Osprey Tales

Courtship in ospreys centers on food and nest sites. In migratory osprey populations, males and females arrive at the nest site separately, the male often arriving several days earlier than the female. Male ospreys sometimes perform a conspicuous aerial display near the nest site. This display usually occurs during early courtship, and serves to attract their mates and to threaten any intruder.

This courtship dance, often called “sky dance” is a spectacular, wild yo-yoing display of flight.  The male impresses the female with his catch and then, after briefly treading air, drops down a hundred feet, before treading air again and then quickly rising.

This video is pretty good, considering it was made with an i-phone.

Once a pair has established a nest, the male begins to deliver food to the female.

Courtship feeding*

During the courtship period the male continually offers food to the female. This behavior continues throughout the breeding cycle, and is critical for pair bond formation and female fidelity.  This feeding continues until the young fledge or the nest fails. Generally, females that receive more food are more receptive to mating attempts by the male.  Females beg for food from their mates, and occasionally from neighboring males if they are not well fed by their mate. Males may protect their paternity by feeding their mate well. They may also protect their paternity by guarding their mate from other males and copulating frequently when she is most fertile (several days before egg laying).

Courtship feeding.

If the dance is spectacular foreplay, then the sex itself is fast and furious, lasting just a few seconds. Don’t miss the next post.

*Courtship feeding

Courtship feeding has been suggested to function in several ways: to advance laying date by improving female condition, to induce a female to copulate or to allow a female to assess her mate. The role of courtship feeding in Ospreys Pandion haliaetus was investigated in British Columbia, Canada. Courtship feeding rate affected the probability of a pair initiating a clutch. Pairs that laid eggs had higher rates of courtship feeding than pairs that did not lay eggs in both 1991 and 1992. Male courtship feeding rate also correlated negatively with the duration of the courtship period. Experimentally increasing the amount of food available to females prior to egg-laying resulted in a non-significant reduction in the duration of the courtship period. This study found no evidence to support the suggestion that female Ospreys trade copulations for food during the courtship period; only 63 of 385 copulations observed were associated with feeds, and courtship feeding rate did not correlate with the copulation rate of a pair. Male provisioning rates, however, were predictable; courtship feeding rate correlated with both male delivery rate to the nest when chicks were 1–2 weeks old and mean brood growth rate. Female Ospreys therefore may be able to predict the quality of subsequent paternal care using courtship feeding rate. As predicted if optimal hatching asynchrony is dependent on food availability, mean brood growth rate, an indirect measure of male parental care, was negatively correlated with hatching asynchrony. This suggests that female Ospreys may manipulate hatching asynchrony in response to male courtship feeding rate, thereby maximizing the productivity of their brood at predicted food levels.

Ozzie and two others in the skein, Victor and Veronica, realized the seriousness of the situation.  They had chosen an easterly route that took them over long stretches of open water, nonetheless it was a flight path well-traveled, known by generations of migrating ospreys before them.  Ozzie had used it in 2011.  It is basically a three stage journey that takes 22 days, not counting a stay over in Cuba.

What could be easier?

The first stage is the hardest.  Ospreys are usually well feed and rested before they start their migration north.  They will lose 20% of their body weight, mostly fat, by the time they arrive at their destinations.  The eastern route requires a sustained three day flight over the South Caribbean Sea until reaching Puerto Rico or The Dominican Republic.

Stage 2 is easier.  Osprey try to stay over land as much as possible.  They follow the islands north west until they get to Cuba;  then fly the length of Cuba to Havana, where they rest a day or two before crossing to Florida.  The dangers on this leg of the journey are high voltage electric utility wires and drunken Cubans with shotguns.

Stage 3.  From South Florida they head north towards whatever home to which they are returning.

The arrival in Puerto Rico or the Dominican Republic/Haiti is the most crucial point of the entire migration. If land is not encountered on the third day of flight, you have got a problem. Your situation is bad; very bad; worse than having an albatross around your neck; your wings are clipped, you might as well get your ducks in a row, you are dead as a dodo, a dead duck, your goose is cooked.  Literally, you have gone too far east and will fly out into the Atlantic ocean until ………………it gives me goose bumps to think about it…………………………….. (Censored by the Happy Fairy).

Ozzie, Victor and Veronica had to think clearly.  Mike and his dim witted entourage were off course five and ten degrees, leading them off shore into the Atlantic Ocean.  Still Ozzie and his two friends needed the V-formation to make it over the South Caribbean Sea.  The plan was to leave the skein at sunrise on day # 3, and the three of them would recalibrate their way to Puerto Rico, and try to make land as a threesome.  This would require a lead change every 2- 3 hours, and receiving only a single wing’s updraft from the leader.  The prospect was daunting, but they had no choice.  Leave the skein or fly out to sea.

“$&#! That stupid Mike”, thought Ozzie.  But cursing would be of no benefit.  The threesome knew what they had to do.

“$&#!, !@#$, $%&!, *&#@!  Anyway”, said Ozzie.

And Victor added, “! #$%#, & %*$!@#!!”

As dawn approached on the third day, Ozzie confirmed that they were horribly off course.  They would miss land fall by 100 miles.  So at 5:30 Tuesday morning (daylight savings time almost threw them off), Ozzie, Victor and Veronica broke from the ill-fated skein and headed west-north-west towards Puerto Rico.

Ozzie, Veronica and Victor

May The Force be with you Ozzie.
But Ozzie has something better than The Force; he has Luck!

Say a prayer for Mike, Alberta and their seven doomed, hapless, star crossed, cognitively impaired friends.
Heaven help them.

March 1, 2014

Harriett explains.

“By necessity, our story must jump ahead one full year. I start my migration home tomorrow and hope to be there the first week of April.  Last year Ozzie arrived in the last week of March and I made it six days later.  That was 2013, the year Ozzie got his big surprise with the new nesting platform”.

“I had planned to tell a few stories of last summer and winter, but they will have to wait. Time has just slipped away.  The Doctor cannot access time-warp coordinates with his current knowledge; he can’t even slow the rate of time flow, so the stories of last summer and winter will have to wait.  But, I am proud to say, we had our first born, Riki, last year and the situation with Angela was finally resolved”.

“Riki is on the right.  I am sorry to say that Riki’s sibling died three days later.  More on the wisdom of nature later”.

Time

“Time is simply a measurement. I assume you are familiar with classical, non-relativistic physics in which it is a scalar quantity like length, mass and electric charge. Time can be combined mathematically with other physical quantities to derive other concepts such as motion, kinetic energy and time-dependent fields. The unit of time is the second. Most people up until the 20th century thought that time was the same for everyone everywhere. In reality of course, rates of time run differently depending on relative motion. Space-time cannot really be separate entities. We live on a space-time line rather than a timeline; the coordinates are set according to the observer’s relative motion”.

“For references please e-mail the Doctor before 8:00 PM”

              Love and kisses,         

            Harriett                                                  

Febuary 20, 2014

All bird feathers evolved from scales. In fact, birds still possess scales in the lower parts of their legs and feet. Feathers are the most complex structure found in present day vertebrates. They aid in flight, thermal insulation, waterproofing, and coloration.

There are two basic types of feathers:
1. Vaned feathers which cover the exterior of the body.
2. Down feathers which are underneath the vaned feathers.

Vaned feathers cover the whole body and give the bird its shape and color. They include both the flight feathers, and the tail feathers.
Down Feathers are smaller but lack the barbules and their accompanying hook-lets so they are not zipped together and do not look so neat. In fact they are soft and fluffy. They provide most of the insulation and are so good at this, that humans for years have collected the “down” from various birds to put into sleeping bags, pillows and quilts.

What is a Brood patch?

Brood patches are areas where the feathers fall out during or immediately prior to incubation of the eggs. These areas of bare skin on the bird’s abdomen are heavily infused with blood vessels and allow the incubating adult bird to transfer heat to the eggs, thus speeding up development of the embryo.

Brood patch on female pied flycatcher
Harriett’s friend agreed to show her Brood Patch. Name withheld

Although feathers are light, an osprey’s plumage weighs more than its skeleton. The bones of an osprey are hollow and contain air sacs. Color patterns serve as camouflage against predators looking for a meal, not to mention courtship displays. Ozzie remembers the Magenta streak in Angela’s brow. It was breathtaking. If Ozzie and Harriett hatch fledglings this year, you will be amazed with their coloration and camouflage.

In earlier post we discussed the evolution of birds. Birds branched off from reptilian dinosaurs in the late Cretaceous period, 100 to 200 million years before present. It is the presence of feathers that is unique to birds. Other animals can fly, other vertebrate animals have beaks or bills, other vertebrate animals lay eggs, but no other living animal has feathers. Every bird has feathers and everything that has feathers is a bird.

A typical contour feather.

Feathers have a basic form of a central hollow supporting shaft called a ‘rachis‘ and a number of fine side branches. These side branches have even finer sub-branches in contour feathers.

The side branches are called barbs and are linked together by a set of barbules and their hook-lets. Barbs have side branches of their own called barbules. The upper ones containing a series of hook-lets and the lower ones without hooks but slightly convex in form to catch the hook-lets of the barbules from the next barb along the shaft. This is perhaps best understood by examining this diagram.

The base of the feather – where there are no side branches – is called the quill and at the base of this is the hollow entrance that was used by blood veins to carry nutrients to the growing feather when it was alive.
The gripping effect of any one set of barbule hook-lets is not great, but like the threads that hold your clothes together the combined effect is sufficient to keep the feathers together. The overall presence of all these barbs and barbules together is called the vane of the wing. The rachis and the vane are the two parts of the feather you see with the naked eye.

Take a moment to examine the structure. Amazing? Yes. Now remember the osprey has voluntary and involuntary control of each and every muscle group that contain these feathers.

“Hope is the thing with feathers that perches in the soul – and sings the tunes without the words – and never stops at all”.
Emily Dickinson

The next post will require a one year leap in time. The entire year of 2013 must be left to future storytelling, since the homeward migration has begun in South America. I will certainly try to fill you in this summer if the action gets slow.

Thanks for reading,

The Doctor

Ozzie and Harriett reached sexual maturity in three years. Some ospreys take longer, but of course Ozzie did not.

The spring and summer of 2010 (Age 3 months – 18 months); was spent at Lake Maracaibo.

Their second breeding season, the spring and summer of 2011 (Age 20 months – 2 years); was spent on The Red Channel Marker, in the North River of Carteret County. Harriett wanted to go back to the Chesapeake Bay area, but it is the male who chooses the nesting site, and Ozzie choose Carteret County. The spring and summer of 2011 was The Summer of Fun.

The Summer of Fun was remarkable for:

– Migration home was easy that year.
– Ozzie and Harriett are head over heals in love with each other.
– They build a very nice nest for themselves on The Red Channel Marker.
– Harriett becomes an expert homemaker.
– Ozzie becomes an expert fisherman.
– Ozzie becomes poetic and recites a beautiful poem to Harriett.
– No eggs were laid, no chicks were born. It was not a nest failure, but a time of maturing love.

The spring and summer of 2012 (age 3 – 4 years); was different.

Ozzie’s return to the The Red Channel Marker was the most memorable and life altering experience of his life. Some birds, in retrospect, recall difficult, overwhelmingly painful times in their past, with nostalgia, and think of them as learning experiences. But what was about to come down in Ozzie’s life, can in no way be remembered as beneficial.

To be continued……………

    1.  Ospreys are birds of prey, whose diet is almost exclusively fish.

            There is no better fisherman on planet earth than the osprey.

2. The osprey is a raptor. Those of us from generation JurassicPark can’t help but think of the terrifying dinosaurs called Velociraptor.

3. Osprey mate for life.

4. The female is slightly larger that the male.  She wears a necklace.

5. North American ospreys migrate to South America every fall to “winter” for the season.  The mates take “separate vacations”.  They use the magnetic fields of the earth to navigate.

6. Ospreys have incredible eyesight. They can see eight times better than humans.  Ospreys are hunters, they must be able to see their prey, sometimes from great distances, and calculate just the right moment to strike. In fact, an osprey can spot a medium-sized flounder from at least one mile away.

7. A skein is the symmetric V-shaped flight formation of migratory birds. The V formation greatly boosts the efficiency and range of flying birds, particularly over long migratory routes.

8. Osprey pairs usually return to the same nest site year after year, and add new nest materials to the old nest each year.

9. The Osprey tolerates a wide variety of habitats, nesting in any location near a body of water providing an adequate food supply. It is found on all continents except Antarctica, although in South America it occurs only as a non-breeding migrant.

10. Human habitat is sometimes an aid to the osprey. The birds happily build large stick-and-sod nests on telephone poles, channel markers, and other such locations. Artificial nesting platforms are common in areas where preservationists are working to reestablish the birds.

11. North American osprey populations became endangered in the 1950s due to chemical pollutants such as DDT, which thinned their eggshells and hampered reproduction. Ospreys have rebounded significantly in recent decades, though they remain scarce in some locales.