are back.  Very soon, perhaps today, the swallows will return — tree, northern rough-winged, and barn.  By end of April we’ll have gray catbirds, blue-gray gnatcatchers, ruby-crowned kinglets, and hints of the big migration in May.
  • April is woodland wildflower time.  Walk in the woods to see bloodroot, spicebush, spring beauties, hepatica, harbinger-of-spring, spring cress, twinleaf, violets and more.  The bees and flies are out visiting the flowers.
  • Pollen counts will rise by the end of the month when the tree flowers bloom.  Those that rely on wind pollination (oaks and pines, for instance) will make allergic folks miserable but all of us will enjoy the downy serviceberries and flowering cherries.

Here’s a taste of Spring to come.

Bloodroot blooming at Cedar Creek Park, Westmoreland County, 19 April 2014 (photo by Kate St. John)

Bloodroot at Cedar Creek Park, Westmoreland County, 19 April 2014 (photo by Kate St. John)


Spicebush in bloom, Schenley Park 2013 (photo by Kate St. John)

Spicebush in Schenley Park, 13 April 2013 (photo by Kate St. John)

It’s a good month to be outdoors.


(photo credits: Yellow-throated warbler by Steve Gosser.  Bloodroot and spicebush by Kate St. John)

p.s. Yellow-throated warblers are southern birds that are expanding their range northward. They’re in southwestern PA but not northern … yet.

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Apr 03 2015

I See Change

Leaves unfurling weeks ahead of schedule, 25 March 2012 (photo by Kate St. John)

Leaves unfurling, 25 March 2012 (photo by Kate St. John)

On a global scale, 2014 was the warmest year ever recorded but climate change is complicated on the local level.  In Pittsburgh we’ve changed into yo-yo extremes.

Pittsburgh’s last two winters were colder than normal but three years ago it was really hot.  Spring came six weeks late in 2014 and six weeks early in 2012.   This photo of leaves opening on March 25, 2012 is impossible during this year’s cold spring.

I noticed the changes in 2012 but wouldn’t have remembered them if I hadn’t taken a picture.  That’s the beauty of keeping a nature journal and it caught the attention of climate journalist Julia Kumari Drapkin.  She noticed that local experience of climate change is ahead of the science curve and often raises interesting questions so she decided to flip the typical reporting model and founded the iSeeChange crowd-sourced almanac.  Everyday observations and questions now become radio stories.

Fast forward to 2015 and iSeeChange has radio partners across the U.S. and in Africa.  The Allegheny Front joined last month so now western Pennsylvanians can record what we see and ask questions about what’s going on in our area.

Last month I signed up for iSeeChange as a quick way to record the signs of spring.  In Pittsburgh it’s been cold and variable (click here for the Allegheny Front’s story) but the weather’s different out West.  Colorado is hot and already has mosquitoes!

You can contribute, too.  As Julia says, “Everyone’s an expert in his own backyard.”  Click here to join the iSeeChange almanac.

Post your observations. Upload photos and sound clips. Ask about what puzzles you.

Outdoor changes are always interesting.  Maybe yours will be on the radio.


Listen to The Allegheny Front in Pittsburgh on WESA-FM 90.5 every Saturday at 7:30am and on other stations in Pennsylvania, New York and West Virginia at the times listed here.  You can also listen any time online at The Allegheny Front.

(photo by Kate St. John)

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Mar 31 2015

More Deer, Less Moose

Moose and deer (both photos from Wikimedia Commons)

What happens when the interval between spring thaw and leaf out gets longer?  Fifty years of detailed observations in New Hampshire’s Hubbard Brook Experimental Forest tell the tale.

In New Hampshire, where snow covers the ground all winter, spring thaw is a welcome event that finally exposes the soil.  Weeks later after lots of warm air and sunshine the trees leaf out.  In between these two events the sun warms the soil, the plants emerge, and wildflowers bloom.

Hubbard Brook Experimental Forest has kept detailed records of temperature, precipitation, snowpack, plants, animals, birds and invertebrates for more than half a century. An analysis of the data, published in BioScience in 2012, showed that the forest is getting warmer and wetter and the interval between spring thaw and leaf out has increased by 8 days.  Climate change is separating spring’s above ground (air) responses from the soil responses.

In the post-thaw interval severe cold events freeze the exposed soil and kill plant buds and invertebrates. This threatens some deciduous trees (yellow birch and sugar maple in New Hampshire) and birds find fewer invertebrates when they return from migration.  The record shows the mix of plants and animals is changing.

There are even changes in large animals.  For the past 50 years the snowpack has declined, an outcome that favors deer over moose and that seems to be happening at Hubbard Brook.

More deer, less moose.  If you write it down now you can see the trend later.

Read more here in Science Daily, December 2012.


p.s. It should be “More Deer, Fewer Moose” but I am quoting one of the articles and happen to like the ungrammatical juxtaposition.

(photo of moose by Ronald L. Bell, USFWS via Wikimedia Commons.  Photo of deer by josephamaker2018 via Wikimedia Commons. Click these links to see the original images.)

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Mar 30 2015

Early Flowering Signs of Spring

Published by under Phenology,Plants

Harbinger of Spring, Cedar Creek, 29 March 2015 (photo by Kate St. John)

Despite this month’s cold weather yesterday’s outing* to Cedar Creek found two early-spring wildflowers.

Bright afternoon sunshine encouraged the wildflowers to bloom but it washed out the colors on the forest floor.  We all searched hard to find this Harbinger of Spring (Erigenia bulbosa).  Here’s a poor photo of the entire plant with an oak leaf for scale. It’s tiny! One leaf is sufficient to hide it.

Harbinger of Spring (photo by Kate St. John)


We also found a lot of Snow Trillium (Trillium nivale) in bloom but I had to be shown each flower because I couldn’t see them in the glare.   My best photo is of the one I stepped on.  Oh how embarrassing!

Snow trillium, 29 March 2015, Cedar Creek (photo by Kate St. John)


* This was a joint outing of the Wissahickon Nature Club and the Botanical Society of Western Pennsylvania.  Feel free to join us as we explore the flora and fauna in western Pennsylvania.  Click here for Wissahickon’s 2015 outing schedule (page 3 of the pdf) and here for the Botanical Society’s calendar.


(photos by Kate St. John)

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