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Rail (bird)

life science Maturity 5-7 Next article →

Rails belong to the avian family Rallidae. This is a large and diverse group of small to medium-sized birds. They are mostly terrestrial, meaning they live on the ground, or semi-amphibious. You can find members of this family on every continent except Antarctica. They thrive in almost every habitat except for dry deserts, polar regions, or high alpine areas. Many species are closely tied to wetland habitats like marshes, rice paddies, and flooded fields.

Rail, from the Game Birds series (N40) for Allen & Ginter Cigarettes MET DP839177
Rail, from the Game Birds series (N40) for Allen & Ginter Cigarettes MET DP839177

They often seek out dense vegetation for nesting and protection.

The physical appearance of a rail can vary significantly. Some species possess long necks, and many have bodies that are laterally compressed. This means their bodies are flattened from side to side, helping them move through thick reeds. Their bills are perhaps their most diverse feature. For instance, the clapper rail has a bill longer than its head. In contrast, the coot has a short and wide bill. The purple gallinule has a massive bill. Some birds, like the horned coot, even have a frontal shield. This is a fleshy extension of the upper bill.

American Coot skeleton
American Coot skeleton

Flight is a unique aspect of Rallidae biology. Most rails have short, rounded wings. While their flight is not powerful, it can be sustained for long periods. This allows many species to migrate annually. However, their weak flight makes them easy to blow off course. This trait makes them common vagrants, which helps them colonize isolated oceanic islands. Because they often prefer running through dense habitats, many species have evolved to be flightless. This is a famous example of parallel evolution. Out of roughly 150 historically known species, 31 evolved flightlessness from volant, or flying, ancestors.

Flightlessness offers several biological advantages on islands. Flying requires immense energy. The keel and flight muscles can take up to 40% of a bird's total weight. By reducing these muscles, a rail lowers its metabolic demands. This energy conservation makes it easier to survive when island resources are limited. This process can also lead to diversification. Different sized flightless rails can evolve on the same island to fill various ecological niches. In rails, flight muscles typically make up only 12% to 17% of their body mass. This low starting point may contribute to how quickly they lose flight. The Laysan rail, for example, evolved reduced wings in only 125,000 years.

Takahe
Takahe

Behaviorally, most rails are omnivorous generalists. They eat a variety of foods, including invertebrates, fruit, and seedlings. Some species are primarily herbivorous. Rails are often shy and secretive, making them difficult to observe in the wild. To communicate in dense vegetation or at night, they use very loud calls. These calls can be whistle-like or squeak-like. In the Old World, birds with long bills are often called rails, while those with short bills are called crakes. In North America, both are simply called rails. The smallest is Swinhoe's rail at 25 grams. The largest is the takahē.

Takahe
Takahe

Human activity has had a profound impact on rail populations. Many island species have suffered disproportionately from environmental changes. When humans colonized islands, they introduced terrestrial predators like cats, foxes, rats, and pigs. Because many island rails are flightless, they cannot easily escape these new threats. It is estimated that several hundred species of island rails have gone extinct due to these changes. In the Pacific, the colonization of islands led to the extinction of 750 to 1,800 bird species, half of which were rails.

Aphanapteryx bonasia
Aphanapteryx bonasia

Some species, like the Guam rail, faced extinction due to the introduction of brown tree snakes.

GuamRail02
GuamRail02

Conservation efforts are currently working to protect remaining species. Some birds, such as the Lord Howe woodhen and the takahē, have made modest recoveries. For the Guam rail, scientists took the last remaining individuals into captivity. These birds are now breeding well in controlled environments. While reintroduction attempts have seen mixed results, these programs are vital for preventing total extinction. Understanding the history and biology of the Rallidae helps scientists protect these diverse and specialized birds.

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🖼️ Images & Media (5)
File:Takahe.jpg
Takahe.jpg
File:American Coot skeleton.jpg
American Coot skeleton.jpg
File:GuamRail02.jpg
GuamRail02.jpg
File:Aphanapteryx bonasia.JPG
Aphanapteryx bonasia.JPG
File:Rail, from the Game Birds series (N40) for Allen & Ginter Cigarettes MET DP839177.jpg
Rail, from the Game Birds series (N40)...
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