Cultural conformity and persistence in Dickcissel song are higher in locations in which males show high site fidelity

Dickcissel (Spiza americana) males occupying territories in cropland sites produced songs that were less similar on average to other Dickcissel songs in their neighborhood than did Dickcissels living in grasslands, where conformity to the local vocal culture was higher. Further, Dickcissel vocal culture changed more quickly over time in cropland sites relative to grassland sites. These differences may have resulted from the lower site fidelity we observed in Dickcissel males in cropland sites relative to grassland sites. We expected this link with site fidelity because we hypothesized that conformity to local culture in Oscine songbirds and the persistence of culture over time and space are promoted by habitats that facilitate stable populations. In contrast, sites in which habitat features cause rapid population turnover provide more territory vacancies and so more opportunities for colonization. Colonization should drive cultural change, either through adult colonists importing foreign cultural variants or young colonists making errors as they learn the local song. This potential link between population turnover and cultural stability may apply to animal cultures more broadly and so may be a fruitful area for further research. Besides the link between site fidelity and cultural change over time, we also investigated the possibility that habitats with different levels of site fidelity might show differences in the spatial scale of song similarity. However, we found no evidence of such a difference. Finally, although our conclusions regarding conformity and change in vocal culture were based on many recorded songs, automated assessments of song similarity imprecisely estimated the overall degree of song similarity. Thus, we may have underestimated the strength of the effects of time and distance on song similarity.

FIFTH REPORT OF THE COMMITTEE FOR ECUADORIAN RECORDS IN ORNITHOLOGY (CERO), WITH COMMENTS ON SOME PUBLISHED, UNDOCUMENTED RECORDS

Wepresent new distributional records of birds in Ecuador evaluated by the Committee for Ecuadorian Records in Ornithology (CERO) from November 2017 through June 2019. This report includes two species new to Ecuador (Pelecanoides garnotii, Conirostrum margaritae), five species with first documented country records (Thaumastura cora, Anous minutus, Setophaga pensylvanica, S. virens, Spiza americana), two species with first documented Galapagos records (Oceanodroma hornbyi, Egretta tricolor), remarkable range extensions for 15 species (Amazilia amazilia, Aramus guarauna, Vanellus chilensis, Attagis gayi, Anous stolidus, Sterna hirundo, Thalasseus elegans, T. sandvicensis, Eurypyga helias, Mycteria americana, Plegadis falcinellus, Gampsonyx swainsonii, Rosthramus sociabilis, Glaucidium peruanum, Thlypopsis sordida), new records of 16 rare species (Oressochen jubatus, Spatula cyanoptera, Podiceps major, Stercorarius longicaudus, Larus belcheri, Pelagodroma marina, Oceanodroma markhami, Egretta rufescens, Plegadis ridgwayi, Buteo swainsonii, Megascops koepckeae, Tyrannus albogularis, Setophaga castanea, Dolichonyx oryzivorus, Icterus chrysater, I. galbula) and additional records for 8 species. Finally, we invalidate previous records of Pyrilia pyrilia published in different sources, reject records of six species submitted to CERO, and discuss six previously published, undocumented records that might prove erroneous. CERO revises and updates the country bird list, which currently stands at 1696 species (1642 confirmed and documented; 54 undocumented).