an unusual sighting

For the past several years, a pair of ospreys have raised 2-3 chicks each year at the local marsh that surrounds Grass Lake, using a high nest platform erected specifically to entice them to breed there..

osprey-pair

The pair of Ospreys on their nest platform in June, 2016.

But this year, they must have arrived a little later than usual, because an interloper arrived first to claim the 50 foot high platform for her own nest.

canada goose-on osprey nest

It looks like Mother Goose tidied up the stick nest, before adding her own downy breast feathers to the nest cup.  Although her nest is well protected from danger of flooding on the osprey platform, it is exposed to aerial predators like Bald Eagles that might fly over.  

What is peculiar about this is that Canada Geese usually nest on land surrounded by or near the water on an elevated mound — but not this elevated!

great blue heron-and-canada geese-

While the hen incubates her eggs on her mounded nest, the gander runs protective interference and wards off potential predators or nosy herons.

Mother Goose usually sits tight on the nest, incubating her clutch of 6-8 eggs for most of a month or so, but Father Goose will take over at times so that the hen can stretch her legs and get a bit of food for herself.  Knowing how much space Canada Geese need to land on water or land, I have to wonder how good they are at making a touch down in the limited space of this nest platform.

Once the ducklings hatch, they usually move immediately into the water with their parents.

canada-goose-and-ducklings-1

It’s safer to be in the water because ducklings are vulnerable to a wide variety of predators on land.

Being nothing more than downy balls of fluff, they certainly can’t fly yet, so what will happen to the ducklings raised on an osprey platform?

Division of labor

In many bird species, males set up and defend breeding territories, and females build the nest, lay the eggs and incubate them — a division of labor that ensures the best possible outcome for their offspring.  In other species, both parents feed their chicks; in still others, just the female, or just the male takes responsibility for providing food to the incubating female as well as the chicks.  The latter is the case for the ospreys I have been observing at a local marsh.

osprey-at-the-nest-

Male osprey bringing a delicious fish to his mate who is incubating her eggs.  The fish are always headless — I wonder if he eats the head?  Does it have some particular nutritional value for him?

Males bring the sticks to the nest, the females arrange them, forming a large nest cup surrounded by a foot or two of sticks and even leafy material around the outside.  Female osprey perform almost all of the incubation, sitting on those 2-3 precious eggs for more than a month! (32-42 days), rarely getting a chance to fly off and spread their wings.  The male brings her food, but she might also get some of her daily energy requirement by metabolizing some of the protein in her inactive flight muscles.  (More about the implications of this in the next post.)

osprey and chicks-

While the chicks are young, they must still be brooded in the cold, shaded in the heat, and need their food diced up for them.

The female remains on the nest to protect them for at least another month, although the male might share some of this time with her.  Meanwhile, he is the chief food provider, bringing as much as 6 pounds of fish to his brood and his mate on a daily basis.

osprey with fish-

This fish still has its head…

Once the chicks are feathered out, grown almost to the size of the adults, and able to stand up and move around in the nest, the female takes some time off, and leaves their care to the male. Now he has to not only feed them, but guard them from potential marauding eagles or owls that might like a tasty osprey chick for dinner.  (An account of this predatory behavior is described here.)

osprey-

Dad is on duty, watching over the nest from a tree nearby.

At about two months of age, having exercised their wing muscles, and practiced “helicoptering” (hovering over the nest), osprey chicks may try a test flight to a nearby tree, where they hang out, still insisting that dad come feed them.

osprey nest and fledglings

The scene at the osprey nest currently — one chick still on the nest, and one in a nearby tree (highlighted brown and white spot). Dad was busy looking for fish, mom was never seen — this is when the chicks are vulnerable to predation.

osprey chick-

This chick was making some incessant begging calls, as the male flew by the nest in search of a fish.

The male flew right in, dropped and the fish, and the chick immediately started picking at it.  Notice the way it stretches out its wings to hide its food from view -- typical raptor feeding behavior.

The male flew right in, dropped the fish, and the chick immediately started picking at it.  So, now they are apparently able to feed themselves. Notice the way the youngster stretches out its wings to hide its food from view — typical raptor feeding behavior.

osprey nest, adult and fledgling-

Now the other chick is making begging calls — dad has to go and get a fish for that chick.

osprey-

Osprey are busy parents during June and July in Minnesota.  This female has finished molting, replacing worn and broken feathers, damaged during her long stint on the nest. Now she must exercise those atrophied wing muscles to get ready for migration.

osprey family update

I’ve been checking the osprey nest each week, and finally got some cooperation from the nestlings, allowing me to photograph their development.

osprey nest

This is what the nest looks like on most days I visit. The chicks are old enough now that mom can leave them for several minutes while she goes fishing.  When their parents are gone, the chicks must be down in the bottom of the nest, where their mottled plumage helps camouflage them.

osprey chicks-

One or both chicks suddenly appeared at the edge of the nest and started making begging calls — loud chips that sound like one note of the adult’s call.  You can just barely see the head of the second chick on the left of the one sitting upright.

osprey chicks-

One of the adults returns shortly after the chicks start begging; I think it might be the female, but she has not brought any fish for the chicks.

osprey chicks-

A nice family portrait, with both chicks sitting upright next to the much larger adult. They are a little more than 1/2 an adult’s size at this stage — approximately 6 weeks of age.

osprey chicks-

Their feathers are largely grown in now, wing feathers are elongating, and body feathers completely cover their naked skin. They spend most of their time lying prostrate in the nest, but every now and then need a good stretch…

Raising the kids

There’s no rest for busy bird parents these days as they patrol, hunt for food, and defend their youngsters. I saw a few examples of this on my nature walk the other day.

canada geese and goslings

The Canada Goose goslings have grown since I photographed them last week and most of them show the adult facial markings. One or two seem younger (smaller) than the others, and one definitely is developmentally behind the others (second from right). Perhaps these younger ones came from a different clutch and were adopted?

osprey and chicks-

There are (at least) wo chicks in the osprey nest, old enough now to stand up in the nest and beg.  

baltiimore oriole at his nest-

Mr. Oriole was busy tending to his chicks. The woven basket nest was well hidden in a clump of leaves and suspended by just a few thin threads from the branchlets above.

baltiimore oriole female-

Meanwhile, Mrs. Oriole was busy searching for something to feed her noisy youngsters.

Family life at the Osprey nest

I’m doing a weekly visit to monitor a local Osprey nest at the same park featured in the last two posts.  It’s a challenge to figure out exactly what is going on there with the aid of the telephoto lens or my binoculars.

osprey at the nest-

This is what it looks like most of the time — usually it’s the female either incubating eggs or sitting over the chicks to protect them from direct solar radiation. I think the chicks have hatched because she is sitting up much higher than she was a couple of weeks ago.  Previously only her head was visible.

osprey at the nest-

When dad arrives with a fish, there is some subtle communication that goes on before the fish is consumed.  

This was actually the second fish that dad brought to the nest.  After he delivered the first one, the two birds stood and looked at each other for a couple of minutes, and then he flew off with the fish in his talons.  Neither of them fed on it or diced it up for the chicks.  Hmmm… not sure what was going on there.

This was actually the second fish that dad brought to the nest.

Standing around thinking about what to do next with that fish…

This was actually the second fish that dad brought to the nest.

OK, let’s eat it. The female fed herself, the male seemed to be tearing off small chunks and leaning way into the nest toward where I assume the newly hatched chick(s) sat.

This was actually the second fish that dad brought to the nest.

When she comes around to his side of the nest, you can see marked differences between the birds. The female (on the left) is larger and is perhaps a little darker.  Her feathers are not smooth and sleek like his.  She needs a good preen job after sitting on eggs and chicks for more than a month.

osprey at their nest

Seems she needs to stretch out her wings as well. Lots of missing feathers there, and they’re looking a little ragged.

I’ll report back again when the chicks get a little bigger and are visible.

breakfast at the osprey nest

I checked the osprey nest at one of the local lakes last week, and it looked like there were sticks being added to it, and one of the adults was sitting in a nearby tree.  Yesterday, I found both adults sitting in trees near the nest, vocalizing, and basking in the early morning sun.

osprey

Now that they are back in town, perhaps there will be some courtship action to be photographed.

Unlike other species of raptors, osprey partners are fairly similar in size and appearance.  Males are slimmer with narrower wings, and fainter spotting on the breast feathers, but it’s hard to tell which is which from this distance.  I am too far away, even with 400 mm of telephoto to see much detail in their feathers.

osprey

This individual sat quietly for about a 1/2 hour while the other bird went fishing.

osprey

After a quick (less than 5 minutes) round trip to the lake, this bird brought back a big chunk of fish, which it proceeded to delicately pick apart.

osprey

Nothing like fresh fish for breakfast…

osprey

That piece of fish was stuck in the talons and to the rough scales on the bottom of the bird’s foot so well that it had to vigorously shake the piece loose to transfer it to the other foot.  I wonder if ospreys are right or left-footed in their preference for holding food while eating??

osprey

The other bird had this comment to make about its partner’s meal…well, it’s always good to get rid of excess weight before going off to fish yourself.

osprey

Breakfast is over, time to get on with other daily activities, like nest building.

the flyover

Where are the warblers that should have arrived here in early May?  I think they flew right over Minnesota this year, in a hurry to get up north and set up housekeeping to raise the next brood of chicks.  Even the few Yellow-rumped Warblers that roamed the lakeside woods for a few days have moved on.  Better luck next year.

But in keeping with the “flyover” theme, I was treated to many flyovers by the local osprey at the marsh today.  First one member of the pair and then its mate circled over head while I fired off the camera shutter.

osprey

This may well be the most photographed bird in my collection. I have gone back to the marsh several times to check on whether there are chicks in the nest yet.

osprey

Those are some amazing long wings — all the better to glide around in circles watching me.

osprey

Part of this circling act may have been hunting, but there were too many trees in the way for me to see whether they actually were diving for fish.

osprey

Feet lowered to go after some fish?

osprey

It’s amazing how agile they are in flight, changing directions quickly and abruptly.

osprey at the nest

At one point, the presumed female gave up incubating for some exercise.  She took off, flew around the nest a couple of times, doing a few swoops and dives, and then settled right back on her eggs.  The incubation period is 36-42 days, so she will be sitting here for some time still.

spring fling

I got back from a two week visit to relatives in California to find that spring was in full swing here in Minnesota.  On my walk around at the local marsh this afternoon, not only were the frogs, turtles, and birds visibly active, there was quite a lot of courtship singing and territorial fighting going on.  I watched a pair of Osprey swoop, circle, dive, land on their stick nest, take off again, fly around more, then finally back at the nest get down to business — yes, that kind of business.  I found an unobstructed view about 150 yards from the nest platform, propped my telephoto on my knees and shot 180 photos!  Here is some of the action I witnessed.

osprey landing on nest

This nest platform has been here several years, and I know this pair have added sticks to it recently because last winter, the nest platform was completely bare.

osprey pair flying

Circling around each other for several minutes — I guess this constitutes courtship flight.

osprey pair-at their nest

osprey pair at their nest

osprey pair at their nest

Male (on the right) displaying to female

osprey pair at their nest

He alternated between showing his rear end and flapping his wings in her face.

osprey pair at their nest

A strange wing fluttering behavior that you might see in a begging chick…sort of submissive for a male.

osprey pair at their nest

Then he took off, circled the nest three times, and came in for a landing

osprey pair at their nest

Some serious braking action here, as he wants to land on her, not the nest.

osprey pair at their nest

Touchdown — ouch — pull your talons in.

osprey pair at their nest

And…success —mission complete.

Just as the finale was taking place, my camera blinked and quit — card full, battery dead.  What a great experience.

If you build it, they will come

In this case, if you build tall enough platform structures near large bodies of water, you can attract nesting osprey.

Even though this osprey tower sits next to a rather tall tree, it lacks wide enough branches near its crown to support an osprey nest

Even though this osprey tower sits next to a rather tall tree, it lacks wide enough branches near its crown to support an osprey nest

Once extremely common in North America, Osprey numbers declined precipitously in the mid-1900s in the U.S. as the birds failed to successfully reproduce.  Chick production fell primarily because of widespread use of pesticides that caused egg-shell thinning and the loss of tall nesting trees near bodies of water due to rural and suburban development.

Many states started osprey reintroduction programs in the 1980s, bringing healthy chicks from remote locations where the birds still bred successfully and hand-rearing them in special “hack boxes” to fledging so that the youngsters would develop a site recognition and fidelity to that area.  And it seems to have worked, because numbers of nesting pairs in areas where ospreys had disappeared have increased exponentially in the last 30 years.

The birds will even use a tall pole that doesn't have a flat nesting platform, like the lights for a baseball field.

The birds will even use a tall pole that doesn’t have a flat nesting platform, like the lights for a baseball field located near a large lake in Maple Grove, MN.

Yesterday, I noticed that the osprey nest platform at Snail Lake (featured in an earlier post) was again occupied (it was unused last spring), and the pair of osprey that had set up housekeeping there was still adding branches to their nest.

One bird sat on the nest and did the stick arranging, while the other bird made several trips with a few odd-shaped sticks.

One bird sat on the nest and did the stick arranging, while the other bird made several trips with a few odd-shaped sticks.

osprey nest

tamping it into place...

tamping that stick into place…

One bird seems to be checking out the fit of the nest.

One bird seems to be checking out the fit of the nest.

and then they both decided to leave...

and then they both decided to leave…

But now that the lakes have unfrozen, hopefully they will finish nest building, lay their eggs and raise their chicks on the plentiful supply of fish in this marsh.

osprey with fish

Charismatic (Minnesota) Fauna

Several fellow Cuba travelers and I visited a former Army ammunition plant (now wildlife area) on a cold, dreary morning today, but we saw about 40 species of birds there.  Among them were a couple of the species photographers love to capture up-close because they are so charismatic. Unfortunately one of them was quite far away.

One of a pair of osprey perched about 1/4 mile from its nest where its mate was resting.

One of a pair of osprey perched about 1/4 mile from its nest where its mate was resting.

I think this is the other adult, whose head is just barely visible, perhaps sitting on eggs or chicks to keep them warm on this frigid day.

I think this is the other adult, whose head is just barely visible, perhaps sitting on eggs or chicks to keep them warm on this frigid day.

We tried to get closer for a better shot but made the bird nervous and it took off.

We tried to get closer for a better shot but made the bird nervous and it took off.

Bad light, moving target, but the head was in focus.

Bad light, moving target, but the head was in focus.

The bird landed in a tree that was closer to us, and in marginally better light.

The bird landed in a tree that was closer to us, and in marginally better light.

There are three osprey nests in this wildlife area, which is managed by the U.S. Army.  Unfortunately, it is closed to the public most of the time, or I would be walking around there every day.

Osprey are common world-wide, but are unusual in that they are the only species in their family.  Not an eagle, not a hawk, nor a falcon, but sharing some of their characteristics, it is a unique and successful specialist on catching fish. They can turn their outer toes backward, like owls, forming a pincer to snag fish.  Sharp spicules on the toe pads and backward pointed scales on the underside of the talons bite into the fish to stabilize it while the bird is flying.

Just as we were leaving the area, my husband spotted a pair of Common Loons (also called Great Northern Loon) swimming close to shore.

Common Loon

Their plumage is so water repellent, you can see droplets beading up on the bird's head.

Their plumage is so water repellent, you can see droplets beading up on the bird’s head.

Loons are powerful flyers, clocking in at more than 70 mph, and can launch themselves like a torpedo in the water, performing kick-turns to change direction abruptly when their prey does.  But their legs are placed so far back on their bodies to enable their underwater maneuvers that they have trouble taking off without a long runway of up to 1/4 mile of open water.  These two loons were swimming in a small lake, so I wonder how they will manage to lift off to finish their migration north.

Common Loons are found throughout North American, Europe and Asia, breeding in northern, inland lakes in the summer and wintering along the coasts of the continents.  According to the Cornell Bird Lab website, a family of loons (adults and two chicks) will eat almost a half-ton of fish over the nesting period (about 12-15 weeks).  So when you see Loons on a lake, you know the fishing is good there.