Eyes on the Wild

I know this is a nature blog, but the birds and animals live in a country where humans have lived for thousands of years too, and I thought that some of you might be interested to see glimpses of Gambian life and culture. We were asked not to photograph people without their permission, so I do not have any street scenes, just a few odds and ends.

This is Omar Kuyateh, who played for us during dinner on two evenings. His instrument is called a kora and it has 21 strings. It is considered a “plucked harp-lute”. Kora players come from traditional jali familes, jali being the Mandinka name for a griot, who passes on oral traditions. Mr Kutayeh made it himself, out of a gourd and a calfskin. Here is one of his songs.

One day, we went to Tanji fish market. En route, the sole of my boot detached itself from the uppers, and my only other shoes were Tevas. So AJ our guide took me to the market, where Muhammed first glued the sole back on, then meticulously sewed it on neatly all the way round with strong black thread and a lethal-looking needle.

He charged me two dollars. It took about 15 minutes, and is as good as new.

At the fish market, there are no jetties or docks; the boats pull in and people wade out to offload the fish:

The boats are painted and named, and they have prows with wooden totems (right rear), and flags (the boat on the left supports the Spanish soccer team Barca!). When they are moored, the gulls and turnstones arrive:

And on shore, boats are pulled up for maintenance:

The fish market wastes nothing. These meticulously filed fish are being dried, and many had been collected dead from the foreshore.

The garbage along the seashore was horrendous, and I do not know if this is local to the fish market, or widespread. The Common Sandpipers below do not seem to care about the garbage festooning the sand behind them.

Amongst the mangrove swamps there are oysters, and these are gathered and cooked for sale (they are not eaten raw). The women collect them from tiny skiffs, many if which are true dugout canoes:

The white heaps on the left are oyster shells. Then, in the evening, from my floating lodge :

I saw them paddling back with canoes full of firewood. They are allowed to collect fallen branches in the national park:

Our guides have good jobs, and they’re usually men. We had one woman, Mariana, in Bonto forest.

She told me that she was 26, that her father had died, and she was the sole support of her mother and three younger siblings. She was a terrific guide.

This is not an easy life, and you become very aware of how extraordinarily privileged you are to fly thousands of miles just to see birds.

One afternoon in The Gambia we ran into a large troop of Guinea Baboons, Papio papio . This is the smallest species of baboon, weighing a maximum of about 26Kg or 57lbs, and is classified as Near Threatened because it is found in only a relatively small area of West Africa (including The Gambia,  Senegal, Guinea, southern Mauritania and western Mali), and its habitat is under threat. Their fur is crimped, making them look fuzzy, and posing a challenge to photographers.

There were lots of young ones in this group, and they were a delight to watch. This looked like a real newborn, being investigated by an adult female. The adult on the right is a male. They are larger and have a sort of mane around the head and shoulders:

The males are more laid back than the males of other baboon species, being more willing to share females, and forming friendships with other males, The little ones hung onto their mothers’ bellies, allowing them to suckle as they hitched a ride.

The adults kept a careful eye on the smallest babies, making sure they didn’t get left behind as the troupe moved past us:

Sometimes they rode on their mother’s backs, like tiny jockeys:

They are remarkably independent from the get-go. This one, who the guide said was only 2 or 3 days old, suddenly stood up, ran along his mother’s spine, and jumped off over her head:

Like all baby animals, a lot of time is spent in play. Also, notice the big male on the right of the group of adults, and his “mane”:

This whole group of maybe 50 baboons moved through the forest, flowing around us, parting only minimally to get past us while we stayed still.

On a different day, we were on the river passing a semi-abandoned park with broad steps cascading down to the water, and another big baboon group was in residence. They sunbathed, and groomed each other:

just hung out:

and bonded.

PS Their intricate social system is not as well studied as that of other baboon species, but this Wikipedia entry gives you some idea:

https://en.wikipedia.org/wiki/Guinea_baboon

I write more often about animals (insects, reptiles, birds, mammals) than plants, but I glory in it all. Look at a corner of my wetlands back here in Maine.

These rusty spikes in the foreground were familiar to the dinosaurs 180 million years ago, and have barely changed since.

They are Cinnamon Ferns, Osmundastrum cinnamomeum, and are considered a living fossil. Their name comes only from their color: don’t put them in your apple pie. Unlike our more modern plants, they do not produce seeds. They reproduce by spores, like fungi do.

The ferns are six feet tall, and they send up specialized dark green fertile fronds,

The fronds are covered in tiny globules called sporangia, within which the spores are gestating.

As they ripen, they turn a cinnamon orange, like the flanking spikes below:

working from the bottom up:

until eventually the whole spike blazes with color:

In extreme close-up, you can see that the tiny globules open up like a clamshell and release their spores:

Each sporangium is by my calculation about 1/60″ inch (0.4mm) across. A spore is about 50 micrometers in size ( a micrometer is 1/1000 of a millimeter). One sporangium can produce up to 500 spores, and a single stem can produce 52 million.

I picked a few ripe fertile fronds and brought them inside. The next morning there was a dusting of green spores on the sheet of paper. The first photo includes an American nickel for scale.

The second one is a close-up of an opened sporangium surrounded by some of its spores:

I have not even tried to photograph the spores themselves in close-up, unless someone would like to lend me an electron microscope?

If you’d like to know more, explore this site:

https://www.amerfernsoc.org/about-ferns

And, to end, a wonderful image of spores by Rogelio Moreno:

The African Goliath Heron, Ardea goliath, is one of the world’s largest flying birds. It weighs up to 5Kg (11 lbs), is 1.5m (5′) tall, and has a wingspan of 230cm, or 7′ 7″.

This one stood in the Gambian mangroves as we drifted along, looking at something overhead:

They hunt passively, waiting for an unwary fish to swim by, and then they pounce with that lethal beak.

They only eat 2 or 3 fish a day, but big ones, over a pound each, so they gobble about 25% of their body weight a day. And they can live for 22 years.

The full glory of this huge bird shows best in flight, I think:

How on earth do they do it? Rayner (1988) is a fascinating article on the aerodynamics of bird flight. Herons have large wings in comparison to their load (weight divided by wing area), which puts them in the same group as thermal soaring birds like hawks, storks, and eagles. They have similarly shaped wings too, broad with squarish tips, and separate primary feathers.

The surprise is that the Goliath Heron can fly at all. It is distinguished by having a very slow wing beat of 1.8 beats per second, and this puts it at the outer limits of all birds and near the theoretical limit of possible flight (apologies for the poor quality of the graphic, I couldn’t find a better one; the vertical axis is wing-beat rate, and the horizontal axis is mass):

PS That very slow wing beat is why I was able to get sharp flight photos even from a moving boat. Here’s another one, just taking off on a different flight, though quite possibly the same heron:

As you can see, gaining height takes time! The jumbo jet of the avian world.

[I seem to be alternating continents, but I still have lots of Gambian birds to show you!]

Wattles are brightly colored fleshy outcroppings, usually on the head of a bird. Some are around the eye, some near the bill or under the chin. They are thought to attract the opposite sex, and indeed in some species they only appear in breeding season, or get larger, or are limited to the males. This trio have wattles in both sexes, all year-round.

The White-crowned Helmetshrike, Prionops plumatus, has a splendid feathered crest, and fleshy yellow eye-wattles that look like an artificial plastic sunflower:

These are social birds, and very versatile.

They forage as a group, eating insects (on the leaves or ground, and occasionally in flight), but also lizards, and fruit.

Somehow they seem rather parrot-like to me.

Common or Brown-throated Wattle-eye, Platysteira cyanea, (female, below) are usually in pairs, foraging for insects in vegetation and in flight. The red eyebrow wattles are fleshy, not feathery.

My final Gambian wattle-wearer is the Wattled Lapwing, Vanellus senegallus, whose yellow wattles droop down from the corners of its bill:

(The bird lurking in middle in the foreground above is a Spur-winged Lapwing).

Both sexes carry wattles.

PS You might have noticed that all the helmetshrikes are looking downwards. One of our group had brought with him an app with the sounds of Gambian birds, and a tiny loudspeaker. He placed it at the base of the tree near the helmetshrikes, and played helmetshrike calls. They were fascinated by it. This is a very controversial technique, many people worry that it disturbs the birds’ natural social order and that it can interfere with courting and breeding. Our guide did not bring this technology himself, but he allowed it to be be used, and none of the rest of us objected. I did discuss the issue with our guide, and he said that he would never allow it to be used in breeding season. We did indeed get a much closer look at some birds than we would otherwise have done, but I feel somewhat guilty that I didn’t protest. Or I may be over-reacting. Let me know what you think in the Comments.

The Proper Use of Playback in Birding

I have also just discovered that the Audubon Society has taken a strong stand against the use of playback, and that none of the photos we (ie me) took using this technique could be entered in their contests:

https://www.audubon.org/news/why-photographers-should-reconsider-using-playback-field

Luckily I never planned to do that anyway.

[All these photos and videos were taken last week at Gardens in the Wild in Framingham, Massachussets, the home of the New England Wildflower Society. Highly recommended! and the frogs are used to people, so they are much less skittish than they are around me in Maine. ]

The American Bullfrog, Lithobates catesbeianus, is a substantial chap. He can weigh up to 0.5Kg, more than 1lb. The bullfrog male’s mating call is low in pitch, with a frequency around 200-300Hz, and can be heard for up to one kilometer. Here is a recording (made in Maine a year or two ago.)

These calls are very very loud, and yet they call with their mouths closed. How do they do it?

When the male calls, he fills his bright yellow throat pouches with air. Each call lasts approximately 0.5 seconds: I have slowed down this video so you see this more clearly:

I had always thought that was why his calls were so loud.

But it turns out that is wrong. The inflated pouches are used as a sort of air reservoir so that air can be recycled to the lungs across the vocal folds where the sound is actually produced. Some sound is indeed then transmitted to the world through these pouches, but that is not the main source. The male has a greatly enlarged tympanum (ear-drum), the round patch behind the eye, as you can see in the photo.

It is this which hugely amplifies the sound energy, being responsible for some 98% of the energy actually transmitted. (Purgue 1997). Its resonating frequencies match those of the calls, so effectively it acts as a drum. (Purgue says you can see the eardrum move, but even when I slow my videos right down I can’t detect this!).

Even if I can’t see the eardrums move, what I can see is the whole body vibrations that are transmitted to the water: look at those ripples radiating outward as the frog calls.

Note also how much smaller the female’s ear-drum is: hers is used just to transmit sound to her inner ear, like ours.

There is always something new to learn: who knew that ear-drums could be a two-way sound system. They even look just like a high-end stereo speaker!

PS More on the generation of the initial sounds: (Ryan and Guerra 2014) ” In most frogs, air is expelled by contracting trunk muscles surrounding the lungs, which pushes the air through the larynx .. The incoming air causes the vibration of the vocal cords and the larynx itself. The air then enters the buccal cavity and passes through the vocal slits to inflate the vocal sac. One of the most conspicuous and near-universal traits of male frogs is the vocal sac. Its main function is to recycle air from the lungs to the vocal sac and back again. The vocal sac also radiates sound.”

PPS The kettle-drums used in classical music are more formally called timpani, essentially the plural of the same word as an ear-drum, tympanum. Hence my title.

PPPS It took about 250 photos to get those two still shots of the 0.5 second period when the vocal sac is inflated!

Although The Gambia was a bird-focussed trip, rules are made to be broken.

Nature tends to be symmetrical: creatures have two hands, four feet, six legs, eight tentacles etc. West African Fiddler crabs, for example, have eight legs and two front pincers, and the females look the same on both sides, unsurprisingly.

BUT, the males are in no way even-handed: one claw is huge and one is tiny. Here is a typical male Afruca tangeri, abut 50mm (2″) wide and 25mm (1″) long, feeding in the tidal mudflats of the mangrove swamps:

The tiny claw is used to delicately select minute portions of food, and the huge claw is used to fight other males:

but also to attract the female, who goes for a nice big claw (and also for the most impressive claw-waving dance.)

Their Portuguese name is ‘boca-cava-terra‘, meaning “mouth-dig-earth”. The small claw is used for feeding, finding food in the mud, and then carrying it to the mouth:

‘

They filter through the muddy mouthful, and then drool out the unwanted residue; their mouth is just below where the two white markings converge:

I took a video of them feeding, all the while keeping their stalked eyes on the other guy. (Notice how the left-hand one occasionally uses his smaller pincer t0 knock off the accumulated debris from his chin.)

The male population is roughly 50:50 left-clawed vs. right-clawed, and depending on their relative claw placement they seem to have techniques for fighting face-to-face or side-by-side. This video shows a different species in combat:

The local Green Monkeys forage for these crabs. Here is a youngster, who came away from the mud-flats empty-handed:

PS Imagine if we used our left arm only for fighting, and our right hand only for eating. Sounds awkward? In fact there are indeed human cultures in which only the right hand is used for food, so we are not as distinct from the fiddler crab as you might imagine.

PPS Now that I think about it, crabs are ornery in other ways too. Most of the world’s creatures navigate the world forwards, but crabs famously scuttle along sideways. I wonder if their brains are just wired differently?

[This is my last kingfisher post from the Gambia. I’m going to give you a break from birds for a little while now, I think. That’s the plan, anyway!]

The Striped Kingfisher, Halcyon chelicuti, is a mere 17cm long. It is another woodland kingfisher.

It swoops down to the ground from around 3m high, to catch insects, with an 80% success rate.

The Malachite Kingfisher, Corythornis cristatus, is a proper kingfisher: it actually fishes, from perches around 2 feet above the water, and prefers shallow water only a few inches deep..

The tiniest of all, at 13cm, it is exquisitely plumaged, a tiny flash of iridescent blue in the mangrove roots:

[A little late for US Mother’s Day, which was two days ago, but worth suspending my kingfisher posts for.]

I slammed on my brakes, because out on the grass in front of a nearby house was a mother red fox with four cubs. No camera, and my beagle quivering with excitement in the truck. So I drove home (5 minutes away), dumped the dog and grabbed the camera.

She was very relaxed, but vigilant:

The cubs were skittish, and scattered when I stopped the truck. They only emerged one at a time:

There was a large rock partly screened by leaves, so they felt safer there, and she groomed them:

Then this one took a nap:

The cubs were quite large:

and copying the mother’s every move:

The cubs looked healthy, and so did she, until she ran.

It then became apparent that although she moved fluidly and fast, she only used three legs, and that her right front leg was injured. Here is a close-up of her front feet, showing that the claws on the unused foot have grown long from lack of contact with the ground:

The leg also looks thinner, as if the muscles have wasted. According to a neighbor, she has been injured for four years, and despite that she has raised cubs every year.

She gets my mother-of-the-year award, Fantastic Mrs. Fox (with thanks to Roald Dahl.)

The Giant Kingfisher, Megaceryle maxima, is a majestic bird measuring 46cm (18 in) . The female (below) has a streaked chest and a reddish lower belly; the male reverses the coloring!

I only ever saw females on this trip,

Although in Zambia five years ago I did see a male:

Back in the Gambia, this one diving on a fish could have been either:

They eat mainly fish, but also frogs and even crabs. And that beak must strike terror into the heart of any target: this is the view the victim gets just before the denouement.

Not as big at 25cm, but far more cheerful, is this Blue-breasted Kingfisher, Halcyon malimbica:

From behind it is a brilliant turquoise:

It is a tree kingfisher, and not a specialist fish-eater. It mainly eats invertebrates, including insects and crabs, beating them on the ground before eating them. That huge bill must help.