the missed shot

We spotted a lone immature Bald Eagle eagle sitting on a branch above the Mississippi River, and we slowly inched our way into the leafy vegetation to get a clear shot of the bird.

immature bald eagle

Of course the bird was facing right into the sun, which made a branch-cluttered shot that much more difficult. It looks like the wind was creating a “back-do” for the bird.

immature bald eagle

The bird was very aware of our approach because it kept turning its head from one side to the other.  I photoshopped out a few branches and lightened up the bird image.  Now we can see its marvelous profile, sharp beak, and big feet.

And now…waiting expectantly for this nervous bird to take-off, so I could get the perfect shot of flying eagle amidst the color of the fall leaves…

eagle flying

Aaarrrgghhh! Not the shot I pictured.  But the tail feathers are nicely in focus!

Roaming the backyard

I am experiencing wildlife withdrawal.  I miss the tremendous diversity of wildlife I saw every day in the African savanna.  Even the local birds have deserted my backyard (of course that could be because the bird feeders were empty for a while). I have roamed the backyard (and the wetlands beyond the backyard) in vain over the last couple of weeks in search of something besides squirrels and chickadees. Finally a couple of yearling deer took pity on me and came in for a visit.

deer eating in the garden

Eat those weeds, and help yourself to a drink of fresh water while you’re at it…

My neighbors tell me this pair has been roaming the neighborhood, gobbling up the last remnants of wildflowers and herbaceous greenery before the hard frosts arrive. They certainly are tame, foraging in the backyard in broad daylight, and even allowing me to stand close (within 25 feet) to them while they eat.

deer eating in the backyard

Yellow leaves don’t have much of the nitrogen-rich chlorophyll left in them, but I guess anything will do.

deer eating in the garden

I love the way they wrap their tongue around the leaves to selectively pull off just the right ones.

Finally, she/he notices me standing there watching.  One ear forward and one cocked back -- just to make sure nothing sneaks up without notice.

Finally, she/he notices me standing there watching. One ear forward and one cocked back — just to make sure nothing sneaks up without notice.  A nice fall deer portrait.

So many choices here of good things to eat.

Immersed in weeds — so many choices here of good things to eat.

deer eating in the garden

The Mongoose, the Hornbill, and the Termite

You wouldn’t think there would be much of a relationship between three such distinct entities, but it turns out the Dwarf Mongoose and the Yellow-billed Hornbill (subject of an earlier post on “flying bananas”) tend to congregate together at abandoned termite mounds, forming a tight interdependent connection with each other.

Dwarf Mongoose colony sunning on a termite mound

On cool spring mornings, Dwarf Mongooses sun themselves on their termite mound home to warm up.

Dwarf Mongoose colony

Dwarf Mongoose are highly social animals, living in colonies of up to 30 animals.

An abandoned or unused termite colony makes the perfect home for mongooses, because it is cool, well ventilated, and usually contains numerous chambers or rooms for the mongooses to use as a retreat from daytime heat or predators.

Dwarf Mongoose foraging

The problem with being a small mammal foraging for insects out on the open savannas of Southern Africa is vulnerability to predation from eagles.

and that’s where the “flying banana” (Yellow-billed Hornbill) comes in…

Yellow-billed Hornbill

Yellow-billed Hornbills can feast on some of the insects scared up by the Dwarf Mongoose’s foraging.  In fact, they have learned to congregate in areas where Dwarf Mongoose colonies are located, because of the increased activity of insect prey there.

The Hornbills are wary birds, cognizant of potential predation by raptors, and will screech in alarm when one is sighted, allowing the mongooses to scramble for cover.  As a result, mongooses don’t tend to come out to forage unless a number of hornbills are present, and hornbills only congregate where there are dwarf mongoose colonies.

And it all starts with the termites that built the durable tower of mud and saliva over hundreds of years.

Termite mounds

Termite mounds in Hwange national park, Zimbabwe, dwarf our safari vehicle in height. They are complex structures inside, with ventilation shafts that encourage air flow and maintain a constant temperature, as well as providing chambers for the development of larvae and pupae.

Mound-building termites (not close relatives of social bees and wasps, but of social cockroaches!) typically locate their home near a source of vegetation, like a rotting tree or shrub thicket.  They harvest the woody vegetation to provide a source of nutrition for a particular fungus which they grow in chambers called “gardens” within the mound, regulating the temperature and airflow to be conducive to fungus growth.  They then live off the fungus garden.

termite mound

The mound is remodeled each day, bringing more termite mud to the surface, adding or resculpting chambers, etc., and modifying the airflow for current outdoor conditions.  The colonies might persist for hundreds of years, with a queen producing millions of offspring, until it finally collapses, leaving a vacant structure for others to take over — like the Dwarf Mongoose.

Flying bananas?

African Hornbills will not win any beauty contests, but their odd anatomy and behavior makes them quite interesting.

Yellow-billed hornbill

The first thing you notice is that huge, yellow bill.

Yellow-billed Hornbill

Locals refer to this Yellow-billed Hornbill as the flying banana, for obvious reasons.  You would think such a large appendage would put a strain on the bird’s neck muscles.

But the upper mandible is actually hollow and relatively light-weight.  Nevertheless, to strengthen the appendage for its intended uses (nest building, fighting, catching prey), the hornbills’ first two neck vertebrae are fused and their neck muscles greatly strengthened.  Strangely, Hornbill tongues are much shorter than their elongate bill, so the birds deftly pick up food bits with the tip of the bill and toss it back into their mouth with a backward flick of their head.

Trumpeter Hornbill

Some hornbill species have adornments on their upper mandibles that enhance sound production, like the resonant chamber in this Trumpeter Hornbill we saw at Victoria Falls in Zimbabwe.  Other species might have bony (or ivory) reinforcement in the mandible casque that can then be used as a battering ram.

A close relative of the Yellow-billed Hornbill, the Red-billed Hornbill, has been immortalized as the character Zazu, in the Lion King movie.

Red-billed Hornbill

A downward-curved red bill–resembling a red chili, means this species is referred to as the flying chili pepper.

Red-billed Hornbill, popularized as Zazu in the Lion King movie

An interesting choice for this character in the movie–they don’t seem all that wise in real life.

Both Red- and Yellow-billed Hornbills were common in the acacia scrub-desert environment of Southern Africa, and they share, along with other Hornbill species, similar eating habits (omnivores that eat whatever they can find) and nesting habits.

Pair of Yellow-billed Hornbills

A breeding pair of hornbills set up housekeeping by first locating an appropriate tree for their nest hole.

After the pair excavate a suitable roost in the tree, the female climbs in, molts all of her feathers, seals herself in with her feces and mud brought by the male, leaving only a tiny slit through which he will feed her for the next few weeks as she incubates the eggs and broods the chicks.  It must get pretty hot and stuffy in there, but the chicks are well protected from predation.

There are 55 species of Hornbills spread over Africa and the Indian sub-continent, all sharing the hollow casque structure of the upper mandible and unusual nesting behavior of the female (sealed into her little tree prison).  The largest, and probably ugliest of them all, is the Ground Hornbill, a species endemic to sub-Saharan Africa.

Ground Hornbill family in Kruger national park, South Africa

Ground Hornbills are large (3 foot tall), entirely terrestrial birds that stalk the grasses and undergrowth for whatever moves.  Their sharp, pointed bill can stab lizards or insects, or pick up nuts and berries.

They are very long lived, reaching 60 years, and only breed every couple of years, depending on the conditions.  Two eggs are laid In a burrow (they can’t dig themselves) but only one chick is usually reared, because they hatch many days apart, and the older one usually eats the younger chick.

Group Hornbill

A candidate for “un-fairest one of all”. The male’s red facial adornments include a pair of fleshy vocal sacs that are used to amplify his call. They don’t really improve his appearance though.

Gentle giants

Giraffes are the tallest terrestrial vertebrates (males stand about 20 feet tall, females slightly less), which opens up leafy resources other browsers like the stately kudus lack, but also present a host of problems for survival.

Giraffe feeding on high vegetation

Stretching to reach those last few leaves on the acacia tree–food is scarce in the dry season in Botswana.

That long neck that makes up 50% of their height makes it a challenge to pump blood against gravity up to the brain.  Consequently, their highly muscular, thick-walled heart has to generate more than twice as much pressure as the human heart does. (Giraffe blood pressure runs about 280/180–normal human blood pressure is about 120/80 or lower).  That’s fine for getting blood to the brain, but blood flow is all downhill to the feet, so how do giraffes keep from getting swollen ankles?  With tight-fitting, elastic skin that acts like compression stockings, the kind they give heart patients to wear.

Giraffe in Botswana

The tallest object in this environment, but just look at those skinny little legs that support the massive upper body mass.

Their height also gives them a bird’s eye view of their surroundings, including predators perhaps lying in wait in the grasses below, but that same height advantage becomes a disadvantage when giraffes need to awkwardly bend over for a drink or food on the ground.

Giraffes feeding on a carcass in Botswana

Two giraffes were taking turns getting a bite of a decaying carcass. They eat bones and cartilage left by scavengers to obtain minerals lacking in their leafy diet.  The giraffe on the right has spread its front legs wide to enable its head to reach the ground.

Just getting into position for a drink or a bite of something on the ground is a mechanical problem in itself.  But lowering its head below the level of the heart poses a great risk of cerebral hemorrhage.  To combat this potential physiological disaster, arterial pressure sensors detect changes in head position and cause an immediate decrease in heart rate and heart contraction strength to decrease blood pressure.

Great vertical height poses problems for other organ systems as well.

Male giraffe feeding on acacia

Giraffes are ruminants, and like cattle, they regurgitate what they have browsed to re-chew it into smaller pieces.  That requires a long, very muscular esophagus, capable of returning food from the stomach to the mouth.

Very long necks require very long nerves running from the brain to the periphery.  For example the nerve that stimulates the vocal cords and muscles that enable swallowing is 5-6 feet long!  It better conduct very fast, or food will go down the wrong tube (i.e., the trachea) when they swallow.

Giraffes love to browse on acacia leaves, but the plants have a great plenty of protective thorns, which the giraffes’s almost prehensile lips and tongue seem adept at working around.

Female giraffe, showing tufts of hair on the horns

That soft upper lip is highly mobile. Inside the mouth is a 20 inch long, highly muscular tongue that can delicately wrap itself around tiny leaves but avoid prickly thorns.  And just look at those long eyelashes, and big brown eyes.  Isn’t she a beauty?  (Hairy tufts at the end of her knobby horns indicate this is a female).

With their graceful walking stride and elevated height, giraffes just epitomize the “gentle giant” title.

The river horse

Probably one of the oddest looking and most intimidating animals in Africa is the hippopotamus (literally translated, river horse).  Hippos are uniquely amphibious, spending most of their day in the water but their nights on land foraging.

Basking hippos, Kruger Park, South Africa

Although occasionally, hippos come out for a sunbath on land.  Their skin may be six inches thick but is still subject to sunburn.  Unlike elephants that throw dirt on their wet skin to protect it, hippos secrete an oily substance from their skin that reflects ultra-violet light, a “hippo sunscreen”.

Hippos foraging at sunset, Chobe national park, Botswana

Out on land just at sunset, the nightly grazing on grasses begins. Hippos might travel 6-10 miles to find enough grass to sustain them for one day.  But surprisingly, this 1.5-2 ton animal eats just 80-100 lbs of food per day, because it has a multi-chambered stomach (like cows) which increases its digestive efficiency.

Despite their short, stubby legs, flat, webbed feet, and rotund girth, hippos can move quickly on land, up to 20 mph (30 kph), at least for short distances, so it would be a mistake to try to outrun one.  Their bulky weight is supported in water of course, where they seem much more “graceful”.

A pod of hippos

Eyes, ears, and nostrils are displaced to the top of a hippo’s head, so they can keep tabs on their environment while floating (well, actually while standing on the bottom).

A pod of hippos

Usually one bull hippo controls a stretch of river or lake area in which dozens of females, calves, and bachelor males hang out in social groups.

Hippos are aggressive, especially when they feel threatened, and their great bulk and quick movements mean humans should maintains respectful distance.  But sometimes, a hippo surfaces for air closer than is comfortable, requiring a speedy retreat.

Hippo in Okavango delta

Fortunately, not an aggressive one, it left our little boat alone.

Hippo yawn, or threat display

But this one may be warning us away, or it could just be a bored yawn.  Those projecting lower canine teeth can grow to 1.5 foot length in big bulls, and do serious damage even to thick-skinned hippos.

Hippo yawn, or threat display

No, this looks more like a threat display, with head raised above the water, and jaws open almost 180 degrees. It kind of reminds me of the Animal on the Pez candy dispenser.  The only reason to open its mouth this wide must be to intimidate or do physical damage to another hippo.  Sort of a “my teeth are bigger than yours” contest…

Small front incisors are used to cut the grass, rear molars are useful grind it before passing the food into the chambered stomach.  Unlike cows, hippos don’t regurgitate the mix and chew their cud.  Projecting canines are used as weapons.

But the most amazing thing to me about hippos is that they are not at all related to the other, diverse, grazing ungulates of the African savanna! nor are they at all related to horses (despite being called the river horse).  Instead, there is clear genetic evidence that their closest relatives are the whales, dolphins, and porpoises.  The common ancestor of hippos and whales branched off well before grazing animals like antelope and horses appeared in the fossil record.

Just in time

We returned from Southern Africa about a week ago, just in time to appreciate the splendor of the fall season as it was reaching peak color.  Walking around my neighborhood and the local lakes was a feast for the eyes.

fall color-birch tree

the birch tree my front yard

fall color-street scene

fall color along the street

fall color-Minnesota woods

fall color-Minnesota woods

Minnesota fall color-lake reflection

Colors reflected in the lake water

fall color in an office building

Fall color reflected in the windows of an office building. How do people that work in this building keep their mind on their work?

Monkey business

If only they could talk, what would they say?

Chacma baboon

“I’m looking for just the right place”

Chacma baboon

“Ahhhh……”

Young vervet monkeys

“Hey, cut it out! Stop pulling my hair”

Young vervet monkeys

“He started it!”

Young vervet monkeys

“Sorry, but this is private”

Male vervet monkey

“Yeah, so what if my privates are showing!” 

Not your typical secretary!

What do you call a cross between an eagle and a crane?

African fish eagle

Suppose this bird (a fish eagle or similar eagle) bred with…

Sandhill crane

A bird like a Sandhill Crane (photographed October 2013 in MN).

The result might look something like this–a long-legged (like the cranes), raptorial (like the eagles) bird called the Secretary Bird.

Secretary bird (from Wikipedia by Yoky)

Secretary bird (from Wikipedia by Yoky).  Extremely long legs allow this strange-looking terrestrial (rather than aerial) predator to travel through tall grass scaring up potential prey, like insects, mice, snakes, lizards, etc. which it quickly immobilizes with its raptorial foot or beak.  Interestingly, the legs are so long and their neck is so short, they have to stoop over to reach the ground with their beak!

It must have been a challenge for early taxonomists to classify this bird, but anatomical characteristics like feet (and later genetics) allied the bird with hawks and eagles, not cranes.

Raptorial feet (from encyclopedia Brittanica)

Clearly, the feet indicate the secretary bird’s (bottom center) raptorial relationship.

But why the name, Secretary bird?

Secretary bird at Hwange national park, Zimbabwe

It got its name from the quill feathers that stand out from its head like the pencils or pens that secretaries used to stick behind their ears or in their hair-dos to have easy access to writing implements.

On our early morning safari drive in Hwange national park in Zimbabwe, we found a very amorous couple of secretary birds just getting off their nightly roost and cementing their pair bond before departing to forage that morning.

A pair of secretary birds on their roosting nest

Rise and shine, it’s 6 a.m.

Secretary birds from Hwange national park, Zimbabwe

A little billing and cooing between the two birds…is he whispering into her ear?

Secretary birds from Hwange national park, Zimbabwe

Before he jumps up on her back to ensure his contribution to the next generation.

Secretary birds from Hwange national park, Zimbabwe

And a few moments later, he is on his way again.

They will spend most of the day on the ground, searching the open savanna for prey, and then retreat to their nocturnal roost at sunset.  A pair might stay in the same area year-round if there are sufficient resources to raise a family.  They rarely migrate around their sub-Saharan environment.

What’s for dinner: fish, snake, or chicken?

We saw quite a few birds of prey on our tours of Southern Africa, but witnessed very few of their attempts at predation.

African fish eagle

Fish eagles, like their North American  cousins, the Bald eagle, are patient sit and wait hunters of open water near streams, marshes, and lakes.  We saw lots of them sitting on a high perch, but none of them actually hunting, or catching anything.  Like ospreys, they have specialized scales on their toes for grasping slippery fish.

Bateleur eagle, Okavango delta

Bateleur eagles are smaller-bodied than fish eagles with very short tails. They hunt primarily birds (pigeons and grouse) in open savanna country. Red face and gray and black wings distinguish them from the other, mostly brown eagles.

Walhlber's Eagle (top) and Tawny Eagle (bottom)

Two species of eagles on the same tree:  Walhlber’s Eagle (top) and Tawny Eagle (bottom).

Tawny eagle

Tawny eagles are quite variable in color (this is a darker form).  Its diet is largely made up of carrion, but it also feeds on a variety of small mammals in dry scrub and savanna areas.

Wahlberg's Eagle

Wahlberg’s eagle doesn’t discriminate in its food choices: reptiles, birds, and mammals make it into its diet. However this bird prefers to hunt the woodland instead of the dry, open steppe, so it is strange to find these two species together here.

Sightings of eagles were common, but smaller hawks were rarely seen in the acacia woodland or the open grasslands.  Instead, that ecological niche of small, mobile bird of prey seems to be taken by Yellow-billed Kites, which we saw frequently and everywhere, as they cruised over land or open water in search of a snack.

Yellow-billed Kite

The tail flares and twists to enable the bird to change direction. They rarely need to flap their wings.

Yellow-billed Kite

They hunt for small fish and invertebrates along the shore, but won’t turn down a nice meal of snake, lizard, bird, or mammal if they find one. Apparently carrion is also acceptable, which makes them true “meativores”.

A pair of secretary birds on their roosting nest

We found a pair of secretary birds on their roosting nest just at sunrise.  This nest is for nocturnal use, not for raising chicks.  These long-legged, terrestrial birds of prey can be confused with cranes, which they resemble, but genetically, they are lumped with the eagles and hawks.  They are diurnal predators of reptiles, insects, and small mammals, which they scare out of the grass by stomping around on the vegetation.

more on the adventures of Secretary Birds tomorrow!