BackgroundThe low prevalence of blood parasites in some bird species may be related to the habitats they frequent, the inexistence of the right host-parasite assemblage or the immunological capacity of the host. Here, we assess the parasite load of breeding populations of Eleonora’s falcon (Falco eleonorae), a medium-sized long-distance migratory raptor that breeds on small isolated islets throughout the Mediterranean basin and overwinters in inland Madagascar.MethodsWe examined the prevalence and genetic diversity of the blood parasites belonging to the genera Plasmodium, Haemoproteus and Leucocytozoon in Eleonora’s falcon nestlings from five colonies and in adults from two colonies from nesting sites distributed throughout most of the species’ breeding range.ResultsNone of the 282 nestlings analysed were infected by blood parasites; on the other hand, the lineages of Plasmodium, Haemoproteus and Leucocytozoon were all found to infect adults. Our results support the idea of no local transmission of vector-borne parasites in marine habitats. Adult Eleonora’s falcons thus may be infected by parasites when on migration or in their wintering areas.ConclusionThe characteristics of marine environments with a lack of appropriate vectors may thus be the key factor determining the absence of local transmission of blood parasites. By comparing the parasite lineages isolated in this species with those previously found in other birds we were able to infer the most likely areas for the transmission of the various parasite lineages.

SummaryThis is the first study reporting the population status and reproductive biology of the Eleonora’s Falcon in Algeria. To determine the status, nest site selection, and breeding parameters, data were collected at Chetaïbi, north-east Algeria in 2010 and 2012. During this period, the number of breeding pairs decreased from 130 to 100, which represents an annual decrease rate of 12.29%. The mean clutch size was 2.6 ± 0.5 (n = 90) and 2.9 ± 0.4 (n = 34) in 2010 and 2012, respectively. Clutches displayed a low rate of hatching (56% and 41%) and productivity decreased from 0.8 chicks/nest in 2010 to 0.4 chicks/nest in 2012. Breeding outcome and productivity were negatively related to sun exposure and were weakly linked to hatching date in 2012 but not in 2010. Although fluctuations in population size have been reported across the species’ breeding range, our results suggest that the Algerian population of Eleonora’s Falcon is experiencing a sharp decline in recent times that also involves the near extinction of a small neighbouring colony. Apart from the effect of environmental factors on breeding performance, this negative population trend is likely to be explained by increasing anthropogenic pressures associated with an upsurge of recreational activities on and around the island as well as the introduction of mammal predators. Active management across the country is urgently needed to mitigate such pressures and ensure the long-term persistence of a bird listed as a priority species for conservation.

Global changes are inducing migratory birds to advance their annual cycle. However, changes in the time of arrival at their breeding grounds have significant fitness implications. This study aims to identify factors affecting the variability in arrival time of migratory white storks (Ciconia ciconia L.) and to determine if their arrival at North African breeding grounds is occurring earlier. We monitored the arrival of ringed white storks at a breeding colony in Algeria between 2017 and 2021. The birds arrived at this breeding colony over an extended period spanning mid-December to mid-June each year. We found that stork arrival was negatively correlated with age and year of arrival, with older birds arriving first and stragglers consisting of first- and second-year birds arriving later. Notably, arrivals have been shifting toward earlier dates at this breeding ground. Furthermore, cluster analysis of arrival dates for each age-class revealed two distinct groups comprising early and late arrivals. Advancement of the annual cycle of the North African white stork population is consistent with phenological shifts induced by global changes and that have been recorded globally in a wide range of living organisms.

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