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The Ruby-Throated Hummingbird in North Dakota


Bird Description


The ruby-throated hummingbird is one of the smallest and widest- ranging of North American hummingbirds. It is the only species of hummingbird found in North Dakota. Both adult male and female are 3 1/2 inches long and have a wing spread of 4 1/2 inches with metallic green backs and grey bellies.

Adult males differ from females, possessing throat feathers that appear black but flash a fiery red or orange in the sunlight. Males have a slightly forked tail, versus the female which has an unforked tail with prominent white spots on the outer corners.

Both adult birds weigh approximately one-eighth of an ounce. When not seen by the observer, the hummer can be detected by its rapid, squeaky note or by the hum of its wings which move at speeds up to 75 strokes per second. A species of moth called the hummingbird moth may, at first glance, be confused with this bird.

Range and Movement

Recorded Sightings of Ruby-throated hummingbirds in North Dakota (Stewart 1975)

JPG -- Recorded Sightings of Hummingbirds

Hummingbirds winter as far south as Costa Rica and leave their tropical homes in late winter to begin moving northward. Many cross the Gulf of Mexico and arrive in southern states by April and in North Dakota by mid-May. Males precede females to the nesting site. Both sexes are usually observed moving singly but occasionally in groups of two or three. Upon arrival, the male begins a courtship flight consisting of rapid, jerky flight accented by a loud wing buzz. The pair chooses habitat consisting of brushy margins adjacent to tracts of deciduous forest, including river floodplain and upland forest.

Habitat and Nesting

In North Dakota, breeding records prior to 1972 indicate birds were fairly common in the Turtle Mountains. Other areas where birds have been reported include the Pembina Hills, the forests associated with Devils Lake, wooded valleys along the Sheyenne and Red Rivers, and occasionally along the Missouri River. Birds are also found in many locations for varying periods of time during the late summer migration in August and occasionally during spring migration.

The compact nests are located in deciduous trees about 5-20 feet above the ground and are constructed with soft fibers from plant species such as milkweed and thistle. Young oak leaves are often utilized and held together by spider's silk or other sticky materials taken from caterpillar cocoons or nests.

The actual nest is about the size of a half dollar and holds two eggs the size of small beans. Sometimes, more than one brood is raised in a season. The female feeds the young for about 25 days upon which time they leave the nest and fend for themselves. If the female lives, she apparently returns to nest in the same location every year.

Feeding

JPG -- Picture of a Hummingbird Feeding

Ounce for ounce, hummingbirds require more calories than any warm-blooded animal (except possibly shrews) to maintain their body temperature of 105 degrees F and to fuel their rapid movement. Hummingbirds find their meals by sight, not smell, and some believe that bright red, orange or yellow flowers are easiest for a bird to see against a backdrop of green foliage.

Nectar is the mainstay of the bird's diet and some species of flowers are preferred over others. Hummingbirds are uniquely adapted for gathering nectar by being able to hover motionless before a flower and make slight up, down, or backwards movements to access a specific point. The nectar of flowers preferred by hummingbirds is about 20 percent glucose sugar. Glucose is chosen over fructose sugar which is found in the more concentrated nectar of insect-pollinated flowers. With an oddly shaped tongue exhibiting a grooved surface allowing for capillary action, the bird hovers near a preferred flower and licks the nectar from the inside by inserting its beak. To supplement its diet, a bird will feed upon various backyard insects to get needed protein, vitamins, minerals, and fat.


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