Immunocompetence and the prevalence of haematozoan parasites in two long-lived seabirds

Abstract

Factors affecting infection of birds by haemoparasites have received much attention during the last decade, since blood parasites can affect fitness components (Merino et al. 2000), community structure (Minchella & Scott 1991, Hudson & Greenman 1998) and evolution (Hamilton & Zuk 1982, Howard 1991). Infection can be influenced by three factors (a) presence of the appropriate vector (Bennett et al. 1992, Little & Earlé 1995, Piersma 1997, Figuerola 1999, Sol et al. 2000, Jovani et al. 2001), (b) presence of the right hostparasite assemblage (Earlé & Underhill 1993, Little& Earlé 1994, Stewart et al. 1997, Blanco et al. 1998, Jones & Shellam 1999) since avian haematozoa are specific to host families or subfamilies (Ricklefs 1992), and (c) immunological capabilities of the host (Ricklefs 1992, Figuerola et al. 1996, Tella et al. 1999). Here we compare the competence of the immune system of European Storm-petrels Hydrobates pelagicus with that of syntopically breeding Mediterranean Yellowlegged Gulls Larus argentatus michahellis