All posts by Kate St. John

From Broad Wings to Red Tails

Broad-winged hawk on migration (photo from Wikimedia Commons)

15 September 2019:

You can tell what month it is at a Pennsylvania hawk watch by noticing the most abundant raptor.

If you’re seeing a lot of broad-winged hawks, it must be September. Broad-wing migration peaks right now; they’ll be gone by the end of the month.

If you’re seeing a lot of turkey vultures and red-tailed hawks it must be October. In the fall of 2018, 90% of the turkey vultures that passed the Allegheny Front Hawk Watch went by in October.

Turkey vulture in flight (photo from Wikimedia Commons)

Red-tailed hawks spread their migration over several months. Last year at the Allegheny Front roughly 25% were seen in September, 50% in October, 25% in November.

Red-tailed hawk at the Allegheny Front, 31 October 2016 (photo by Steve Gosser)

If golden eagles are at their most abundant, it must be mid-October to mid-November. It’s my favorite time of year at the Allegheny Front.

Golden eagle at the Allegheny Front, 2 Nov 2016 (photo by Steve Gosser)

Pennsylvania hawk watches are about to switch from broad-wings to red-tails. Count the raptors to find out what month it is. 😉

(Broad-winged hawk and turkey vulture photos from Wikimedia Commons; click on the caption to see the originals. Red-tailed hawk and golden eagle by Steve Gosser)

Goldenrod In Stages

Goldenrod is going through its paces this month. Here are a few of the stages you’ll see in a native of Pennsylvania, Canada goldenrod (Solidago canadensis).

Buds like these may be hard to find in September because …

Goldenrod buds (photo from Wikimedia Commons)

… Goldenrod is in full bloom.

Flower plume of Solidago canadensis (photo from Wikimedia Commons)

Insects are busily fertilizing the flowers this month. By late September they’ll dry out and develop seeds.

Goldenrod in late September, after flowering (photo from Wikimedia Commons)

In October the seeds are ready to blow on the wind.

Goldenrod gone to seed, October 2016 (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)

Take A Birding Break

Click here to watch the video

Would you like to take a birding break?

Spend a few minutes watching fall warblers in Central Park in a video by Quoteny, recorded August to October 2014.

Enjoy the birds’ delicate beauty or challenge yourself to identify them, listed them below in order of appearance.

Click here to watch the video.

In order of appearance:

  • Magnolia warbler
  • Black-and-white warbler
  • Black-throated blue warbler
  • Common yellowthroat
  • American redstart (female or immature)
  • Palm warbler
  • Hooded warbler (adult male)
  • Northern parula
  • Yellow-rumped warbler (notice that in this view it isn’t showing any yellow)
  • Red-eyed vireo
  • Blackpoll warbler (bathing)
  • Northern waterthrush
  • Ovenbird (mesmerized by a rat)

(photo is a screenshot from video by quoteny on YouTube)

Is The Blob Back Again?

Sea surface temperature anomalies in northeast Pacific, 2014 and 2019 (maps from NOAA)

In the fall of 2014 a persistent weather pattern in the northeastern Pacific stopped the normal upwelling of cold water from Alaska to California. Sea surface temperatures rose 7 degrees F.

When that happened, cold water nutrients and organisms stayed too far below the surface to feed the fish, birds and animals that depend on them. Species starved throughout the food chain including crabs, sea stars, salmon, Cassin’s auklets, common murres, and sea lion pups.

Cassin’s auklet takes off (photo from Wikimedia Commons)

This month a similar weather pattern has created a similar temperature anomaly. NOAA says it already ranks as the second largest marine heatwave in the northern Pacific Ocean in 40 years — second only to “the Blob.” (see maps above)

If the weather doesn’t change soon, if the winds don’t pick up and stir the sea, then “The Blob” will be back again and it will be bad news for everything in the northeastern Pacific.

Learn what happened during The Blob of 2014-2015 in this vintage article: Death By Warm Water.

(maps from NOAA, photo from Wikimedia Commons; click on the captions to see the originals)

Turtles Ride Out The Storm

Loggerhead sea turtle off Sandy Point, Abaco, 2006 (photo from Wikimedia Commons)

Loggerhead sea turtles (Caretta caretta) live underwater but must surface to breathe and walk up the beach to lay their eggs. They’re vulnerable to extinction due to loss of nesting habitat, fishing bycatch and vessel strikes. Scientists also wondered: Do tropical storms pose risks for adult sea turtles?

In June 2012 just before Tropical Storm Debby began to spin off of Florida’s Gulf coast, scientists tagged a loggerhead sea turtle with a GPS tracking device. Nicknamed Eleanor, she laid eggs on the beach and returned to the sea near Sarasota. Then the storm arrived.

Would the storm hurt Eleanor? They watched her for clues.

Tagged loggerhead sea turtle returning to the sea after laying eggs, Archie Carr NWR, Florida (photo from Wikimedia Commons)

Before the storm Eleanor saved energy for her next egg-laying excursion by resting on the seabed and only moving when she surfaced for air.

When Tropical Storm Debby arrived, Eleanor was caught in it and swept north by its current. The storm churned for four days with sustained wind speeds of 65 mph. Eleanor was active the entire time.

Tropical Storm Debby, 24 June 2012 (photo from Wikimedia Commons)

Instead of resting she swam, dove, and surfaced. Amazingly, this used no more energy than she would have expended on producing 2% of her next set of eggs. Meanwhile the storm pushed her 62 miles (100 km) north of her nesting beach.

Loggerhead sea turtle (photo from Wikimedia Commons, Creative Commons license)

When the storm was over, Eleanor swam south, found her nesting beach, and laid her next clutch just 250 feet (75 m) from her last one.

Sea turtle tracks after egg laying (photo from Wikimedia Commons)

The study concluded that tropical storms don’t pose much risk to adult sea turtles like Eleanor.

Unfortunately, as researcher Maria Wilson pointed out, “Sea turtle nests are extremely vulnerable to passing storms. The storm that Eleanor easily survived destroyed almost 90% of nests on the beach where she and several hundred other female turtles had laid their eggs.”

The study concluded that when it comes to protecting seas turtles we should focus on protecting nests and helping newly hatched turtles. We don’t need to worry about the adults. They can ride out the storms.

Read more in this article at Science Daily. Note: These are not photos of Eleanor.

(photos from Wikimedia Commons; click on the captions to see the originals.)

Locust Swarms Act Like Facebook

Mormon cricket, Sept 2014 (photo from Wikimedia Commons)

In the American West there’s a 3-inch long katydid called a Mormon cricket (Anabrus simplex) that cannot fly but it sure can walk.

We hardly notice Mormon crickets until millions swarm and march across the landscape, advancing more than a mile a day like a Biblical plague of locusts. Naturally scientists wondered what makes them do it.

Swarm of Mormon crickets heading eastward through a culvert on Halfway Highway, Oregon, circa 1939 (photo from Wikimedia Commons)

A 2006 study discovered that the swarms are driven by hunger and fear. The crickets are hungry for protein and salt so they start to migrate, but the bugs are cannibals and will eat each other if they can. Those at the back of the pack pursue the front line to catch and eat them. Fear forces the crickets to keep track of their neighbors and constantly on the move.

Despite the danger from behind, individuals sometimes double back into the crowd. If enough of them do it the whole swarm changes direction. How does this happen? What signals such a change?

In 2011, a study of locust swarming behavior at the Max Planck Institute worked on a computer model to predict the bugs’ behavior. Nothing adequately mirrored the swarms’ movements until researchers applied a social networking model that predicts the movement of human opinion on Facebook and Twitter. Somehow the locusts walking in one direction convince others to walk in the same direction. As researcher Gerd Zschaler remarked,

We concluded that the mechanism through which locusts agree on a direction to move together (sometimes with devastating consequences, such as locust plagues) is the same we sometimes use to decide where to live or where to go out: we let ourselves be convinced by those in our social network, often by those going in the opposite direction.

We don’t necessarily pay more attention to those doing the same as us, but many times [we pay more attention] to those doing something different.

Swarms of locusts use social networking to communicate, Science Daily

Our opinions move like swarms of locusts.

Swarms of locusts act like Facebook.

p.s. If you’ve never seen a swarm of Mormon crickets click here for a National Geographic video. Read more about locust swarming behavior in Science Daily.

(photos from Wikimedia Commons, click on the captions to see the originals)

Ahhh Chooo!

Common ragweed flower head (photo from Wikimedia Commons)

Ragweed season officially began August 15 and runs through September. I’m not allergic to it, but those of you who are may want to know the enemy and learn how to avoid it.

First, a primer on what is NOT ragweed.

Goldenrod is not ragweed. Ragweed (Ambrosia sp. on left) is a wind-pollinated plant with green flowers on thin spikes. Goldenrod (Solidago sp. on right) is a bee-and-butterfly pollinated plant with yellow flowers in a feathery plume. Don’t worry about those yellow flowers. Goldenrod is not busy spreading pollen; it’s busy attracting bees.

Ragweed (on left) and goldenrod (on right), photos from Wikimedia Commons

Ragweed (Ambrosia genus) is a member of the Aster family native to the Americas but now spread to Europe. The most common species in Pennsylvania, common ragweed Ambrosia artemisiifolia, grows easily by the side of the road and in disturbed places. It doesn’t stand out.

Common ragweed’s female flowers are nearly hidden in the leaf axils and pollinated by the wind.

The male flowers are the ones to worry about. Perched on spikes, facing downward, and loaded with pollen, a slight tap is all it takes to release a cloud of pollen. Imagine what the wind can do!

Closeup of male ragweed flowers in the field (photo from Wikimedia Commons)

A single plant may produce about a billion grains of pollen per season, and the pollen is transported on the wind. It causes about half of all cases of pollen-associated allergic rhinitis in North America. … Ragweed pollen can remain airborne for days and travel great distances, affecting people hundreds of miles away. It can even be carried 300 to 400 miles (640 km) out to sea

Ragweed article, Wikipedia

It’s hard to avoid these pollen grains because they’re so pervasive, but you can be forewarned of a bad pollen day at pollen.com. On the other hand, your nose might know before the website does!

A grain of ragweed pollen (photo from Wikimedia Commons)

Meanwhile, don’t walk past this plant unawares. Here’s what it looks like in a weedy patch.

Ragweed, growing like a weed (photo from Wikimedia Commons)

Know your enemy.

(photos from Wikimedia Commons; click on the captions to see the originals)

(*) Different species of goldenrod have different flower cluster shapes — it’s not always a plume. However tall goldenrod, pictured above, is the one most often called ragweed by mistake.

Viceroys Taste Sour In The Absence of Royalty

Monarch (left) and Viceroy (right) butterflies (image from Wikimedia Commons)

Viceroy butterflies (right) mimic monarchs (left) and queen butterflies (below) because monarchs and queens taste terrible.

According to the Batesian mimicry theory, viceroys resemble inedible butterflies to protect themselves from being eaten.

Queen butterfly (photo from Wikimedia Commons)

But what happens when there are no monarchs or queen butterflies around and the local predators learn that viceroys are safe to eat? The viceroys change their tactics.

A 15 year study in northern Florida — where queen butterflies don’t live — found that in the absence of queens the viceroys retain a chemical in their bodies that makes them taste sour. Thus they aren’t eaten. In fact they thrive.

Viceroys are different in the absence of royalty.

Read more at “A tasty Florida butterfly turns sour” in Science Daily.

(photos from Wikimedia Commons, click on the captions to see the original)

Fringetree Fruit

Fringetree fruit, 31 August 2019 (photo by Kate St. John)

One advantage of botanizing the same place over and over again is that you get to know what grows where. You remember a plant that draws attention in the spring, forget it in the summer when it’s boring, then notice it again in fall. Because it’s in the same location, you know what it is.

The identity of this dangling blue fruit was a puzzle until I remembered that it’s hanging from the fringetree that put on a floral show in May.

One flower of a fringetree in Schenley Park, 18 May 2018 (photo by Kate St. John)
One flower of a fringetree in Schenley Park, 18 May 2018 (photo by Kate St. John)

Each flower can become a blue fruit.

(photos by Kate St. John)

Watch Out, Miami!

Screenshot from Modeling the Greenland Ice Sheet by NASA Goddard

This summer’s arctic heat wave caused rapid melting of the Greenland ice sheet and raised fears that it may disappear in 1,000 years. If it does, our models for future sea level rise are way too low.

That news was eclipsed this week by Hurricane Dorian’s devastation of the Bahamas and threats to the East Coast. The Carolinas took a beating but Miami, pictured below during Hurricane Irma, was spared.

Hurricane Irma in Miami Beach, 10 Sept 2017 (photo from Wikimedia Commons)

Interestingly, Miami has more to worry about from Greenland than from any hurricane.

On 1 August 2019 CNBC wrote, “The historic heatwave that scorched Europe last week has moved to Greenland, where it’s expected on Thursday to melt away 12 billion tons of water from the ice sheet and irreversibly raise sea levels across the world. … This week’s melt alone is estimated to permanently raise global sea levels by 0.1 millimeters.”

A measurable sea level rise in only one week?! NASA Goddard modeled the future of the Greenland ice sheet in the video below. If all of it melts, the sea will rise 80% more than we expected.

Miami should be especially worried about Greenland. Not only will it add a lot of water to the ocean but it’s location will force the water to rise even more in Miami due to uneven gravitational forces around the globe. Learn more about the relationship between location and sea level rise at Which Glaciers Will Flood Your City?

Map of glacial contribution to sea level rise in Miami (screenshot from NASA JPL)
Map of glacial contribution to sea level rise in Miami (screenshot from NASA JPL)

Watch out, Miami! Greenland is going to make a splash.

(Greenland screenshot and video from NASA Goddard, photo of Miami Beach during Hurricane Irma from Wikimedia Commons, screenshot of glacial contribution to sea level rise from NASA JPL)