Monthly Archives: March 2015

The Scouts Are Coming

Bird Behavior, Migration

Adult male purple martin (photo by Cajay on Wikimedia Commons)

You know Spring has sprung when the swallows return.  Tree swallows arrive first (seen in Allegheny County already!) but soon the bravest purple martins return from Brazil.  Though they rely on flying insects for food, adult males are so anxious to begin breeding that they fly home as soon as they can.

Purple martins (Progne subis) are cavity nesters with a long term relationship to humans.  Native Americans first provided nesting gourds and European immigrants followed suit so that now, for more than 100 years, all the purple martins in eastern North America nest in human provided housing.

Purple Martin house, Cape May Point, NJ (photo from Wikimedia Commons)

Last Thursday at Wissahickon Nature Club Bob Allnock, a purple martin landlord from Butler County, taught us about the housing and habits of these amazing birds.  We learned that the same purple martins return year after year to their successful nest sites.   The earliest males get the best condos so they hurry to get home.  The landlords call them “scouts.”

Scouts are always adult males who’ve bred before and know exactly where they’re going.  Adult females return later and then, weeks later, the subadult males and females arrive.  They’re in their first year of breeding and haven’t found a home yet.  If you’re trying to establish a new purple martin colony, these are the birds you wait for.

Right now purple martin landlords in western Pennsylvania are anxiously awaiting their first scouts.  As soon as one arrives the landlord updates the Purple Martin Conservation Association (PCMA) website with the date and location.  They also update when they see the first subadults so that landlords of unoccupied colonies can be on the lookout to attract these new birds.

How far north has Spring advanced? Where are they scouts right now?  Click here on the PCMA website for the Scout Report.

 

(photos from Wikimedia Commons. Click on the images to see the originals)

Peregrine Quest: Mixed Results

Nesting & Courtship, Peregrines

Peregrine Quest view from Flag Plaza, 3/22/15 (photo by Kate St. John)

On Sunday afternoon five of us scoured Downtown Pittsburgh looking for the peregrine falcon pair who haven’t used the Gulf Tower nest since March 10.  They’ve got to be nesting somewhere by now, but where?  Our Peregrine Quest came up with mixed results.

Doug walked Gateway Center/Market Square.  Denise and her husband checked midtown including the 2012-2013 nesting zone. I checked Penn/Liberty and went to the North Shore for a wider view and John English went to Flag Plaza.  Only John saw peregrines and he saw them almost immediately.  (UPDATE: See Doug’s comment below.)

After John texted me with two peregrine sightings back-to-back — one flew past BNY Mellon down the Forbes-Fifth canyon and one perched on UPMC (U.S. Steel Building) —  I raced over to Flag Plaza to see them, too.  I hadn’t been there long before we saw an exciting but silent interaction.

A female peregrine was flying around UPMC and approaching the building again from the left when a male peregrine popped out from behind the building (using it as a blind) and attacked her from above!  She evaded his dive-bombing and sailed around UPMC one more time, then circled up and sailed off toward Oakland.

Here’s a map of the buildings (red pins), the peregrine perch (green pin), our vantage point (brown pin), and the peregrine flight paths during our half hour of watching.   After the attack the male perched on UPMC for a while but we missed seeing him leave.

View Downtown Pittsburgh, Peregrine Tussle, 3/22/15, 2pm in a larger map

 

Why would a male peregrine attack a female during nesting season?  The only time I’ve seen this happen is when the pair has eggs in the nest, the female is busy at the nest, and a new female shows up.  The male then defends his territory, nest, and mate from an intruding female.  So my guess is that the Downtown peregrines already have a nest.

We learned that they’re spending time at this end of town, but we still don’t know where they’re nesting.

 

(view from Flag Plaza, photo by Kate St. John with lousy late afternoon light)

Reminder: March 29 Outing at Schenley Park

Books & Events, Schenley Park

Coltsfoot blooming (photo from Wikipedia under GNU Free License) Just a reminder that I’m leading a bird and nature walk on Sunday March 29, 8:30am in Schenley Park.  Meet at Bartlett Shelter.
(Note that Schenley Drive is closed until 9:00am for CMU Buggy Race practice.)

Click here for more information and for updates if the walk is canceled for bad weather.

Maybe we’ll see coltsfoot.

 

(photo of coltsfoot from Wikimedia Commons. Click on the image to see the original)

 

 

Birds As Musical Notes

Beyond Bounds

Birds on wire (photo from Wikimedia Commons)

Bird photography can be disappointing.  It’s difficult to get depth without good lighting, but every once in a while two dimensions are stunning and an eye for cropping is all you need.

This photo of brown-headed and/or bronzed cowbirds in Silao, Mexico looks like musical notes.  Can you play this tune?

 

Click here to see the original uncropped photo, and here to see this exceptional one in larger format on Wikimedia Commons.

(photos from Wikimedia Commons.  Click on the links to see the originals)

Analemma

Weather & Sky
Analemma photo taken 1998-99 outside Bell Labs in NJ by Jack Fishburn (GNU free licensing, Wikipedia)
Analemma photo taken 1998-99 outside Bell Labs in NJ by Jack Fishburn (photo from Wikipedia)

21 March 2015

The word Analemma sounds like a girl’s name or perhaps an exotic fruit but in fact it’s the name for that figure 8 hanging in the sky above.  You won’t see it in Nature but you may have seen it as a symbol printed on an old-fashioned globe of the world.

Technically speaking an analemma is the location of one celestial body as viewed from another for one complete orbit.  Practically speaking it’s the Sun’s position throughout the year at the same location and time of day on Earth.   I was surprised to learn it’s a figure 8 but that’s because the Earth’s orbit is elliptical and tilted.

This photo took a whole year to create.  Every other week in 1998-1999, Jack Fishburn took a photograph of the sun’s position from his office window at Bell Labs.  He was careful to place the camera in the exact same position and snap the photo at the same time of day (correcting back to Standard Time during Daylight Savings).  After collecting a year of photographs he overlaid them to create the analemma.

Tunc Tezel did the same thing at Baku, Azerbaijan and made it a movie here.

You can create your own analemma if you’re persistent (one whole year) and precise (same camera location and time of day for every photo) and have access to Photoshop.

When you’re done you’ll know that the top of the 8 is the summer (northern) solstice, the bottom is the winter (southern) solstice, and the crossover point is both equinoxes.  Today, one day after the Northern Equinox, the sun is very near the center of the analemma.

 

(photo by Jack Fishburn via Wikipedia GNU Free License. Click on the image to see the original)

Peregrine Quest! March 22, 1pm, Downtown

Books & Events, Peregrines

Empty Gulf Tower nest, 19 March 2015 (photo from National Aviary falconcam at Gulf Tower)
The empty nest at the Gulf Tower, Downtown Pittsburgh

They’ve done it again!  The Downtown peregrines have been absent from the Gulf Tower since March 10 … yet they have been seen Downtown.

Apparently they are planning to nest somewhere else … but where?  Let’s find out.

Join Pittsburgh Falconuts on our quest to find the Downtown peregrines.  We’ll meet on Sunday March 22 at 1:00pm at the Dunkin’ Donuts at 28 Market Square and fan out from there.

If you can’t make it, wish us luck.  We’ll need it!

 

Thanks to John English of the Pittsburgh Falconuts Facebook page for organizing this quest.

(photo of the empty Gulf Tower nest from the National Avairy falconcam)

 

The Crocus Report

Phenology, Plants & Fungi

Crocuses at Phipps, 18 March 2015 (photo by Kate St. John)

Ta dah!  We’ve reached a milestone in The Signs of Spring.  It’s time for the crocus report.

Yesterday morning the crocuses at Phipps Conservatory’s outdoor garden were just about to pop open.  The bright sun warmed the mulch and after another hour they had opened halfway.  I can say with confidence that they bloomed on March 18.

Crocuses opening at Phipps (photo by Kate St. John)

Is this late for crocuses?   I checked back through my blog posts, linked below, to collect their blooming history in Pittsburgh’s East End:

So … though this winter has seemed very cold the crocuses are not delayed too, too long.

 

(photos by Kate St. John)

p.s. They may have bloomed during Monday’s heat but I didn’t walk over to Phipps until yesterday.

Listening to the Secret Sounds Of Trees

Trees, Winter Weeds & Trees
Woman listening with headphones (photo from Wikimedia Commons)
Woman listening (photo from Wikimedia Commons)

18 March 2015

When the trees leaf out six weeks from now we’ll once again hear the sound of rustling leaves.  Did you know that trees also make secret sounds we cannot hear?

Last year an article by Sarah Zhang in Gizmodo caught my attention.  Eavesdropping On The Secret Sounds Of Trees describes the art and science of a Swiss research team, headed by Marcus Maeder, who recorded the internal sounds of trees.

The project, fittingly called trees, attached sensitive microphones to trunks, branches and even leaves, then recorded the sounds and analyzed them in light of simultaneous environmental factors such as drought.  Click here to hear the clicks, pops, hisses and taps made by a Scots pine (Pinus sylvestris).

Closer to home our trees are getting ready for spring, the sap is running, and it’s maple sugaring time in North America.

Maple sugar bucket hanging on a tree (photo from Wikimedia Commons)
Maple sugar bucket hanging on a tree (photo from Wikimedia Commons)

And so I wonder …

If we had those special microphones could we heard the sap rising in the maples? 

Yes!

In 2010 Alex Metcalfe installed headphones on a copper beech at Oakville Galleries in Oakville, Ontario. Anyone could listen to the tree using his installation — and so can you with this video. Wow!

(photos from Wikimedia Commons. Click on the images to see the originals)

Looking For Luck on St. Patrick’s Day

Plants & Fungi

A selection of four-leaf clovers (photo from Wikimedia Commons)

On the day that shows off the three-leafed clover — the St. Patrick’s Day’s shamrock — what are the odds of finding a lucky four-leafed one?  It’s harder than you think.

First of all you have to find clover.  Clover used to be common in every lawn because it was mixed with grass seed to provide natural fertilizer for the grass.  But now clover is absent because lawn care products poison all broad-leafed plants.  Clover is broad-leafed so it dies, too.  No luck for the folks with “perfect” lawns!

Then you have to find the odd ball four-leafed mutation among a sea of three-leafed plants.  On white clover (Trifolium repens) there are usually three leaflets per leaf.  (That’s one leaf on the stem).  But sometimes there’s a mutation and a recessive gene expresses into four.  What luck!  Even rarer and luckier, five leaflets.

On your first hunt through the clover patch, you have a 1 in 10,000 chance of finding a four-leafed clover and a 1 in a million chance of finding the five-leafed variety, according the Minitab statistics blog.   In other words, you’re lucky to find one.  If you do, mark the spot because more lucky leaves are likely to appear on that plant.

Looking for four-leafed clovers today in March’s still-brown grass may be a challenge but here are some tips to help you search.

And save yourself some time.  Don’t look for luck in a perfect lawn.

 

(photo from Wikimedia Commons, CC by SA 3.0.  Click on the image to see the original)