Answer to the Riddle

   We found the source of the Mockingbird's aggression. It wasn't the ripening figs after all. I spotted a mocker with a worm in its beak standing on an azalea bush near my car. I stepped back and watched as it jumped down into the azalea bush and fed the worm to a chick hidden in the bush. I could bearly see the squirming chick through the azalea blossoms. What a lovely resting place, surrounded by flowers ! The mockingbirds have been protecting a fledgeling.

Robert

Defend yourself !

   There is a team of Northern Mockingbirds (Mimus polyglottos) that have begun making aerial swoop attacks against me any time I am in the front yard. I walk to get the mail; I am attacked. I check the ripeness of my figs; they swoop down at my head. I walk out of the garage and down the driveway; again I am the target of aerial bombardments from the mocker air force.

   The Northern Mockingbird is famous for its amazingly varied songs. It can imitate the sound of other birds. In fact it has so many different songs in its repertoire, that the tremendous variety of songs it can sing is an easy way to identify the mockingbird by sound, without having to actually see the bird.

But I have noticed that during these aerial attacks, the mockers do not sing. They glare down at me and make a single loud sharp chirp. Then another mocker will respond from another perch. I interpret this as defensive behavior, but I cannot perceive the nest or nestling that they are defending.

Northern Mockingbird

   One mocker is stationed on the roof of the house. One is stationed in the magnolia tree. And the third is parked in the Leland Cypress tree. They may be defending nestlings, but I think it is the figs. Last year the Mockingbirds helped us eat the yummy figs on that fig tree. I am certain the birds are aware of the figs in that tree and they surely see them quickly ripening.

   If you visit my house, save yourself ! Wear a hat.

   Robert

photo courtesy of rfowler

Empty Nest

It looks as if the American Robin ( Turdus migratorius ) chicks have fledged. Today the nest is empty. It was time for the chicks to fly away.

All three chicks started as eggs. We don't have a precise date for the laying of the eggs. We noticed the mother sitting for long stretches on the nest and suspected there were eggs there. But we did not see the chicks until nine days ago. They were fed worms by both parents. They got plump, and looked crowded inside the nest. And then... today, we saw an empty nest.

Good luck to them.

How to Identify a Mississippi Kite

   In Memphis it is not difficult to find a Mississippi Kite (Ictinia mississippiensis). You need but look up. This hawk-like bird looks black against the sun as it soars like a kite in the sky, but it is actually deep gray in color. Berry and I saw one perched on a casino sign one time and focused our scope on it to get a close-up view. It's eyes are very expressive. It has a black mask around its scarlet eyes.

   The Mississippi Kite flies very high in the air, higher than most other birds of prey. Then it swoops quickly to catch insects and small birds.

Mississippi Kite

   Here is how to identify this magnificent bird. It's easy. Note that the tip of each wing comes to a point. In mid-flight the tail of the Mississippi Kite will almost be a perfect triangle. Remember, it will seem to have a black profile in the sky, but you may be able to tell the head is slightly lighter than the body. If you look very closely, you will sometimes notice a small notch in the feathers of the trailing edge of each wing.

   That is a Mississippi Kite. Have fun birding !

Robert

photos courtesy of christopher

Turdus Migratorius Times Three

   Here is a photographic peak inside the nest. The chicks have hatched. It looks like there are three nestlings. The third beak is low in the nest, the patch of yellow in the silhouette of the one on the left.

Inside the Nest

   The parent birds are busy. I have seen both of them standing on the edge of the nest, feeding worms to the chicks.

Robert

photo courtesy of rfowler

Trip Report 6 May 2011

   Berry and I took a day trip through flooded downtown Memphis, making our way to Arkabutla Lake, in northern Mississippi. Here are photos from near the Missisippi River.

Journalists on Beale Street

Flooding in South Memphis

Memphis Police spending tax payer's money

The small green street sign says Riverside Drive

Temporary Road in response to the flooding

   Finally we got down to Arkabutla and had a nice picnic of cold fried chicken. We saw these birds.

• Mississippi Kite
  
• Chimney Swift
  
• Northern Mockingbird
  
• Common Grackle
  
• Barn Swallow
  

Barn Swallow (Hirundo Rustica)

• Rock Dove
  
• American Robin
  
• Red Winged Blackbird
  
• Indigo Bunting
  

Indigo Bunting (Passerina Cyanea)

• Canada Goose
  
• American Crow
  
• Eastern Meadowlark
  
• Double Crested Cormorant
  
• Baltimore Oriole
  

Baltimore Oriole (Icterus Galbula)

• Great Blue Heron
  
• Killdeer
  
• Brown Thrasher
  
• Great Egret
  

Great Egret (Ardea Alba)

• Brown Headed Cowbird
  
• Northern Cardinal
  
• Eastern Wood Pewee
  

Eastern Wood Pewee (Contopus Virens)

• Eastern Kingbird
  
• Bluejay
  
• Summer Tanager
  

Summer Tanager (Piranga Rubra)

• Common Ground Dove
  
• European Starling
  
• Eastern Bluebird
  

Robert

photos courtesy of rfowler, tsohl, lelliot, bogi, informzoo, ctaylor, and jspendelow

Happy Birthday!

   I walked underneath the Robin's nest today and it looked empty. There was no mother bird on the nest. I did not worry. Even expectant mothers need to stretch their legs. I went about my day. When I came home, I looked up and saw the Robin standing on the edge of her nest, dangling a long juicy worm down into the nest. That could only mean one thing.

   ♫ Happy birthday to you... ♫

Robert

Bin Laden is dead !

US Navy Seal Team Six killed the terrorist, Osama Bin Laden in a three-story house in Abbottabad, Pakistan, near the capital city of that country. This has nothing to do with birds, but this is great news for all.

The Mating Dances of Spring

   I was lucky enough to witness yesterday the mating dance of the Brown Thrasher (Toxostoma rufum). A pair of these beautiful birds were fluttering up to each other on a pebble path next to the grape trellis in our backyard. It is not a complicated dance.

   We have had Brown Thrashers living in our yard for several years. The last nest we spotted was in a tall bush in between our house and that of our next door neighbor. The rufous brown feathers, curved beak and striped breasts of Brown Thrashers make these birds unmistakable.

   Six or seven years ago, Berry and I were lucky enough also to see the mating dance of the Pileated Woodpecker (Dryocopus pileatus). We were birding behind a casino in Tunica, Mississippi. The pair of large woodpeckers played peek-a-boo on either side of a large branch. We were 25 feet away, inside a car, with binoculars and a clear shot. It was amazing.

   Here is an excellent video of two Pileated Woodpecker's mating dance. They are dancing around a tree. A third woodpecker approaches but is chased away. This dance lasted ten minutes, according to the author. I am not the author of this video. Thanks to srb1071 on Youtube.



Robert

Osmolarity Problem in Western Gulls

   I was studying the osmolarity problem of sea gulls. How do these beautiful animals maintain a constant level of sodium chloride in their bodies ? They must live in and drink sea water to survive. How do they get rid of the extra salt so their cells do not swell and burst ? And how does this compare with the same osmolarity problem in salmon which swim from fresh water into salt water and then back into fresh water during their life cycle.

   According to Macfarland, Martin and Freedman¹ in the Journal of Cellular and Comparative Physiology, Western Gulls (Larus occidentalis) use various enzymes in its beak to secrete salt through the avian nasal salt gland. The salt gland is stimulated to secrete its highly concentrated fluid (700–800 mm Na) by enzymes which cause a nerve reflex in the back part of the eye. The tears from both eyes then mix in the nasal septum. The excessive NaCl excretes from these orifices on the beak of the gull.

Monterey Gull

   In this photograph of gull's head, you can see the small dimpled orifice on the upper side portion of its beak. That is the avian nasal salt gland. When it discharges saline waste, it looks like the gull is weeping or has sinus problems.

   According to Mark Briffa², a marine biologist at the University of Plymouth, the Atlantic Salmon (Salmo salar) does the same osmolarity trick using different means. The surface cells of the gills secrete the salt. As the salmon enters the sea, there is an involuntary change in the cellular structure of the gills which enables them to start secreting salts. This is not strange, in that all marine fish must do. The salmon's trick is that he turns it on in salt water and turns it off in fresh.

Atlantic Salmon

Robert

photos courtesy of jurvetson, pnicklen

¹McFarland, L. Z., Martin, K. D. and Freedland, R. A. (1965), The activity of selected soluble enzymes in the avian nasal salt gland. Journal of Cellular and Comparative Physiology, 65: 237–241. doi: 10.1002/jcp.1030650210

²Mark Briffa, forum administrator,
http://www.thenakedscientists.com/