Reproduction
In order to attract females, male sakers engage in spectacular aerial displays, in common with many other members of the genus Falco. Male sakers soar over their territories, calling loudly. They end their display flights by landing on or near a suitable nesting site.
In closer encounters with a mate or prospective mate, sakers bow to each other, and many interactions incorporate some element of bowing. Males also often feed their mates during the nesting period. When wooing a potential mate, a male will fly around, dangling prey from his talons, or will bring it to the female in an attempt to prove that he is a good provider.
Mating System: monogamous
Sakers are generally two to three years old before they begin breeding. There can be 2 to 6 eggs per brood, but generally the number is between 3 and 5 (on average 4). After the third egg is laid, full incubation begins, and usually lasts for about 32 to 36 days. In general, as is true for most falcons, males offspring develop faster than females.
The young hatch with their eyes closed, but they open in a few days. They have two downy nestling plumages before attaining juvenile plumage. They attain adult plumage when a little over a year old, after their first annual molt.
Females reach sexual maturity about a year before males; they occasionally breed in their first year, but usually not until their second or third year, and some wait until their fourth year. Males, on the other hand, begin breeding in their second year at the very earliest; most wait until the third or fourth year, and some males don’t begin breeding until their fifth year.
Breeding interval: Saker falcons breed once a year.
Breeding season: Sakers breed in the springtime. Copulation may occur as often as several times a day for a period of 4 to 8 weeks before any eggs are laid.
Range eggs per season: 2 to 6.
Range time to hatching: 32 to 36 days.
Range fledging age: 45 to 50 days.
Range time to independence: 65 to 85 days.
Range age at sexual or reproductive maturity (female): 1 to 4 years.
Average age at sexual or reproductive maturity (female): 2-3 years.
Range age at sexual or reproductive maturity (male): 2 to 5 years.
Average age at sexual or reproductive maturity (male): 3-4 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization
Young sakers begin to fly at about 45 to 50 days of age, but remain within the nesting territory, dependent on their parents for food, for another 30 to 45 days, and occasionally longer. If they encounter a large localized source of food, brood mates may remain together for some time.
While still in the nest, chicks chirps to get a parent’s attention if they are isolated, cold, or hungry. In addition, females may make a soft “chip” noise to prompt their young to open their beaks to receive food. Mothers will pass over a chick that is begging but has a full crop in order to feed a chick that has not eaten enough. When a brood is well-fed, the chicks get along better than in a brood subject to food scarcity. In a well-fed brood, the chicks share food as well as explore with each other once they begin to fly. In contrast, when food is scarce, chicks guard their food from one another, and may even try to steal food from their parents. If a chick dies and the rest of the brood is hungry, they will eat their dead sibling, but fratricide has never been observed.
Parental Investment: altricial ; pre-fertilization (Provisioning); pre-hatching/birth (Provisioning: Male, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Protecting: Male, Female); pre-independence (Provisioning: Male, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning
- Anderson, S., J. Squires. 1997. The Praire Falcon (Section 3-Prairie Falcons and Other Raptors). Austin: University of Texas Press.
- Cade, T. 1982. The Falcons of the World. London: Cornell University Press.
