ÉTAT DE SANTÉ DES POUSSINS DE LA MÉSANGE MAGHRÉBINE Cyanistes teneriffae

Some aspects of the ecology of an African Blue Tit population breeding in a lowland Cork Oak Quercus suber woodland in north-eastern Algeria and the impact of parasite load on the body conditions of nestlings were studied during three years (1998 to 2000). The mean clutch size was 6.8 eggs and the mean number of fledged young was 4.5 per nest, thus indicating a fairly good breeding success in that Mediterranean oak woodland. The inventory of ectoparasites in nests and their impact on nestlings showed that 80-100% of nests were infested by mites (Dermanyssus), ticks (Ixodes), diptera (Protocalliphora) and fleas (Ceratophyllus). Moreover, this heavy parasite load seems to have not negatively affected the body parameters of the nestlings (tarsus length, mass at 15 days) and it had only a little effect on mortality. These data show that parents must have strongly invested in parasitized broods to compensate the potential costs of parasite load by increasing feeding frequency and care to nestlings (verified by successful feeding frequency). Our results suggest that the host species shows behavioural defence strategies against pressures by parasite. Finally, Diptera larvae do not seem to have harmed nestlings in the same way than it has been shown for nestlings in Corsica. In this Algerian population the direct impact of parasite larvae on nestlings could not be reported during the three study years.