Arne J. Lesterhuis’s scientific contributions

The avifauna of Ñeembucú is currently one of the most understudied within Paraguay, with the true diversity present likely to be greatly underrepresented. In the interests of contributing an up-to-date species list for the department, we present 46 new documented bird records, as well as a list of all 330 documented birds within the department. We also provide documentation for 39 additional species that have been previously reported in the department but without supporting evidence. Many of the newly documented species are not surprising and highlight the substantial lack of robust ornthological work occurring in the Ñeembucú department currently.

Five cases of bird entrapment in the social webs of Parawixia bistriata (Araneidae: Araneinae: Araneini) are reported from the Paraguayan Chaco. These are the first reports of avian entrap-ment for this species, and add one new family (Thraupidae) and four new species to the global biological inventory of bird species caught in spider webs. The wing chord and masses of the largest two species, Tyrannus melancholicus (Tyrannidae) and Columbina picui (Columbidae) greatly exceed the maximum reported for other Neotropical species. It is argued that possibility of mortality from entrapment is not merely a matter of mor-phometry as has been previously suggested, but includes other factors such as spider species, silk type, and area of entangle-ment. A possible temporal relationship between the growth and life history of this spider and the potential for entrapment is postulated. It is proposed that increased deforestation in the Paraguayan Chaco could lead to an increase in avian entrapment in this webs of this species.