Eleonora’s falcon runs bird prisons?!

A small bird believed to have imprisoned by an Eleonora’s falcon on the Mogador archipelago. (Image credit: Abdeljebbar Qninba)

One population of Eleonora’s falcon is reported to keep little birds alive inside rocky prisons — a behavior not seen in any other raptor species.

Eleonora’s falcon: The raptor that imprisons birds live by stripping their feathers and stuffing them in rocks

Some are skeptical as am I. This goes back 10 years and I see no proof that I can find. Also, a bird stuffed in a hole can get back out. Did anyone hear any more about it?

The Warden.


  1. Hmmm… Caching behaviour is well-known in falcons—even some trained birds, notably merlins, will cache, especially if flown in high condition. But freshness is unlikely to be a major consideration. When we hacked peregrines, we typically left anywhere from several days’ to a week’s worth of quail on and around the hackbox immediately prior to release, so that we would not have to disturb the eyasses around fledging time—and so that they would not learn to associate those provisions with humans.

    I’m very skeptical of falcons caching live birds—as you say, what’s to keep them from escaping? And it would be contrary to the nature of the falcon: the so-called coup de grace, in which the falcon severs the quarry’s cervical spine with the tomial tooth, is so hardwired that longwings will typically “dispatch” birds that are already dead (quail from the freezer, for example). The only exception seems to be for a brief period during the breeding season when parent falcons will release live prey for the fledglings, already accustomed to aerial food transfers, to chase and (re-)catch for themselves.

    More to the point, in his monograph on Eleonora’s falcon, Helmut Walter discusses caching behaviour at length, but never reported the caching of live prey—and Mogador was one of his study sites! In fact, he noted that his subjects at Paximada in Greece would typically consume cached prey by the end of the same day, whereas the falcons at Mogador cached so many surplus birds that they began to accumulate, and he eventually resorted to raiding the caches or “larders”, discarding the uneaten birds in the ocean so that they would not be double-counted. (And, circling back to the topic of freshness: “they [cached bird carcasses] stank more from week to week where I did not interfere”, again because the falcons were caching more quarry than they could eat.)

    Based on available information, I’m inclined to agree with Simmons that a bird like the one in the photo represents not a “prisoner” or live cache but a survivor (for the moment), hard-pressed by one or more falcons until it found at least temporary refuge in the porous rocks. (Migrant passerines may have to “run the gauntlet” with dozens of Eleonora’s falcons dominating the airspace in what Walter describes as a “falcon wall”, so this desperate hiding behaviour is not as far-fetched as it might otherwise seem. Songbirds generally migrate at night anyway, so darkness will afford an opportunity to make good an escape. It is only the extreme length of the journey, often across the Mediterranean and the Sahara in one throw, that puts these birds at the falcons’ mercy in the first place; Walter estimates that depending on winds, the combined crossing might take 40 to 60 hours of flight time.)

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