Archive for September, 2013

Sep 11 2013

On The Move

Published by under Migration,Songbirds

Swainson's thrush (photo by Shawn Collins)

Last night in Bath, Maine I heard thrushes migrating in the dark.  As they fly they make short contact calls to keep the flock together. Among the calls, I was able to identify two species.

The first call was plentiful and sounded like the single note of a spring peeper.  Those were Swainson’s thrushes (above).  Click here to hear the peep sound at the beginning of the recording.

The second sound was less frequent.  There were fewer of this species, their call note lasted longer and descended roughly.  By listening at the Macaulay Library online I determined they were gray-cheeked thrushes (below).  Click here to hear.

Gray-cheeked thrush (photo by Shawn Collins)

 

Last night the birds were on the move while the weather was good.  Today will be hot.  Tonight will be stormy.

 

(photos by Shawn Collins)

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Sep 10 2013

Sappy Nests

RBNU_9697353680_70396a3c93_rsz_shawncollinsRed-breasted nuthatch (photo by Shawn Collins)

Red-breasted nuthatches are the first bird I hear every morning in Maine.  What are they up to?

Right now they’re spending a lot of time caching conifer seeds to last them through the winter.  All summer long they ate arboreal arthropods (insects in trees) but now they’re switching to seeds, hiding them under bark or in sapsucker holes, covering the opening with lichen or plant matter. If there aren’t enough cones they move south, as so many did last winter.

Though they depend on cone-bearing trees for food, red-breasted nuthatches prefer to nest in dead or dying birches or aspens whose trunk is softened by disease or rot.  They often pick a birch with a broken top.  The lady digs the nest hole while her mate watches and brings her food.  She throws sawdust out of the hole leaving a telltale pile below the nest.  I’ve never seen this because I’m never in Maine during nesting season.

If I came here in the spring — or spent time watching the few red-breasted nuthatches who nest near Pittsburgh — I would see this amazing nesting habit:  To protect their eggs and nestlings they collect pine sap on the tips of their bills or on a little piece of bark, then smear it around the opening of the nest.  The male smears sap on the outside, the female smears it on the inside.  Experiments have shown this sticky mess keeps away both predators and competitors.

Adult nuthatches are very skillful at zooming straight into the nest without touching the sides — those who don’t are eliminated from the gene pool — so how do the nestlings fledge without getting stuck?  According to Birds of North America Online, parent nuthatches place small clumps of fur on the sticky inner nest rim on the day of fledging.

They make a stick-free launch zone for the kids to leave the sappy nest.

(photo by Shawn Collins)

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Sep 09 2013

Which Cone Is Wetter?

Published by under Plants,Quiz

Wet and dry pine cones, head on (photo by Kate St. John)

While writing about dripping pine cones I learned that mature cones open and close many times and can do so for many years.

They do this in response to wetness — even after they release their seeds, even after they’ve fallen from the tree.  In fact the open/closed status of fallen cones is a simple indication of wildfire risk because it shows the dryness of the forest floor.

So what does a wet cone look like?  Can you tell which one is wet and which is dry, above?

Here’s a view of the tail end.

Tail end of wet and dry white pine cones (photo by Kate St. John)

And here’s an overhead view.

Wet and dry white pine cones side by side (photo by Kate St. John)

 

By now you’ve probably guessed the answer so you’re ready to play Cone In A Bottle.

Put the closed cone in a bottle and wait for it to open.  If you want to get the cone out, do you add water or remove it?

The answer is in the comments below.

(photos by Kate St. John)

5 responses so far

Sep 08 2013

Rabbit-foot Clover

Published by under Plants

Rabbit-foot clover (photo by Ivar Reidus via Wikimiedia Commons)

I never see rabbit-foot clover (Trifolium arvense) in Pittsburgh but it’s easy to find along the roadsides in Maine (where I happen to be).

Originally from Europe, it prefers dry sandy soil, field edges, and waste places.   This beautiful specimen was photographed in Estonia.

You can see how the flower got its name.

 

(photo by Ivar Reidus via Wikimedia Commons.  Click on the image to see the original.  This was a featured photo in August 2013.)

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Sep 07 2013

Parachutes

Published by under Plants

Solidago caesia seeds (photo from Wikimedia Commons)

While looking for a picture of blue-stemmed goldenrod (Solidago caesia) I ran across this stunning photo of its seeds.

Here they look like tiny parachutes, barely noticeable when on the plant.

Now I have something new to look for.

(photo by Steve Hurst at USDA-NRCS PLANTS Database via Wikimedia Commons. Click on the image to see the original)

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Sep 06 2013

Even One Species Makes a Difference

Bumblebee (photo by Marcy Cunkelman)

In yesterday’s blog I mentioned the pesticide episode in Wilsonville, Oregon last June that killed 50,000 bumblebees.  This prompted me to wonder…

What would happen if just one species of wild bee completely disappeared from an area?

Computer models suggest that the remaining bees would take up the slack and none of the flowers would suffer.  Recent research shows this isn’t so.

Berry Brosi of Emory University and Heather Briggs of University of California Santa Cruz conducted a bumblebee study at the Rocky Mountain Biological Lab near Crested Butte, Colorado where native larkspur is visited by 10 of the 11 local bumblebee species.

They divided the wildflower meadows into 20 square meter plots.  In the manipulated plots, they used nets to capture and exclude just one bumblebee species.  In both the control and manipulated plots their team of Emory University undergraduates followed all the bumblebees everywhere, noting the flowers they visited.

Though bees are generalists they usually specialize in gathering nectar from particular species at the height of their blooming.  If you watch bumblebees on Joe Pyeweed in an August meadow you’ll notice they visit all the Joe Pyeweed in succession even though there are lots of other flowers to choose from. This benefits the flowers because the bees are wearing pollen from their own species.  The researchers confirmed this when they swabbed the bumblebees for pollen and analyzed the results.

In the control plots in Colorado, everything proceeded as expected.  78% of the bees focused on their favorite flower species. Larkspur seed production was normal.

Not so in the manipulated plots. With only one species missing, reduced competition for the flowers prompted the bumblebees to “play the field.”  Only 66% of the bumblebees focused on their favorite flowers.  The larkspur suffered, producing 1/3 less seed.

So the answer is:  If one wild bee species disappears some wildflowers will decline dramatically.

Everything’s connected to everything else.

Read more about the bumblebee study here in Science Daily.

 

(photo by Marcy Cunkelman)

p.s. No bumblebees were hurt during the study.  They were all captured and released.  Quite a feat!

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Sep 05 2013

Threats To Bees: Connect The Dots

Published by under Insects, Fish, Frogs

Honey bees on a flower, Slovenia (photo from Wikimedia Commons)

After I met Joan Guerin’s honey bees this summer I became attuned to news that affects them.  An article about the greening of Florida’s citrus trees raised an alarm.

Since 2006 a third of the honey bee colonies in the U.S. have suddenly collapsed and died.  Their disappearance is not merely a honey crisis, it’s a food crisis because the majority of our crops are pollinated by commercially tended honey bees.  Fruits, soybeans, sugar beets, alfalfa… the list of crops is huge and worth over $15 billion.

In the U.S. most news reports say “We don’t know what causes bee collapse. It’s probably a number of factors including pesticides, parasitic mites, inadequate food, and a new virus” yet on April 29 the European Union banned three pesticides for two years to save their bees.  This came 16 years after French bee-keepers concluded that neonicotinoids harmed bees and ultimately caused their colonies to collapse.

In the mid-1990s French beekeepers experienced brutal bee population losses that coincided year after year with the sunflower honey season.  What had changed?  In the mid-1990s French sunflower growers began planting seeds coated with a neonicotinoid pesticide called imidacloprid that protects plants by becoming a systemic insect poison in the roots, stems, leaves, pollen and nectar.  Bees are insects. It ultimately killed them, too.  Even low doses weaken the bees’ immune systems so the EU placed imidacloprid, clothianidin, and thiametoxam on a two year moratorium.

Not so in the U.S. and the U.K.  The Guardian points out that despite evidence from beekeepers around the world, regulators in our two countries prefer to take the chance of not regulating a bad substance rather than accidentally stopping a good one.  Neonicotinoids are used on 95% of our corn and canola and the majority of our bee-pollinated crops and they persist in soil and water even after the treated plants are gone.  Some disturbing events in the U.S. point to additional trouble ahead.

In June a landscaping company in Wilsonville, Oregon sprayed 65 linden trees in a Target parking lot with the pesticide “Safari” that contains dinotefuran neonicotinoids.  They did this for cosmetic reasons — to kill aphids that cause the lindens to dot sap on the cars below — but the result was catastrophic.  The trees were blooming.  50,000 bumblebees died.  The only way people stopped additional deaths was to drape the trees with nets so the bees couldn’t touch them.

Last weekend I read about the “greening” of Florida’s citrus trees.  This is not a happy color change but the sad irreversible death of all citrus trees from a bacteria carried by the Asian citrus psyllid.  Initially the only solution was to chop down infected trees but some farmers decided to keep on farming by nurturing their trees and using intensive systemic insecticides to kill the Asian citrus psyllid.

Imidacloprid, the chemical implicated by French beekeepers and now banned by the European Union, is being used to “save” the citrus groves.

Citrus groves require honey bees to pollinate them.

Connect the dots.  Oh no!

(photo by Mihael Simonič from Wikimedia Commons. Click on the image to see the original)

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Sep 04 2013

Three Sumacs And Two Imposters

Published by under Plants,Trees

Sumac fruit (photo by Kate St. John)

In July I took photos of sumacs along the Montour Trail but didn’t identify the species and assumed these first two were staghorn sumac.  Wrong!

As I started to write this article I examined the photos and noticed a big difference between them.  The red fruit spike above is fuzzy.  The one below is smooth.   Not only that, you can see that the stems on the top one are also fuzzy but the stems below are smooth.

Fruit of smooth sumac (photo by Kate St. John)

In southwestern Pennsylvania we have three common sumac species that bear pointed red fruit clusters:

  • Staghorn sumac (Rhus typhina), at top, has fuzzy fruit and stems and is named “staghorn” because the fuzzy fruit spike resembles a stag’s horn in velvet.
  • Smooth sumac (Rhus glabra), above, is smooth just like its name.
  • Shining sumac (Rhus copallina) is easily identified by its winged stems.

I haven’t seen Shining Sumac lately so here’s a photo from Wikimedia Commons.  See how the stem has wings (like wingstem) between the leaflets?

Leaves and flower of Shining Sumac (photo from Wikimedia Commons)

 

There are two more plants we call “sumac” whose leaves resemble these plants but they aren’t in the genus Rhus:

  • Poison-sumac (Toxicodendron vernix) is in the cashew family (as is Rhus) but it’s closely related to poison ivy and causes the same rash.  Its stems are smooth, like smooth sumac, but its flowers and fruit are not in dense spikes.  Fortunately poison sumac only grows in swamps and bogs so you’d have to go out of your way to touch it.  Click here for a photo.
  • And finally there’s a plant we call “sumac” which isn’t related at all.  Tree of Heaven (Ailanthus altissima) is an invasive tree from China with compound leaves that resemble sumac.  However its leaflets are notched, especially at the base, and the tree produces seeds instead of a fruit spike.  Notice the notches on the leaflets and the heavy cascade of seeds in this Wikimedia photo.   This is NOT sumac.   It grows anywhere, even in abandoned parking lots.

Ailanthus leaves and seeds (photo from Wikimedia Commons)

 

Three real Rhus sumacs and two imposters.

(photos by Kate St. John except where noted.  Click on the Wikimedia photos to see their originals)

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Sep 03 2013

Giant Bird Coming To Pittsburgh

Published by under Books & Events

Florentijn Hofman's Giant Rubber Duck in Syndey Harbor (photo courtesy of Florentijn Hofman's Rubber Duck Project)

Pittsburgh bird watchers!  In case you haven’t heard, the largest duck on the planet is migrating to our three rivers on September 27.

Last seen in Hong Kong Harbor, Florentijn Hofman’s Rubber Duck is making his very first visit to the United States and has chosen to land in Pittsburgh thanks to the Pittsburgh Cultural Trust’s International Festival of Firsts.

Rumor has it he will begin his U.S. voyage on the Ohio River near the West End Bridge, swimming upstream to roost on the Allegheny River near the Roberto Clemente Bridge (a.k.a. the Sixth Street Bridge) — but check here at the Pittsburgh Cultural Trust website for last minute details.

As you can imagine his movements are constrained by his height, reputed to be 50 feet tall.  (There is some disagreement on this.  Some media outlets say he’s only 40 feet tall.  We’ll have to ask the American Ornithologists’ Union for a ruling on this.)

Don’t miss this opportunity to add this species to your Life List!

September 27 in Pittsburgh.  Be there!

 

(photo of the Rubber Duck in Hong Kong harbor courtesy of Florentijn Hofman’s Rubber Duck Project. Click on the duck to watch a video of him in Hong Kong)

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Sep 02 2013

Resident or Migratory?

Flock of Canada geese on pond in Ottawa, Canada (photo from Wikimedia Commons)

Normally we don’t pay much attention to the immigration status of Canada geese but it’s going to be an important distinction in Pennsylvania when early Canada goose hunting season opens today.

It seems hard to believe but the subspecies Branta canadensis maxima (Giant Canada Goose) was nearly extinct in 1900 due to overhunting and habitat change.  Many states conducted reintroduction programs to help the geese along.  Here in Pennsylvania the birds so did well that there are nearly 280,000 resident maxima Canada geese, almost double the management goal of 150,000.

How do you determine the citizenship status of a Canada goose?   By time of year and location.  Only Pennsylvania residents are here in September.  Migratory geese won’t be leaving Canada until the lakes begin to freeze in October and even then the South James Bay population visits the northwest corner of the state (Lake Erie to Pymatuning) and the Atlantic population stays well east of the Appalachians and south of I-80.  In most of Pennsylvania, Canada geese are residents.

Why don’t our resident geese migrate?

Geese travel in family groups which collect at staging areas to join larger flocks.  The young geese learn the migratory paths from their parents.  If their parents don’t migrate the whole family stays put.  The reintroduced geese had no one to teach them to migrate so they and their descendants live here year round.

The resident geese know our habits and will gather in the no-hunt zones this month.  You may see more of them on our city rivers and in county parks in the days ahead.

Meanwhile, remember that fall is here and with it comes hunting season.  Wear blaze orange, especially if you visit State Gamelands where it’s required even if you’re not hunting.

 

(photo of Canada geese in Ottawa, Ontario from Wikimedia Commons.  These geese are migratory.  Click on the image to see the original)

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