Tapaculos: Rhinocryptidae

Tapaculos are a diverse family of small perching birds that live in Central and South America. They range in size from about 4 to 9 inches (10 to 23 centimeters) and weigh anywhere from 0.4 to 6.5 ounces (11 to 185 grams). Tapaculos are one of the most primitive families of songbirds.

Tapaculos are also one of the most varied families of birds. The fifty or so species have only a few physical characteristics in common. Tapaculos are very poor flyers. They have short, rounded wings, but unusually strong feet and large claws. Internally the sternum, or breastbone, of these birds is different from the sternum of birds that are better flyers. In most birds, even domestic chickens, the sternum has a projection or bulge called a keel. The keel creates more surface area for the muscles used in flight to attach to the bone. Birds like tapaculos that are nearly flightless do not need this extra area where flight muscles can attach, so their breastbones do not have a keel.

Tapaculos are generally solid color grayish or brown birds, although some have lighter-colored spots or patterns. In most species, the males and females look similar, although the females tend to be slightly smaller. Most tapaculos have short tails. Their feathers fall out easily and it is thought that this is a way of fooling predators, animals that are hunting them.

Different species of tapaculo may be difficult or impossible to tell apart by sight. Some species look alike and can only be identified based on their song, their weight, and the habitat in which they live. Others are so similar that they can only be told apart by genetic testing. Ornithologists, scientists who study birds, are not in complete agreement about how many species of tapaculos exist and how they should be classified.