“Laying that first egg felt good and Ozzie is so proud. Ozzie has dramatically cut back on his cloacal kisses, which is natural and genetically programed.”
“Here are a few facts and figures you should know”.
On average, the period from first mating to egg laying.
1st Egg 16 days
2nd Egg 19 days
3rd Egg 22 days
Age at first breeding: 3-5 years
Number of eggs: Usually 3
Size of eggs (mm): 62 x 46
Incubation period: 35-42 days
Fledging period: 53 days
“Remember this date: April 9th”.
“It is an important date. This is the date from which we will anticipate the upcoming events.
“To understand osprey reproduction, one must know a bit about osprey anatomy”, said Harriett. “The Doctor will explain”.
The cloaca
The cloaca is the posterior opening that serves as the only opening for the intestinal, reproductive, and urinary tracts of birds. The cloaca of males and females are the same. This confuses some humans. But, it’s not too hard to understand, if you take it step by step. First look at the digestive system of birds, then the urinary system and then the reproductive system. Then, just put them all together. It’s easy.
I do not think Harriett would mind showing us hers. Hang on a second. Let me ask.
OK, here it is:
Ozzie wants to show his too.
Copulation
Copulation is the method in which a male bird fertilizes the ovum of a female bird.
The male and female press their cloaca’s together for a few moments to transfer sperm to the female. Each copulation last about 15 seconds; it is fast and furious.
The arrival of the female is followed by a period of courtship that can last for up to three weeks. During courting the pair spends time together on the nest. The male brings the female all of her food.
When a pair of ospreys meet and start forming a bond the female wants the male to prove he will be able to provide for her and the chicks. She begs for food on his nest and he tries to meet her needs (courtship feeding).
Females in older pairs are fed more than females in younger pairs. It points to an inexperienced male.
Once they are settled at a site and start courtship feeding, mating can occur at almost any time.
An Osprey’s mating call consists of a brief “hew” and is repeated many times.
Most copulations take place at the nest because females spend most of their time there, but they can occur anywhere. No elaborate ritual or display precedes mating. Females sometimes appear to solicit copulations by tipping forward with raised tail and dropped wings, but this is subtle behavior and hard to decipher. At other times, it seems that the males mount with no signal from their mates, flying in from behind (like Yeat’s Zeus landing on Leda) or fluttering up onto the female from the nest edge.
Leda was daughter of the Aetolian king Thestius, and wife of king Tyndareus of Sparta. She was the mother of Helen of Troy. Leda was admired by Zeus, who seduced her.
Leda and the Swan by William Butler Yeats
~
A sudden blow: the great wings beating still
Above the staggering girl, her thighs caressed
By the dark webs, her nape caught in his bill,
He holds her helpless breast upon his breast.
~
How can those terrified vague fingers push
The feathered glory from her loosening thighs?
And how can body, laid in that white rush,
But feel the strange heart beating where it lies?
~
A shudder in the loins engenders there
The broken wall, the burning roof and tower
And Agamemnon dead.
Being so caught up,
So mastered by the brute blood of the air,
Did she put on his knowledge with his power
Before the indifferent beak could let her drop?
In general osprey copulations begin about 14 days before, and peak in the few days before the start of egg laying. They occur frequently, but only 39% of copulations result in cloacal kiss. It may take 160 copulation attempts to sucessfully fertilze a female to form a clutch of eggs.
Copulation occurs most often in the early morning. Female ospreys spent almost of their time (more than 95%) at the nest as they are fed there by the male. There is no association between courtship feeding and copulation, and hence no evidence that females trade copulations for food. Males maximized the time they spent at the nest with the female just prior to and during egg laying.
During copulation the female displays a posture of drooped wings and horizontal body, with her tail pointed up and to one side.
Note the female is receptive. She lifts her tail to offer her cloaca.
To mate, the male has to get on top of the female’s back. The female has to bring her tail up while the male brings his down.
Males mount females gently, talons closed and tarsi resting somewhat precariously along the female’s back; vigorous flapping helps the male maintain balance. If the female is receptive, she tips forward to allow the male’s tail to scissor under hers. Successful copulations, those in which the cloacae touch, depend on this forward tilt.
Unreceptive females refuse copulations by keeping a horizontal posture or by tipping back on their tails, so males just stand there flapping or slide off. Failed copulations are common. Young pairs are less likely to copulate successfully than old pairs, largely because young males are reluctant to transfer food, leaving their mates unreceptive to breeding.
This female is unreceptive.
They may continue mating until the hen lays the eggs. Pairs mate most frequently just prior to egg laying. Earlier copulations may have little to do with fertilization, serving instead to test a mate’s receptiveness (strengthen the pair bond) and to synchronize the development of the gonads. This latter aspect is especially important in young females (3 -4 year olds) because females arrive back at their nests with ovaries only partially developed, then going through a period of rapid ovarian development. In this phase, ovaries gain 5 to 15 times their initial weight before descending the oviduct.
The female calls the shots for successful mating; she needs to raise her tail and tilt forward so that the male can curl his tail under hers and achieve a cloacal kiss. This contact enables the sperm to pass from his cloaca into hers.
A male will land on a female’s back many times without this final contact being made. Studies have shown only 30-40% of attempts are successful. Early copulations stimulate the growth of eggs within the female’s ovary and strengthen the pair bond. The last 3 or 4 days before eggs are laid are the most critical for fertilization.
In a successful copulation the sperm travel to the female’s oviduct. This is where the various stages of egg development occur. First, the sperm fertilizes an egg which has been produced during ovulation and already has a yolk. Then the principal coating of albumin is applied before the outer and inner shell membranes are added. These stages take about 5 hours. Next the calcareous shell forms. The background pigments are laid down. The egg stays within the uterus for about 20 hours and tiny glands excrete the streaks and patterns that result in the darker markings on the shell. Finally the egg is laid. The eggs weigh between 60 and 80g and are about the size of duck eggs. The background color ranges from off white to pale brown, the mottling is red or dark brown. The first egg is usually the largest.
The osprey is one of our planets most widespread birds of prey. They can be found on every continent except Antarctica.
Ospreys in North America nest from northern Alaska; along the Atlantic coast as far south as the Florida Keys, and along the Pacific coast as far south as Mexico. The geography of their nesting sites affect the type of nest they build, and its placement.
Generally, Ospreys reach sexual maturity and begin breeding around the age of three to four, though in some regions with high osprey densities, such as Chesapeake Bay, they may not start breeding until five to seven years old. Sometimes there is a shortage of tall structures, restricting the number of safe, suitable nest sites. If there are no nesting sites available, young ospreys may be forced to delay breeding.
Human osprey enthusiast in these regions often erect platforms to provide more sites suitable for nest building.
First-year birds stay in South America during the spring. This is the notorious 18 months of a young osprey’s life. The adult birds return north. The immature osprey won’t leave the wintering grounds until their second year, and they won’t breed until they’re three or four.
Each year the older birds return to the exact site of last year’s nest. How they do it remains a cryptic wonder of nature. I doubt humans will ever figure it out.
Ospreys want their nest sites out in the open for easy approach. They look for structures with a wide, sturdy base and safety from ground predators (such as raccoons). Nests are usually built in trees on snags, treetops, or crotches between large branches and trunks. Usually the male finds the site before the female arrives.
Every year their first priority is to re-build and bolster the nest. The female places and arranges most of the new sticks while the male acts as the gofer.
I hope you can open this file. Besides the nest building, you can see how easy it is to distinguish male from female. The male has an all-white chest and neck, whereas the female wears a necklace. Listen to their vocalizations; more on bird talk later.
The nest is constructed of sticks and branches, and is added to annually. An osprey’s nest may weigh as much as 400 pounds.
Nests usually are renovated and reused annually either until the base collapses or until the nest is damaged in a storm. Nests often are five feet across and two to three feet deep when they are first built and increase in size each year thereafter. Smaller birds, including House Sparrows and Monk Parakeets, sometimes nest within an Osprey’s nest. Osprey pairs can construct their nests in as few as seven to 10 days.
Ospreys deliberately chose highly visible nesting sites, or perhaps it’s more accurate to say that such a site makes the surroundings highly visible to the osprey. The nest sites are always near water with good visibility and limited access for predators.
The species’ preference for out-in-the-open nests may explain why nestling ospreys wear camouflaging coats of mottled down. Hopefully we will see some nestlings this summer. Aerial predators such as bald eagles, gulls, crows, and ravens have difficulty spotting the young from above.
Ospreys have traditionally nested in the bare branches of dead trees. Typical nest sites are dead or relatively open live trees, in or within a few kilometers of open water.
Regarding dead trees, ospreys have a penchant for tall trees devoid of their upper branches. They settle on top of the exposed trunk, giving them 360 degrees of visibility.
Examples:
Rocky outcrops
Rocky outcrops just offshore are used if available. Many are renovated each season, and some have been used for 70 years. The nest is a large heap of sticks, driftwood and seaweed.
On the Ground
Sometimes ospreys nest on the ground. As long as it is save from predators, why not?
Channel markers
Channel markers are favorite osprey nesting sites.
Red for the sanguine Green for the phlegmatic
There is always the osprey that has to be different.
Light Towers
Some ospreys enjoy the spotlight.
Construction equipment
This mischievous couple shut down a construction project in south Florida for six months last year. I can hear the cursing now.
It has happened before; more than once!
Ospreys are federally protected by the US Fish and Wildlife Service under The Migratory Bird Treaty of 1918. You cannot touch them!
The Headline News reports: “Osprey nest delays the removal of a construction crane” “Empire Construction Company goes bankrupt over Osprey controversy” “Construction suprentendent arrested for moving osprey nest”
These sites are for high energy, emotionally charged ospreys with electric personalities, that do not mind high tension. They are thrill seekers who occasionally like to have a tingle or get a buzz on. Shocking news does not bother them.
Cell phone towers, Microwave towers
Mostly chatty females, Geeks and Nerds
Highway Child
Patriotic American Osprey family Supporter of NASA
“It has come to the Doctor’s attention; there are children and grandchildren watching us. We osprey mature rapidly compared to the human species. I believe my understanding of human culture exceeds the Doctor’s understanding of ours, and I don’t mind telling you, I am offended by the Doctor’s comments regarding the Cultural Differences Argument.
Nonetheless, I offer this token of love to the children and grandchildren of the Doctor’s friends. The more we learn about each other, the better the world will be. This is someting the Doctor and I do agree upon”
But, before we go on;
The following section is considered G for general audiences.
In the case that you detect any PG, PG-13, R, or NC-17 content, please let the Doctor know.
Do you want to see some baby ospreys? Well, they are right here:
Here they are with their mother. She feeds and protects them until they are big and strong.
Their father catches fish for them and will teach them how to fly.
See the fish. It’s dinner time!
Come back and check out this web page any time you like. I guarantee it will be awesome, and you will learn some things that your parents and grandparents have not told you.
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.
“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”
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.
Osprey Tales 