If humans aim to sustainably coexist with wildlife, we must understand how our activity impacts the communication systems of urban animal populations. We know much about the effects of anthropogenic noise on bird song, but relatively little about how avian visual signals are affected by urbanization. Such an effect may occur if urbanization alters the food available to species with color based on carotenoids, which they must obtain from their diet. Over 3 years, we compared a comprehensive suite of visual signals in male and female Northern Cardinals (Cardinalis cardinalis) in a rural and an urban population. We predicted that urban birds would have enhanced carotenoid-based signals as they likely have access to more carotenoids from invasive plants that thrive in cities. We used reflectance spectrometry, digital image analyses, and avian visual models to quantify hue, saturation, and brightness of chest (male), underwing (female), and bill (male and female) signals. Compared to rural males, urban males had redder chest feathers in 1 year and redder bills in every year. Urban females had more saturated underwing color than rural females in every year. These color differences were sufficient to be distinguished by the avian visual system. Female bill color did not vary between sites. Interestingly, urban birds had significantly reduced mass-related body condition compared to rural birds. Thus, urban males and females can display enhanced carotenoid-based signals despite being in relatively poor condition. We suggest that urban birds have more access to carotenoids from invasive honeysuckle (Lonicera spp.) than rural birds. This color enhancement could affect the information content of the signals and the dynamics of the social and mating systems. These results stand in stark contrast to the predominant trend of decreased color in urban birds and highlight the complex and varied potential effects of urbanization on animal communication.

Si los humanos pretenden coexistir con la vida silvestre, debemos entender cómo nuestras actividades impactan los sistemas de comunicación de poblaciones animales urbanas. Ya sabemos bastante acerca de los efectos del ruido antropogénico en el canto de las aves pero se conoce relativamente poco acerca de cómo las señales visuales aviares son afectadas por la urbanización. Este efecto podría ocurrir si la urbanización altera la alimentación de la que dispone la especie cuyo color se basa en los carotenoides, que deben obtener de su dieta. Durante 3 años comparamos un conjunto completo de señales visuales en machos y hembras de cardenal norteño (Cardinalis cardinalis) de poblaciones rurales y urbanas. Nuestra predicción fue que las aves urbanas iban a mostrar señales más fuertes basadas en carotenoides, ya que tienen acceso a mayor cantidad de carotenoides provenientes de plantas invasoras que proliferan en las ciudades. Usamos espectrometría de reflectancia, análisis de imagen digital y modelos visuales aviares para cuantificar el tono, la saturación y el brillo de las señales del pecho (machos), la parte inferior del ala (hembras) y el pico (machos y hembras). Comparados con los machos de zonas rurales, los machos de zonas urbanas tenían más rojas las plumas del pecho en un año y el pico más rojo en cada año. Las hembras de zonas urbanas tenían mayor saturación de color en la parte inferior del ala que las hembras de zonas rurales cada año. Estas diferencias de color eran suficientes como para ser distinguidas por el sistema visual de las aves. El color de pico de las hembras no varió entre sitios. De manera interesante, las aves urbanas tienen significativamente menos condición corporal relacionada con la masa que las aves rurales. Así, tanto machos como hembras de zonas urbanas pueden desplegar señales basadas en carotenoides a pesar de estar en relativamente peor condición que las aves rurales. Sugerimos que las aves urbanas tienen mayor acceso a los carotenoides a través de la madreselva invasora (Lonicera spp), que las aves rurales. Este incremento de color podría afectar el contenido de la información de las señales y las dinámicas de los sistemas sociales y reproductivos. Estos resultados contrastan con la tendencia general de que las aves urbanas tienen menos color que las rurales y resaltan los potenciales efectos complejos y variados de la urbanización en la comunicación animal.

Palabras clave: color de pico, color de plumaje, espectrometría de reflectancia, modelo visual aviar, urbanización.

Red-ruffed Fruitcrow (Pyroderus scutatus scutatus) occurs in humid forests of Brazil, Paraguay, and Argentina. The bird has disappeared from many regions of Brazil due to deforestation but is still found in well-preserved forests as well as fragments surrounding large urban areas. The reproduction of the P. s. scutatus subspecies is not well known, with only 1 nest described. Given this scenario, we provide another nest description and information on this subspecies' reproduction and chicks, and document insect and small vertebrate feeding at a location near the largest urban area in South America. This record was made in 2018, in an Atlantic Forest reserve next to the city of São Paulo. We found 2 large chicks at a nest that differs from a previously described nest in having a simpler structure. Our record is remarkable because this nest was found in the degraded area of a forest fragment close to the large urban area, which is very different from the well-preserved areas of Atlantic Forest where the previously known nest was found. Since this reserve is close to a continuous and well-preserved region of Atlantic Forest, and has areas that are in good condition, we speculate that the location of this nest may have been chosen due to an available food supply. The discovery of this nest highlights the importance of forest fragments for the conservation of this cotingid.

O pavó (Pyroderus scutatus scutatus) ocorre nas matas úmidas do Brasil, Paraguai e Argentina. Desapareceu de muitas regiões do sudeste do Brasil devido ao desmatamento, mas ainda é encontrada tanto em regiões florestais preservadas, como fragmentos do entorno de grandes áreas urbanas. A reprodução do P. s. scutatus é pouco conhecida, tendo apenas um ninho descrito. Com base neste cenário, apresentamos a descrição de um novo ninho, informações sobre reprodução, filhotes e alimentação de insetos e pequenos vertebrados dessa subespécie em uma localidade próxima da maior área urbana da América do Sul. O registro foi feito em 2018, em uma reserva de Mata Atlântica ao lado da cidade de São Paulo. Encontramos dois filhotes grandes em um ninho diferente de um anterior conhecido, por ter uma estrutura mais simples. Nosso registro é notável porque este ninho foi encontrado na área degradada de um fragmento florestal próximo da área urbana, bem diferente das áreas bem preservadas de Mata Atlântica onde os ninhos anteriormente conhecidos foram encontrados. Pela reserva estar próxima de uma região contínua e bem preservada da Mata Atlântica e ter áreas em melhor estado de conservação, especulamos de que o local pode ter sido escolhido devido a oferta de alimentos disponíveis. A descoberta deste ninho mostra o potencial dos fragmentos florestais para a conservação desta espécie de cotingídeo.

Palavras-chave: Brasil, comportamento, Cotingidae, história natural, Mata Atlântica.

Studies on the migratory behavior of songbirds are important to inform full annual cycle conservation. We remotely tracked the early fall migratory movements of both juvenile and adult Savannah Sparrows (Passerculus sandwichensis) that were tagged on their natal/breeding territories in southwestern Ontario, Canada, where the Motus Wildlife Tracking System has the highest density of automated receivers in North America. Our primary aims were to describe and compare adult and juvenile migratory movements during the early part of migration, compare frequency of detection of juveniles versus adults as a proxy for minimum apparent survival, and describe potential migration routes and overwintering areas. Juveniles initiated migration approximately a month earlier than adults. Both juveniles and adults typically made their first migratory flight in a southwest direction, but some juveniles displayed subsequent exploratory movements that were not in a southwest direction, potentially to collect information for next year's breeding site selection. Detection rates early in migration were similar, but low, for adults and juveniles (34% and 39% respectively), suggesting that juveniles that had survived the fledgling period likely did not experience high mortality during the subsequent 2 months prior to their fall migration. Long-distance detections of 2 adults preliminarily suggest that individuals from this southern Ontario breeding region may travel west of the Appalachian Mountains along the Mississippi flyway during fall migration. Our study aligns with previously reported patterns of age-specific migratory behavior from other Savannah Sparrow populations and contributes to our overall understanding of the migratory ecology of this species.

Los estudios de comportamiento de ave migratorias son importantes para conocer su ciclo anual completo de conservación. Monitoreamos de manera remota los movimientos migratorios de otoño temprano tanto de juveniles como de adultos de gorrión Passerculus sandwichensis que fueron marcados en sus territorios natales/reproductivos en el sudoeste de Ontario, Canadá, donde el Sistema de Monitoreo de Vida Silvestre Motus tiene la mayor densidad de receptores automáticos de Norteamérica. Nuestros objetivos primarios fueron describir y comparar los movimientos migratorios de adultos y juveniles durante la parte inicial de la migración, comparar la frecuencia de detección de juveniles versus de adultos como proxy de la sobrevivencia aparente mínima así como describir potenciales rutas migratorias y áreas de hibernación. Los juveniles iniciaron la migración aproximadamente un mes antes que los adultos. Tanto juveniles como adultos típicamente hicieron su primer vuelo migratorio en dirección sudoeste, aunque algunos juveniles desplegaron movimientos exploratorios posteriores que no eran en dirección sudoeste, posiblemente para colectar información para la selección del sitio de reproducción del año siguiente. Las tasas de detección de migración temprana fueron similares, aunque bajas, para adultos y juveniles (respectivamente 34% y 39%), lo que sugiere que los juveniles que sobrevivieron a su etapa de volantones posiblemente no tuvieron una alta mortalidad durante los 2 meses que siguieron a la migración otoñal. La detección a larga distancia de 2 adultos sugiere preliminarmente que los individuos de esta región de reproducción al sur de Ontario podrían viajar al oeste de las Appalachian Mountains a lo largo del río Mississippi durante la migración de otoño. Nuestro estudio se alinea con patrones previamente reportados de patrones migratorios específicos por edad de otras poblaciones de gorrión Passerculus sandwichensis y contribuyen al entendimiento general de la ecología migratoria de esta especie.

Palabras clave: aves canoras, migración otoñal, orientación migratoria, telemetría, tiempo migratorio.

The breeding success of birds can be influenced by habitat characteristics (e.g., vegetation cover and weather), species interactions (e.g., predation and parasitism), and species' intrinsic factors (e.g., behavior and nest structure and location). Information about breeding traits is crucial to better understand population dynamics. Here, we performed probabilistic modeling of Dark-billed Cuckoo (Coccyzus melacoryphus) nests to assess the effect of habitat and nest parameters (e.g., time, season, nest site, clutch size, and brood size) on daily survival. We carried out this study in northeastern Brazil during the rainy seasons (Jan–Jun) of 2017 and 2018. To assess daily nest survival and the effects of habitat and nest covariates, we located and monitored 61 nests every 2–3 d following the Mayfield protocol and analyzed these data using information-theoretic model-selection program MARK. We found a higher daily survival during incubation than during the nestling period, with a positive effect of clutch and brood size. Models constrained by the covariates year, breeding season time, species of plant supporting the nest, nest height, and nest concealment were not supported. Success for the incubation and nestling periods were 19% and 11% by Mayfield, and 33% and 4% by MARK model averaging, corresponding to a total nest-period success of 2.1% and 1.5% for each method, respectively. The positive relationship found between survival and clutch size for the Dark-billed Cuckoo seldom occurs in birds from tropical regions. As expected for tropical birds, we recorded high predation and low breeding success.

O sucesso reprodutivo de aves pode ser influenciado por características do habitat (como cobertura vegetal e clima), interação de espécies (predação e parasitismo) e fatores intrínsecos da espécie (comportamento, estrutura e localização do ninho). Informações sobre as características de reprodução das aves são cruciais para entender melhor a dinâmica das populações. Executamos modelagens probabilísticas e estimamos a sobrevivência do ninho do Coccyzus melacoryphus para verificar o efeito dos parâmetros do habitat e dos ninhos (tempo, estação reprodutiva, local do ninho, tamanho da postura e da ninhada). Realizamos o estudo no Nordeste do Brasil durante as estações chuvosas (janeiro–junho) de 2017 e 2018. Para estimar a sobrevivência dos ninhos, os efeitos do habitat e das covariáveis do ninho, localizamos e monitoramos 61 ninhos em intervalos de 2–3 dias seguindo o protocolo de Mayfield e analisamos os dados através do programa de seleção de modelos probabilísticos MARK. A modelagem mostrou maior sobrevivência durante a incubação quando comparado ao período de filhotes, com efeito positivo do tamanho da postura e da ninhada. Encontramos uma maior sobrevivência diária durante o período de incubação do que o período de ninhego, com um efeito positivo do tamanho da postura e da ninhada. Os modelos limitados pelas covariáveis ano, época da estação reprodutiva, suporte da planta, altura e camuflagem do ninho não foram suportados. O sucesso para os períodos de incubação e ninhego foi de 19% e 11% por Mayfield, 33% e 4% pela média do modelo MARK, correspondendo a um sucesso reprodutivo total de 2,1% e 1,5% para cada método, respectivamente. A relação positiva encontrada entre a sobrevivência e o tamanho da postura para o C. melacoryphus raramente ocorre em aves de regiões tropicais. Como esperado para aves tropicais, registramos alta predação e baixo sucesso reprodutivo.

The song of the Seaside Sparrow (Ammospiza maritima) is a 2-phrase song, with a complex introduction and a terminal buzz, that has previously been shown to exhibit some interindividual and between-population variation. Comparatively little is known about geographic variation in Seaside Sparrow song, or if song structure corresponds to either subspecies or coastal lineages (Atlantic vs. Gulf of Mexico). We collected recordings from all recognized subspecies throughout the species' range to ask whether variation in Seaside Sparrow song corresponds with subspecies or coastal lineage designation. Coastal lineage groups of Seaside Sparrow varied significantly with respect to a number of frequency and temporal characters. Most notably, frequencies of the introductory syllable within the first phrase were higher for the Gulf coast lineage whereas frequency measures for the terminal syllable within the first phrase were lower. Additionally, the number of syllables in the first phrase was greater within the Gulf coast group. A multiple logistic regression analysis using 6 song measures classified coastal lineage groups with 96% accuracy but failed to differentiate 7 subspecies for which we had sufficient data.

El canto del gorrión Ammospiza maritima es un canto de 2 frases, con una introducción compleja y un zumbido final, con cierta variación interindividual y entre poblaciones mostrada anteriormente. En comparación a lo anterior, se conoce poco de la variación geográfica de su canto o si la estructura del canto corresponde a subespecies o a linajes costeros (del Atlántico vs el Golfo de México). Recopilamos grabaciones de todas las subespecies reconocidas a través del rango de la especie para investigar si la variación del canto de este gorrión corresponde con subespecies o con denominaciones de linajes costeros. Los linajes de grupos costeros de gorriones variaron significativamente con respecto al número de frecuencia y caracteres temporales. Notablemente, las frecuencias de la sílaba introductoria en la primera oración eran más altas para el linaje costero del Golfo mientras que las medidas de frecuencia de la sílaba terminal dentro de la primera oración eran más bajas. Además, el número de sílabas de la primera frase era mayor en el grupo costero del Golfo. Un análisis de regresión múltiple usando 6 medidas de canto clasificados en grupos de linajes costeros con 96% de precisión pero falló en distinguir 7 subespecies que tenían datos insuficientes.

Palabras clave: acústica, aves canoras, frase, frecuencia, sílaba, subespecie.

Tree Swallows (Tachycineta bicolor) are migratory aerial insectivores that breed across North America and have experienced long-term population declines. Although the mechanisms behind these declines have proved difficult to identify, emerging methods for studying migration staging areas could provide new insights. Tree Swallows congregate in staging roosts during fall migration, gathering at sunset to roost overnight, then leaving at sunrise to feed or continue their migration south. Using a particularly large roost site in Connecticut, USA, we used NEXRAD Level III data to calculate metrics of reflectivity corresponding to snapshots of morning roost size each day. Using these metrics as measures of relative abundance, we tested predictions about the effects of wind and date on daily roost size and day-to-day changes in relative abundance. We found that radar reflectivity around the roost decreased with higher wind speeds during the morning emergence and when wind speeds were high the previous day. In addition, we found a temporal pattern of roost abundance corresponding to a peak of migration around the end of August for this stopover site. Our results provide insight into the sensitivity of Tree Swallow responses to wind conditions and lay the groundwork for future studies using NEXRAD to examine links between migratory behavior and declines in swallow populations.

Las golondrinas Tachycineta bicolor son aves migratorias insectívoras que se reproducen a lo largo de Norteamérica y han sufrido declives poblacionales a largo plazo. Aunque los mecanismos de estos declives ha sido difíciles de identificar, métodos emergentes para estudiar sitios de descanso migratorio podrían dar nuevas perspectivas. Estas golondrinas se congregan en dormideros temporales durante la migración de otoño, reuniéndose al atardecer para pasar juntas la noche, posteriormente dejando el sitio al amanecer para alimentarse o continuar su migración hacia el sur. Utilizando un dormidero particularmente grande en Connecticut, USA, utilizamos datos NEXRAD Level III para calcular métricas de reflectividad que correspondían a instantáneas diarias del tamaño del dormidero matutino. Usando esos datos como medida de abundancia relativa, probamos las predicciones acerca de los efectos del viento y la fecha en el tamaño diario del dormidero y cambios diarios en la abundancia relativa. Encontramos que la reflectividad del radar alrededor del dormidero decrecía con velocidades mayores de vientos durante las emergencias y cuando las velocidades de vientos eran mayores el día anterior. Además, encontramos un patrón temporal en la abundancia del dormidero correspondiente al pico migratorio alrededor de finales de agosto para este sitio de parada. Nuestros resultados brindan una visión de la sensibilidad de la respuesta de la golondrina Tachycineta bicolor a las condiciones de viento y sienta las bases para futuros estudios utilizando NEXRAD para examinar los vínculos entre el comportamiento migratorio y los declives poblacionales de golondrinas.

Palabras clave: aeroecología, insectívoros aéreos, parada, radar, dormidero.

Nest site selection is critical for reproductive success in birds. Several bird species including Barn Swallow (Hirundo rustica gutturalis) typically nest near human settlements, presumably because this reduces their risk of predation. Here, we investigated the nesting habits of Barn Swallows in South Korea. We predicted that abandoned houses would not be chosen even if these houses provided similar nesting conditions compared to occupied houses. We conducted surveys across South Korea and recorded human occupancy, house structure, the number of active and old nests, and the deterioration condition of houses. Among the recorded active nests, 95% were located in inhabited houses (n = 38), whereas only 5% were observed in abandoned houses (n = 2). Interestingly, human presence was a significant factor in the occurrence of active nests, whereas house structure had no appreciable effect. Among the nest site characteristics, the number of old nests was significantly higher in inhabited houses than in abandoned houses. Further, ∼97% of inhabited houses were not damaged, whereas 50% of the abandoned houses were damaged, potentially affecting the nesting site selection of Barn Swallows. Our results are consistent with our hypothesis that Barn Swallows prefer to nest in human-inhabited houses. As house structures suitable for nesting are reduced due to rapid urbanization, and as swallow nests are actively eliminated by human residents, the reproductive success of Barn Swallows in South Korea can be significantly reduced.

La selección de sitio de anidación es crítica para el éxito reproductivo de las aves. Varias especies de aves, incluyendo golondrinas Hirundo rustica gutturalis, anidan cerca de asentamientos humanos, posiblemente porque esto reduce su riesgo de depredación. Aquí estudiamos los hábitos de anidamiento de golondrinas Hirundo rustica gutturalis en Corea del Sur. Predecimos que las casas abandonadas no van a ser elegidas, aun cuando esas casas ofrecen condiciones de anidamiento similares a las casas habitadas. Hicimos búsquedas en Corea del Sur y registramos ocupación humana, estructura de la casa, número de nidos activos y la condición de deterioro de la casa. De los nidos activos registrados, 95% se encontraban en casas habitadas (n = 38) mientras que solo el 5% se observaron en casas abandonadas (n = 2). Interesantemente, la presencia humana era un factor significativo en la presencia de nidos activos, mientras que la estructura de la casa no tenía efecto importante. De las características del sitio de anidación, el número de nidos viejos era significativamente superior en casas habitadas que en casas abandonadas. Además, 97% de las casas habitadas no presentaban daños, mientras que el 50% de las casas abandonadas estaban dañadas, afectando potencialmente la selección de sitio de anidación de las golondrinas Hirundo rustica gutturalis. Nuestros resultados concuerdan con nuestra hipótesis de que las golondrinas Hirundo rustica gutturalis prefieren anidar en casas habitadas. Por la reducción de las casas con estructuras aptas para la anidación de golondrinas por la urbanización rápida y por la eliminación activa de nidos de golondrina por los residentes humanos, el éxito reproductivo de las golondrinas Hirundo rustica gutturalis en Corea del Sur podría reducirse significativamente.

Palabras clave: casa abandonada, conservación, ecología de anidación, habitación humana, Hirundinidae, noreste asiático.

The global abundance of Spot-billed Duck (Anas zonorhyncha) has declined dramatically in recent decades. Ecological information of its wild populations, particularly regarding nest site selection, is scant. We studied the nest site selection and breeding ecology of this duck in Caohai National Nature Reserve, its southernmost breeding site in the Guizhou Province of China. The aquatic vegetation of Caohai is composed of 2 different landscapes with small patches (in Site A) or large patches (in Site B). We studied the habitat preferences of breeding Spot-billed Ducks at 3 spatial scales: landscape, patch, and nest site. In total, we surveyed 413 patches during the breeding seasons of 2014–2016 (298 in Site A and 115 in Site B). We found no nests in Site A, but surveyed 88 patches with 254 nests and 27 patches without nests in Site B. Unlike the open-cup nests known from other breeding localities, the nests of the Spot-billed Duck in Caohai were dome-like structures with a lateral entrance. Patches with nests were significantly larger than patches without nests in total area, circumference, and shape index. In Site B, a negative binomial regression showed that the number of nests was positively correlated with sedge vegetation within the patch area. The reduced model from a binary logistic regression indicated that the total vegetation cover and the distance to bank had positive impacts on nest site selection of this duck in Caohai, but water depth had a negative influence. Our study suggests good concealment is a necessity for the Spot-billed Duck to construct nests in Caohai. Our survey using infrared cameras in 2021 did not record male parents participating in incubation (n = 47 cameras). The mean mass of eggs (46.91 ± 0.36 g) and clutch size (8.48 ± 0.08 eggs) values were lower than those reported for the Xianghai National Nature Reserve, a breeding stronghold for the Spot-billed Duck in northeastern China. The nest success rate in Caohai (nests where at least 1 egg hatched) was 40.4% (n = 47 nests) and the hatching success rate was 91.4% (n = 134 eggs from 19 successful nests). Maintaining the emergent hydrophyte vegetation is the primary means to conserve the nesting habitat of the Spot-billed Duck in Caohai and it is necessary to strictly enforce the law against human disturbance.

Blood samples from birds are used to address a wide variety of questions and to assess individual attributes such as gender, condition, and physiological status. As the use of blood samples expands, researchers have begun to investigate whether sampling has negative impacts on the individuals being sampled. The majority of studies to date have examined survival probability, mostly finding no detectable effect on survival or recapture rate. Significantly fewer studies have looked for effects of collecting a blood sample on measures of reproductive success. Of those that have, none found a detectable effect unless both parents were bled prior to incubation. Since fitness is determined by both survival and reproductive success, we used data from a population of Field Sparrows (Spizella pusilla) in northeastern Pennsylvania for which no negative effect of blood sampling on apparent survival was found and tested whether taking a blood sample affected measures of reproductive success. We found no evidence that clutch size, egg volume, number of offspring fledged, and nest success/failure differed between bled and unbled birds, suggesting minimal impact of blood collection in this population.

Las muestras de sangre de aves son usadas para responder una serie de interrogantes y evaluar atributos individuales como el género, la condición y el estatus fisiológico. Conforme se ha expandido el uso de muestras de sangre, los investigadores han empezado a preguntarse si este muestreo tiene impactos negativos en los individuos muestreados. La mayoría de estudios a la fecha han examinado probabilidad de sobrevivencia, encontrando principalmente que no había efecto detectable en la sobrevivencia o la tasa de recaptura. Significativamente menos estudios han investigado los efectos de la toma de muestra en medidas de éxito reproductivo. De los que lo hicieron, ninguno encontró efectos detectables a menos que ambos padres fueran sangrados previo a la incubación. Puesto que la capacidad adaptativa se determina tanto por la sobrevivencia como por el éxito reproductivo, usamos datos de una población de chingolo campestre (Spizella pusilla) del noreste de Pensilvania, para la cual no se había encontrado efectos negativos del muestreo de sangre en sobrevivencia aparente y probamos si tomar una muestra de sangre afectaba sus medidas de éxito reproductivo. No encontramos evidencia de que el tamaño de puesta, el volumen de huevo, el número de crías que se emanciparon y éxito/fallo de anidación difirieran entre aves sangradas y no sangradas, lo que sugiere un impacto mínimo de la toma de sangre en esta población.

Palabras clave: ave canora, éxito de anidación, muestreo de sangre, múltiples puestas, tamaño de puesta.

The Northern Bobwhite (Colinus virginianus) is a well-studied game bird with documentation of life history dating back over a century. With recent technological advancements, various transmitter types are used to gather survival and location data of individuals. Very high frequency (VHF) transmitters have conventionally been used, but the advancement of GPS technology has facilitated more precise, accurate data. Our objectives were to evaluate the trade-offs in survival for bobwhites fitted with backpack-style GPS transmitters and necklace-style VHF transmitters. In March 2017, we developed a backpack harness using Teflon ribbon to attach 5 g GPS units to 12 (n = 6 male, n = 6 female) bobwhites and we fitted 68 (n = 28 male, n = 40 female) bobwhites with 6 g necklace-style VHF transmitters. Individuals fitted with a GPS backpack transmitter were over 4 times more likely to die on a given day (Ψ^AD = 0.026 ± 0.011) than individuals fitted with the traditional necklace-style VHF transmitter (Ψ^AD = 0.006 ± 0.002). Additionally, the probability of surviving the study period was 0.18 and 0.66 for individuals with a GPS and VHF transmitter, respectively. We recommend researchers consider trade-offs associated with both transmitter types, specifically regarding survival and financial cost. We suggest that if GPS transmitters are necessary, that they resemble the necklace-style VHF transmitter.

La codorniz Colinus virginianus es un ave cinegética cuya documentación de historia de vida remonta a más de un siglo. Con avances tecnológicos recientes, varios tipos de transmisores han sido usados para recopilar información de sobrevivencia y localización de individuos. Transmisores de alta frecuencia (VHF) han sido usados convencionalmente, pero el avance de tecnologías de GPS ha facilitado datos más precisos y exactos. Nuestros objetivos fueron evaluar las concesiones para la sobrevivencia para las codornices equipadas con transmisores GPS tipo mochila y transmisores VHF tipo collar. En marzo del 2017, desarrollamos un arnés de mochila usando cinta de teflón para sujetar unidades GPS de 5 g a 12 codornices (n = 6 machos, n = 6 hembras) y equipamos a 68 (n = 28 machos, n = 40 hembras) codornices con transmisores VHF tipo collar de 6 g. Los individuos a los que se les colocó un transmisor tenían más de 4 veces más probabilidades de morir en un día determinado ((ΨAD = 0,026 ± 0,011) que los individuos equipados con el transmisor VHF tradicional de collar (ΨAD = 0,006 ± 0,002). Además, la probabilidad de sobrevivir al periodo de estudio fue de 0,18 y 0,66 para los individuos con un transmisor GPS y VHF, respectivamente. Recomendamos a los investigadores que tengan en cuenta las repercusiones asociadas a ambos tipos de transmisores, especialmente en lo que respecta a la supervivencia y al costo económico. Sugerimos que, si los transmisores GPS son necesarios, se asemejen al transmisor VHF de tipo collar.

Palabras clave: sobrevivencia, transmisor GPS, transmisor VHF.

The breeding biology and ecology of the Little Tinamou (Crypturellus soui) is poorly known due to its secretive habits and cryptic coloration. We used radio telemetry and temperature data-loggers to monitor radio-tagged tinamous and nests in the subtropical wet forest life zone in a protected rural site near Cali, Colombia, between February 2013 and March 2015. Population density was higher on a transect in continuous primary forest than in 3 transects in second-growth forest fragments. Peak breeding occurred during the main rainy season of September–December. Simultaneous female and male home range overlap during incubation indicates behavioral monogamy in 4 radio-tagged pairs. The absence of female home range overlap with that of an incubating male suggests an instance of polygynandry. Male home range size was greatest prior to breeding (3.76 ± 2.31 ha, minimum convex polygon) and decreased in size during the egg and chick stages. Parental care was provided only by males, which displayed moderately high nest attendance during incubation (77.5% ± 4.5% on nest per 24 h period) and while foraging with chicks after hatching. Females vocalized more frequently and with different vocalizations than males. Females were larger than males in body mass (by 8.8%), body length (by 9.5%), tarsus (by 9.4%), and wing (by 9.4%). Our sexual dimorphism findings are consistent with female defense of territory. Adults were diet generalists, 72% ± 29% of the fecal samples examined contained material of 9 plant species and 9% ± 13% of the fecal samples contained pieces of 4 orders of arthropods.

La biología reproductiva y ecología del tinamú chico (Crypturellus soui) es pobremente conocida debido a sus hábitos huidizos y coloración criptica. Entre febrero 2013–marzo 2015, utilizamos radio telemetría y data loggers de temperatura para monitorear individuos con radiotransmisores y nidos en una zona rural protegida cerca de Cali, Colombia. El traslape simultaneo de áreas de ámbito doméstico durante la incubación en 4 parejas de adultos indica monogamia conductual. La ausencia de traslape del área de ámbito doméstico de la hembra con el macho que se encontraba incubando sugiere un caso poliginandria. El área de ámbito doméstico de los machos fue más grande previo a la anidación (3.76 ± 2.31 ha, polígono mínimo convexo) y disminuyó su tamaño durante las etapas de huevos y polluelos. El cuidado parental fue realizado solamente por machos, que mostraron una atención del nido moderadamente alta durante la incubación (77.5 ± 4.5% sobre nido por un periodo de 24 h) y mientras forrajea con los polluelos después de la eclosión. Las hembras vocalizaron más frecuentemente y con diferentes cantos que los machos. Las hembras presentaron mayor masa corporal (8.8%), longitud corporal (9.5%), tarso (9.4%) y ala (9.4%) que los machos. Los resultados de dimorfismo sexual son consistentes con defensa de territorio. Los adultos tuvieron dietas generalistas, 72 ± 29 % de las muestras fecales examinadas contenían material de 9 especies vegetales y 9 ± 13 % de las muestras fecales contenían fragmentos de 4 órdenes de artrópodos.

Palabras clave: anidación, área de ámbito doméstico, densidad poblacional, dieta, incubación, reproducción, vocalizaciones.

Age-assortative pairing in birds has rarely been documented in passerines, most examples coming from relatively long-lived non-passerines with stable pair bonds. In a sample of 17 pairs of breeding McKay's Buntings (Plectrophenax hyperboreus) from St. Matthew Island, Alaska, documented through archived specimens, 14 were paired assortatively by age class (SY or ASY). This is one of the highest levels yet observed in a passerine. The mechanism(s) responsible for this are unknown in this little-studied taxon, but evidence to date suggests that active mate choice is involved. This observation adds to our limited knowledge of the breeding biology of one of North America's least studied birds. It also highlights one of the many uses of specimen series in our understanding of complex natural history phenomena that can be difficult to assess though field observation.

La selección por edad en aves ha sido raramente documentada en aves paserinas y la mayoría de ejemplos vienen de aves no paserinas relativamente longevas que tienen lazos estables de pareja. En una muestra de 17 parejas reproductivas de escribano de McKay (Plectrophenax hyperboreus) de St. Matthew Island, Alaska, documentadas a través de especímenes depositados, 14 se encontraban emparejadas selectivamente de acuerdo a su rango de edad (SY o ASY). Este es uno de los niveles más altos observados hasta ahora en aves paserinas. El (o los) mecanismo (s) de esto son desconocidos para este taxón poco estudiado, pero la evidencia conocida sugiere que una selección activa de pareja está involucrada en el proceso. Esta observación suma a nuestro poco conocimiento de la biología reproductiva de una de las aves menos estudiadas de América del Norte. También resalta uno de los muchos usos de las series de especímenes para comprender fenómenos complejos de historia natural que pueden ser difíciles de evaluar a través de observaciones en campo.

Palabras clave: biología reproductiva,cohorte,lazo de pareja,selección de pareja.

House Sparrow (Passer domesticus) populations have been negatively affected in various regions of the world because of the urbanization process, although in Brazil the factors involved are still poorly understood. Through standardized sampling, our study aimed to assess the effects of an urbanization gradient on the abundance of House Sparrows in the city of Campo Grande, in central-western Brazil. We recorded House Sparrow and Saffron Finch (Sicalis flaveola) abundance and the percentage of urbanized area (impervious surface) in 61 hexagons of 16 ha each. We surveyed sparrows by using fixed-radius (50 m), 10-min point counts (4 points/hexagon). We recorded 897 House Sparrows and 408 Saffron Finches in all sampled hexagons, with abundance ranging from 0 to 68 House Sparrows/hexagon (∼1 individual/ha) and from 0 to 22 Saffron Finches/hexagon (0.42 individual/ha). We found a significant relationship between House Sparrow abundance and the proportion of hexagon impervious surface according to a quadratic equation, as well as more birds in areas that exhibit moderate to high urbanization than in low urbanization. Multilevel Structural Equation Models showed that House Sparrows were negatively (but nonsignificantly) affected by buildings and trees >5 m in height, positively affected by buildings <5 m in height (houses), and Saffron Finch abundance had a positive but nonsignificant effect in House Sparrow distribution. Even for a bird considered common and adapted to urban conditions, cities seem to have barriers for the establishment of House Sparrows. Simple urban architectural considerations, such as the establishment of roof openings or the management of town squares and vacant lots that allow the growth of seed grasses, could help these birds to continue using urban landscapes.

As populações de pardais (Passer domesticus) têm sido afetadas negativamente em várias regiões do mundo devido ao processo de urbanização, embora no Brasil os fatores ainda sejam mal compreendidos. Por meio de amostragem padronizada, este estudo teve como objetivo verificar os efeitos de um gradiente de urbanização sobre a abundância de pardais na cidade de Campo Grande, na região centro-oeste do Brasil. A abundância de pardais e canários-da-terra (Sicalis flaveola) e a porcentagem de área urbanizada (superfície impermeável) foram registradas em 61 hexágonos de 16 ha cada um. As amostragens foram feitas por pontos de escuta por 10 min em 4 pontos/hexágono, considerando-se um raio de 50 m. Registramos 897 pardais e 408 canários-da-terra em todos os hexágonos, com abundância variando de 0–68 pardais/hexágono (∼1 indivíduo/ha) e de 0–22 canários-da-terra/hexágono (0.42 indivíduo/ha). Encontramos uma relação significativa entre a abundância de pardais e proporção da superfície impermeável no hexágono de acordo com uma equação quadrática, bem como mais aves em áreas que apresentam níveis de gradiente de urbanização moderado a alto do que em níveis altos. Modelos de Equações Estruturais Multinível mostraram que pardais foram negativamente (mas não significativamente) afetados por edifícios com altura superior a 5 m e árvores e positivamente afetados por edifícios <5 m de altura (casas), enquanto a abundância de canários-da terra teve um efeito positivo não significativo. Mesmo para uma espécie de ave considerada comum e adaptada às condições urbanas, as cidades podem apresentar barreiras ao estabelecimento de pardais. Técnicas arquitetônicas simples como o estabelecimento de fissuras em telhados ou o manejo de praças e terrenos baldios que permitem o crescimento de gramíneas que produzem sementes podem contribuir para que essas aves continuem frequentando as paisagens urbanas.

Predation is the most important cause of nest failure in the Chinese Grouse (Tetrastes sewerzowi). However, no studies have been conducted to document the nest predators responsible for nest predation events. During 2012–2016, we monitored 17 nests using infrared video cameras to identify nest predators of Chinese Grouse. Six nests were preyed upon during the incubation period. We successfully identified the predators responsible for 5 depredated nests: Asian badger (Meles leucurus), hog badger (Arctonyx collaris), and Blue Eared Pheasant (Crossoptilon auritum). The Asian badger was responsible for 3 of these nest predation events. We recorded Siberian chipmunk (Tamias sibiricus) and an unidentified rodent species attempting to prey upon grouse eggs, but none of them were successful.

I show cases of atypical molt in the primaries of Harris's Hawk (Parabuteo unicinctus harrisi). Molt of the primaries in accipitrid raptors typically proceeds sequentially one feather at a time from the inner primary, P1, to the outer primary, P10. In larger species, not all primaries are replaced annually, resulting in Staffelmauser (“stepwise” or “relay” molt). From 2002 to 2022, I captured 545 Harris's Hawks in south Texas, either undergoing or having finished third prebasic molt or older, undergoing the second prebasic molt, or in Basic II plumage. I report herein on 6 instances in which 1 or more primaries were skipped or replaced out of order during the annual molt in Harris's Hawk: 5 undergoing the second prebasic molt and 1 undergoing third prebasic molt. I found 1 published case of skipped primaries in Griffon Vultures (Gyps fulvus) and another in a White Stork (Ciconia ciconia). One possible cause of this could be damaged primary follicles.

Muestro casos de muda atípica en las primarias del halcón Parabuteo unicinctus harrisi. La muda de las primarias en rapaces accipítridos procede típicamente de manera secuencial, una pluma a la vez a partir de la primaria interna, P1, hacia la primaria externa, P10. En las especies más grandes, no todas las primarias son reemplazadas anualmente, lo que resulta en una Staffelmauser (muda “por etapas” o “relevos”). Del 2002 al 2022, capturé 545 halcones de Harris en el sur de Texas, ya sea que estaban durante o al final de su tercera muda prebásica o de más edad, que estén realizando la segunda muda prebásica o que estén en el plumaje básico II. Aquí reporto 6 instancias en las que 1 o más primarias fueron saltadas o reemplazadas en desorden durante la muda anual en halcones de Harris: 5 durante la segunda muda prebásica y 1 durante la tercera muda prebásica. Encontré 1 reporte publicado de primarias saltadas en buitres Gyps fulvus y otro en cigüeñas Ciconia ciconia. Una posible causa de esto serían folículos primarios dañados.

Palabras clave: muda primaria desordenada, salto de muda primaria.

The primary driver of nest failure for terrestrial birds is depredation, especially for ground-nesting species that are vulnerable to a diverse guild of predators. However, descriptions of how complex predator–prey interactions happen, and ultimately lead to nest failures, are scarce. Herein, we provide observations collected from cameras stationed at nest sites as part of a larger study on Northern Bobwhite (Colinus virginianus) and Scaled Quail (Callipepla squamata) nesting behavior in the Oklahoma Panhandle during 2016. We observed 2 multi-episode (i.e., multiple predator visits) diurnal nest depredation events at a nest of each species. In both instances, repeated nest depredation by hispid cotton rats (Sigmodon hispidus) as well as 2 different snake species resulted in nest abandonment. We observed that cotton rats routinely visited nest sites (up to 11 times in 1 diurnal period), and often entered the nest during off bouts (64% of off bouts) of the incubating females. By detailing interspecific interactions involved in nest depredation, we provide a glimpse into the complexity of the nesting ecology of ground-dwelling birds. These observations further reinforce the potential pitfalls of categorizing nest depredation events without camera data.

El factor principal de fracaso de la anidación en aves terrestres es la depredación, especialmente en especies que anidan en el suelo y son vulnerables a un gremio diverso de depredadores. Sin embargo, las descripciones de cómo ocurren las interacciones complejas depredador-presa, que llevan en última instancia al fracaso de la anidación, son escasas. Aquí proporcionamos observaciones realizadas con cámaras trampa ubicadas en sitios de anidación como parte de un estudio más grande sobre comportamiento de anidación de las codornices Colinus virginianus y Callipepla squamata en Oklahoma Panhandle durante el 2016. Observamos 2 eventos de depredación diurna de nido de episodios múltiples (es decir visitas de múltiples depredadores) en un nido de cada especie. En ambos casos, la depredación repetida del nido por ratas Sigmodon hispidus así como de 2 especies diferentes de serpientes resultó en el abandono del nido. Observamos que las ratas visitaron rutinariamente los sitios de anidación (hasta 11 veces en un periodo diurno) y entraron al nido durante las salidas (64% de las salidas) de las hembras que incuban. Al detallar interacciones interespecíficas involucradas en depredación de nidos, damos un vistazo a la complejidad de la ecología de anidación de las aves terrestres. Estas observaciones refuerzan más los posibles obstáculos de categorizar los eventos de depredación de nido sin usar cámaras trampa.

Palabras clave: aves terrestres, cámara, codornices, depredadores de nido.

GPS has revolutionized the study of bird migration by revealing details of migration routes, timing, and connectivity not discoverable through other methods. To date studies tracking migrations of raptors using GPS have been restricted to species whose size, behavior, and habitat permit the use of solar-rechargeable GPS transmitters. We tested the use of battery-powered GPS transmitters programmed on highly conservative fix schedules to track migrations of Long-eared Owls (Asio otus), a medium-sized forest owl. Long-eared Owls (n = 5) were fitted with GPS transmitters on their wintering grounds in New Jersey and tracked over the subsequent months. Mortality among the GPS-tagged owls was high, consistent with previous reports in related species. Surviving owls (n = 2) migrated north beyond currently recognized eastern North American range limits, spending summers at 50–55°N in spruce-moss and spruce-lichen (taiga) forests in a vast undeveloped region of northern Quebec. This pilot study demonstrates that lightweight, battery-powered GPS transmitters programmed on highly conservative fix schedules can reveal long-distance movements in medium-sized (e.g., <300 g) birds. This approach may help addresses data deficiencies for birds whose habitat and behavior would cause solar transmitters to perform poorly, particularly species for which details of large-scale movements are lacking.

El uso de GPS ha revolucionado el estudio de la migración de aves al revelar detalles de rutas migratorias, tiempos de migración y conectividad que no hubieran podido ser descubiertos por otros métodos. Hasta ahora los estudios usando migraciones de rapaces habían sido limitados a especies cuyo tamaño, comportamiento y hábitat permitían el uso de transmisores GPS recargables solarmente. Probamos el uso de transmisores GPS con batería programados en plazos fijos muy conservadores para seguir la migración de búho Asio otus, un búho de bosque de tamaño medio. Varios búhos (n = 5) fueron equipados con transmisores GPS en su zona de hibernación en New Jersey y monitoreados en los meses siguientes. La mortalidad de los búhos marcado con GPS fue alta, lo que es consistente con reportes anteriores en especies relacionadas. Los búhos sobrevivientes migraron hacia el norte más allá del límite de su rango de distribución conocido en Norte América, pasando el verano en bosques de abeto/musgo y de abeto/líquenes (taiga) a los 50–55°N en regiones muy poco desarrolladas al norte de Quebec. Este estudio piloto demuestra que transmisores de batería de poco peso programados en plazos fijos muy conservadores pueden revelar movimientos a larga distancia en aves de tamaño medio (por ejemplo, <300 g). Este enfoque puede ayudar a llenar vacíos de información para aves cuyo hábitat y comportamiento están poco estudiados debido al mal desempeño de los transmisores solares, particularmente especies de las que no se tienen detalles de movimientos a larga distancia.

Palabras clave: Argos, conectividad, rastreo, satélite, transmisor.

Turkey Vultures (Cathartes aura) were observed feeding on ripe avocado fruit (Persea americana) even though carrion was readily available. Similar to previous reports, such as observations of Turkey Vultures feeding on fruits of the African oil palm (Elaeis guineensis), my observations suggest that Turkey Vultures incorporate nutrient-rich food into their diet regardless of whether it is derived from plants or animals.

Se observaron zopilotes cabeza roja (Cathartes aura) alimentándose de frutos maduros de aguacate (Persea americana), aun cuando tenían carroña fácilmente disponible. Similar a reportes previos, como observaciones de zopilotes Cathartes aura alimentándose de frutos de palma africana (Elaeis guineensis), mis observaciones sugieren que los zopilotes cabeza roja incorporan alimentos ricos en nutrientes en su dieta sin importar si son de origen vegetal o animal.

Palabras clave: alimentación atípica, cámaras trampa, Florida, frugivoría, Montgomery Botanical Center.

Many species of birds are known to collect and incorporate mammalian hair into their nests, presumably to augment their reproductive success. Birds source it from dead animals, shed hairs, and even live animals. Here, we report theft of hair (kleptotrichy) from a live cow by 2 Large-billed Crows (Corvus macrorhynchos culminatus) in India, along with photographic evidence. The crows strenuously plucked the hair from the tail of a resting cow. The crows flew away with beakfuls of hair and returned after 5 min to repeat the same. The function of kleptotrichy is not clearly known—thermal regulation and predator/parasite deterrence have been offered as explanations. This is the first report of kleptotrichy by Large-billed Crows from a live mammal.

Muchas especies de aves son conocidas por colectar e incorporar pelo de mamífero a sus nidos, supuestamente para aumentar su éxito reproductivo. Las aves lo extraen de animales muertos, pelo caídos o hasta animales vivos. Aquí reportamos robo de pelo (cleptotriquia) de una vaca viva por 2 cuervos Corvus macrorhynchos culminatus grandes en India, junto con evidencia fotográfica. Los cuervos arrancaron con fuerza pelos de la cola de una vaca en reposo. Los cuervos se fueron volando con los picos llenos de pelos y regresaron 5 min después para repetir lo mismo. La función de la cleptotriquia no es claramente conocida—se ha explicado tentativamente por regulación térmica y disuasión depredador/parásito. Este es el primer reporte de cleptotriquia de un animal vivo de un cuervo de esta especie.

Palabras clave: córvido, material de nido, pelo de mamífero, recolecta de pelo, robo de pelo.