Leaves and Merlins

Hornbeam seeds with spider/insect cocoons, 21 Nov 2021 (photo by Kate St. John)

27 November 2021

Nature was busy this week. Spiders or insects wove tiny white cocoons inside this hornbeam seed structure. Chickadees look for these cocoons and eat the tasty treats inside.

As predicted, Schenley Park’s gingkos lost all their leaves in a single day — 20 November.

Gingkos shed all their leaves on Schenley Drive, 20 Nov 2021 (photo by Kate St. John)

Norway maples were not far behind on the 24th.

Three trees on 24 Nov 2021: 1 bare, 2 maple fallen leaves, 3 red oak leaves waiting (photo by Kate St. John)

I went to Schenley Park golf course to find a merlin just before sunset on 23 November. Instead I found three merlins jostling for the highest perch on the highest hill. The tallest snag in this photo is not the highest perch but the dot on top is merlin #2 of 3 who is watching the airshow as 2,500 crows fly over from the Allegheny Valley to where? Crows were still passing overhead when I left.

After sunset the sky still glowed.

Cathedral of Learning, Heinz Chapel, and WQED’s transmission tower after sunset 23 Nov 2021, Pittsburgh, PA (photo by Kate St. John)

(photos by Kate St. John)

Very Tiny Possums

Adult male honey possum, Tarsipes rostratus from Scott National Park in the southwest of Western Australia in torpor (photo by Don Bradshaw via researchgate.net)

The honey possum (Tarsipes rostratus), is a tiny species of marsupial that feeds on the nectar and pollen of a diverse range of flowering plants in southwest Australia.

Who is the other cute possum mentioned in the tweet above?

The little pygmy-possum (Cercartetus lepidus) is the world’s smallest possum, as small as a mouse and considered a threatened species in South Australia.

Government of South Australia

After the 2019 bushfires on Kangaroo Island, Australia, scientists feared the little pygmy possum was dead. Instead…

Definitely cute!

(honey possum photo from researchgate.net; tweets embedded from @LettsGetSnakes and @BBCWorld)

Unusual Crowds of Birds

Crows in winter (photo by Oliver via Flickr Creative Commons license)

24 November 2021

People form crowds, cattle are in herds, dogs in a pack, whales in a pod and birds in flocks. But we have special group names for some species. For instance, a flock of crows is a murder, a flock of starlings is a murmuration.

Here are five unusual crowd names for birds, as listed at The Spruce.

A college of cardinals: Northern cardinals, which are red, were named for Roman Catholic cardinals whose vestments are red. The Church’s body of cardinals is called the College of Cardinals. Fall and winter are the only times when you’ll see a college of northern cardinals. They don’t flock in the breeding season.

A ‘college’ of cardinals in Oklahoma, Feb 2015 (photo from justabirdthing via Flickr Creative Commons license)

A flamboyance of flamingos: Of course.

A flamboyance of American flamingos (photo from Wikimedia Commons)

A charm of goldfinches: This group name originated in England where the native European goldfinch has a (charming) red face.

A charm of goldfinches on teasel (photo by Natural England via Flickr Creative Commons license)

A palette of painted buntings: Flocks of painted buntings are hard to find, but even a lone male is a palette of color.

Male painted bunting in Freeport, TX(photo from Wikimedia Commons)

A committee of vultures: This committee is distracted as a latecomer joins them.

A committee of turkey vultures in Pennsylvania (photo from Wikimedia Commons)

Vulture committees have a long and colorful history which continues to this day. I am reminded of Lewis Nordan’s 2003 book, Wolf Whistle, set in 1955 Mississippi where vultures are “buzzards,” described and quoted in this Amazon review:

Ancient buzzards named after Southern politicians take up daily residence on a telephone wire above Arrow Catcher’s main street. “The buzzards were named Vardaman and Bilbo and Hugh White and J.P. Coleman and Ross Barnett and other names of past and future governors and senators of the sovereign state of Mississippi.”

The committee pictured above is in Pennsylvania.

p.s. See more flock names at The Spruce.

(photos via Flickr and Wikimedia Creative Commons licenses. Click on the captions to see the originals)

Talking Turkey: The Band of Brothers

Three male wild turkeys displaying (photo from Wikimedia Commons)

23 November 2021

When we gather over turkey this week we won’t be thinking of the wild birds that inhabit our parks and neighborhoods. But wild turkeys will be social gathering, too, in flocks that are like extended families.

Members of wild turkey (Meleagris gallopavo) flocks are often siblings. The males are usually brothers and though only one male, the dominant brother, gets to mate with the ladies the brothers work together to protect their territory. This 2013 article, Band of Brothers, explains the pecking order.

Sometimes the band of brothers causes trouble. For instance, they don’t recognize their own reflection so they attack those turkeys on the shiny car.

Moral of the story: If you part outdoors in turkey country, it’s best to have a dirty car.

p.s. Click here to see two turkeys chase the police in McCandless Twp last January.

(photo from Wikimedia Commons, click on the caption to see the original)

Why Do Zebras Have Stripes?

Zebra stripes (photo from Wikimedia Commons)

22 November 2021

While thinking of the wild zebras of Maryland, I wondered …

Why do zebras have stripes? There are many theories.

Are zebra stripes for camouflage from predators?

No. A 2016 study by Univ of Calgary and UC Davis examined the visual acuity of the zebras’ top predators, including lions and hyenas, and compared it to what zebras and humans can see.

Predators of zebras: spotted hyena and lion (photos from Wikimedia Commons)

The study found that beyond 50 meters (about 164 feet) in daylight or 30 meters (about 98 feet) at twilight, when most predators hunt, stripes can be seen by humans but are hard for zebra predators to distinguish. And on moonless nights, the stripes are particularly difficult for all species to distinguish beyond 9 meters (about 29 feet.) This suggests that the stripes don’t provide camouflage.

UC Davis: Zebra Stripes Not for Camouflage

In fact, to distant lions and hyenas, zebras look as plain as a wild ass.

Photos of three zebra species and African wild ass from PLOS ONE: Zebra stripes through the Eyes of Their Predators, Zebras and Humans

Are zebra stripes for identifying each other?

Each zebra has stripes as unique as our fingerprints. No two zebras are the same. We humans can visually identify individual zebras by their patterns (see below). However, the same 2016 study found that zebras don’t see their own stripes as well as we do.

Do zebras use the stripes for identity? Not exclusively.

Two zebras in the wild (photo from Wikimedia Commons)

Wikipedia explains that a new zebra mother imprints her own striping pattern, scent and vocalization on her foal so the youngster will recognize and follow her.

Are zebra stripes for cooling?

Maybe. A 2015 study at UCLA posited that the stark black-and-white stripes set up convention waves on the animals’ coats, making them cooler in the African sun. Wider stripes cool better than narrow ones. To support the theory, among the three species of zebras (shown above with wild ass) the widest striped live in the hottest part of Africa while the narrow-striped live in the cooler region.

This theory has not been tested, though.

Are zebra stripes for protection against biting flies?

Yes. This has been fully tested by biting flies, zebras, and horses wearing zebra coats.

A horse dressed as a zebra to investigate fly behavior in England (Credit: School of Biological Sciences/University of Bristol), embedded from NYTimes article quoted above

In a 2019 study — Benefits of zebra stripes: Behaviour of tabanid flies around zebras and horses — zebras and horses wearing zebra stripes were exposed to biting flies. The flies could not land on the stripes.

The zebra stripes seemed to dazzle the flies so much that they couldn’t manage a controlled landing. Flies zoomed in too fast and either veered off just in time — or simply bumped into the zebra and bounced off. The flies didn’t seem to like the zebra coats on horses, either, but their bare heads were fair game.

New York Times: Why Do Zebras Have Stripes? Scientists Camouflaged Horses to Find Out

Protection from flies is a big advantage for zebras because they have short, bite-able coats and “they are uniquely susceptible to the diseases carried by the flies.”

However, there is no simple answer.

“Really, the striping is kind of extraordinary, so you need something extraordinary to explain it.”

Why do zebras have stripes? It’s not for camouflage

There are many reasons for having stripes but only the zebras know for sure.

Zebras at Ngorongoro Crater, Tanzania (photo from Wikimedia Commons)

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

Appreciating Crows

American crow in Castle Shannon, Pittsburgh (photo by Christopher Bailey via Wikimedia Commons)

21 November 2021

Pittsburgh’s winter crow flock has been avoiding my North Oakland neighborhood for three weeks now and I miss them. When I see them in the late afternoon, if I see them at all, they are flying very high in a steady stream. Where are going? Does anyone know?

The only crows I see are too few or too high for me to appreciate their raucous calls and aerial antics so I enjoyed them this recent video from #LesleytheBirdNerd. Listen to a crow Meow!

Like the video? Subscribe to Lesley’s channel at https://www.youtube.com/c/LesleytheBirdNerd/

If you know where Pittsburgh’s crows are roosting (spending the night), please leave a comment below. I’d love to find them.

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

Seen This Week

Ginkgo turning yellow at Schenley Park, 13 Nov 2021 (photo by Kate St. John)

20 November 2021

This week we had a last blast of fall color, a partial lunar eclipse and a surprising confirmation of pigeon fertility. Here are a few scenes from 12-19 November.

The ginkgo trees (Ginkgo biloba) turned yellow and will probably drop their leaves in a single day. Red oaks and hickories made a bright splash of color at Phipps’ outdoor garden on Monday.

Red oak at Phipps garden, 15 Nov 2021 (photo by Kate St. John)

Some beech leaves were already brown though the leaf veins were still yellow. Beech leaves cling to the smaller trees all winter, becoming paper thin and rattling in the wind.

Beech leaves turn brown though the veins are still yellow, Schenley Park, 15 November 2021 (photo by Kate St. John)

On Wednesday 17 November four of us drove north hoping for water birds but were disappointed by the lack of bird activity, particularly after the clouds moved in. Colorful leaves were scarce in Crawford County, especially at Conneaut Outlet swamp where high water killed the trees. This scene says “November in western Pennsylvania.”

Conneaut Outlet, Crawford County, 17 Nov 2021 (photo by Kate St. John)

On 18 November I saw a pigeon feeding two babies at its nest on Filmore Street near the Cathedral of Learning. Yes, nesting in November! Feral rock pigeons (Columba livia) breed year round if there’s enough food — and there is at this pile of birdseed on the corner.

Birdseed for pigeons at S. Dithridge & Filmore, 18 Nov 2021 (photo by Kate St. John)

As expected the partial lunar eclipse was obscured by clouds in Pittsburgh at 4am on 19 November. Only a tiny bright uneclipsed sliver is visible. The clouds are lit from below by the city lights.

Partial lunar eclipse obscured by clouds. Only the bright sliver shows in Pittsburgh, 19 Nov 2021 (photo by Kate St. John)

More leaves fell this week but most of the trees are not yet bare. Here’s a week’s worth of change at Schenley Park, 12 and 19 November.

Maples are bare, oaks are red, Schenley Park, 12 Nov 2021 (photo by Kate St. John)
Not yet. Most of the trees are Not bare. Schenley Park, 19 Nov 2021 (photo by Kate St. John)

The leaves are hanging on about two weeks longer than they used to. When will most of the trees be bare in Pittsburgh? Soon.

(photos by Kate St. John)

Remembering a Wintry November

Snow and ice after a winter storm (photo from Wikimedia Commons)

19 November 2021

This week’s weather was mild with highs up to 65oF and most lows above freezing until this morning. Not so seven years ago.

For three days in mid November 2014 a winter storm hammered the Great Lakes and brought unusually cold weather to western Pennsylvania. Pittsburgh was very cold without much snow but there was an amazing storm in Buffalo, New York. Here are two vintage articles that tell the story.

A reason to be grateful for very cold weather: Winter is a Great Pest Control System

How birds avoided the Buffalo blizzard of 18 November 2014. Avoiding The Storm

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

Bitter Nuts

Bitternut hickory nuts with peeling and whole husk (photo by Kate St. John)

18 November 2021

In case you don’t think tree names are descriptive consider the bitternut hickory (Carya cordiformis). Closely related to pecans (Carya illinoinensis) the nuts are so unpleasant that even squirrels avoid them. That explains why I found so many on the ground at Yellow Creek State Park on 6 November.

I didn’t know what they were so I brought several home to identify them. The thin husk that splits just halfway up the hard shell is diagnostic for bitternut hickory. I cracked one open.

Bitternut hickory nuts: whole, cracked and still in husk (photo by Kate St. John)

It resembles a pecan, as it should since it’s a “pecan hickory.”

Bitternut hickory nut cracked open (photo by Kate St. John)

Is the nut bitter? I usually don’t sample wild food but why not? I tasted a tiny bit.

Yow! Bitter! Astringent. I washed out my mouth several times before the taste went away. No wonder squirrels avoid these. Wikipedia says rabbits eat them, though.

Bitternut hickory nutmeat (photo by Kate St. John)

Obviously the nuts are not valuable to humans but the wood is hard and durable, used for furniture, paneling, tool handles, ladders and for smoking meat — as in hickory-smoked bacon.

The smoke may be nice but not the bitter nuts.

Further reading: Here’s how to identify the bitternut hickory in winter.

(photos by Kate St. John)