Peregrine Falcon Status in Iowa Report
The scientific name for peregrine falcon is Falco peregrinus which means wandering falcon. During migration, peregrines may travel great distances. Peregrines nesting in the Arctic are known to migrate to Central and South America during the winter.
Peregrines are a bird of prey (raptor) and part of the Falconidae (falcon) family. There are 5 falcon species in the United States: Gyrfalcon, peregrine falcon, prairie falcon, merlin and American kestrel. The peregrine, merlin, and kestrel all once nested in Iowa. Now only the merlin does not nest here.
Peregrines are a crow-sized bird. Females are larger and weigh 32-34 ounces (about 2 pounds) while males weigh 18-20 ounces. From beak to tail peregrines are 13 to 16 inches long. During their first year, the young falcons will have a chocolate brown plumage with streaks on the belly. After one year of age, they will obtain the adult coloration which is slate blue on the back, white under the chin with black speckling and salmon on the breast. All peregrines have the dark mustache stripe under each eye.
Growth and Development
- Peregrines tend to be monogamous and maintain long-term pair bonds. Courtship includes aerial dives and the male presenting food to the female. Mating occurs in spring, and egg laying usually begins in early April.
- Female peregrines lay a clutch of 3 to 5 eggs. Both the male and female incubate the eggs and tend the young after hatching. Incubation is 31 to 33 days.
- Nests are simply a scrape in the dirt or gravel of a cliff ledge, building alcove, or nest structure.
- When hatched, the young peregrines are about the size of baby chickens (2 oz.) and have a light coat of white down. Unlike chickens, peregrines are helpless for the first couple weeks.
- Young peregrines (eyases) can walk when 2 to 3 weeks old and start tearing their own food that the adult brings when about a month old. When they are about 6 weeks old, they begin to fly but still cannot capture their own food. After they have been flying for about a month they start catching prey. When they are 9 to 12 weeks old, they hunt and care for themselves.
- Males develop faster than females, and young males usually fly first.
- Young peregrines migrate out of northern climates during winter months to the southern U.S. or further south. A female hatched in Des Moines in 1994 was captured and released 30 km south of Mexico City, Mexico in March 1995.
- Sixty percent of the young falcons die during their first year. After their first year, they stand an 80 percent chance of survival in subsequent years and may live to be 12 to 15 years old. In 2000, the oldest known falcon nesting in the Midwest was a 14 year-old female.
- A peregrine is usually sexually mature at 2 or 3 years of age; however, one-year-old birds have been known to nest successfully.
- Peregrines can fly straight-away at 60 mph. When they fold their wings and go into a dive (stoop), they can reach speeds of up to 260 mph.
- Peregrines feed mostly on other birds such as pigeons, starlings, blackbirds, ducks, jays, doves, and sparrows. An adult bird eats one to two blackbird-sized birds per day.
- The peregrine population has never threatened populations of other birds. As a predator, the number of existing peregrines is much less than the populations of the birds they feed on.
- Peregrines are very territorial, so within suitable habitat, peregrines space their nests at least one mile apart. Some territories and nests in Europe have been documented for hundreds of years.