Yuma Ridgway's Rail

Yuma Ridgway’s rails primarily eat crayfish, small fish, frogs, and aquatic invertebrates.

Yuma Ridgway’s rails are secretive birds that are more often heard than seen. Their bodies are laterally compressed, and they can steer right and left, which enables them to move efficiently through cattails and other emergent vegetation. Yuma Ridgway’s rails under cover or in the open walk upright with a deliberate step and may twitch their tails. When alarmed, they will run into vegetative cover with their bodies held horizontal. Yuma Ridgway’s rails do not usually perch above the ground; however, an individual may climb into a shrub or tree.

Despite a lack of webs between their toes, adult Yuma Ridgway’s rails are good swimmers, sitting high in the water with the head held up. The swimming motion is slightly jerky, likely due to the continued “walking” motion of the legs used for propulsion. Individuals are known to dive underwater and may hold onto submerged vegetation to stay down in response to threats or use its wings to “swim” through the water. Yuma Ridgway’s rails do not swim for long distances as researchers rarely saw an individual swim channels more than 100 feet (30 meters). Downy chicks are unable to float or swim and are susceptible to drowning when their down gets wet. The availability of areas with stable shallow or no standing water for the chicks to move across and forage in is an important consideration for human-related changes in water levels in occupied marshes.

The Yuma Ridgway’s rail, when flying short distances within or between patches of habitat is an awkward flier with a slow, weak, and fluttering flight, legs dangling with the head held high. However, as evidenced by recent telemetry studies that showed long distance migration, the Yuma Ridgway’s rails are successful strong fliers over longer distances. This type of flight is more duck-like, with the head, tail and legs held in a straight line and steady, rapid wing beats.

Adult Yuma Ridgway’s rails possess a long, slightly de-curved bill, a laterally compressed body, and relatively long legs and toes compared to body size. The Yuma Ridgway’s rail is one of the smaller subspecies of rails, with adult males standing 8 inches tall (20 to 23 centimeters). Sexes can be differentiated based on the use of several external measurements.

Adult males weigh 9.3 ounces (266.8 grams) on average. Females are slightly smaller, averaging between 8 ounces (226.2 grams) and 6.8 ounces (193.0 grams). 

Adult Yuma Ridgway’s rails of both sexes are similar in plumage. The upper mandible (bill) is dark grey, fading to orange at the base and the tip. The head and scapular (shoulder) area are grey, with browns and oranges appearing on the sides of the neck and under the head. The chin and upper throat are white, and there is a light eyebrow stripe extending from above the eye to the upper mandible. The breast is tawny to burnt-orange in the male, and a brick-orange in breeding females. The upper body is light grey to dark brown, becoming blotchy and dominant on the rump and distally on the wings. The underside and flanks forward of the legs are dark grey with vertical white stripes. The tail is dark brown above and white below. Legs are un-feathered and orange in color. Adult rails have a basic pre-body molt in May to August, with the simultaneous molt of rectrices and remiges which impact flight. Flightless birds are found between mid-July and the end of September. A second, pre-alternate molt, which does not include flight or tail feathers, occurs from September to December.

Hatchlings are downy black, with many having some white downy feathers on their anterior abdominal region. The young retain their black down for about a month then molt into juvenile plumage. During this stage, young often resemble the eastern congener of clapper rails. The second body molt takes six to seven weeks, with the juveniles obtaining the buffy adult ventral plumage. Juveniles are difficult to distinguish from adults after September.

Male Yuma Ridgway’s rails will give “kek” calls during the start of breeding season.

It is assumed that Yuma Ridgway’s rails reach maturity around one year of age. Clutch size can range from 5 to 10 eggs and incubation occurs within 23 to 28 days. After hatching, adults remain with the chicks for approximately six weeks, protecting them at night in brooding nests/platforms and accompanying them on foraging trips. Because chicks are unable to float or swim due to their downy feathers, adult Yuma Ridgway’s rails may carry chicks when needed to protect them from adverse conditions. It is assumed that chicks will molt into juvenile plumage after a month, and that juveniles will molt into adult plumage after six to seven weeks. 

We do not know how long an adult Yuma Ridgway’s rail lives.

At the start of breeding season (February to March), male Yuma Ridgway’s rails will give “kek” calls. If successful in attracting a female, pair bonding occurs shortly thereafter. Once paired, the bond lasts at least until the end of the breeding season. Nesting begins in March with a peak in mid-May on the lower Colorado River and from May to June at the Salton Sea. Once a nest is complete, the Yuma Ridgway’s rail lays clutches of eggs.