Sep 19 2017

Traveling Together?

Published by under Migration

Blackpoll warbler, Sept 2012 (photo by Marcy Cunkelman)

Blackpoll warbler, Sept 2012 (photo by Marcy Cunkelman)

As warblers migrate through Pennsylvania we find them feeding together in mixed flocks during the day.  Does that mean they were traveling together overnight?  Maybe not.  Warblers often have very different breeding and wintering destinations, making it hard to coordinate their trips.

Here are two extreme examples. Blackpoll and pine warblers look similar but you can't find two more different migration strategies. Their breeding and wintering grounds are as far apart as it gets.

The blackpoll warbler, above, is a long distance champion who travels 7,000 miles from his breeding grounds in North America's boreal spruce and fir forests to wintering grounds in South America.  To shorten the trip some of them fly non-stop over the Atlantic Ocean for 88 hours to reach South America's shore.

The pine warbler, below, never travels that far. His breeding and winter ranges are completely contained within North America from southern Canada to Florida and he's found year-round in the southern U.S.  Pine warblers breed in parts of Pennsylvania.

Pine warbler in April (photo by Anthony Bruno)

Pine warbler (photo by Anthony Bruno)

 

The maps below -- blackpoll (left), pine warbler (right) -- tell the story in three colors: Yellow is breeding range, Blue is wintering range, Green is year-round.

Range maps for Blackpoll and Pine warblers (maps from Wikimedia Commons) Colors: yellow=breeding, blue=wintering, green=year-round

Range maps for blackpoll and pine warblers (maps from Wikimedia Commons). Colors are: yellow=breeding, blue=wintering, green=year-round

 

As you can see, blackpolls leapfrog over the pine warbler's range.

Though I saw blackpoll and pine warblers in a mixed flock in Perry County last weekend, they probably weren't traveling together.

 

(photo of blackpoll warbler by Marcy Cunkelman; pine warbler by Anthony Bruno; maps from Wikimedia Commons: blackpoll and pine)

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Sep 18 2017

Schenley Park Outing: September 24, 8:30am

Published by under Books & Events

Monarch butterfly on goldenrod (photo by Marcy Cunkelman)

Monarch butterfly on goldenrod (photo by Marcy Cunkelman)

Let's get outdoors!

Join me on a bird and nature walk in Schenley Park on Sunday September 24, 2017 -- 8:30am - 10:30am.

Meet me at Schenley Park Cafe and Visitor Center where Panther Hollow Road meets Schenley Drive.

We'll visit Phipps Run and Panther Hollow Lake, looking for fall flowers and migrating birds.  I'm sure we'll see goldenrod though I won't know what species it is. (Goldenrods are hard to identify!)  Perhaps we'll see migrating monarch butterflies because the weather has been so warm.

Dress for the weather and wear comfortable walking shoes. Bring binoculars and field guides if you have them.

Before you come, visit the Events page in case there are changes or cancellations.  The outing will be canceled if there’s lightning (unlikely this Sunday but you never know).

NOTE!  The Great Race will run on Forbes and Fifth Avenue this Sunday. Approach Schenley Park from the Boulevard of the Allies and you'll avoid the detours.  Here's the road closure list and timing.

 

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Sep 18 2017

Rainbow Wonders

Published by under Weather & Sky

Double rainbow in my neighborhood at dusk, 14 Sept 2017 (photo by Kate St. John)

Double rainbow in my neighborhood at dusk, 14 Sept 2017 (photo by Kate St. John)

Last Thursday evening my husband and I were treated to a gorgeous double rainbow with parallel color bands under the main arc.  What are these wonders and what causes them?

First, some fascinating basics: Rainbows are caused by light hitting water droplets and being reflected, refracted and dispersed by them:

We saw the rainbow at dusk while the sun peeked below rain clouds and were surprised we could see the entire arc. Only those located at the geometric center of the rainbow, the antisolar point, can see it end to end.

Rainbow panomara (photo by Rick St. John)

Rainbow panomara (photo by Rick St. John)

Have you ever noticed that the sky under the rainbow is brighter than the sky outside it?  True!  Click here for an explanation (fourth paragraph).

And then there's the fancy stuff: the double rainbow and the extra bands under the arc.  To illustrate them I'll use this photo from Alaska that shows all of the features at the same time. Click on the image to open a high definition version in a new window and see them up close.

Double rainbow and supernumerary rainbows on the inside of the primary arc, Alaska (photo by Eric Rolph via Wikimedia Commons)

Double rainbow and supernumerary rainbows on the inside of the primary arc, Wrangell-St. Elias National Park, Alaska (photo by Eric Rolph via Wikimedia Commons)

Double rainbows happen when light bounces twice inside the raindrops before it exits.  The light goes inside, reflects off the back wall, reflects off the front wall, and then exits.  Double rainbows are parallel to the main rainbow, are not as bright, and their colors are reversed -- red-to-violet instead of violet-to-red.  I never noticed that. I'll have to watch for it next time.

The faint color bands just under the main rainbow arc are called supernumerary rainbows.  Wikipedia says they cannot be explained using classical geometric optics but they occur when the water droplets are less than 1 mm in diameter.  Fancy rainbows are complicated!

And finally, the end of the rainbow. From our vantage point it was in front of that tree on the horizon.

End of the rainbow in my neighborhood, 14 Sept 2017 (photo by Kate St. John)

End of the rainbow in my neighborhood, 14 Sept 2017 (photo by Kate St. John)

Irish legend has it that leprechauns hid their pots of gold at the end of the rainbow. I wonder whose house was there.

Rainbows move away as you approach.  There's no way to know.

 

(photos of neighborhood rainbow by Rick & Kate St. John. Alaskan rainbow by Eric Rolph via Wikimedia Commons)

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Sep 17 2017

The Marbled Godwit’s Bill

Published by under Water and Shore

Marbled godwit (screenshot of video by Steve Gosser)

Marbled godwit (from video by Steve Gosser)

Yesterday's blog described an online class from Cornell Lab for identifying shorebirds.  Here's a shorebird you'll really enjoy seeing, especially when you know who he is.

The marbled godwit (Limosa fedoa) breeds in northern prairies and at Hudson Bay, then migrates to the Atlantic, Pacific and Gulf coasts to spend the winter.

The bird is 16.5 to 19 inches long but that includes a 3-5 inch dark-tipped pink bill.  The females are larger than males, big for a shorebird but small compared to a roseate spoonbill (click here to see).

The godwit's bill is a great tool for finding food.  Its length allows him to probe deeply for small mollusks, bristle worms, insects, leeches (yes!) and sago pondweed tubers, and it's so sensitive that he can feel his prey without having to see it.

Click on the screenshot above to see Steve Gosser's video of a marbled godwit at Conneaut Harbor, Ohio early this month. Watch as she probes rapidly, then pulls up her beak to swallow a morsel.  She plunges her bill so deeply that her face goes underwater.

She was one hungry bird!

 

(screenshot from video by Steve Gosser)

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Sep 16 2017

Shorebird ID Class: Online from Cornell

Be A Better Birder - online Shorebird ID class with Kevin McGowan

Do you find shorebirds hard to identify?  Cornell's Bird Academy has the online class for you.

logo_cornell_bird_academy

"As summer ends, shorebirds head from their Arctic breeding grounds to their southern wintering areas, passing through most of North America on their way.

What better time to build your shore-birding skills?

To celebrate the season, we have re-issued the recordings of Kevin McGowan's 5-part webinar series on Shorebird Identification, last presented live in 2014.

Over five hours of video instruction help you get to know the markings and behaviors of all the common shorebirds found in North America, 47 species in all.

The entire series is only $29.99 with unlimited access to all the archived video material plus downloadable handouts for each session to help you take notes."

Learn at your own pace with this archived five-part class.  Click here or on the logo above to sign up for the series.

 

(screenshots from Cornell Bird Academy)

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Sep 15 2017

The Chimney Air Show

This month chimney swifts (Chaetura pelagica) are migrating to South America, leaving before the weather's too cold for the flying insects they eat on the wing.

At dusk the flocks swirl around large chimneys then dive in to roost.  This video from New Glasgow, Nova Scotia shows them streaming into an old schoolhouse chimney.  Wow!

Don't worry when you see smoke coming out of the chimney at the end of the video. An observer explains:  "There are actually two flues in the chimney. The chimney swifts use the larger flue, while the smoke is vented from the smaller flue, so the birds are safe. In fact, they probably benefit from the bit of heat that comes from the smaller flue."

Stake out a chimney in town to enjoy the air show or monitor a wooden chimney swift tower near you.

Chimney swifts are declining and listed as "Near Threatened" so Audubon of Western Pennsylvania has placed chimney swift towers in our area.  ASWP needs your help tracking whether swifts are using the towers during migration.  Click here for information on how you can help.

 

(video from JimHowDigsDirt on YouTube)

p.s. Thanks to Joe Fedor for sending me ASWP's chimney swift news.

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Sep 14 2017

Where Peregrines Nest in the Wild

Precipice Trail, Acadia National Park (photo from Wikimedia Commons)

Precipice Trail, Acadia National Park (photo from Wikimedia Commons)

This year, for the first time since 1984, my husband and I aren't at Acadia National Park this month but I think of it every day.  If I was there I'd be stopping by the base of this mountain to scan for peregrines.  It's one of the few wild places where I know they nest.

On Throw Back Thursday here's a description of the peregrines' wild nest sites at Acadia with news from 2010:

Where The Peregrines Nest

 

(photo of the Precipice Trail at Acadia National Park from Wikimedia Commons; click on the image to see the original)

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Sep 13 2017

In Hot Water

Two men holding an Atlantic sailfish caught off the coast of Port St. Lucie, Florida (photo from Wikimedia Commons)

Two men holding an Atlantic sailfish caught off the coast of Port St. Lucie, Florida, 2010 (photo from Wikimedia Commons)

The warming ocean has been in the news lately as the most powerful Atlantic hurricanes ever recorded -- Harvey's rain and Irma's wind -- slammed into Texas, the Caribbean, and Florida.  The ocean is hotter now than any time since record keeping began in the 1880's and, though hotter water doesn't cause hurricanes we've learned it makes them worse.  Uh oh!

There's another sign the ocean is warming.  Fish are on the move.  A wide variety of species including sole, haddock, herring, and black sea bass have left places too warm for them and migrated to cooler water.

For example an enormous Atlantic sailfish (Istiophorus albicans), normally off the coast of Florida above, was caught in the Cape Cod Canal in August 2013.  It was the first Massachusetts record.

It's not just temperature that makes fish move.  Warm water has less oxygen, so it's harder to breathe, and more carbon dioxide so it's more acidic.  Acidic water holds less calcium carbonate, the building block of sea shells including those of tiny copepods.  With fewer tiny organisms there's less food all the way up the food chain.

Fish swim away from these "deserts" but some animals can't move very far. Think of lobsters, now gone from Long Island Sound.

The changes in species affect both fishermen and nesting seabirds.  The old catch limits refer to fish that can't be found because they've moved north, and baby puffins starve because the new species are too big for them to swallow.

From more powerful hurricanes to fish leaving home, we're in hot water!

 

Read more in this article from Yale e360: Feeling the Heat: How Fish Are Migrating from Warming Waters

(photo from Wikimedia Commons; click on the image to see the original)

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Sep 12 2017

Wild Things Outside!

Published by under Mammals

For the past two mornings I've heard wild things screaming in my backyard at 5am.  It's two hours before sunrise. What are those weird sounds?

Raccoons!  And they're fighting!

I didn't go outdoors to record them but I found two videos that include the sounds -- above in Toronto, below on someone's roof.

 

Why are raccoons fighting in my backyard?  I believe it's the watering hole effect.  It's been very dry in Pittsburgh so my birdbath is one of the few sources of water.  All the animals come for a drink before their bedtime and BAM!

A word to the wise: Don't go outdoors to visit the raccoons.  They may have rabies.

 

(videos from YouTube; click on the YouTube logo on each one to see its original)

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Sep 11 2017

The Zig Zag Web

Published by under Insects, Fish, Frogs

Yellow garden spider female with prey (photo by Kate St.John)

Yellow garden spider female with prey, Virginia Beach, 5 Sept 2017 (photo by Kate St.John)

Last week in Virginia Beach my mother said, "Come see my spider."  We stepped out the front door and there she was, an impressive yellow garden spider with a zig zag web.

Yellow garden spiders (Argiope aurantia) are very common orb weavers but we rarely notice them until late summer when the females have reached full size, about an inch long.   At this point their webs are also large with conspicuous vertical zig zags(*) giving them this alternate name in Virginia: the sewing machine spider.

My mother's spider hid behind her web which in turn was camouflaged by the light colored brick behind it.  (Click here to see a more obvious zig zag.)  In these photos the spider is packaging prey in gauze or perhaps eating it.

Yellow garden spider with prey (photo by Kate St.John)

Yellow garden spider with prey (photo by Kate St.John)

My mother pointed out a smaller web nearby with a smaller spider in it, only 0.2 to 0.3 inches.  It was the male who will eventually come courting, but he has to be very careful and quick.  His goal is to deliver both sperm packages without being attacked.  After delivering the second one he dies a natural death.  Then the female eats him.

Soon the female will lay 500 to 1,000 eggs in a small brown sac which will overwinter and hatch in early spring.  The tiny spiderlings are cannibals, too, but those who survive will play out the same story next year.

If you find a yellow garden spider you can enjoy it in peace.  Even though the females are large, they won't bite unless you grab them (egads!) and their venom is harmless to humans.

Read more about these and other Pennsylvania native spiders in this fact sheet from Penn State.

 

(photos by Kate St. John)

(*) The zig zag is called a stabilimentum.

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