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).

Effect of Foraging and Nest Defense tradeoffs on the Reproductive Success of Wood Storks (Mycteria americana)

In many species of birds, parental care is provided by both parents to maximize offspring survival, and there may be important trade-offs between maximizing food gathering and nest protection during the nesting period. The role of parental care in determining reproductive success was investigated in Wood Storks (Mycteria americana), and specifically how the trade-off between frequency and duration of foraging trips, and nest protection has contributed to the nesting outcome. Parental behavior of 85 pairs of Wood Storks was monitored throughout the nesting season in two breeding colonies in Palm Beach County, Florida. Wood Storks have gradually increased the frequency, but not the duration, of foraging trips as chicks developed. The ratio of hatchlings to fledglings was positively associated with the frequency of foraging trips during late chick development. Intra-specific aggressions resulting in nest takeovers have affected 32 % of the nests under study. Occurrence of nest takeovers have been higher for later-breeding pairs, and was happened primarily in the first few weeks of incubation, but was not affected by the degree of joint nest attendance of both parents. These results establish a functional link between parental effort and reproductive outcome in Wood Storks, and highlight the importance of frequent foraging trips, but not nest attendance, by parents.

Blood parasites infecting the Hoatzin (Opisthocomus hoazin), a unique neotropical folivorous bird

The Hoatzin (Opisthocomus hoazin) is the only extant member of the order Opisthocomiformes. This unique South American bird lives in the riparian lowland vegetation characteristic of the Amazon and Orinoco basins. Hoatzins nest in communal social units close to water bodies; they are strictly folivores being the only bird with pregastric fermentation in the crop. Because of the complex logistics involved in capturing this bird, there is a knowledge gap on its parasites. This study documents two distant lineages of haemosporidian parasites (Plasmodium spp.) in a juvenile and two adults sampled in the Cojedes state, Venezuela. Although negative by microscopy, the parasite identification was possible by using molecular methods. We estimated the phylogenetic relationships on the parasite cytochrome b (cytb, 480 bp) gene and the mitochondrial DNA. We found one of the parasites lineages in two individuals (nestling and adult), and the corresponding fragment of cytb was identical to a one found in Wood Stork (Mycteria americana) from Brazil. The other lineage, found in an adult, has an identity of 469 out of 478 bp (98%) with Plasmodium sp. GAL-2012 (isolate THAMB08) from Brazil. Although a morphological description of these parasites was not possible, this is the first molecular study focusing on Hoatzin haemosporidian parasites and the first documentation of Plasmodium infections in the Hoatzin from Venezuela. Furthermore, we reported microfilaria in two adults as well as hematological parameters for six individuals. Information on hematological parameters could contribute to establishing the necessary baseline to detect underlying conditions, such as infections, in this bird species.

Joint seasonality in geographic and ecological spaces, illustrated with a partially migratory bird

As most species live in seasonal environments, considering varying conditions is essential to understand species dynamics in both geographic and ecological spaces. Both resident and migratory species need to contend with seasonality, and balance settling in favorable areas with tracking favorable environmental conditions during the year. We present an exploratory framework to jointly investigate a species’ niche in geographic and ecological spaces, applied to wood storks (Mycteria americana), which are partially migratory wading birds, in the southeastern U.S. We concurrently described monthly geographic distributions and climatic niches based on temperature and precipitation. Geographic distributions of wood storks were more similar throughout the year than were climatic niches, suggesting that birds stay within specific areas seasonally, rather than tracking areas of similar climate. However, wood storks expressed consistent selection of warm areas during the winter, and wet areas during the summer, indicating that the selection of seasonal ranges may be directly related to environmental conditions across the entire range. Our flexible framework, which simultaneously considered geographic and ecological spaces, suggested that tracking climate alone did not explain seasonal distributions of wood storks in breeding and non-breeding areas.