Which animals, in all of the animal kingdom, have the best eyesight? You guessed it!
Birds of Prey (Raptors).
Falcon
Eagle
Hawk
Owl
Vulture
Osprey
. The Greatest Fisherman
And who is the best fisherman in all the animal kingdom? I know you know.
The Osprey!
The osprey is the greatest fisherman on planet earth
. Raptor Eyes
The visual accuity of raptors is legendary. The keenness of their eyesight is due to a variety of factors; raptors have large eyes for their size, and the eye is tube-shaped to produce a larger retinal image. The retina has a large number of receptors per square millimeter, which determines the degree of visual acuity. The more receptors an animal has, the higher its ability to distinguish individual objects at a distance, especially when, as in raptors, each receptor is attached to a single ganglion. Raptors have foveas with far more rods and cones than the human fovea. This provides them with spectacular long distance vision. In general raptors have distance vision 6 to 8 times better than humans.
. Forward Facing Eyes
The forward-facing eyes of raptors provide binocular vision, which is assisted by a double fovea. The raptor’s adaptations for optimum visual resolution has a disadvantage in that its vision is poor in low light level.
Forward facing eyes
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. The Osprey Stare
The arrangement of the feathers above the osprey’s eyes serves to reduce glare from the water surface when the bird is hunting for its staple diet of fish. It also gives the osprey its distinctive stare.
The Doctor has more, much more to tell you about our eyes and our incredible eyesight. It does not seem all that ammazing when you have it from birth, but I can “see” how those of you less fortunate could be envious.
Harriett returns to her nest. Carefully she straddles her eggs; arranges them, wriggles to get them below her brood patch, and contentedly huddles down.
The Doctor enjoys the soft, incoming, telepathic waves of happiness.
Broodiness In wild birds
Broodiness is the behavioral tendency to sit on a clutch of eggs to incubate them, often to the exclusion of other behaviors including feeding and drinking. Broodiness is usually associated with female birds, although males of some bird species become broody.
A wide range of incubation habits is displayed among birds. Body heat from the brooding parent usually provides the constant temperature required.
The most common pattern is the female does all the incubation, as in the Indian Robin.
Indian Robin
Or most of the brooding, as is typical of ospreys.
Osprey
In some species, such as the Whooping Crane, the male and the female take turns incubating the egg.
Whooping Crane
In others, such as the cassowaries, only the male incubates.
Cassowarie
The male Mountain Plover incubates the female’s first clutch, but if she lays a second, she incubates it herself.
Mountain Plover
In all the species of wade-pipers the males become broody rather than the female. The females leave the nest after finishing laying to let the males incubate the eggs and take care of the young.
Red-neck wadepiper
Emu males become broody after their mates start laying, and begin to incubate the eggs before the laying period is complete.
Emu
A small number of atypical birds such as Passeriformes of the genus Molothrus do not become broody but lay their eggs in the nests of other species for incubation, known as brood parasitism.
The Australian Brushturkey (Alectura lathami) also does not become broody, rather, it covers the eggs with a large mound of vegetable matter which decomposes keeping the eggs warm until hatching.
Australian Brush Turkey
The Crab-Plover, (Dromas ardeola), which live on the coasts and islands of the Indian Ocean, let their eggs incubate primarily by the heat of the sun and will leave their nests unattended, occasionally for days at a time.
The Namaqua Sandgrouse of the deserts of southern Africa, needing to keep its eggs cool during the heat of the day, stands over them drooping its wings to shade them. The humidity is also critical, and if the air is too dry the egg will lose too much water to the atmosphere, which can make hatching difficult or impossible. As incubation proceeds, an egg will normally become lighter, and the air space within the egg will normally become larger, owing to evaporation from the egg.
Incubation refers to the process by which osprey hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period.
Incubation time is defined as the period from the laying of the last egg until that egg hatches. The incubation time of osprey eggs is 34 to 40 days.
An egg is an organic vessel in which an embryo first begins to develop. The egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing embryo can survive on its own.
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until hatching.
The act of sitting on eggs to incubate them is called brooding.
Harriett Brooding
Broodiness is the behavioral tendency to sit on a clutch of eggs to incubate them, often to the exclusion of other behaviors including feeding and drinking. Broodiness is usually associated with female birds, although males of some bird species become broody.
Heating the Egg
For an osprey egg to develop normally, it must be exposed for a considerable length of time to temperatures a few degrees below the normal 104 degrees, which is avian body temperature. The ideal incubation temperature for many birds’ eggs is human body temperature, 98.6 degrees. Most birds create the required temperature by sitting on the eggs and incubating them, transferring heat via a temporarily bare area of abdominal skin called the brood patch.
Brood patch on female pied flycatcher
Osprey egg temperature is regulated, in response to the environment, by varying the length of time she sits on them. Ospreys can sense the egg temperature with receptors in their brood patches. This helps them regulate their attentiveness (time spent incubating) more accurately. Since the embryo itself increasingly generates heat as it develops, periods of attentiveness generally decline as incubation progresses.
Eggs are turned periodically – osprey turn their eggs every 20 to 40 minutes. The turning helps to warm the eggs more evenly, and to prevent embryonic membranes from sticking to the shell.
A chromosome is a structure of DNA, protein, and RNA found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences.
A gene is the molecular unit of heredity of a living organism.
Asexual reproduction is a mode of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only.
Sexual reproduction is a process that creates a new organism by combining the genetic material of two organisms.
There are two main processes in sexual reproduction.
1. Meiosis – is a type of cell division necessary for sexual reproduction in animals, plants and fungi. The number of sets of chromosomes in the cell undergoing meiosis is reduced to half the original number, typically from two sets to one set.
The cells produced by meiosis are called gametes. In many organisms, including all animals and land plants gametes are called sperm in males and egg cells or ova in females.
2. Fertilization – involving the fusion of two gametes and the restoration of the original number of chromosomes.
The gamete (sperm or egg) carries one full set of chromosomes that includes a single copy of each chromosome.
Osprey male gamete (sperm cell)
The female gamete (the egg or ovum) is the female haploid reproductive cell.
Osprey ovum (the egg)
The egg cell is not capable of active movement, and it is much larger than the motile sperm cells.
When egg and sperm fuse, a diploid cell (the zygote) is formed, which gradually grows into a new organism.
Osprey zygote
When does life begin? Does a zygote have a soul? Is live on earth precious? Is it worth saving? Is life on earth dispensable in the interest of higher forms? What if the inter-galactic DOT wishes to build a modern cosmic space though-o-fare that planet earth obstructs? Eminent domain?
It’s not easy to see our two eggs. We keep them covered all the time. The Doctor was quick today though and got these two video clips.
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. Today – (Easter Sunday)
Ozzy, What a guy!
Watch how he takes over the incubation and gives me a fish. He’s still a little bit awkward; it takes him 30 seconds or more to get situated, but he is right there for me all the time. I really love him.
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Incubation begins when the first egg is laid. Subsequent eggs are laid one to three days apart, with 2-4 eggs in each clutch (never seven days apart!). The female usually takes on most of the responsibility of incubation, seldom leaving the nest except to feed. The male will take over incubation until she returns.
On average, the male will “spell” the female ten times per day.
Ozzy giving Harriett a break
Incubation lasts 34 to 40 days and if the eggs are fertile, they will hatch in the order they were laid.
Both osprey parents have a brood patch, although the female will incubate the majority of the time (around 70%).
Incubation can be a bit sporadic until the second egg arrives. I believe we observed this the first few days after Harriett laid her first egg. As one of our readers has commented, “maybe, just maybe, Harriett didn’t start incubating the first egg immediately as osprey eggs can remain viable for quite awhile before the incubation process begins”. This would also result in a shorter hatching interval, thus giving the second chick a better chance of survival.
During the evening, the female will normally do all the incubating.
Harriett got up on the wrong side of the nest this morning.
A bad feather day for Harriett
“I know what you are thinking, Doctor! So why don’t you just cut it out! Have a little deference for an egg laying female. Didn’t anyone teach you basic etiquette? Where are your manners?
“Wow, Harriett. Have you got a bug up your cloaca”? The Doctor responded.
“In my??? Why you unfledged primate”!!! Harriett ejaculated.
The Doctor did not realize how touchy Harriett was over having laid only one egg this week. In addition, being relatively new to telepathy, he did not realize his thoughts could be so easily read. Maybe he should change his password.
“I’m sorry, Harriett, said the Doctor. “But I’ve been telling my friends……”
“Oh! Shut down!” Harriett interrupted. “You are just making things worse…… Shut down and sign off”! Do it now!”
Indignation’s bad breath suffused the Doctors senses.
Indignation
What the Doctor did not know, at this time, was the degree of Harriett’s distress. The Doctor quietly and gently tuned in to Harriett’s aura.
“I thought I felt another egg coming today, but maybe it is just my imagination. Ozzie has been anxious all day. I do not mind saying that this first egg is real beauty. It is far and away the prettiest egg I have ever laid”. Perhaps my hopes are unrealistic, but I was thinking about 3 eggs this year. Ozzie is acting strange. He has not brought me a fish today. I hope he is not mad at me; why should he be? Surely he does not know about Havana.
“Having an argument with Harriett is a very unpleasant experience”, said the Doctor.
He fretted about it most of the afternoon. But, by evening all hurt feelings had resolved.
“It’s a lot easier to be angry at someone than it is to tell them you’re hurt”, he thought.
The Doctor was not angry. The Doctor never gets angry. He could sense Harriett checking him out from a distance and it made him feel needed.
“There is no better place to contemplate the creation of beauty than in your own back yard; a spider web, a blade of grass or a robin’s nest half way up your shade tree. In the springtime the beauty of life radiates so brilliantly that even humans stop and take notice”.
“From Photosynthesis to Oxidative Phosphorylation, living organisms are pumping out ATP like an interstellar nebula throwing off cosmic radiation”.
The Aesthetics of Osprey Eggs
Osprey eggs are considered one of the most beautiful of all bird eggs. There is no contest among the other raptors. They have long been admired for their unusual coloring. Most osprey eggs have a brownish mottled coloring.
Others have rich browns,
and some have a white to cream-colored background covered with dots.
Here we see swirls as dark mahogany.
This particular clutch is very cinnamon.
Clutch-mates tend to have some artistic consistency, but there is enough variation that one wants to admire each entire clutch as an avian work of art.
Oology
The stunning beauty of osprey clutches was not lost on the old naturalists. In the 19th Century the hobby of egg-collecting, was very popular.
Osprey egg-collecting played a major role in the population decline in the 19th and 20th centuries. There was even a little journal devoted to it, “The Oologist”.
Even now in some regions osprey populations remain low, even as the osprey population is starting to rebound.
There are still museum cases full of old Osprey eggs in Europe. Some are well preserved in these curio, throwback collections.
“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.
Osprey Tales 