Eleonora's Falcons keep or imprison their prey alive

Eleonora's Falcon (Falco eleonorae) is mainly insectivorous outside the breeding season. During the latter season, which is very late (from July to October) as an adaptation to coincide with autumnal bird migration, both adults and chicks consume migrating birds (mainly passerines but also small non-passerines like Hoopoe and swifts) that fly through Mediterranean islands and Atlantic coast.

During a fieldwork study in the framework of PIM-Initiative in 2014, Qninba et al. recorded an unusual predation behaviour by this falcon in the Mogador archipelago (Essaouira), off Moroccan Atlantic coast. The authors remarked that Eleonora's Falcons kept alive some of the captured prey. To do this, "the falcons keep or ‘imprison’ some preys in a relatively deep cavity or in a fissure of rocks from where they can’t escape as their flight feathers (both tail and wings feathers) were already pulled out (photo 1 of the Chiffchaff). Or by keeping them trapped in a tight and deep hole which makes them unable to move neither their wings nor their hanging legs (photo 2 of the Common Whitethroat)".

The authors reported also that this behaviour can occur even before the eggs hatch, and was already well known to a local fisherman who is staying in the archipelago in a more or less regular basis for decades.

The authors interpreted this hitherto unknown behaviour for this falcon or for any other raptor species as a form of food storage behaviour. They wrote: “Keeping prey alive, one or two days (the precise period not yet known), may allow the falcon to have a fresh food on the right moment, because the dead prey brought to the nest and untouched can no longer be consumed as it dries out too quickly”.

This unusual predation behaviour was described in this paper published in the last issue of Alauda:

Qninba, A., Benhoussa, A. Radi, M., El Idrissi, A., Bousadik, H., Badaoui B. & El Agbani, M.A. 2015. Mode de prédation très particulier du Faucon d’Éléonore Falco eleonorae sur l’Archipel d’Essaouira (Maroc Atlantique)Alauda 83(2): 149-150.

Common Chiffchaff (Phylloscopus collybita) stored at the bottom of a crevice after it’s wing and tail feathers were pulled out, Mogador island, Morocco, September 2014 (Abdeljebbar Qninba).
Common Whitethroat (Sylvia communis) immobilised in a deep and very small hole, Mogador island, Morocco, September 2014 (Abdeljebbar Qninba).