Abstract We collected data during three consecutive breeding seasons (2015-2018) to assess the effects of Taphropiestes plaumanni (Coleoptera: Cavognathidae) on its bird hosts in a native forest of central eastern Argentina. We monitored bird nests for T. plaumanni in 207 nests of Masked Gnatcatcher (Polioptila dumicola, Polioptilidae), 302 nests of Vermilion Flycatcher (Pyrocephalus rubinus, Tyrannidae), 55 nests of Blue-and-yellow Tanager (Pipraeidea bonariensis, Thraupidae), 99 nests of Small-billed Elaenia (Elaenia parvirostris, Tyrannidae), 23 nests of Yellow-browed Tyrant (Satrapa icterophrys, Tyrannidae), and other passerine species nesting in the same forest patches. We found 13 nests in which nestlings showed evidences of parasitism of which four species are new hosts for this parasite (Vermilion Flycatcher, Masked Gnatcatcher, Red-crested Cardinal Paroaria coronata, Thraupidae, and Fork-tailed Flycatcher Tyrannus savana). Skin lesions caused by T. plaumanni larvae consisted in lacerations and crusts on the belly and chest areas. In one parasitized nest of Vermilion Flycatcher and one parasitized nest of Masked Gnatcatcher we observed the death of nestlings after being parasitized. This study adds new species to the list of hosts for this parasite, reports nestling skin lesions in nests with T. plaumanni parasitism, and reports for the first time the death of parasitized nestlings. 20152018 2015 2018 (2015-2018 Coleoptera (Coleoptera Cavognathidae Argentina T 20 Polioptila dumicola Polioptilidae, Polioptilidae , Polioptilidae) 30 Pyrocephalus rubinus Tyrannidae, Tyrannidae Tyrannidae) 5 Blueandyellow Blue yellow Pipraeidea bonariensis Thraupidae Thraupidae) 9 Smallbilled Small billed parvirostris 2 Yellowbrowed Yellow browed Satrapa icterophrys patches 1 Redcrested Red crested coronata Forktailed Fork tailed savana. savana . savana) areas 2015201 201 (2015-201 3 201520 (2015-20 20152 (2015-2 (2015- (2015 (201 (20 (2 (

Urbanization processes alter natural habitats and birds respond differently depending on the degree of disturbance in the environment. In this contribution we analyze the effect of habitat alteration on the diversity and evenness of bird communities in Cariló, Buenos Aires province, Argentina. Like many seaside localities on the sea coast of Buenos Aires, natural habitats of Cariló have been almost completely replaced by the replacement of natural habitats of dunes with several species of pine trees. We counted birds seasonally in transect located in relics of peripherical natural environments of Cariló and in urban areas with different degrees of alteration. We found out that in the natural environment the diversity and evenness indexes were higher in relation to the altered environments and that, within this environment replaced by pine trees, the diversity of birds was lower in the environments with less disturbance. We attribute this last result to the largest area of parks and ornate gardens that characterize the downtown area of the city, that allows a greater environment heterogeneity that would be favoring birds. Faced with this scenario of replacement of natural habitat with pine plantations, we highlight the local inhabitants’ efforts to maintain extensive large area of parks and ornate gardens. However, our results show a negative effect of this habitat replacement; therefore, we recommend the authorities to come up with strategic urbanization designs that do not harm the complex structure of natural ecosystems and the birds that inhabit them.

Los procesos de urbanización alteran los hábitats naturales y las aves responden de manera diferente según el grado de disturbio en el ambiente. En este estudio analizamos el efecto de la alteración del hábitat en la diversidad y equidad de la comunidad de aves de Cariló, provincia de Buenos Aires, Argentina. Como muchas localidades balnearias de la costa marítima de Buenos Aires, en Cariló se han reemplazado casi por completo los hábitats naturales forestando las dunas con varias especies de pinos. Se realizaron conteo de aves estacionalmente en transectas ubicadas en relictos de ambientes naturales periféricos a Cariló y en zonas urbanas con distinto grado de alteración. En el ambiente natural los índices de diversidad y equidad fueron mayores en relación a los ambientes alterados y, dentro de este ambiente reemplazado por pinos, la diversidad de aves fue menor en los ambientes con menor grado de disturbio. Atribuimos este último resultado a que los sectores más urbanizados y céntricos, con más edificaciones y tránsito de personas y vehículos, son los que cuentan con más áreas de parques y jardines ornamentados, permitiendo una mayor heterogeneidad del paisaje que favorecería a las aves. Frente a este escenario de reemplazo de hábitat natural por plantaciones de pinos, destacamos los esfuerzos de los habitantes y gobernantes de Cariló por mantener extensas superficies parquizadas. No obstante, nuestros resultados indican un efecto negativo de este reemplazo, por lo que recomendamos a las autoridades contar con diseños estratégicos de urbanización que no perjudiquen la compleja estructura de los ecosistemas naturales ni de las aves que los habitan.