SummaryThe approximate totals for each part of the range may now be tabulated(a) Northwest Africa 250 pairs(b) Western Mediterranean 130(c) Central Mediterranean 150(d) Eastern Mediterranean(i) Aegean Crete 850‐1,150 pairs(ii) Cyprus 150–300This gives a grand total of 1,550‐2,000 breeding pairs. Owing to the probable existence of undiscovered colonies not allowed for in the individual estimates, this total may be too small; on the other hand, many of the estimates for Aegean colonies were made fifty or more years ago, since when, on the analogy of the only two colonies in that area about whose history anything is known, there has probably been a decline in numbers. It should be remembered, too, that the size of many colonies has only been guessed. In spite of these uncertainties, however, I would suggest that the total world population of Eleonora's Falcons is under 4,000 birds, about half of which breed in the Aegean and Crete.The most important areas where large colonies perhaps remain to be discovered are the Dodecanese and Algeria. Birds have been recorded in summer from the Tuscan Archipelago (Arrigoni degli Oddi&Damiani 1911, Moltoni 1954), the Ligurian Sea (Giglioli 1889), Pantelleria (Moltoni 1957 a), the Adriatic (Moltoni 1957 b), the Ionian Islands (Reiser 1905) and elsewhere (e.g. Provence, Leveque&Vuilleumier 1958, and even Central Spain, Lilford 1866), and, though most of these records are from the early part of the summer, it is possible that some of them represent hitherto undiscovered breeding populations. There was once a colony at Gibraltar, but this has long since ceased to exist (Bate 1928, on palaeolithic cave remains). Irby (1895) points out that the Rev. John White's “Hobbies”, which he says bred on the Rock, must have been Eleonora's Falcons and in the seventeenth century Eleonora's Falcon bred on the lies ?Hyeres (?Arcussia 1644: 60).SummaryThe known facts about Eleonora's Falcon are brought together, and contributions to existing knowledge made, under the headings Characters, General Habits, Food, Breeding, Breeding Distribution and Numbers, Migration, and Predation. It is shown that the breeding season is from mid‐July to October, that Eleonora's Falcon is a largely crepuscular feeder, that it is a summer visitor to its breeding haunts, and that it is dimorphic. The total world population is estimated to be rather less than