Lanner falcon

Appearance

It is a large falcon, at 43–50 cm length with a wingspan of 95–105 cm. Eurasian lanner falcons have slate grey or brown-grey upperparts; most African subspecies are a paler blue grey above. The breast is streaked in northern birds, resembling greyish saker falcons, but the lanner has a reddish back to the head. Sexes are similar, but the browner young birds resemble saker falcons even more. However, sakers have a lighter top of the head and less clear head-side patterns. The lanner's call is a harsh ""wray-e"".

Naming

The lanner falcon was described by the Dutch zoologist Coenraad Jacob Temminck in 1825 under the current binomial name "Falco biarmicus". The type locality is Caffraria and the Cape of Good Hope. "Falco" is Late Latin for a "falcon", from "falx", "falcis" "sickle". The Swedish naturalist Carl Linnaeus had used the specific epithet "biarmicus" for the bearded reedling and Temminck clearly believed that the word meant "bearded" but it is likely that Linnaeus was using the Latinized form for Bjarmaland, a district in northern Russia. The English word "lanner" is believed to come from the Old French "lanier" meaning "cowardly". The first recorded use of the word in English is from around 1400.

This is presumably the oldest living hierofalcon species. Support for this assumption comes mainly from biogeography agreeing better with the confusing pattern of DNA sequence data in this case than in others. Nonetheless, there is rampant hybridization and incomplete lineage sorting which confounds the data to a massive extent; molecular studies with small sample sizes can simply not be expected to yield reliable conclusions in the entire hierofalcon group.

In any case, the radiation of the entire living diversity of hierofalcons seems to have taken place in the Eemian interglacial at the start of the Late Pleistocene, a mere 130,000–115,000 years ago; the lanner falcons would thus represent the lineage that became isolated in sub-Saharan Africa at some time during the Riss glaciation already.

There are five recognised subspecies:
⤷  "F. b. biarmicus" Temminck, 1825 – The nominate subspecies, ranges from the Democratic Republic of the Congo to southern Kenya south to South Africa
⤷  "F. b. feldeggii" Schlegel, 1843 – Italy to Turkey, Azerbaijan and northwestern Iran
⤷  "F. b. tanypterus" Schlegel, 1843 – northeastern Africa to Arabia, Israel and Iraq
⤷  "F. b. erlangeri" Kleinschmidt, O., 1901 – northwestern Africa
⤷  "F. b. abyssinicus" Neumann, 1904 – southern Mauritania to Ethiopia and Somalia south to Cameroon and northern Kenya

Distribution

Lanner falcons are predominantly located in open habitats and can range from the forest edge to the desert. However, they are most commonly found in open savannah and sour grasslands. In South Africa, they commonly inhabit the east of the country in grasslands and move into the Fynbos, Nama Karoo and Southern Kalahari during the non-breeding season.

Despite this movement, they are not truly migratory birds, and are usually limited to local movements. These movements may be in response to seasonal rains and altitudes, where higher elevations are inhabited during breeding season, and lower elevations are inhabited out of breeding season.

Behavior

Before the breeding season, both males and females show mutual soaring and flapping flight which are closely synchronized from April to June. Near nesting sites, pairs have also been seen to power-dive together.

Once eggs are fledged, the female predominantly stays with and feeds the juveniles. However, the male takes over this role when the female needs to hunt. When the juveniles are about 25 days old, the female is commonly seen perched near the nest, but still spends a large amount of time in the nest with the juveniles. When the juveniles are about 39 days old, the female does not spend large amounts of time in the nest anymore and both the female and male are actively hunting.

Reproduction

Lanner falcon have a laying period in July which suggests a strategy to fledge young before the heat and heavy rain of the summer as well as before the influx of migratory birds during December to February. This timing may improve foraging conditions for juveniles which can increase the success of breeding. Breeding success for these falcons is largely affected by environmental conditions. The incubation period is thought to be 32 days and the nesting period to be 44 days. However, juveniles have been present near nests up  to ten weeks after fledgling. The mean fledgling rate is 2.24 young per successful pair which is typical of large falcons, however, the mean number of individuals fledged overall per territorial pair is 1.3 which is low and may be due to the number of unproductive years towards the end of each territory's occupancy.

Food

Lanner falcons most commonly prey on other birds, including doves, pigeons and domestic chickens or fowls. These falcons have also been seen to prey on small mammals, reptiles and invertebrates. In Africa and Israel, lanner falcons were observed as hunting bats.It usually hunts by horizontal pursuit, rather than the peregrine falcon's stoop from a height, and takes mainly bird prey in flight. However, these raptors make use of a multitude of hunting styles, including stooping after soaring, attacking from a perch, attacking from a fast, low coursing flight and aerial attacks from a perch. Lanner falcons also exhibit co-operative hunting with high success rate specifically when hunting jackdaws, where the use of visual contact is used to coordinate the chase. Males most commonly make the initial attack, yet the prey is usually caught by the female.

Predators

Lanner falcons are of Least Concern on the IUCN Red List, yet they can still be negatively affected through anthropogenic process, directly and indirectly.

Direct anthropogenic threats to these raptors include nest robbery, vehicle collisions, electrocution from power lines and persecution. As chicks can barely fly when leaving the nest they are vulnerable and easy to catch, they are threatened by being captured for falconries and through being caught and killed by angry farmers as a result of these birds sometimes preying on domestic chickens.

Indirect anthropogenic threats include loss of suitable habitats as a result of human expansion and the intensive use of pesticides for agriculture.

Defense

Lanner falcons usually nest on sheer cliff faces, and lay three or four eggs. They do not have strict nesting regulations and as a result are more common and do not show a patchy distribution. As a result they also make use of old crow nests and are sometimes seen nesting on pylons, trees and less steep cliff faces.