The Ecology of Tick Parasitism on Densely Nesting Peruvian Seabirds

Abstract

Densely nesting Guanay Cormorants (Phalacrocorax bougainvillii), Peruvian Booby (Sula variegata), and Peruvian Brown Pelican (Pelecanus occidentalis thagus) deserted eggs and young in response to high densities of argasid ticks (Ornithodoros amblus). Alternative causes of desertion such as human disturbance, predation, disease, heat, and food shortage did not fit the evidence. Tick predators were less effective at controlling ticks than were frequent human harvestings of guano. A review of the avian and medical entomological literature indicates that ticks and other ectoparasites may be strong determinants of nesting success and of nest structure and duration of use.

Green nesting material has a function in mate attraction in the European starling

“…The 'nest protection' hypothesis suggests that volatile compounds in green nest material have biocidal effects on parasites and pathogens (Widmann 1922;Johnston & Hardy 1962;Wimberger 1984;Clark 1991). In many species parasites and pathogens lead to nest desertion, egg spoilage, and reduced growth and survival of nestlings (Feare 1976;Hitchner 1980;Duffy 1983;Hesse 1985;Møller 1990;Loye & Zuk 1991;Richner et al 1993;Oppliger et al 1994;Merino & Potti 1995). A finding consistent with this hypothesis is that species that frequently reuse their nests over successive years and that may suffer more from wintering nest ectoparasites use fresh green nest material more often than species that build a new nest each year (Wimberger 1984;Clark & Mason 1985).…”

Censo de Ornithodoros amblus Chamberlin (Acarina: Argasidae) en la isla Mazorca, Lima, Perú

“…Se distribuye desde la Isla Lobos de Tierra en Lambayeque (06°28´ LS, 80°50´ LW) hasta las Islas Ballestas, en el departamento de Ica (13°44Ĺ S, 76°24´ LW) y ha sido colectada en diecisiete localidades en cinco departamentos del Perú 6,7 . Inclusive ha sido colectado en las costas norte de Chile en los nidos de gaviotas del género Larus spp.…”

“…Se señala como método de muestreo para O. amblus, la colecta de cucharones de guano y piedras para el censo de adultos y ninfas de esta garrapata 6,9 . Esta garrapata pasa un periodo de tiempo de su ciclo de vida sumamente corto sobre el ave hospedera (3,72% a 6,61%), mayormente en la etapa larval 5 .…”

Ferruginous Pygmy-Owl (Glaucidium brasilianum) and Eastern Screech-Owl (Megascopes asio): New Hosts for Philornis mimicola (Diptera: Muscidae) and Ornithodoros concanensis (Acari: Argasidae)

“…In describing the effects of parasitism of botfly larvae on nestling beechey jays (Gymnorhinus cyanocephalus), Winterstein and Raitt (1983) noted that parasitized nestlings could not hold their head up or stand by day 20, and ''They suffered from severe spasms that caused their bodies to shake continuously during the measurement period.'' Ticks of the genus Ornithodoros are hematophagous parasites that commonly feed on adult birds and nidicolous nestlings (Duffy, 1983;Keirans et al, 1992;Ramos et al, 2001;Norcross and Bolen, 2002). Nest desertion was attributed to high infestation of Ornithodorus on gua-nay cormorants (Phalacrocoras bougainvillii), Peruvian boobys (Sula variegata), and brown pelicans (Pelecanus occidentalis) (King et al, 1977a, b;Duffy, 1983;Wilkinson et al, 1994).…”

“…Ticks of the genus Ornithodoros are hematophagous parasites that commonly feed on adult birds and nidicolous nestlings (Duffy, 1983;Keirans et al, 1992;Ramos et al, 2001;Norcross and Bolen, 2002). Nest desertion was attributed to high infestation of Ornithodorus on gua-nay cormorants (Phalacrocoras bougainvillii), Peruvian boobys (Sula variegata), and brown pelicans (Pelecanus occidentalis) (King et al, 1977a, b;Duffy, 1983;Wilkinson et al, 1994). Results from a study of cattle egrets (Bubulcus ibis) suggest that infestations exceeding 24 ticks (Argas robertisi)/chick can cause nestling mortality (McKilligan, 1996).…”