0:07

Hello and welcome. This

0:10

is the Science of

0:12

Birds. I am your

0:14

host, Ivan Philipson. The

0:16

Science of Birds podcast

0:18

is a light-hearted

0:21

exploration of bird

0:23

biology for lifelong

0:25

learners. This episode,

0:27

which is number 114, is

0:30

all about the Osprey. This

0:32

bird's scientific name

0:35

is Pandian halitis.

0:37

It's a distinct handsome raptor and

0:39

it's found across most of

0:41

the world and it has

0:43

many fans among bird lovers.

0:45

If I had to pick just one

0:48

word to associate with the Osprey, that

0:50

word would be fish. This bird

0:52

is all about catching and eating

0:54

fish. It's not surprising then

0:56

that some other common names

0:59

in English for this species

1:01

include fish hawk, fishing hawk,

1:03

and river hawk. But I say why

1:05

stop there. How about aquahawk or

1:07

river raptor? Stream eagle or

1:09

H2O spray? I don't know.

1:12

Yeah, and just where did the

1:14

name Osprey come from anyway?

1:16

Well, stick around and we'll

1:18

answer that in a little bit.

1:21

Something I had to double

1:23

check when I sat down to

1:25

create this episode was the

1:27

correct word to describe more

1:29

than one Osprey. In other

1:32

words, what's the plural form

1:34

of Osprey? The answer is

1:36

ospreys. So just like one

1:38

might say, look at all those

1:40

chickens. Look at all those chickens.

1:42

We should say, look at all

1:44

those ospreys. But part of

1:47

my dumb little brain wants

1:49

me to say, look at all

1:51

those osprey. Maybe because it seems

1:54

to have the word prey tucked

1:56

in there, and prey is the

1:58

same in both singular... plural

2:00

form. And with birds, some of

2:03

them have names like grouse, scop,

2:05

and quail, which can work both

2:07

ways. So yeah, in case you

2:10

didn't know, the plural of Osprey

2:12

is Osprey's. These birds are revered

2:15

in both folklore and modern culture.

2:17

For example, there's the Boeing V22

2:19

Osprey, an American military aircraft that

2:22

looks... Like what would happen if

2:24

a helicopter and an airplane made

2:26

a baby together? And then there's

2:29

the company Osprey that makes backpacks

2:31

and travel gear. We name sports

2:33

teams after Ospreys. There's a book

2:36

publishing company in the UK called

2:38

Osprey and so on. I suspect

2:41

that a lot of you listening

2:43

right now think that Ospreys, the

2:45

birds, are really cool. And I

2:48

agree. This is one of my

2:50

favorite raptors, and I'm excited to

2:52

finally be making this episode. First,

2:55

we'll cover the physical traits of

2:57

ospreys, their appearance and their sounds.

3:00

Next, we'll dig into the species'

3:02

geographic distribution, habitats, migration patterns, and

3:04

evolution. And of course, we'll take

3:07

a look at what these birds

3:09

eat and how they breed. Okay,

3:11

we have a lot to talk

3:14

about, so let's get into it.

3:24

The Osprey is such a widespread

3:26

bird around the world, I'm betting

3:28

that you already know what one

3:30

looks like. But in the spirit

3:32

of being thorough, let's go ahead

3:34

and consider the body structure of

3:37

the species. The basic shape is

3:39

similar to that of a large

3:41

hawk or an eagle. The Osprey

3:43

is not technically a hawk or

3:46

an eagle, and we'll get into

3:48

why that is soon, but it's

3:50

close enough if you're trying to

3:53

picture what this bird looks like.

3:55

All spray wing spans range from

3:57

59 to 71 inches or 150

4:00

to 180 centimeters. This bird is

4:02

a bit larger than a red-tailed

4:04

hawk, but significantly smaller than a

4:07

bald eagle. Females are larger than

4:09

males, which is typical in raptors.

4:11

Adult female osprey can be up

4:14

to 25% heavier than males. And

4:16

as raptors go, the osprey has

4:18

a kind of small head. And

4:21

it has a medium-length tail, although

4:23

some have described it as short,

4:25

but I also saw some describing

4:28

it as long, so let's compromise

4:30

and call it medium. And these

4:32

birds have exceptionally long wings. I

4:35

think we all agree on that.

4:37

The silhouette made by the wings

4:39

has a different shape when an

4:42

osprey soars and when it glides.

4:44

Soaring and gliding are similar but

4:46

different modes of flight. Remember that

4:48

when a bird is soaring, it

4:51

stays in the air without flapping

4:53

and without losing altitude, and sometimes

4:55

even gaining height. Like when the

4:58

bird is riding a thermal or

5:00

an updraft of wind. Gliding, on

5:02

the other hand, is more of

5:05

a controlled fall. The bird is

5:07

slowly losing altitude, but in a

5:09

smooth forward motion. Anyway, when an

5:12

osprey is soaring, its wings look

5:14

really long and elegant. It can

5:16

look like a large gull, especially

5:19

when seen head-on, because the wings

5:21

are held in an uplifted bow

5:23

posture, sort of like the drawing

5:26

of a bird that a five-year-old

5:28

kid might make, like a shallow

5:30

letter M. But when an osprey

5:33

glides, the wings take on an

5:35

even more distinctive shape. The wings

5:37

are bent, with the wrist jutting

5:40

far forward. The primary feathers of

5:42

the hand angle sharply backward of

5:44

the carpal joint. So if you're

5:47

looking straight up at a gliding

5:49

osprey, or straight down on it,

5:51

I suppose, you see that the

5:54

bent wings create, again, the shape

5:56

of the letter M, but even

5:58

more dramatically. So if you see

6:01

a gliding raptor... It's probably an

6:03

Osprey if it looks like a

6:05

flying M. Not to be confused

6:08

with a flying V- which is

6:10

a model of futuristic-looking electric guitar

6:12

introduced by the company Gibson in

6:14

1958. Moving on to look at

6:17

the bird's head. It's got a

6:19

classic raptor profile with a strongly

6:21

curved bill with a hook at

6:24

the tip. In adults, the bill

6:26

is typically dull blackish with a

6:28

bluish-gray seer. Remember that the seer,

6:31

C-E-R-E, is the fleshy covering at

6:33

the base of the upper mandible.

6:35

the area around the nostrils. The

6:38

large eyes of an osprey are

6:40

a piercing yellow color in an

6:42

adult bird, but youngsters in the

6:45

first year of their life typically

6:47

have orange-ish red eyes. Looking at

6:49

the opposite end of the body,

6:52

we have the feet. The legs

6:54

and feet are white. But there's

6:56

a lot more to say about

6:59

the osprey's foot. This is a

7:01

beautifully well-adapted fish-catching apparatus. First of

7:03

all, wow! The talons on this

7:06

bird are serious. They're black, slender,

7:08

exceptionally long, and wickedly hooked. And

7:10

the talons are also rounded when

7:13

you look at them in cross

7:15

section. Other raptors typically have grooved

7:17

talons. The large talons of an

7:20

osprey are nearly uniform in size.

7:22

In many other raptors we see

7:24

more variation in talon size among

7:27

the toes. For example... Hawks and

7:29

Eagles in the family exhibitity have

7:31

significantly larger talons on digits 1

7:33

and 2 compared to 2, 3,

7:36

and 4. Digit 1 is the

7:38

toe that faces backward, sort of

7:40

like a thumb. Digit 2 is

7:43

the forward-facing toe on the inside,

7:45

closest to the bird's midline. You

7:47

can think of digit 2 as

7:50

sort of like your index finger.

7:52

So, Ospreys have extra long, curvy

7:54

talons, and they're all more or

7:57

less the same size. The talons,

7:59

that is. But one of the

8:01

Ospreys superpowers is it's a bill-

8:04

to rotate the fourth toe, digit

8:06

four, backward. Normally this toe faces

8:08

forward and it's the one on

8:11

the outward edge, like your pinky

8:13

finger. The normal foot position for

8:15

an osprey, like when it's perched

8:18

on a tree branch, is to

8:20

have three toes forward and one

8:22

toe facing backward. In birds we

8:25

call this toe arrangement an isotactyl.

8:27

That's what you see on a

8:29

typical songbird or a typical raptor.

8:32

But remember that one of the

8:34

alternative toe arrangements seen in some

8:36

other birds is called zygadactyl. A

8:39

zygadactyl foot has two toes facing

8:41

forward and two facing backward. We

8:43

see this with woodpeckers, owls, and

8:46

cuckoos. So when an osprey is

8:48

diving, rocketing downward to catch a

8:50

fish, it rotates digit four around

8:53

so that it faces backwards. So

8:55

a diving osprey has zygadactyl feet.

8:57

Temporarily, two toes face forward and

8:59

two face backward. We can say

9:02

that the feet of this bird,

9:04

therefore, are semi-Zygidactyl. Among raptors, only

9:06

owls share this special ability of

9:09

being able to switch between an

9:11

isidactyl and zygidactyl arrangements. We'll talk

9:13

a little bit more about osprey

9:16

feet when we get into how

9:18

these birds hunt for fish. But

9:20

let's move on now to look

9:23

at the plumage color and pattern

9:25

on the osprey. Adult ospreys have

9:27

dark brown upper parts and mostly

9:30

white underparts. The breast is white,

9:32

often with brown speckling or a

9:34

darker necklace, especially in females. The

9:37

head is white with a dark

9:39

stripe through the eye, and that

9:41

black mask on an otherwise white

9:44

head is a distinct and striking

9:46

feature. And of course the yellow

9:48

eyes really pop because they're surrounded

9:51

by black feathers. Under the wings,

9:53

if you're looking up at an

9:55

osprey, you'll see it has dark

9:58

patches at the wrists. Those are

10:00

called carpal patches and they really...

10:02

stand out, so they're a good

10:05

field mark for this bird. Also

10:07

the flight feathers are barred when

10:09

seen from below. Males tend to

10:12

be slimmer with less breast marking,

10:14

while females show more dark feathers

10:16

on the chest and neck. Some

10:19

regional differences exist in plumage. For

10:21

example, Caribbean birds are wider, and

10:23

North American ones are darker-bodied with

10:25

paler breasts compared to those in

10:28

Europe. We'll talk some more about

10:30

regional differences in a few minutes.

10:32

Juvenile birds look a little bit

10:35

different. They have a buffy wash

10:37

on the nape and breast. And

10:39

the dark feathers on their backs

10:42

are edged with white. So the

10:44

feathers on the back of a

10:46

juvenile osprey look sort of scaly.

10:49

Now let's check out the sounds

10:51

that ospreys make. Their vocalizations. These

10:53

are all simple whistling or screaming

10:56

sounds. The pitch of these calls

10:58

is usually a little lower in

11:00

females. And that might be simply

11:03

because a female has a larger

11:05

body. Ornithologists have identified five basic

11:07

call types for ospreys. First, there's

11:10

the alarm call. It's given when

11:12

a potential predator is spotted at

11:14

a distance. Young ospreys that are

11:17

almost at the fledging age also

11:19

give alarm calls in response to

11:21

humans near the nest. This call,

11:24

the alarm call, is a series

11:26

of short, clear notes. Then we

11:28

have the solicitation, or food begging

11:31

call. Only the female makes this

11:33

sound. You hear it a lot

11:35

in Osprey breeding colonies. The food

11:38

begging call is triggered by the

11:40

presence of the male near the

11:42

nest. and it reaches a fever

11:44

pitch when the male is coming

11:47

in carrying a fish in his

11:49

talons. That's when the female is

11:51

like, oh would you look at

11:54

that? That is my man. My

11:56

man's got a fish. Give me

11:58

that fish, baby. Give me that

12:01

fish." Yeah, that's what she's like.

12:03

But sometimes a female osprey makes

12:05

the food-begging call when her mate

12:08

is just sitting there, perched near

12:10

the nest, doing nothing. Ornithologists suspect

12:12

the female in this case might

12:15

be signaling to her mate to

12:17

get off his lazy butt and

12:19

go fishing already. Next we have

12:22

the guard call. This one is

12:24

made by both sexes. It's a

12:26

succession of slow whistled notes that

12:29

fall rapidly in pitch. Some say

12:31

it sounds like a whistling kettle

12:33

taken rapidly off a stove. Ospreys

12:36

make the guard call when there's

12:38

an intruding osprey that gets too

12:40

close to their nest. Within, let's

12:43

say, 300 to 1,000 feet, or

12:45

0.1 to 0.3 kilometers. The defending

12:47

ospreys on their home turf often

12:50

show some behaviors at the same

12:52

time they make the guard call.

12:54

They might fly around, land on

12:57

purchase, or chase the intruder. If

12:59

the guard call and these display

13:01

behaviors don't spook the intruding osprey

13:04

into leaving, the home team gets

13:06

even more ramped up and they

13:08

bring out the big guns. They

13:10

start using the excited call and

13:13

the screaming call. These sounds have

13:15

more of a wavering pitch. Now

13:17

I wish I had a perfect

13:20

audio recording for each of the

13:22

five calls to play for you,

13:24

so that you can hear some

13:27

examples. But unfortunately I just couldn't

13:29

track them all down. But I

13:31

do have a nice recording made

13:34

by my friend Bruce. In it,

13:36

you're going to hear three individual

13:38

ospreys, recorded in Florida. Two of

13:41

them were flying around overhead, while

13:43

the third one, the one that

13:45

sounds the loudest, was perched in

13:48

a large snag. a dead tree.

14:19

Now it's time to talk

14:22

about the family of the

14:24

Osprey, as well as the

14:26

origin of its common and

14:28

scientific names. Remember when I

14:30

said that the Osprey is

14:32

not a hawk or eagle?

14:34

Well, one of the really

14:36

cool things about the Osprey,

14:38

Pandian halitus, is that this

14:40

species belongs to its own

14:42

family. It is not in

14:44

the hawk and eagle family

14:46

exhibitity. No, the Osprey family

14:48

is Pandyanadi, and it has

14:50

just one species. When a

14:52

taxonomic family has just one

14:54

species like this, we would

14:56

say this is a monotypic

14:58

family. Monotypic meaning just one

15:00

type, right? Monotypic. The family

15:02

pandionity has just one species,

15:04

and therefore it has just

15:06

one genus as well, Pandian.

15:08

Remember the hierarchy of taxonomic

15:10

levels? It goes domain, kingdom,

15:12

phylum, class, order, genus, genus,

15:14

genus, genus, genus, and species,

15:16

and species. When one of

15:18

these levels is monotypic, it

15:20

contains just one of whatever

15:22

the next level down is.

15:24

In other words, the next

15:26

subordinate taxonomic level. So when

15:28

we say monotypic family, that's

15:30

supposed to mean that there's

15:33

just one genus within that

15:35

family. Because genus is the

15:37

next level below family. So

15:39

if we just imagine there

15:41

were actually five bird species

15:43

all belonging to the genus

15:45

Pandian... And Pandian was the

15:47

only genus in the family

15:49

Pandyanadi, we should still say

15:51

that this is a monotypic

15:53

family, because it has just

15:55

one genus. But it seems

15:57

that when birders talk about

15:59

monotypic... What they mean is

16:01

a family with just one

16:03

species. Of the approximately 250

16:05

bird families in the world,

16:07

the number that fit this

16:09

criterion is somewhere between 30

16:11

and 40. It depends on

16:13

which bird taxonomy you're using.

16:15

Well, of those 30 to

16:17

40 bird species that belong

16:19

to a monotypic family, our

16:21

friend Pandian Hallyetus is quite

16:23

possibly the most famous of

16:25

all. the one recognized by

16:27

the most people around the

16:29

world. And the Osprey certainly

16:31

has the largest geographic distribution.

16:33

Anyway, that was a bit

16:35

of a tangent, but I

16:37

hope it made sense. Now

16:39

let's consider the names of

16:41

the Osprey. Where did the

16:44

English name Osprey come from?

16:46

Well, this one has kind

16:48

of a convoluted history. It

16:50

starts with a guy named

16:52

Pliny the Elder. Have you

16:54

heard of him? Pliny was

16:56

a Roman guy. his real

16:58

full name being Gaius Plenius

17:00

Secundus, and he was an

17:02

author, a naturalist, and a

17:04

naval commander, who lived in

17:06

the first century CE. He's

17:08

best known for his massive

17:10

encyclopedia called the Naturalis Historia.

17:12

This set of 37 books

17:14

attempted to catalog all known

17:16

knowledge of the natural world

17:18

at the time, at least

17:20

from the Roman perspective. It

17:22

covered everything from astronomy and

17:24

geography to zoology, botany, mineralogy,

17:26

medicine, and art. Pliny the

17:28

Elder didn't always get things

17:30

right, however. He compiled a

17:32

lot of his info from

17:34

second or third hand sources

17:36

like travelers, soldiers, and earlier

17:38

writers. So some tall tales

17:40

made their way into the

17:42

naturalist historian. Like the idea

17:44

that barnacle geese are born,

17:46

not by hatching out of

17:48

eggs, but by emerging out

17:50

of barnacles, or even growing

17:53

out of driftwood. Pliny also

17:55

included some fantastical humanoid creatures.

17:57

in his books. For example,

17:59

there are the blemii, a

18:01

race of people who don't

18:03

have heads. Instead, their faces

18:05

are in their chests. And

18:07

I'm not joking, there really

18:09

is a bunch of crazy

18:11

stuff like that in these

18:13

books. Well, Pliny wrote about

18:15

birds in his naturalis historian,

18:17

too. One of them he

18:19

named the Ossifrega. That translates

18:21

as bone breaker, which is

18:23

pretty hardcore. It seems the

18:25

bird Pliny was referring to

18:27

was the species we know

18:29

today as the bearded vulture,

18:31

or Lamergyre. That old world

18:33

vulture has a specialized diet.

18:35

It breaks open the bones

18:37

of dead animals to eat

18:39

the marrow inside. So it

18:41

is a bone breaker. So

18:43

here you've got a bird

18:45

Pliny the Elder is calling

18:47

the Ossifrega. Hundreds of years

18:49

after Pliny's time, some French

18:51

scholars in medieval times took

18:53

the word Asifrega and they

18:55

mistakenly thought it referred to

18:57

the Osprey. They called it

18:59

the Osprey. That word eventually

19:01

made its way into the

19:04

English language, first as hasprey,

19:06

then Osprey and Asprey. And

19:08

finally we ended up, of

19:10

course, with Osprey. So the

19:12

oss, in osprey, originally comes

19:14

from the Latin word for

19:16

bone. And the full name

19:18

has its origin in a

19:20

case of mistaken identity. Kind

19:22

of silly, but it stuck

19:24

and here we are. Also,

19:26

I think it's time to

19:28

bring back the name Pliny.

19:30

And if we did, we

19:32

would always have to use

19:34

it in the form of

19:36

Pliny the Something-er. Pliny the

19:38

Elder, Pliny the Uglier, Pliny

19:40

the Dumpster, Pliny the Birder.

19:42

The possibilities are endless. So,

19:44

if you're pregnant and you

19:46

haven't chosen a name for

19:48

your baby, I'm just saying...

19:50

Now, how about the scientific

19:52

name, Pandian Helietas? Pandian was

19:54

the name of a couple

19:56

different mythical Greek kings of

19:58

the city Athens. Apparently,

20:01

it was King Pandy in the second

20:03

they had in mind when they came

20:05

up with the Osprey genus. That

20:07

king had a child named Nysus,

20:10

who was, for some reason, transformed

20:12

into a hawk. And that myth

20:14

was the inspiration for the

20:16

Osprey. But in that case, doesn't

20:18

it seem like Nysus would have

20:20

been a better name? But how about

20:22

the second part, the specific

20:25

epithet of the scientific

20:27

name? Halaitis. This one is

20:29

pretty straightforward. It comes from

20:31

the Greek and it means

20:33

sea eagle. Halleetus, spelled

20:35

slightly differently, is also the

20:38

genus name of some large

20:40

actual eagles, including the

20:42

white-tailed eagle, stellar sea

20:44

eagle, and the bald

20:46

eagle. Now we've established that the

20:49

osprey isn't an eagle, and

20:51

it isn't a hawk. But the

20:54

avian family that's

20:56

most closely related to

20:58

the Osprey is

21:00

indeed Exipatriti, the family

21:03

of the Eagles and

21:05

Hawks. This leads us

21:07

into the topic of

21:09

evolution. Because the most

21:11

recent common ancestor of

21:13

the Osprey, Hawks and

21:16

Eagles appears to have

21:18

lived about 50 million

21:20

years ago years ago. Paleontologists

21:23

haven't discovered any fossils of

21:26

that very ancient ancestor yet,

21:28

but analysis of genetic data

21:30

from living birds gives us that

21:33

estimated divergence time of roughly 50

21:35

million years ago. That's when

21:37

the Osprey lineage split and went

21:39

off on its own tangent of

21:42

evolutionary history. Evidence from genetic

21:44

data also points to the geographic

21:46

origin of the Osprey, and that

21:48

origin is somewhere in the Americas.

21:51

most likely here in North

21:53

America. From here, ospreys may

21:55

have spread down the east

21:57

coast of Asia before they

21:59

colonize. the Australasian region.

22:01

That's hard to say,

22:04

Australasian region. Later, Ospreys

22:06

radiated out from Indonesia and

22:08

Oceania to settle in the

22:10

rest of Asia and in

22:12

Europe. Today, the species has

22:14

four geographically distinct populations. One

22:17

of them is widespread across

22:19

the Americas. But there's a

22:21

second distinct population in the

22:23

Caribbean. A third is found

22:25

across Europe and Asia, and

22:27

the fourth population is restricted

22:29

to Australia, New Guinea, and

22:32

some other islands in the

22:34

Southwestern Pacific Ocean. Genetic analyses

22:36

suggest that these four groups

22:38

have diverged from each other

22:40

over the last 1.16 million

22:42

years. And these groups are

22:44

different enough that we treat

22:47

them now as subspecies. And

22:49

some ornithologists have argued that

22:51

one or two of these

22:53

subspecies should be elevated to

22:55

full species status. I think

22:57

there is still some debate

22:59

around this idea. In any

23:02

case, there are some consistent

23:04

differences in the appearances of

23:06

the subspecies. For example, the

23:08

Caribbean Osprey, Pandian halietas ridgeway

23:10

eye, has a very pale

23:12

head and breast. and the

23:14

Australasian subspecies, Pandian halietis crustatus,

23:17

sports a dark breastband and

23:19

a pale head. When it

23:21

comes to the distribution of

23:23

the Osprey, well, I've already

23:25

pointed out that it's found

23:27

across most of the planet.

23:29

This bird is, therefore, a

23:32

cosmopolitan raptor. In fact, this

23:34

is probably the raptor species

23:36

with the largest range. The

23:38

Paragon Falcon is a close

23:40

contender, however. And interestingly, these

23:42

two raptors, the Osprey, and

23:44

the Peregrine Falcon are both

23:47

conspicuously absent from New Zealand.

23:49

And the Osprey is also

23:51

not found on the island

23:53

of Madagascar. This seems kind

23:55

of mysterious to me, because

23:57

it doesn't seem like New

23:59

Zealand or Madagascar are too

24:02

far away from their nearest

24:04

continents to ever be colonized

24:06

by Ospreys. But it is

24:08

what it is, mysterious or

24:10

not. In any case, the

24:12

Osprey is found on every

24:14

continent. Every single one of

24:17

them. Except, except for the

24:19

continent that no self-respecting bird,

24:21

cosmopolitan or otherwise, would ever

24:23

willingly set its feet upon.

24:25

Yes, the name of that

24:27

continent is Antarctica. The fish

24:29

in its coastal waters are

24:32

under no threat from Ospreys.

24:34

Penguins, yes, and some seabirds,

24:36

but not Ospreys. Ospreys are

24:38

tough, adaptable birds. They live

24:40

in many environments. but the

24:42

challenges of Antarctica are just,

24:44

apparently, too much. But what

24:46

is the typical habitat for

24:49

an Osprey? Where do they

24:51

like to live? Ospreys are

24:53

found in a wide variety

24:55

of habitats, including lakes, rivers,

24:57

boreal forests, mountain valleys, temperate

24:59

and subtropical coastlines, and even

25:01

salt-flat lagoons in the desert.

25:04

Despite this diversity, Osprey habitats

25:06

share several key features. Maybe

25:08

the most important is an

25:10

abundant and accessible supply of

25:12

fish within a reasonable flying

25:14

distance from the nest, like

25:16

less than 6 to 12

25:19

miles or 10 to 20

25:21

kilometers. Shallow waters generally provide

25:23

the easiest access to fish.

25:25

Another key feature is the

25:27

availability of nesting sites. Bossprays

25:29

need open nest sites that

25:31

are safe from predators, particularly

25:34

mammals. And these sites are

25:36

typically elevated. such as at

25:38

the tops of trees on

25:40

large rocks located over water

25:42

or on cliffs. And the

25:44

third key feature of osprey

25:46

habitat is a sufficiently long

25:49

ice-free season. This allows there

25:51

to be enough time to

25:53

raise a family through the

25:55

spring and summer before snow

25:57

and ice return in the

25:59

autumn. And when the chilly

26:01

weather does return, many ospreys

26:04

that breed in the temperate

26:06

latitudes, well, they clear out.

26:08

They migrate south to find

26:10

fish in warmer climates. This

26:12

is true for ospreys that

26:14

breed in most of northern

26:16

North America and Eurasia, and

26:19

their migratory journeys can be

26:21

thousands of miles. For example,

26:23

ospreys that breed in the

26:25

northeastern United States, such as

26:27

those in Maine or New

26:29

York, typically migrate south along

26:31

the U.S. East Coast, cross

26:34

over Florida, and then fly

26:36

across the Caribbean Sea before

26:38

reaching their wintering grounds in

26:40

northern South America. They spend

26:42

the non-breating season in places

26:44

like Colombia, Venezuela, and Brazil.

26:46

And that's an epic one-way

26:49

journey of about 4,000 to

26:51

5,000 miles, or 6,400 to

26:53

8,000 kilometers. So this bird

26:55

migrates farther than almost every

26:57

other raptor. Most North American

26:59

ospreys are migratory, and most

27:01

of them have left the

27:04

continent by November. But there

27:06

are some non-migratory osprey populations,

27:08

too. The best examples are

27:10

the Caribbean subspecies and the

27:12

Australasian subspecies. Those guys occupy

27:14

the same habitats all year.

27:16

And that kind of makes

27:19

sense because they live in

27:21

relatively warm or even tropical

27:23

environments. So no need to

27:25

clear out in winter. Among

27:27

birds in general, most migrants

27:29

make one or more stopovers

27:31

to refuel with food. So

27:34

most birds treat foraging and

27:36

migration as temporarily separated activities,

27:38

not things that they do

27:40

simultaneously. Ospreys, however, do things

27:42

a little differently. They've got

27:44

a trick that allows them

27:46

to fuel their journey continuously

27:49

by hunting along the way.

27:51

It's called the fly and

27:53

forage strategy. An offspring on

27:55

a 5,000 mile migration journey

27:57

can just swoop down to

27:59

a lake or wherever, snatch

28:01

up a fat fish, then

28:04

keep on flying. No need

28:06

to stop over for any

28:08

length of time. The Osprey

28:10

carries the fish in its

28:12

talons like a fifth grader

28:14

carrying a lunchbox on the

28:16

way to the bus stop.

28:19

Do kids still use lunchboxes?

28:21

Is that still a thing?

28:23

Man, lunchboxes were a serious

28:25

business when I was like

28:27

eight years old. They always

28:29

had a theme, some cartoon

28:31

or a movie. I had

28:34

a metal lunchbox that was

28:36

based on the return of

28:38

the Jedi. Star Wars and

28:40

whatnot, you know, circuit 1983.

28:42

And I had another one

28:44

that was all about Indiana

28:46

Jones boxes were dope, man.

28:49

I think I might have

28:51

had a My Little Pony

28:53

lunchbox at one point. Maybe.

28:55

I have a vague memory

28:57

of that. Probably a traumatic

28:59

memory that I've been repressing.

29:01

Who knows? But yeah, Ospreys

29:04

will sometimes carry fish a

29:06

long way from where they

29:08

caught them. It's a grab

29:10

and go lunch for the

29:12

road. The Osprey has one

29:14

of the most well-known comeback

29:16

stories in bird conservation. Between

29:19

the 1700s and the early

29:21

20th century, these birds were

29:23

often persecuted. They were killed

29:25

because, I guess, people saw

29:27

them as competition for fish.

29:29

For example, ospreys were driven

29:31

to extinction in England by

29:34

1847 because of persecution and

29:36

egg collecting. Similarly, they were

29:38

extirpated in Southern California by

29:40

the 1920s. But then there

29:42

were major population declines from

29:44

the 1950s to the 70s.

29:46

Osprey numbers dropped dramatically in

29:49

areas like the US Atlantic

29:51

Coast. Chesapeake Bay and the

29:53

Great Lakes. In some places,

29:55

over 90% of breeding pairs

29:57

disappeared. The main cause was

29:59

DDT, a pesticide that was

30:01

sprayed widely to control mosquitoes

30:04

and agricultural pests. The problem

30:06

was DDT passed through the

30:08

food chain to reach hot

30:10

sprays, other raptors and other

30:12

animals. And it caused some

30:14

major damage. This process of

30:16

accumulation through the food chain

30:19

starts with DDT being sprayed

30:21

in agricultural areas. The pesticide

30:23

then gets washed into aquatic

30:25

ecosystems like rivers and lakes

30:27

through runoff. There it gets

30:29

absorbed by tiny plankton. And

30:31

then it gets more and

30:34

more concentrated as it moves

30:36

up the food chain. Small

30:38

fish eat the plankton and

30:40

larger fish eat those small

30:42

fish. Ospreys, being top predators

30:44

that eat lots of large

30:46

fish, can end up with

30:49

high concentrations of DDT and

30:51

its byproduct DDE in their

30:53

bodies. Eggs laid by these

30:55

contaminated birds have unnaturally thin

30:57

shells. So when an adult

30:59

Osprey tries to incubate such

31:01

fragile eggs, they break. This

31:03

phenomenon led to widespread nest

31:06

failures and population declines for

31:08

ospreys. This crisis, which hit

31:10

other bird species just as

31:12

hard, helped to reveal how

31:14

harmful DDT was. And, thankfully,

31:16

that led to the pesticide

31:18

being banned in the U.S.

31:21

in 1972. After the ban,

31:23

Ospreys started to rebound. Nesting

31:25

success improved and people began

31:27

putting up nest platforms, which

31:29

Ospreys readily accepted. These platforms

31:31

became super important in the

31:33

recovery process. especially where trees

31:36

had been cut down or

31:38

shorelines had been developed. And

31:40

reintroduction programs helped bring the

31:42

birds back to parts of

31:44

the U.S. Great Britain and

31:46

Europe where they had vanished.

31:48

Today, Osprey numbers are strong

31:51

across much of the species

31:53

range. Estimates of the worldwide

31:55

breeding population range from 100,000

31:57

to 1.2 million. In North

31:59

America, many populations are growing

32:01

steadily, at about 2% per

32:03

year, from 1966 per year

32:06

from 1966 to 2019. So

32:08

the species is now listed

32:10

in the least concern category

32:12

by the IUCN. And that

32:14

reflects the Osprey's vast range

32:16

and its globally stable population.

32:18

And yet, not everything is

32:21

perfect. For example, in Chesapeake

32:23

Bay on the east coast

32:25

of the US, Osprey Nest

32:27

Success has dropped again. This

32:29

is possibly because of a

32:31

decline in the local population

32:33

of Menhaden. a key food

32:36

fish for ospreys. And scientists

32:38

aren't quite sure yet what's

32:40

causing that decline, like why

32:42

the menhaden are declining. But

32:44

other threats to ospreys, in

32:46

general, include fishing line entanglement

32:48

dependence on all those man-made

32:51

nest sites that need upkeep

32:53

and water quality issues. Because

32:55

ospreys are top predators in

32:57

many aquatic ecosystems, they can

32:59

tell us something about the

33:01

overall health of those systems.

33:03

So the Osprey is an

33:06

indicator species. If water quality

33:08

sucks or the plankton and

33:10

fish aren't healthy, the local

33:12

Osprey population is probably going

33:14

to suffer. And hey, speaking

33:16

of fish, it's time to

33:18

talk some more about what

33:21

and how Ospreys eat. 99%

33:23

of an Osprey's diet is

33:25

fish. This species is what

33:27

biologists call an obligate pissivore,

33:29

or some say pysivore. Some

33:31

other raptors like Baldi... Well,

33:33

they like to eat fish

33:36

too. There are also fish

33:38

owls, fishing owls, and the

33:40

six species of fish eagles.

33:42

Fish eagles are all in

33:44

the genus Icteophaga, and that

33:46

literally means fish eating. But

33:48

none of those raptors are

33:51

as specialized in their piscivorous

33:53

diet as the osprey. A

33:55

wide variety of fish are

33:57

taken. For example, over 80

33:59

species of fish have been

34:01

recorded in the diets of

34:03

North American ospreys. And in

34:06

Florida, as a more specific

34:08

example, the dominant prey include

34:10

gizzard shad, threadfin shad, sunfish,

34:12

speckled trout, mullet, and crappy.

34:14

And yes, if you didn't

34:16

know, there really is a

34:18

fish species with the unfortunate

34:21

common name, crappy. But I

34:23

guess some people say croppy.

34:25

using a euphemistic pronunciation shift

34:27

to make the word sound

34:29

less vulgar, you know, like

34:31

saying pysivore, because saying pysivore

34:33

makes you nervous. Anyway, as

34:36

another example, research on ospreys

34:38

in the Willamette River, here

34:40

in my home state of

34:42

Oregon, found that 90% of

34:44

their diet is composed of

34:46

just two fish species, large-scale

34:48

sucker and northern pike minnow.

34:51

The typical fish prey for

34:53

ospreys, in general, fall within

34:55

a length of roughly 6

34:57

to 14 inches, which is

34:59

15 to 36 centimeters. And

35:01

the typical weight of each

35:03

fish is about 0.3 to

35:06

0.7 pounds, or 0.13 to

35:08

0.32 kilograms. Now I said

35:10

that 99% of an ospreys

35:12

diet is fish. So you

35:14

might be wondering about the

35:16

remaining 1%. What are the

35:18

other things that Ospreys sometimes

35:21

eat? Well, first of all,

35:23

it's very rare for an

35:25

Osprey to eat anything other

35:27

than fish. But, that said,

35:29

these birds have been observed

35:31

eating things like snakes, amphibians,

35:33

crustaceans, small mammals, and even...

35:36

carrying. But again, this is

35:38

rare. We'll talk about the

35:40

hunting or foraging method of

35:42

ospreys in a moment. But

35:44

first, let's look at their

35:46

unique physical adaptations that are

35:48

related to catching fish. First,

35:51

ospreys have keen eyesight that's

35:53

well adapted for detecting fish

35:55

below the water's surface from

35:57

a height of 30 to

35:59

130 feet, or 10 to

36:01

40 meters. They can even

36:03

adjust the angle of their

36:06

dive to compensate for the

36:08

refraction of light as it

36:10

passes from air to water.

36:12

This is similar to what

36:14

kingfishers do. You remember that?

36:16

I talked about that in

36:18

episode 102, which was all

36:21

about the common kingfisher. Earlier

36:23

in this episode, we discussed

36:25

the ability of an osprey

36:27

to rotate one of its

36:29

toes so that two digits

36:31

face forward and two face

36:33

backward. This semi-zygadactylae ability transforms

36:36

the bird's feet into highly

36:38

effective fish traps. And remember

36:40

that the talons are long

36:42

slender and deeply curved, and

36:44

they're rounded in cross-section. The

36:46

shape of the talons is

36:48

ideal for hooking into the

36:51

flesh of a fish. The

36:53

skin on the toes and

36:55

feet of the osprey are

36:57

also adapted for gripping fish.

36:59

The pads on the soles

37:01

of the feet are covered

37:03

in sharp, spine-like projections called

37:05

spicules. These act like barbs

37:08

or sandpaper, giving them extra

37:10

traction on a slippery fish.

37:12

So you can think of

37:14

the feet of an osprey,

37:16

sort of like the textured

37:18

latex gloves used by fishermen

37:20

or gardeners. When an osprey

37:23

hits the water in pursuit

37:25

of fish, it risks becoming

37:27

water-logged and drowning. Raptors in

37:29

general are not known for

37:31

their swimming skills. So another

37:33

adaptation of the Osprey is

37:35

that its plumage is dense

37:38

and oily. This prevents the

37:40

plumage from becoming water-logged. It

37:42

allows the Osprey to dive

37:44

relatively deep and to resume

37:46

flight more easily. Those other

37:48

fish-loving raptors I mentioned earlier,

37:50

well those guys mostly snatch

37:53

fish right at the water's

37:55

surface. They don't really dive

37:57

into the water the way

37:59

an osprey does. Getting back

38:01

into the air from the

38:03

water requires powerful wing strokes.

38:05

The bones in an osprey's

38:08

wings appear to be adapted

38:10

for this purpose. Special features

38:12

include a prominent deltoid process

38:14

on the humorous, that's the

38:16

upper arm, and a relatively

38:18

long manus. The deltoid process

38:20

serves as a lever and

38:23

an attachment site for important

38:25

flight muscles. And the manus

38:27

is basically the bird's hand.

38:29

A powerful wing stroke not

38:31

only helps an osprey take

38:33

off from the water after

38:35

a dive, it also allows

38:38

the bird to hover. And

38:40

hovering is part of the

38:42

actual dive sequence. So let's

38:44

go ahead and get into

38:46

that. Ospreys typically hunt by

38:48

flying 30 to 130 feet

38:50

above the water or 10

38:53

to 40 meters, as I

38:55

said. They're flying over the

38:57

water, flapping or gliding. But

38:59

when it spots a fish,

39:01

an Osprey may hover for

39:03

a few moments before taking

39:05

the plunge. And that's what

39:08

these birds do. Their foraging

39:10

technique is called plunge diving.

39:12

Other birds that hunt this

39:14

way include gannets and boobies,

39:16

brown pelicans, and many kingfishers.

39:18

But the Osprey is the

39:20

only raptor that is a

39:23

true plunge diver. So, after

39:25

locking onto a fish with

39:27

its eyes, with laser focus,

39:29

and maybe hovering for a

39:31

few beats, the Osprey goes

39:33

for it. It rockets downward.

39:35

It throws its legs forward

39:38

in front of its head.

39:40

The feet are brought close

39:42

together. The toes splay and

39:44

swivel into their zygodactal arrangement,

39:46

and the hooked claws form

39:48

a murderous fish trap. At

39:50

the last moment, the Osprey

39:53

throws its wings backward and

39:55

the feet are what hit

39:57

the water first. If

40:00

all goes according to plan, the

40:03

bird now has a fish locked

40:05

in its talons. Ospreys catch fish

40:07

in only the top three feet

40:10

or one meter below the surface.

40:12

They don't make super deep dives.

40:14

If the captured fish is big

40:17

and strong, it might make things

40:19

hard for the osprey and the

40:21

two struggle against each other for

40:24

a while. With or without a

40:26

fish, the osprey eventually uses its

40:28

long powerful wings to take off

40:31

from the water. The success rates

40:33

of dives like this vary among

40:35

regions and among studies, but the

40:38

rough average is about 25%. So

40:40

about one quarter of all dives

40:42

end with a fish being carried

40:45

away and eaten. I'll put a

40:47

link in the show notes to

40:49

a beautiful video clip from a

40:52

BBC documentary. It shows the dive

40:54

of an osprey in slow motion,

40:56

and it really shows how the

40:59

bird struggles in the water with

41:01

the fish before getting back into

41:03

the air. Having successfully caught a

41:06

fish, an osprey will typically maneuver

41:08

the fish in its feet to

41:10

face forward, taking advantage of the

41:13

fish's streamlined shape to reduce aerodynamic

41:15

drag. So you'll almost always see

41:17

the fish with its head facing

41:20

forward when it's being carried by

41:22

an osprey. This is kind of

41:24

morbid, but since I imagine it

41:27

sometimes takes a while before the

41:29

fish dies, its last moments must

41:31

be pretty surreal. I mean, it

41:34

was just swimming around, enjoying its

41:36

day, when bam! It's suddenly caught

41:38

by this feathered beast from the

41:41

heavens. And now, just moments later,

41:43

the fish is flying through the

41:46

air, far above the water. That

41:48

must be a crazy experience. But

41:50

yeah, poor fish. I guess, circle

41:53

of life and all that. Anyway...

41:55

Ospreys can sometimes reduce their search

41:57

times looking for fish by observing

42:00

other ospreys that have been successful.

42:02

They're like, hey Sally, check out

42:04

that guy. He caught a fish.

42:07

Let's see if we can retrace

42:09

his step. to find the school

42:11

of fish that he found. And

42:14

seriously, I'm not joking, this is

42:16

a real behavior we see in

42:18

Ospreys. Well, some of them anyway.

42:21

This kind of information transfer among

42:23

Ospreys doesn't seem to be universal,

42:25

but still, it's pretty cool. Now,

42:28

just because you're an Osprey that

42:30

caught a fish doesn't mean you

42:32

get to actually eat that fish,

42:35

because sometimes you have to deal

42:37

with pirates. The bald eagle is

42:39

famous for acting as a klepto

42:42

parasite on Ospreys. An eagle waits

42:44

for an osprey to do all

42:46

the hard work. Then the eagle

42:49

swoops in like a pirate. It

42:51

lunges at the osprey. The much

42:53

larger, more powerful raptor can intimidate

42:56

the osprey into dropping its lunch,

42:58

which is then scooped up by

43:00

the eagle. I'll put a link

43:03

in the show notes to another

43:05

video that shows this kleptoparacitic behavior

43:07

in eagles. Now it's time to

43:10

talk about the breeding biology of

43:12

the osprey. Ospreys are monogamous. They

43:14

form pair bonds that often last

43:17

for the lifetime of the birds.

43:19

Although not all pairs stay together

43:21

every year, particularly if breeding is

43:24

unsuccessful, most osprey pairs reunite at

43:26

the same nest site each breeding

43:29

season. This fidelity, both to each

43:31

other and to the nest site,

43:33

reinforces the bond between mates and

43:36

helps them be more successful in

43:38

raising brood after brood year after

43:40

year. The pairs form and are

43:43

reinforced through courtship behaviors, usually in

43:45

the vicinity of the nest. One

43:47

of the most outstanding features of

43:50

osprey courtship is the aerial display

43:52

known as the sky dance. During

43:54

this performance, the male ascends above

43:57

the nest in a slow undulating

43:59

flight. He dangles his legs below

44:01

him and sometimes he carries a

44:04

fish or a stick. Meanwhile he

44:06

makes a loud high-pitched screaming. call.

44:08

Another important aspect of Osprey courtship

44:11

is courtship feeding. This is where

44:13

the male brings fish to the

44:15

female before she starts to lay

44:18

eggs. And if the pair actually

44:20

breed, she's going to depend on

44:22

him for an extended time. This

44:25

courtship feeding behavior serves multiple functions.

44:27

It reinforces the pair bond, nourishes

44:29

the female during egg formation, and

44:32

provides a signal about the male's

44:34

ability to provide fish for a

44:36

future brood. Research in British Columbia

44:39

has shown that the frequency of

44:41

courtship feeding is positively correlated with

44:43

both the likelihood of egg-laying and

44:46

later chick provisioning. So it seems

44:48

a female can assess a male's

44:50

fishing skills early on if he's

44:53

really good at courtship feeding. And

44:55

if he's a good provider like

44:57

that, she wants to give that

45:00

guy on lock. He's a keeper.

45:02

Now, how about territoriality? Ospreys are

45:04

generally solitary outside of the breeding

45:07

season, but their behavior becomes more

45:09

socially complex during the nesting period.

45:12

In some regions, they form loose

45:14

breeding colonies, with several nests clustered

45:16

together. Within these colonies, groups of

45:19

ospreys can sometimes be seen soaring

45:21

together. Ospreys in densely packed colonies

45:23

seem to suppress overt aggression. They

45:26

recognize and tolerate familiar neighbors while

45:28

remaining defensive toward unfamiliar intruders. This

45:30

allows them to nest in high

45:33

densities with minimal conflict. I guess

45:35

this is kind of how I

45:37

live. I live in the heart

45:40

of a busy neighborhood in Portland

45:42

in a cluster of apartments and

45:44

condos. In order to minimize conflict,

45:47

I have to suppress my natural

45:49

tendency to be overtly aggressive. I

45:51

tolerate my familiar neighbors. Just barely.

45:54

When it comes to nesting, Ospreys

45:56

combine their instinctive engineering skills with

45:58

an opportunistic attitude. Males typically

46:01

select the nest site and they

46:03

gather most of the building

46:05

materials. A male might gather sticks off

46:07

the ground, but he will also break

46:09

them off of trees while in mid-flight.

46:11

I've seen this in action and it's

46:14

pretty amazing. The male delivers sticks

46:16

to the female at the nest

46:18

site and she arranges them. Nest

46:20

construction begins even before

46:22

full pair bonding and continues

46:25

throughout the breeding season, especially

46:27

after hatching or nest failure.

46:29

Nests are bulky structures built

46:31

from large sticks and padded

46:34

with softer materials like grass,

46:36

moss, seaweed, and bark. And

46:38

Ospreys frequently incorporate human-made

46:40

materials into their nests. Things

46:43

like plastic bags, nylon mesh

46:45

bait bags, bailing twine, beech

46:48

toys, and even dried cow

46:50

manure. One nest was even found

46:53

to have the desiccated, sort of

46:55

mummified body of a great blue

46:57

herrin in it. Yikes! That was

47:00

probably a tactic the

47:02

Ospreys used to scare

47:04

away any potential nest

47:06

invaders. Because, as everyone

47:09

knows, the scariest mummies

47:11

of all are great blue

47:13

heron mummies. So like I

47:15

said earlier, Ospreys tend to

47:17

use the same nest site

47:20

over and over, year after

47:22

year. Over time, nests can become

47:24

enormous. reaching 10 to 14 feet

47:26

deep or 3 to 4 meters

47:28

and up to 6 feet across.

47:31

Under natural historical conditions,

47:33

Ospreys nested in treetops

47:35

or on cliff edges.

47:37

But they're opportunistic, so

47:40

they'll also nest among large

47:42

boulders on the coast, in

47:44

mangroves, and even on the

47:46

ground on islands where there

47:48

are no terrestrial predators. I've

47:50

also seen ospreys nesting among

47:53

the spines of massive

47:55

cardone cactuses in Baja

47:57

California. Now as we've already touched

47:59

on, these... birds have adapted

48:01

to use artificial nest sites

48:03

in response to widespread habitat

48:05

loss. Today, many ospreys use

48:07

man-made structures such as utility

48:09

poles, radio towers, channel markers,

48:11

and especially erected nesting platforms.

48:13

And as we were talking

48:15

about earlier, those artificial platforms

48:17

have become critical to the

48:19

recovery and conservation of ospreys.

48:21

In some places, 90 to

48:23

95% of nesting pairs use

48:26

these artificial supports. Such is

48:28

the state of things. So

48:30

we've got to nest, now

48:32

it's time for eggs. A

48:34

typical Osprey clutch contains one

48:36

to four eggs, with three

48:38

being the most common. Eggs

48:40

are laid sequentially, and they're

48:42

incubated primarily by the female,

48:44

with some assistance from the

48:46

male now and then. The

48:48

incubation period lasts 36 to

48:50

42 days. The first egg

48:52

is often significantly larger than

48:54

the others, which may contribute

48:56

to an early size advantage

48:59

for the chick that hatches

49:01

first. So yeah, offspring chicks

49:03

usually hatch asynchronously, meaning there

49:05

can be a gap of

49:07

up to four or five

49:09

days between the first and

49:11

last hatching. This creates a

49:13

size hierarchy within the brood.

49:15

In times when fish are

49:17

scarce, older chicks may dominate

49:19

feedings and outcompete their younger

49:21

siblings. Sadly, this sometimes leads

49:23

to the starvation of the

49:25

youngest chicks. Parental care is

49:27

a joint effort with distinct

49:29

roles. The male primarily provides

49:32

food, often feeding himself first

49:34

before delivering fish to the

49:36

female and chicks. The female

49:38

breaks the fish into small

49:40

pieces and distributes it among

49:42

the begging chicks, typically starting

49:44

with the most vigorous beggar.

49:46

And who is the most

49:48

vigorous beggar? That's right. It's

49:50

usually the largest, oldest chick.

49:52

As the chicks mature, parents

49:54

gradually adjust their provisioning strategies.

49:56

At first, they bring dead

49:58

or incomplete... passitated fish. Later

50:00

they deliver live fish encouraging

50:03

the chicks to develop some

50:05

basic skills in fish manipulation.

50:07

Fledging occurs around 50 to

50:09

55 days after hatching, but

50:11

young ospreys might remain near

50:13

the nest and continue to

50:15

depend on their parents for

50:17

some time. But as far

50:19

as I know, there isn't

50:21

much scientific evidence that parent

50:23

ospreys teach their offspring how

50:25

to dive and catch fish.

50:27

So the young birds probably

50:29

rely on instinct and practice

50:31

to feed themselves. This idea

50:33

is supported by situations where

50:36

ospreys have been raised by

50:38

humans. Because once released into

50:40

the wild, those captive raised

50:42

birds have learned to fish

50:44

on their own. Reproductive success

50:46

in ospreys depends heavily on

50:48

food availability and nest site

50:50

security. Ample fish resources and

50:52

stable nesting platforms significantly increase

50:54

the chances of fledging healthy

50:56

chicks. And those healthy chicks,

50:58

if they're lucky, they can

51:00

live up to about 25

51:02

years in the wild, although

51:04

a more typical lifespan might

51:06

be closer to 7 to

51:09

10 years. With each passing

51:11

year, experienced bonded pairs are

51:13

more likely to succeed in

51:15

raising their young, as long

51:17

as the conditions of their

51:19

environments around the nest remain

51:21

favorable. Earlier

51:27

I described the Osprey as

51:29

an indicator species for aquatic

51:31

ecosystem health. The argument for

51:33

this idea rests on several

51:35

key factors. First, Ospreys are,

51:37

as we know, obligate pissivores.

51:39

This specialized diet directly links

51:41

their well-being to the health

51:43

and abundance of fish populations

51:45

in their foraging areas. As

51:47

top predators in aquatic food

51:50

webs, ospreys are particularly susceptible

51:52

to the bioaccumulation of environmental

51:54

contaminants such as as DDT

51:56

and mercury. Another reason the

51:58

Osprey can serve as an

52:00

indicator species is because these

52:02

birds are relatively easy for

52:04

scientists to study and monitor.

52:06

They have conspicuous nesting habits,

52:08

for example, often on these

52:10

artificial platforms and they're in

52:12

open areas. Changes in Osprey

52:15

population size or their reproductive

52:17

success and the presence of

52:19

contaminants in their eggs or

52:21

blood. can therefore provide valuable

52:23

insights into the overall health

52:25

of the local aquatic ecosystem.

52:27

Finally, the broad distribution of

52:29

the Osprey across various aquatic

52:31

habitats also makes this a

52:33

potentially useful indicator species for

52:35

monitoring contaminant levels in rivers,

52:37

lakes, reservoirs, and estuaries worldwide.

52:40

So we should celebrate the

52:42

Osprey. This is an amazing

52:44

bird for many reasons. It's

52:46

found around the world. It

52:48

belongs to a monotypic family

52:50

that's been evolving independently from

52:52

other raptors for 50 million

52:54

years. It's a highly specialized

52:56

fish-killing machine. It's elegant and

52:58

beautiful. And it can teach

53:00

us a lot about the

53:02

interconnectedness of the natural world.

53:05

That, my friends, does it

53:07

for our episode on Pandian

53:09

Halaitis. I hope you enjoyed

53:11

it and that you learned

53:13

something new here today. For

53:15

well-known birds like the Osprey,

53:17

I sometimes worry that my

53:19

listeners already know everything there

53:21

is to know about it.

53:23

So I try to dig

53:25

deep to find some factoids

53:27

that are relatively obscure. Things

53:30

I think might excite you

53:32

to learn. I try anyway.

53:34

And those of you who

53:36

try and succeed at supporting

53:38

this podcast as members of

53:40

my patron community, well I

53:42

owe you an enormous thank

53:44

you. Your support is what

53:46

keeps me going. You keep

53:48

the fire lit. My newest

53:50

patron supporters are... John Gettys,

53:52

June Lee, Aaron Donahoe Bellman,

53:55

Alana, Yvonne Wright, Claire Wing,

53:57

Margaret Hurley, and Cedric. I

53:59

thank each of you for

54:01

believing in what I'm doing

54:03

here and for helping to

54:05

make educational material like this

54:07

freely available to everyone. If

54:09

you have some interest in

54:11

supporting this podcast as well,

54:13

you can check out my

54:15

Patreon page at Patreon.com/Science of

54:17

Birds. There's also a support

54:20

the show link in the

54:22

show notes. And just a

54:24

reminder that if you decide

54:26

to become a supporter, you'll

54:28

want to sign up on

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a desktop computer or an

54:32

Android mobile device. Because if

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you sign up using the

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Patreon app on an iPhone,

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Apple is going to charge

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us and steal our money.

54:42

You can also shoot me

54:45

an email if you have

54:47

something you'd like to share

54:49

with me. Maybe your thoughts

54:51

about the podcast, your favorite

54:53

euphemistic pronunciation, or which kind

54:55

of mummy you prefer to

54:57

decorate your house with in

54:59

order to deter would-be invaders.

55:01

Whatever the case, you can

55:03

reach me at Ivan at

55:05

Science of Birds.com. This is

55:07

episode 114. You can check

55:10

out the show notes for

55:12

this episode along with some

55:14

photos of Ospreys that I

55:16

handpicked for you. on the

55:18

Science of Birds website, which

55:20

again, Science of Birds.com. I'm

55:22

Ivan Philipson and true fact

55:24

about me. You know how

55:26

99% of an Osprey's diet

55:28

is fish? Well, 99% of

55:30

my diet is popcorn and

55:32

peanut butter and jelly sandwiches.

55:35

True fact. Thanks for listening

55:37

and I'll catch you in

55:39

the next episode. Cheers.