Letter 13: Avian Biodiversity

You've probably heard a lot about biodiversity (and the fact that the world's biodiversity is decreasing). The biodiversity in Kenya and Tanzania was amazing. In just three weeks, we saw six species of monkeys, fifteen species of antelopes, and more than 450 species of birds, as well as the big cats and so much more.

One of the main reasons for this vast diversity is that the Rift has made East Africa an "evolutionary hotspot". By throwing up mountains and pulling down the rift, tectonic forces have split the landscape into smaller and smaller pieces, isolating plants and animals from others that like the same environment and giving them the chance to evolve on their own. Eventually, when the monkeys (or birds or lizards) can't mate with those on another mountain because they can't get across the Rift, they become different from one another. We saw this in the Colobus Monkeys, for example; the different populations are becoming quite distinct from one another.

The man who was our guide on this trip, Terry Stevenson, is listed in the Guiness Book of World Records (along with two of his friends) for having seen more species of birds on a single day (342) than anybody else, anywhere, ever. This was in Kenya in 1986. Alas, it would probably not be possible today, even for somebody as skilled as Terry, because there are many fewer birds in Kenya today than there were in 1986, primarily because there are so many more people.


One morning, Terry told us that he was going to take us to see a particularly rare bird, Sharpe's Longclaw.

He told us that it has never been a very common bird, since it is confined to a rather specific habitat, undisturbed moorlands. However, it was doing fine until about five years ago, when people decided to build a new town right in the middle of its range.

He warned us that the last time he'd been there, a few months earlier, there was only one field left unplowed in the area where the Longclaws had always lived. When we neared that place, I could hear the sadness in his voice when he saw that that field, too, had been plowed. We got out of the van and walked through it, however, and found a small area at the back that was still undisturbed. Not only that, we found a pair of the Longclaws there! However, we all left the area feeling very sad, knowing that when the rains come again it is very likely that their last remaining habitat will be plowed. There are probably a few Sharpe's Longclaws left in one of the more inaccessible mountain ranges, but I fear their days are numbered.

Thus the species blink out one at a time.

Town built on Sharpe's Longclaw habitat
Town built on Sharpe's Longclaw habitat
Kenya
(Click on any of the photos to enlarge them)

But while we can still do it, let's celebrate the biodiversity we still have, by looking at a few photos of some of the other wonderful birds we saw on our trip.

This is a bird you can see in Florida, the Cattle Egret, but in Kenya, it gets to use a Zebra as a lookout post.

It's a native of Africa, but has managed to introduce itself to the Americas (probably as a result of having been blown across to South America). In Africa, it follows large mammals around so that it can catch the insects that they stir up in the grass as they pass. In Florida, you can often see it following large mowers around, such as on the median strips of the highways.

Zebra and Cattle Egret
Zebra and Cattle Egret
Nairobi National Park

This is the Grey Crowned-Crane, which is a close relative of two birds you can see in Florida.

(Notice the fluffy yellow feathers crowning its head.)

In your area, with a bit of effort, you can see two other species of cranes, the Sandhill Crane and the terribly-endangered Whooping Crane.

Most of the world's crane species are in trouble, primarily from habitat loss. Large birds, like large mammals, tend to need quite a bit of land.

Grey Crowned-Crane
Grey Crowned-Crane
Ngorongoro Crater

This is a bird like nothing you have in Florida, the Kori Bustard.

It is the heaviest bird that can actually fly.

Kori Bustard
Kori Bustard
Ngorongoro Crater

This very odd bird is called the Secretary-Bird.

You may be surprised to learn that it is closely related to hawks, like that Black Kite who stole the boiled eggs from the picnics. Instead of soaring above the plains looking for animals to catch, the Secretary-Bird stalks around the plains looking for snakes to catch. It has adapted to a lifestyle quite dissimilar to that of other birds of prey, but it still builds a stick nest in the treetops much as they do. (Breeding behavior evolves very slowly, because it is so critical that any change is likely to be a bad one.)

Secretary-Bird
Secretary-Bird
Serengeti

I'm sure you'll recognize these birds, a pair of Ostriches.

Since they can't fly, they must build their nests on the ground and then protect them from anything that would like to eat the eggs or babies. The female is the bird on the right. She has very subdued coloring because she sits on the nest during the day and must be as nearly invisible as possible. (When she is sitting on the nest, she stretches her long neck along the ground, so that her head won't stick up above the grass and give her away.) The male, whose coloring is more pronounced, sits on the nest at night when nobody can see him anyway.

Ostrich pair
Ostrich pair
Tarangire

Now, let me show you three more unusual large birds.

This is a Saddle-billed Stork.

Saddle-billed Stork
Saddle-billed Stork
Serengeti

This is a pair of Red-billed Hornbills.

Red-billed Hornbills
Red-billed Hornbills
Tarangire

And this is a Hamerkop (which means "hammer head"):

Hamerkop
Hamerkop
Lake Nakuru

Just to be fair, I'll also show you a few small birds, too, starting with the "coverbird" on Terry's book, Field Guide to the Birds of East Africa, the Red-and-yellow Barbet.

Red-and-yellow Barbet
Red-and-yellow Barbet
Tarangire

This is the Scarlet-chested Sunbird, one of the dozens of species of sunbirds found in Africa.

It's a tiny little thing that lives on nectar like our hummingbirds but is quite unrelated to them. It had its feathers all fluffed up because the morning was cold.

Scarlet-chested Sunbird
Scarlet-chested Sunbird
Lake Nakuru

And here is one of the most spectacular of Africa's small birds, the Lilac-breasted Roller.

They're called Rollers because they like to do acrobatics when they're flying.

Lilac-breasted Rollers
Lilac-breasted Rollers
Lake Nakuru

This will be my last letter about our trip (though I'll be happy to try to answer any more questions you may have). Lee and I have enjoyed sharing the experience with you.

Aunt Melinda