Racing Pigeons And Raptors

Pigeons (Columba livia) and the raptors who hunt them have evolved together for millions of years. The raptors’ successful hunts leave only the fastest, most maneuverable pigeons. Speedy, elusive pigeons mean only the most skillful raptors can survive.  Most of us never get to see this interaction so this dramatic video from Romania is a real treat.

In 9 minutes Porumbeiro shows how his racing pigeons work to elude two raptors: first a peregrine falcon (Falco peregrinus), then a northern goshawk (Accipiter gentilis). 

The pigeons stay in a tight flock because raptors can’t pick out a victim in a moving ball of birds. The raptors try to separate one bird from the group by slicing through the flock. If it works, the raptor pursues the lone bird.

Who will win?

(video by pomumbeiro on YouTube)

Harlequins Warn of Mercury

Male harlequin duck (photo from Wikimedia Commons)

Some birds are canaries in the coal mine, telling us that something’s gone wrong long before we notice it.  Harlequin ducks (Histrionicus histrionicus) are performing that service in Alaska.

A 2017 study by the Biodiversity Research Institute looked for mercury in Alaska’s coastal waters by testing blood samples and molted feathers from harlequin ducks at Kodiak and Unalaska Islands. Blood samples were used because they indicate recently consumed mercury. Molted feathers show mercury when the feathers were formed a year before. 

The study found mercury in harlequins from both locations but those at Unalaska, midway in the Aleutian chain, had eight times more than those at Kodiak, nestled in the Gulf of Alaska. The study then tested the ducks’ main food at Unalaska — blue mussels — and found it there, too.

This is important news for Aleutian residents because they eat lots of seafood.  It also matters to the rest of us since Unalaska’s main port, Dutch Harbor, is the largest fisheries port in the U.S. by volume caught.  

Mercury apparently increases westward in the Aleutian chain. A 2014 study found mercury in fish above the human consumption limit at the western island of Agattu.

Where is the mercury coming from?  In the continental U.S. airborne mercury comes from coal-fired power plants and is regulated and reduced by the EPA.  It can also come from active volcanoes, obviously out of our control.

At this point scientists don’t know where the mercury is coming from, but China’s coal-fired industries are a good bet.  The prevailing wind in the Aleutian Islands originates in Asia more than six months of the year.

Winds over water in the Pacific and Bering Sea, 10 Dec 2018 (screenshot from earth “visualization of global weather conditions, forecast updated every three hours.” )

Unfortunately Alaskans can’t prevent mercury pollution that reaches them from Asia.  Meanwhile the harlequins warn of danger.

(photo of harlequin duck from Wikimedia Commons, screenshot of global winds from earth visualization website; click on the caption links to see the originals)

It Rimes

Rime scene in Helsinki, Finland (photo from Wikimedia Commons)

We don’t have flowers in December but we do have ice and it comes in many forms.  Here’s the first in a series on ice, starting with my favorite:  Rime.

The word “rime” comes from Old English hrim which meant hoarfrost or a chill mist or fog.  Nowadays hoarfrost and rime are not the same thing. Hoarfrost doesn’t form in fog. To get rime there has to be cold fog or the location has to be in the clouds. For that reason, “Rime shouts, Mountains!”  It’s easy to find rime at high altitudes.

Rime at Jay Peak, Vermont (photo from Wikimedia Commons)

Rime forms when super-cooled water drops (in fog or a cloud) crystallize on cold objectsSoft rime is feathery and so lightweight that it can’t break the trees.  Hard rime is denser and comb-like.  Both are white because they contain trapped air.

Soft rime on a small branch (photo from Wikimedia Commons)

The best part about rime is that it can form in a light wind. When it does it points toward the wind because each new crystal is deposited on the windward side. This is counter-intuitive; it’s the opposite of rain.

What direction did the wind blow through this fence?

Rime on a chainlink fence (photo from Wikimedia Commons)

Rime can even coat snowflakes. Graupel, which looks like hail, is actually a rime-coated snowflake.  I wonder if these pop when you step on them.

Garupel in Elko, NV (photo from Wikimedia Commons)
Graupel in Elko, NV (photo from Wikimedia Commons)

This month is a good time to find rime in the Laurel Highlands. My best experience with it was during an east wind at the Allegheny Front Hawk Watch.  No one else was up there to enjoy it.  It was way too foggy!

Click here to see more rime photos including a “rime doughnut” at Summitpost.

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

A Sound That Reminds Me of Home

Last March while birding along Panama’s Pipeline Road we heard a sound that reminded me of home. 

The bird was loud and its sound was tropical — not a Pennsylvania bird — but something about it seemed familiar.

Here’s what we heard:

Rufous piha (audio from Xeno Canto XC107022)

Our guide identified it as the rufous piha (Lipaugus unirufus) a member of the Cotinga family.

So why was his song familiar?  

I used to hear a similar sound in the Wetlands Room at the National Aviary. The sound is gone now — the bird passed away — but for many years his voice defined that room.

Screaming piha (audio from Xeno Canto, XC444908)

The screaming piha (Lipaugus vociferans) is a member of the Cotinga family native to the Amazon. The bird looks boring but his voice is not.

Screaming piha (photo by Dick Daniels via Wikimedia Commons)

It’s too bad he’s no longer with us at the National Aviary.  His voice from the Amazon reminds me of Pittsburgh.

(photo of rufous piha by Amy E. McAndrews on Flickr, Creative Commons license; photo of screaming piha from Wikimedia Commons; audio from Xeno Canto. Click on the captions to see the originals.)

Who’s On The Wire?

Bird on a wire at Carrizo Plain, CA (photo from BLM via Wikimedia Commons)

Here’s a bird you won’t see in Pennsylvania.  He was photographed at Carrizo Plain National Monument, 100 miles (as the crow flies) northwest of Los Angeles, California.

Quiz:  Who is this on the wire? … Notice his long legs.

(photo by Bob Wick, BLM via Wikimedia Commons; click on the caption to see the original)

Raven Gets Creative

Crows are common in the city but ravens are rare so I was surprised to hear a raven this week in Schenley Park.  It called and circled overhead waiting for its companion to arrive. “Brrrock! Brrrock!”  When the second raven caught up they flew away together.

I see ravens in town about twice a year but I only hear them make the Brrrock call.  If I lived where common ravens (Corvus corax) are common, I’d hear their wide variety of sounds.

This video from Anchorage, Alaska gives you an idea of the ravens’ vocal range.  He starts with Brrrock.   Then he gets creative.

(video by dougbrown47 on YouTube)

There’s Never Just One Mouse

Emmalina looks at the source of the mousey sound, Nov 2011 (photo by Kate St. John)

On Throw Back Thursday:

Seven years ago when my cat alerted me to a mouse under the heat duct, I knew in my head that there’s never just one mouse.  But my heart refused to listen and I said to myself, “Of course there’s only one mouse, and when I catch that one I’m done.”

Hah!  Every fall I’m reminded that there are victories but in a 111 year old house you’re never done. Thankfully there are so few mice this fall that Emmalina has not noticed them.  Does this mean there are none or that she’s too old to care?

On Throw Back Thursday, here’s how naive I used to be about mice.  It started with Mouse in the House and followed up with The Observer Effect.

p.s. The photo at top is seven years hold. Here’s a recent one of Emmy, 12 years old now, playing with her treat ball.

Emmy plays with her treat ball, Nov 2018 (photo by Kate St. John)

(photos by Kate St. John)

From Parakeets to Jelly Beans

Male rose-ringed parakeet (photo from Wikimedia Commons)

One thing leads to another:

  • News of a parakeet leads to a food named for pigeons
  • The food leads to the plant it grows on
  • The plant is also cultivated to host an insect
  • The insect creates a sticky substance called lac
  • We harvest the lac to make shellac and use it on …
  • … furniture …
  • … and jelly beans.

The parakeet:  When I learned that rose-ringed parakeets (Psittacula krameri), above, are a nuisance in India because they devastate the pigeon pea crops I wondered … What are pigeon peas?

The food: Pigeon peas (Cajanas cajan) are a tropical legume first cultivated in India 3,500 years ago. The peas are used like lentils as a staple food in Asia, Africa and South America.  I’m sure I’ve eaten pigeon peas without knowing their English name.

Immature raw pigeon peas (left); Mature & split (right) (images from Wikimedia Commons)

The plantCajanas cajan plants are grown for their peas (inside the bean pods) and as the host of a beneficial insect, Kerria lacca.

Pigeon pea plant with seed pods and a flower (photo from Wikimedia Commons)

The insect:  Scale insects lead sexually dimorphic lives. The males can fly to find females, but they don’t eat. The females are immobile, permanently attached to their host plant, sucking its sap. To protect themselves the females produce a sticky covering called lac. Kerria lacca females, shown below, use several trees as their host plants including pigeon peas.

Lac tubes deposited by Kerria lacca insect (photo from Wikimedia Commons)

We harvest the lac to make shellac.  According to Wikipedia, we “infest” the host plants with Kerria lacca females. When the branches are well coated we cut them (sticklac), scrape, sieve and heat to remove impurities (seedlac), then use heat or solvent extraction to create shellac

Alcohol dissolves shellac and makes it spreadable but the liquid form has a 1-year shelf life.  Shellac is stored as flakes and mixed with alcohol at the time of use.

Shellac flakes in various colors (photo from Wikimedia Commons)

The furniture:  Shellac is a superior finish, especially for antiques, but it is fussy.  When I was a kid my father refinished furniture in his spare time and at one point tried shellac. We kids quickly learned “Don’t touch that table!”  Damp glasses left water rings (which faded), alcohol marred it, and household cleaners damaged it.  However, shellac is beautiful.

Restorer applying shellac hand polish to a table (photo from Wikimedia Commons)

And back to food:  When mixed with edible alcohol, food grade shellac makes the shiny coating on jelly beans and other candies.

Jelly beans (photo from Wikimedia Commons)

One thing leads to another, from parakeets to jelly beans.

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

The Inaccessible Rail

Inaccessible Island rail (photo by Brian Gratwicke via Wikimedia Commons)

If you’ve ever gone looking for rails, you know they are usually inaccessible. They live in tall dense marsh grass and won’t come out for anything except the sound of another rail — and then only in the breeding season.

But there is in fact a truly inaccessible rail.  The Inaccessible Island rail (Atlantisia rogersi) is the smallest flightless bird in the world, extremely rare, and vulnerable to extinction.  He lives only on Inaccessible Island.

He made news in October because he cannot fly yet new DNA studies show that his ancestors, related to black rails, did fly more than 2,300 miles from South America over the South Atlantic Ocean to Inaccessible Island.  They arrived 1.5 million years ago.

This was a surprise because the island, which is in the Tristan de Cunha archipelago, is closer to Africa than to South America as shown below. (Click on the map or its caption to explore it on Google Maps.)

Location of Inaccessible Island on the globe (screenshot from Google Maps)

The island is called Inaccessible because it is.  It’s almost impossible to land on the narrow beach — most attempts fail — and the cliffs are so steep that the top is inaccessible.

Panorama of Inaccessible Island (photo from Wikimedia Commons)

The island’s walls dwarf the people exploring the beach, below. 

Inaccessible Island beach, people in the distance (photo by Brian Gratwicke via Wikimedia Commons) 

Fortunately this tour group got lucky. They were able to land and they found the rail. A member of the group, Brian Gratwicke, took these photos.

Read more about the origins of the Inaccessible Island Rail in this article from Researchgate.

(photos by Brian Gratwicke via Wikimedia Commons; map screenshot from Google maps; click on the captions to see the originals)

The Lookout Bird

Dusky-throated antshrike at banding station (photo courtesy of Cameron Rutt)

When you’re vulnerable to predators it pays to stick together and have a good lookout to warn you of danger.

The dusky-throated antshrike (Thamnomanes ardesiacus) doesn’t look important but he’s quick to notice the presence of hawks and falcons and has a distinctive alarm call that wakes up the forest to impending danger.  It turns out that he’s key to the foraging location and cohesion of his mixed species flocks in the Amazon.

Early this year, a study by San Francisco State University temporarily removed dusky-throated antshrikes from their mixed species flocks in Peru. They discovered that within hours the flocks left their semi-open mid-story locations for denser parts of the forest.  Often the flocks without an antshrike completely dissolved.

What does the alarm call sound like?  Is it loud? Does it grab your attention? You bet!  Here’s the sound of a worried dusky-throated antshrike:

His role in the flock works so well that the same mix of species sticks together for generations. As San Francisco State Professor Vance Vredenburg remarked, “You come back to the same habitat after 20 years, and the same flocks are using the same areas of the forest.”

Read more about the study here in Science Daily.

p.s. When the antshrike is not afraid he sings this buzzy, rising song. (audio by Peter Boesman at Xeno Canto #271766)

Dusky-throated antshrike song (Xeno Canto 271766)

(media credits: photo of dusky-throated antshrike by Cameron Rutt, audio alarm call from Macaulay Library, audio song from Xeno Canto; click on the captions to see the originals)