Falco biarmicus

Lanner Falcon (Falco biarmicus)

The lanner falcon, scientifically known as Falco biarmicus, is a medium-sized bird of prey recognized for its presence across Africa, southeastern Europe, and parts of Asia. It thrives in open environments, ranging from forest edges to deserts, and is most commonly observed in savannah and grasslands. Historically, the lanner falcon holds cultural significance, with suggestions that it, or the peregrine falcon, was the sacred falcon species of ancient Egyptians, often depicted in their deities.

Taxonomy and Etymology

First described by Coenraad Jacob Temminck in 1825, Falco biarmicus belongs to the genus Falco. The genus name Falco is derived from the Late Latin word for falcon, referencing the sickle-shaped wings. The specific epithet biarmicus is thought to be a Latinized reference to Bjarmaland, a historical region in northern Russia, rather than a descriptor of being "bearded" as Temminck may have initially believed. The English common name, "lanner," is believed to originate from the Old French term lanier, meaning "cowardly," with its first recorded use in English dating to around 1400. It is considered the oldest living hierofalcon species, though genetic data can be complicated by hybridization and incomplete lineage sorting.

Description and Distribution

A large falcon, the lanner falcon typically measures between 43–50 cm in length with a wingspan of 95–105 cm. Eurasian lanner falcons (subspecies F. b. feldeggi) often display slate grey or brown-grey upperparts, while most African subspecies exhibit a paler blue-grey coloration. A distinctive feature is the reddish hue on the back of the head. Though sexes are similar, juvenile birds are browner and can resemble saker falcons, from which they can be distinguished by a darker crown and more defined head-side patterns.

Habitat and Behavior

Lanner falcons are predominantly found in open habitats, including savannah and grasslands, but can also be found near forest edges and in desert regions. While they exhibit local movements, often responding to seasonal rains and altitudinal changes, they are not considered truly migratory. Pairs engage in synchronized mutual soaring and flapping flights before the breeding season, and may also perform synchronized power-dives near nesting sites. Once eggs hatch, the female primarily cares for and feeds the young, with the male taking over feeding duties when the female needs to hunt. Both parents actively hunt once the juveniles are about 39 days old.

Diet and Hunting

The primary prey of the lanner falcon consists of other birds, such as doves and pigeons, and they have also been known to take domestic chickens. Their diet extends to small mammals, reptiles, and invertebrates, and they have been observed hunting bats in Africa and Israel. Hunting strategies are varied, commonly involving horizontal pursuit rather than the high stoops characteristic of the peregrine falcon. They also hunt by soaring and stooping, attacking from perches, or engaging in fast, low coursing flights. Cooperative hunting, particularly when targeting jackdaws, has been documented, utilizing visual cues for coordination.

Nesting and Breeding

Lanner falcons typically nest on sheer cliff faces, laying between three and four eggs. Their nesting habits are adaptable, and they will also utilize old crow nests, pylons, and trees. The breeding season, with a laying period in July, is thought to be timed to allow fledging before extreme summer heat and heavy rains, and before the influx of migratory birds. This timing may enhance foraging opportunities for the young. The incubation period is estimated to be around 32 days, with a nesting period of approximately 44 days, though juveniles may remain near nests for up to ten weeks after fledging. While the mean fledgling rate per successful pair is typical for large falcons, the overall number of young fledged per territorial pair is lower, suggesting factors like unproductive years may influence reproductive success.

Threats and Conservation

Globally, the lanner falcon is classified as Least Concern by the IUCN. However, the species faces significant threats from human activities. Direct threats include nest robbery, collisions with vehicles and power lines, and persecution. Chicks are vulnerable to capture for falconry, and adult birds may be killed by farmers concerned about predation on domestic chickens. Indirect threats comprise habitat loss due to human expansion and the widespread use of agricultural pesticides, which can impact prey availability and the falcons themselves.