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Research & Exploration
Field Dispatch
APRIL 2005

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Photograph by Cyril Ruoso
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Birds of a Different Color

Madagascar's Paradise Flycatchers

In the dry southern tip of Madagascar, an aging bridge crosses what's left of the Photo: Paradise FlycatchersMandrare River, now throttled by silt from deforested lands upstream. The bridge leads to a lush 300-acre (100-hectare) patch of forest known as the Bealoka reserve. Some of it is dark and gloomy, cloaked by a high canopy of tsatsake trees. Sunlight filters through more open parts where tamarind trees grow. Throughout the forest echo the calls of about a hundred bird species.
 
One of the most recognizable is the harsh retret retret of the Madagascar paradise flycatcher. Males are visually unmistakable, with tails three times their body length streaming behind them—and with a colorful twist that has drawn biologist Raoul Mulder to camp in Bealoka for parts of the past nine years.
 
Adult male Madagascar paradise flycatchers come in two distinct color types, or morphs, a rare phenomenon among birds. (Males of only one other known bird species, a Eurasian sandpiper called the ruff, have such color variations.) One flycatcher morph, the rufous type, is reddish brown; the white morph is mostly white and black. Once these plumages emerge—after about three years or so—they're permanent. But why the two different hues?
 
In nature, color evolves in part to attract mates. If one male flycatcher color had a mating advantage, the other should have gone extinct. It hasn't, so each color must provide some sort of benefit—and that's where things get complicated.
 
It's possible, says Mulder, that female flycatchers choose to mate with whichever morph type is less common at the time, a form of sexual selection known as the rare-male effect.
 
Geographic location may also play a role. One morph color may stand out better—and thus attract more females—in bright, open spaces, while the other may be more visible in dense shade. But he who gets the most dates may also die young, because the morph color that females prefer may also be more visible to forest predators.
 
Mulder thinks the white morph is more susceptible to predation. "Our color measurements show that white morphs are more conspicuous than rufous males," he says. "We've set up trials using stuffed mounts of both male types. The white ones are always attacked first. The predators are sparrow hawks, and we've seen them kill white males."
 
So, do females prefer their mates in white? "Since white males suffer more predation, you might expect them to have a mating benefit to compensate for this cost," says Mulder. "But the data suggest that females are highly unfaithful to both male types."
 
In breeding season, a female lays up to three eggs on consecutive days. Though she pairs with one male that helps tend the nest, she may also copulate with males in nearby territories and can store their sperm, so each egg could be fertilized by a different father.
 
Using DNA analysis, Mulder and his team have determined the paternity of some 700 nestlings. Half the nests held chicks fathered by different males of one or both colors. "Females apparently do not have fixed preferences for particular males or morph types," says Mulder. In future studies he hopes to detect paternity patterns that may shed more light on the mystery of flycatcher color.
 
—John L. Eliot
 
DID YOU KNOW?

The island nation of Madagascar is famous for having a high level of endemism in its plant and animal species—that is, they are native to this particular place and do not occur naturally anywhere else in the world. In general, though, Madagascar has a relatively low level of species diversity: It is not home to a very high number of species, although a large proportion of those that do live here are endemic. This is particularly true when it comes to birds. Compared with other bird communities at the same latitude, and even with other large islands such as Borneo, this island is home to a relatively small number of bird species—only about 250. Of these species, however, more than half—52.2 percent—are endemic to Madagascar. And compared with islands like New Zealand or the Hawaiian Islands to which human visitors have brought familiar animals, Madagascar is home to an extremely low number of introduced species: only four, or 1.5 percent of the nation's bird species. (In Hawaii, by comparison, more than half the bird species are not native to the islands.)
 
—Robin A. Palmer
 


WEB LINKS

Berenty Reserve
bibliofile.mc.duke.edu/gww/Berenty/index.html
Just a few miles from the tiny reserve of Bealoka, where National Geographic grantee Raoul Mulder is studying the Madagascar paradise flycatcher, the larger Berenty Reserve contains many of the same plants and animals. At this website you can see pictures of the area's flora and fauna (including the paradise flycatcher) and listen to sounds of the forest, such as the calls of parrots and the grunts, howls, and yaps of lemurs.
 
The Wilds of Madagascar
www.pbs.org/wgbh/nova/madagascar
From dry canyons to rain forests, Madagascar boasts a fascinating variety of landscapes, which are home to an abundance of plant and animal life. Produced in connection with a public television show on the wildlife of Madagascar, this site includes sections about legends of the Malagasy people, video of the places visited in the show, and photographs of Madagascar's deserts, forests, villages, and more.
 
Madagascar Page
www.sas.upenn.edu/African_Studies/Country_Specific/Madagascar.html
To learn more about Madagascar, visit this site, which includes links to sites on all sorts of topics: Malagasy news, art, plant life, languages, and pictures and sounds of the island's famous lemurs.



BIBLIOGRAPHY

Langrand, Olivier. Guide to the Birds of Madagascar. Yale University Press, 1990.
 
Mulder, R. A., Mariarison, R., and Emahalala, R. E. "Ontogeny of Male Plumage Dichromatism in Madagascar Paradise Flycatchers Terpsiphone mutata." Journal of Avian Biology, vol. 33 (2002), 342-8.