Madagascar: Unique and Imperiled

Our international birding trip this winter was to Madagascar, the fourth largest island in the world, after Greenland, New Guinea, and Borneo. It is located in the Indian Ocean, about 250 miles off the coast of southeastern Africa. Madagascar is nearly a thousand miles long and about 350 miles wide, oriented from NNE to SSW. The Tropic of Capricorn runs through the southern part of the island. For nearly its entire length, an escarpment rises slightly inland from the eastern coast, reaching a few thousand feet elevation. This escarpment traps moisture from the Indian Ocean, supporting a narrow band of rainforest habitat on its slopes, and creating a rain shadow to the west in the extensive highlands.

Elevation is lost more slowly towards the western coast, with aridity increasing from east to west and also north to south. Two notable dry forest types occur at low elevations near the west coast, a deciduous forest farther north, and the famous spiny forest of the far southwest. Although there is a reasonable amount of eastern rainforest remaining, both dry forest types are critically imperiled.

Madagascar is typically visited fairly late in their “travel career” by birders as the total list of species is relatively low, and the travel and birding are somewhat difficult. The Central Plateau, which occupies most of the island, has been devastated by deforestation and subsequent erosion; it is singularly depressing to traverse. Distances are great, the road system is poor, and internal flights are unreliable, so unfortunately a lot of time is spent crossing this plateau, to reach peripheral areas with often limited remaining native habitat. It was the precariousness of these remnants of native habitat that caused us to travel to Madagascar sooner rather than later; even nationally protected areas may be unable to withstand the pressure of the increasing population. Madagascar is often considered the second most vulnerable natural history destination after the Philippines.

Madagascar broke off from the Indian subcontinent about 88 million years ago. Most animals currently inhabiting the island arrived subsequently, rather than being relicts from Gondwanaland. In many cases, a single colonization event has led to dramatic subsequent radiative adaptation and speciation, making Madagascar one of the most interesting places on the planet, from an evolutionary viewpoint. For example, a single proto-lemur species arrived, presumably on a raft of vegetation that floated across the Mozambique Channel, giving rise to about one hundred species of lemurs in five endemic families. Similarly, each of the other terrestrial mammal groups (rodents, carnivores, and tenrecs) each arose from a single colonization event.

There are two avian orders, three families, and one subfamily that are found only in Madagascar or the nearby Comoros Islands, and these are particular targets for visiting birders. The first order contains only one species, the Cuckoo-Roller, and so is termed “monotypic”. (There is only one other monotypic avian order, comprising the Hoatzin, so in some sense these two species can be considered as being the most distinct extant birds.) The second endemic order consists of the three species of mesites (pronounced MEE-sights). The endemic families are the Ground-Rollers (5 species), Asities (4 species, pronounced ah-SEE-tees), and Malagasy Warblers (11 species). Lastly, the endemic subfamily contains the Vangas, 21 species derived from a single colonization event, and exhibiting a remarkable range of bill shapes and other adaptations by which they are able to exploit many formerly vacant ecological niches.

In addition to the interesting birds and mammals, Madagascar is noted for its reptiles and amphibians (“herps”), and particularly for its chameleons, geckos, and frogs. The latter, although extremely numerous (there are an estimated 500 species on the island, of which only 300 have been scientifically described), are difficult to observe, at least when we visited at the very beginning of the rainy season. But chameleons (some large) and geckos are quite evident.

The combination of scarce colonization events, incompletely filled ecological niches, isolation, and radiative adaptation have led to extremely high levels of endemism in many habitats and plant and animal groups. Although numbers vary a bit between habitats and groups, among native terrestrial plants and mammals, endemism rates often are around 90%, meaning that only 10% of the species are found anywhere else in the world. These endemism rates are much higher than those found on other large islands of the world.

On this tour, with Field Guides, Inc., we sampled the eastern rainforest at Ranomafana National Park (NP) and Andasibe-Mantadia NP; the deciduous forest at Ankarafantsika NP; and the spiny forest on private lands in Ifaty. Local guides familiar with the locations of territories and sometimes nests of the endemic birds were absolutely crucial to finding these species, more so than in any other place we have birded. Other areas and habitats we visited included the scenic sandstone formations around Isalo NP, the interesting dry forest in Zombitse NP, coral uplands east and south of Toliara, and coastal areas around Mahajunga and Ifaty, and northeast of Brickaville.

Although most of these locations are well known, the latter is less so, and deserves special mention. We stayed at the Palmarium Hotel, which is reached via boat and has many introduced and habituated lemurs on its grounds. From the hotel there are regular guided evening excursions to Aye-aye Island; these take a couple of hours including the  half-hour boat ride each way. This small island was artificially isolated from a much larger barrier island by the cutting of a canal, to localize a native population of Aye-ayes. This bizarre lemur, in a family of its own, is fairly widespread in Madagascar but is generally very difficult to see. Here, however, they are observed nightly at feeding sites where a few coconuts are put out for them. With the thermal scope, we also found sleeping Madagascar Green Pigeons, and Webb’s Tuft-tailed Rat, a native rodent we saw high in a tree. Visiting Aye-aye Island is a very special experience!

We did very well on endemic birds and mammals on this trip. We saw all the endemic avian orders, families, and subfamilies, finding the Cuckoo-Roller, all 3 mesites, 4 of 5 ground-rollers, 2 of 4 asities, 5 of 11 Malagasy Warblers, and 16 of 21 vangas. In total, we saw 102 of about 130 endemic bird species. We had excellent luck with mammals as well, finding 24 species of lemurs spanning all five lemur families, as well as two native rodents in their endemic subfamily. In addition, we saw 5 species each of chameleons and geckos, and another 19 miscellaneous native species, representing 7 new families for us. Our only notable milestone of the trip was Eileen seeing her 400^th lifetime worldwide native mammal, a cute Gray Bamboo Lemur at Ranomafana NP. She ended the trip with 414 mammals and 3347 birds. I finished with 429 mammals and 3462 birds, plus 5798 plants, 175 butterflies, 168 herps, and 158 others, a grand total of 10,190.

But perhaps what we will remember best from this trip are the evocative, primeval calls of the Cuckoo-Roller and the Indri (the largest lemur), which embody the essence of this utterly unique and imperiled land.