Associated Smithsonian Expert: Gary R. Graves, Ph.D.

Dr. Gary Graves had an early childhood fascination with birds that eventually led him to his role as curator of birds at the National Museum of Natural History.

Photo by Don Hurlburt, Smithsonian Institution

Dr. Gary Graves is a research zoologist and curator of birds at the Smithsonian National Museum of Natural History where his research focuses on the ecology, biogeography, and evolution of birds. His early childhood fascination with birds led to graduate studies at Louisiana State University and Florida State University: "I am unapologetically curious about natural history and the ways that natural history observations catalyze important ecological and evolutionary discoveries." His dissertation work focused on speciation of birds in the Andes Mountains of Peru. He has also conducted fieldwork in Brazil, Ecuador, Panama, Colombia, Polynesia, Canada, and in more than half the states in the USA. His current research efforts are split between the analysis of complex data sets based on the collective resources of the World's great museums and conducting field research in Jamaica, the great forests of the eastern USA, and in the Sonoran Desert.

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Ostrich (Struthio camelus) running
Courtesy of Amcaja, via Wikimedia Commons, CC-BY-SA

About Ostriches (Order Struthioniformes): Locomotion

Ostriches are birds, but they can not fly. Their breastbones are flat, lacking the usual keel where flight muscles attach. Ostrich flight muscles are small, and they have fancy plumage instead of flight feathers. Ostriches, however, are great runners. Long legs raise their center of gravity high off the ground, like horses. An ostrich may stand more than 2 meters tall (6.5 feet) and run more than 60 kilometers per hour (38 miles/hour). Strong but lightweight pelvic bones anchor large muscles. An ostrich really catches its stride when chased by a predator such as a cheetah. It takes less energy to walk, though, and they spend most of the day walking around. Ostriches walk on their toes with a rolling motion of their flexible feet, leaving an even footprint. While they do not bury their heads in the sand, they do sometimes sit down and rest their heads on the ground.

Malachite Sunbird (Nectarinia famosa) feeding on flower nectar
Courtesy of Steve Garvie from Dunfermline, Fife, Scotland, via Wikimedia, CC-BY


About Birds (Class Aves): Feeding

All modern birds have bills and no teeth. The shape of a bird's bill says a lot about what it eats, for example whether it specializes in seeds (stout , cracking bill), fish (pointy, spearing bill), or plants (wide, serrated bill). Birds swallow their food without chewing, so it travels to the stomach whole or in large pieces. Bird digestive tracts have some special features for digesting chunky food. A pouch in their throat (the crop), is used to store food to be digested later, or regurgitated to feed the young. An extra, muscular stomach (the gizzard) grinds food up. Birds are endotherms, using heat they make internally to keep warm. While a few species allow their body temperature to drop at night (torpor), a nearly constant body temperature is maintained by most birds most of the time. Continuously making heat requires fuel to burn, in the form of food. So, birds spend a lot of time eating.