The peregrine falcon (Falco peregrinus) has been affected by persecution, pollution, trade and habitat degradation, but it is considered a flagship conservation success story because of successful reintroductions. However, in the UK there were never formal reintroduction programmes for peregrine falcons, and it appears that UK populationsand specifically the Sussex peregrines of the English south coastrecently recovered from a population crash unassisted. To study this, we obtained samples from contemporary populations in southern England, Ireland, continental Europe, domestic-bred peregrine falcons, and from England prepopulation crash. Using microsatellite and mtDNA control region data, the genetic diversity and structure, signatures of genetic bottlenecks, and potential origin of the Sussex peregrines was investigated. We found low levels of genetic diversity across all peregrine falcon populations, low but significant genetic differentiation among all populations, and a few private alleles, indicating some level of genetic structure in European peregrines. Although we could not pinpoint the origin of the Sussex peregrines, the data suggests that it is not likely to have originated from escaped domestic birds or from adjacent European populations. The results obtained here parallel other studies on peregrines elsewhere showing low genetic diversity but genetic structure. We conclude that not enough time elapsed for genetic erosion to occur due to the population bottleneck, and that at least for the Sussex peregrines there is no need for genetic conservation by wild-take and subsequent captive breeding programmes as long as current protection measures remain in place.

25The peregrine falcon (Falco peregrinus) has been affected by persecution, pollution, trade and 26 habitat degradation, but it is considered a flagship conservation success story because of 27 successful reintroductions. However, in the UK there were never formal reintroduction 28 programmes for peregrine falcons, and it appears that UK populationsand specifically the 29 Sussex peregrines of the English south coastrecently recovered from a population crash 30 unassisted. We obtained samples from contemporary populations in southern England, 31 Ireland, continental Europe, domestic-bred peregrine falcons, and from England pre-32 population crash. Using microsatellite and mtDNA control region data, the genetic diversity 33 and structure, signatures of genetic bottlenecks, and potential origin of the Sussex peregrines 34 was investigated. We found low levels of genetic diversity across all peregrine falcon 35 populations, low but significant genetic differentiation among all populations, and a few private 36 alleles, indicating some level of genetic structure in European peregrines. Although we could 37 not pinpoint the origin of the Sussex peregrines, the data suggests that it is not likely to have 38 originated from escaped domestic birds or from adjacent European populations. The results 39 obtained here parallel other studies on peregrines elsewhere showing low genetic diversity 40 but genetic structure. We conclude that not enough time elapsed for genetic erosion to occur 41 due to the population bottleneck, and that at least for the Sussex peregrines there is no need 42 for genetic conservation by wild-take and subsequent captive breeding programmes as long 43 as current protection measures remain in place.44 45