Monthly Archives: August 2016

Update Your Scorecard

Bird Behavior, Peregrines
Magnum at the Cathedral of Learning nest, 12 August 2016, 5:15pm (photo from the National Aviary falconcam at Univ of Pittsburgh)
Magnum at the Cathedral of Learning nest, 12 August 2016, 5:15pm (photo from the National Aviary falconcam at Univ of Pittsburgh)

Get ready to update your scorecard.  There have been two! changes in female peregrine ownership at the Cathedral of Learning so far this weekend.

Friday evening “NR” saw a black/red banded female at the nest and posted a comment that Magnum was back on August 12 at 5:15pm — that’s 17:15 time code on the camera.  The photo above clearly shows Magnum’s bands.

Then Saturday night, August 13 at 6:52pm, members of Pittsburgh Falconuts saw Hope on camera calling loudly.  Terzo was nearby but he waited almost four minutes to join her.  Though her black/green bands are hard to read here, we know it’s Hope based on multiple snapshots.  She visited the nest again alone in the 8 o’clock hour.

Hope returns to the nest, 13 August 2016 at 6:52 pm (photo from the National Aviary snapshot camera at Univ of Pittsburgh)
Hope returns to the nest, 13 August 2016 at 6:52 pm (photo from the National Aviary snapshot camera at Univ of Pittsburgh)

 

So here’s the state of play at the Cathedral of Learning pre-dawn on August 14.  I’m writing this before they wake up and change things again!

  • 30 Nov 2015: Hope arrives at the Cathedral of Learning
  • 8 April 2016 (same day):  Hope retains site after unbanded immature female visits the nest.
  • 23 April 2016 (same day): Hope retains site after a banded adult female (black/red) visits the nest.
  • 22 June 2016:  Magnum (black/red 62/H) claims the Cathedral of Learning.
  • 24 June 2016: Hope regains the site.
  • 2 August 2016: Unbanded young female claims the Cathedral of Learning.
  • 6 August 2016: Hope regains the site.
  • 12 August 2016:  Magnum (black/red 62/H) claims the Cathedral of Learning.
  • 13 August 2016: Hope regains the site.

As of this writing I have no idea where Magnum is but she knows her way around.  She’s been to the Cathedral of Learning before, possibly on April 23 and certainly on June 22.  Her home base has been the Neville Island I-79 Bridge, to which she returned after her last visit.

I don’t know how long Hope will stay this time.  Don’t even ask!

As I said on August 6, no humans ever see how these turnovers occur.  As far as I can tell no peregrines get hurt.

Thank you to NR and to all of you who check the Cathedral of Learning falconcam for peregrine activity.  Without your help we’d never know how interesting this summer has been.

 

(photo from the National Aviary falconcam at Univ of Pittsburgh)

Why It Feels SO HOT Outside

Weather & Sky

It’s not the heat, it’s the humidity.  But its not the relative humidity.(*)

As a raw number, relative humidity doesn’t tell you anything.  The video above shows how the same amount of water produces different relative humidities depending on air temperature.

For example, early yesterday morning in my backyard it was 80 degrees with relative humidity 79%.  Last Tuesday it was 66 degrees with relative humidity 83%.

So didn’t yesterday’s 79% humidity feel better than 83% last Tuesday?  No!  Yesterday’s 80 degrees held a lot more water.

Dewpoint (the temperature at which the air is so saturated that it rains or produces dew) is the helpful number that tells us that.  If you know the temperature and relative humidity you can calculate the dewpoint here.

The National Weather Service in Chicago made a chart to describe how we feel at various dewpoints.  I’ve marked it in red to show my own heat-averse opinion.  (Click on the screenshot to see their dewpoint video that includes this chart.)

How dewpoints feel (chart from NWS Chicago video, altered to show how it feels to me)
How dewpoints feel (chart from NWS Chicago video, altered to show how it feels to me)

So here’s what was really going on this week and why it felt so hot yesterday even though the temperature never reached 90 degrees.  Notice that the relative humidity was at its lowest yesterday afternoon.

Date/Time Temperature Relative Humidity Dewpoint Comfort Range
Tuesday Aug 9, 7am 66oF

83%

 61oF Rather humid, almost comfortable
Friday Aug 12, 7am 80oF

79%

72oF

 Oppressive
Friday Aug 12 afternoon, 2pm 88oF

59%

72oF

 Oppressive

 

Find out the dewpoint before you go outdoors and you’ll know whether you want to brave it!

 

(*) p.s. See the comments!

(video from Richard Clements on YouTube. screenshot from NWS Chicago video. Click on the screenshot to see the video)

Shorebird Practice

Musings & News, Water and Shore
A photographer and shorebirds at the Mingan Archipelago, Quebec (photo from Wikimedia Commons)
A photographer and shorebirds at the Mingan Archipelago, Quebec (photo from Wikimedia Commons)

It’s shorebird time and many of us are confused. In southwestern Pennsylvania we only see these birds on migration and a lot of them look alike.

I’m not good at shorebirds but I want to be better.  What to do? Practice!  Here are some tips I’m using this month, written down so I don’t forget.  Maybe they’ll help you, too.

Here’s a quick summary:

  1. Prepare in advance.
  2. Take your time.
  3. For some brown/gray shorebirds, 3 field marks are all you need:
    1. Size compared to other birds,
    2. Beak shape, size and color,
    3. Leg length (relative to body) and color.

Still stumped? You’ll have to read …

THE WHOLE LIST:

Prepare in advance:

  • Choose a birding location with lots of shorebirds so you can compare sizes, shapes and behavior.
  • Before you go, narrow your choices to what’s possible at that location at that time of year. Make a list. Highlight the common ones.  Bookmarks help.
  • Take field guides(*), a scope(+), a sun hat, and maybe a chair.  These birds stay put. So will you.

Methods in the field:

  • Take your time!  Study their behavior.  Quick impressions don’t work.
  • Pick one bird to identify.  Learn it well then move on.
  • Don’t focus on plumage yet unless the bird has really striking colors or patterns.  (Plumage is the least useful field mark on difficult shorebirds.)
  • Size: Compare to other shorebirds.  (ex: smaller than a killdeer?)
  • Silhouette:
    • Beak shape: Long or short? Straight or Curved up or down? Convex (bulged) or thin?  Sharp tip or blunt?
    • Legs: Long or short relative to the body?
    • Neck: Long? Short? “No-neck”?
    • Head: Big or little? Round or long?
    • Body: Chunky? Thin? Stubby? Long?
  • Color of beak and legs.  (Sometimes size, beak and legs are all you need)
  • Behavior:
    • Stands tall or always crouched?
    • In a tight flock or solo?
    • Does it stand in water? Or does it stay at the edge, hating to get its feet wet?
    • Does it peck daintily? Grab and go? Move its bill like a sewing machine needle?
    • Does it chase waves?  (field mark of a sanderling)
  • Now look at plumage (adults + juveniles this month).  Does it match your guess?
  • Can’t make up your mind? Repeat the process.

 

If all else fails, hope for a peregrine or merlin to stir them up. Some species are impossible until they open their wings (willets, black-bellied plovers).  And it’s always nice to see a falcon.

 

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

p.s. Did I miss anything?  Do you have a tip for shorebird practice?  Please post it in a comment.

Footnotes:  Here are some great guides to use at home or while sitting in the field. These books are big and heavy.
(*) For plumage and field marks: The Sibley Guide to Birds, 2nd Edition.
(*) For detailed behavior of each species (No pictures): Pete Dunne’s Essential Field Guide Companion

(+) Scope: If you have a really good camera it can out-perform a scope. Photos show the details frozen in time.

Tree Crickets Tune Their Ears

Insects
Tree cricket (Oecanthus sp.), Ohio (photo from Wikimedia Commons)

10 August 2016

Bug noise is everywhere on hot summer nights. Some of the singers are tree crickets.

Tree crickets (subfamily Oecanthinae) live on every continent except Antarctica.  Camouflaged to match their habitat, these long, skinny, nocturnal insects live in trees and shrubs where they eat just about anything. They’re especially fond of aphids.

Male tree crickets “sing” to attract a mate by rubbing the ridges of their wings together, shown in the video below. (If there’s no sound when you play the video, click on the Play arrow in the black blob below the video.)

recording of tree cricket from Wikimedia Commons

The females don’t sing but they certainly listen.  Each species has a distinctive range of frequencies.  The ladies ignore the cacophony of other species. They only listen for their own. Click the arrow to hear the cricket.

Because insects are cold-blooded they move slower in cold and faster in heat, so they trill faster when the weather’s hot.  This means the frequency, and thus pitch, of their songs goes up in higher temperatures.  Here’s the sound of a snowy tree cricket (Oecanthus fultoni) at different temperatures.

So here’s an interesting problem:  Female tree crickets recognize their own species by the frequency of the trill, but the frequency increases as the temperature rises.  How do they recognize the higher-pitched songs?

In a study published last April, researchers at the University of Toronto Scarborough used laser Doppler vibrometry to measure vibrations inside the crickets’ ears.  The instruments were so sensitive that they could see changes at the cellular level.

The study found that “as the temperature changes, tree cricket ears adjust at a cellular and therefore mechanical level to match the changing frequency of the song.”

Read more about it here in Science Daily.

(video of a tree cricket “singing” in Alameda County, California from Wikimedia Commons)

7 Oecanthus species in western Pennsylvania as shown at Oecanthinae.com:  Four-spotted (O. quadripuntatus), Snowy (O. fultoni), Black horned (O. nigricornis), Pine (O. pini), Narrow winged (O. niveus), Two spotted (Neoxabea bipunctata), Davis’ (O. exclamationis)

A Plant With a Place in American History

Plants & Fungi

American Groundnut flowers, August 2014 (photo by Kate St. John)
American Groundnut flowers, August 2014 (photo by Kate St. John)

These mauve-brown flowers aren’t big and showy but they have a place in American history.

American groundnut (Apios americana) is a perennial vine in eastern North America with tuberous roots that are good to eat.  Many Native American tribes cultivated the plant, dug the roots and ate them like potatoes. The Lenape people called them “hobbenis” or hopniss.

Flower and leaves of American groundnut (photo from Wikimedia Commons)
Flower and leaves of American groundnut (photo from Wikimedia Commons)

When Europeans arrived in North America they knew nothing of the plant but learned quickly from the natives to avoid starvation.  The Wampanoag taught the Pilgrims where to find it and how to cook it.  It was probably on the menu at the first Thanksgiving.

Here’s what a freshly dug harvest looks like:

Tubers ("potatoes") of American groundnut (photo from Wikimedia Commons)
Tubers of American groundnut (photo from Wikimedia Commons)

Europeans took hopniss back to the Old World and tried raising it as a crop, but the projects were soon abandoned because Apios americana doesn’t grow well in monocultures and it isn’t large enough to harvest until it’s two to three years old.

More recently the wild foods community has rediscovered hopniss but its desire to grow with other plants — and engulf them — is frustrating to tidy gardeners.

This month is a good time to see American groundnut in the wild.

It’s blooming now in western Pennsylvania.

 

Note:  If you decide to forage for this plant get permission from the landowner before you begin.  This goes for public lands too. For instance, it is illegal to take flowers, plants and animals from Pittsburgh City parks and Allegheny County parks.

(flower photo by Kate St. John. Remaining photos from Wikimedia Commons; click on the images to see the originals.)

 

Asleep In Flight

Bird Behavior
Great frigatebird carrying sleep monitoring equipment (photo by Bryson Voiron from Nature Communications article)
Great frigatebird with sleep monitoring equipment (photo by Bryson Voiron from Nature Communications article)

8 August 2016

On transoceanic airplane trips the passengers try to sleep in flight but the pilots stay awake. (Thank heaven!)  Many birds, including swifts, sandpipers and songbirds, fly non-stop over the ocean for so long that scientists guessed the birds would have to sleep along the way.  But how? Wouldn’t they crash?

As part of their daily lives, great frigatebirds (Fregata minor) fly non-stop for weeks, eating flying fish and ocean-surface food in trips that can span two months and 22,000 miles.  These large birds live over the ocean but not on it because their feathers aren’t waterproof.

Great frigatebirds have got to sleep some time so researchers led by Niels C. Rattenborg of the Max Planck Institute fitted more than a dozen females with instruments to measure sleep and flight time.  The great frigatebird, above, has a sleep-measuring headset and a GPS backpack.

The results of the sleep study were surprising.

Scientists knew that, on land, birds can sleep with only half the brain while the other half stays alert for danger. They found that great frigatebirds half-sleep in the air, too, but sometimes both hemispheres sleep at once for more than two minutes.  They do it while circling on an updraft.

Another surprise was how little the birds slept, clocking only 42 minutes/day in the air compared to 12 hours/day on land.  If they were humans they’d be seriously sleep deprived.

Amazingly the frigatebirds’ performance was not affected by lack of sleep and when they got home they caught up on sleep in their first days on shore.  How many of us wish we could live like that!

Find out more here at Gizmodo or in the report here in Nature Communications.

(photo of great frigatebird with sleep measuring equipment by Bryson Voiron from  “Evidence that birds sleep in flight,” Nature Communications)

Wear Gloves

Plants & Fungi

Arrowleaf tearthumb, flower (photo by Kate St. John)
Arrowleaf tearthumb, flower (photo by Kate St. John)

Don’t pick this flower unless you wear gloves.

Arrowleaf tearthumb (Polygonum sagittatum) is a sprawling annual vine in the Buckwheat family that grows in moist areas.  Individual plants are three to six feet long but you’d have to untangle them to prove it.  I don’t recommend doing that.

The stems are lined with tiny hooks that bend toward the root of the plant.  If you pull the plant with your bare hands … Owww!  It tears your thumb.

Arrowleaf tearthumb: the hooks (photo by Kate St.John)
Arrowleaf tearthumb: the hooks (photo by Kate St.John)

 

We found arrowleaf tearthumb at Jennings Prairie yesterday.  The flowers are quite small so it’s easy to overlook.  Here’s my thumb near the stem to give you some perspective.

Arrowleaf tearthumb: the stem and my thumb (photo by Kate St. John)
Arrowleaf tearthumb: the stem with a thumb nearby (photo by Kate St. John)

 

Remember to wear gloves.

 

(photos by Kate St. John)

 

Another Turnover

Peregrines

If you’re keeping track of female peregrine ownership at the Cathedral of Learning, it changed again this afternoon.

On Tuesday, August 2 an unbanded young female (1.3 years old) arrived on the scene and bowed with Terzo at the nest.  She was present for four days.

Then at 3:25pm today, August 6, Hope reappeared on camera with Terzo.

The action so far has been:

  • 30 Nov 2015: Hope arrives at the Cathedral of Learning
  • 8 April 2016 (same day):  Hope retains site after unbanded immature female visits the nest.
  • 23 April 2016 (same day): Hope retains site after banded adult female visits the nest.
  • 22 June 2016:  Magnum (black/red 62/H) claims the Cathedral of Learning.
  • 24 June 2016: Hope regains the site.
  • 2 August 2016: Unbanded young female claims the Cathedral of Learning.
  • 6 August 2016: Hope regains the site.

I hasten to add that no humans ever see how these turnovers occur.

@PittPeregrines‘ video above pretty much sums it up.

Stay tuned.  I’m sure there will be more turnovers in the future.

 

(video from @PittPeregrines on Facebook)

Big and Beautiful

Insects
Royal Walnut or Regal Moth (photo by Don Weiss)
Royal Walnut or Regal Moth (photo by Don Weiss)

6 August 2016

Beautiful moths come in all sizes.

The royal walnut or regal moth (Citheronia regalis) is the largest moth in the western hemisphere north of Mexico.  With a wing span of 3.75 to 6+ inches (females are largest), it lives in deciduous forests from New Jersey to eastern Kansas and east Texas to Florida.

Citheronia regalis is always big but not always beautiful.  As a caterpillar it’s so scary-looking that it’s called a hickory horned devil.  Here’s the final instar on a child’s hand.

Hickory horned devil, final instar of regal moth (photo from Wikimedia Commons)

True to its name the caterpillar feeds on walnuts, hickories and a lot of other trees.  Since their only job is to procreate the adults never eat. They live only a week.

Now’s a good time to find this big and beautiful moth in southwestern Pennsylvania.

(photo by Don Weiss)