Eurasian blue tit. Parus caeruleus (Warsaw, Poland) Common chiffchaff. Phyllosscospus collybita (Rio Guadarrama, Madrid) Rofous-naped Wren. Campylorhynchus rufinucha (Curu, Costa Rica) Warbling Vireo. Vireo gilvus (Uinta Mountains, Utah, US)