They built bigger ships, larger gantry cranes and more sophisticated containers. Heavy lifting is done by machines such as overhead cranes or forklifts. Common birds are storks, cranes and marabou. Some telescopic tower cranes also have a telescopic jib. The valley hosts sandhill cranes each winter. These were equipped with 175 trucks, 65 cranes, 55 excavators and 13 bulldozers. There are 22 endangered species of birds including hawks, falcons, buzzards, cranes and owls. Sandhill cranes have been tried as foster parents for whooping cranes in reintroduction schemes. Containers handled by means of lifting gear, such as cranes, overhead conveyors, etc. In older model designs of hydraulic truck cranes, there were two engines. The company produced FMC Link-Belt branded cranes and excavators. Golden eagles have killed some young whooping cranes and fledglings. There are many types of tower cranes. Her team towed improperly parked vehicles using six tow trucks ("cranes") for traffic control. It is one of two known nesting sites of whooping cranes.