scholarly journals Resident bird species track inter-annual variation in spring phenology better than long-distance migrants in a subalpine habitat

2022 ◽  
pp. 100050
Author(s):  
Jørgen Skavdal Søraker ◽  
Bård Gunnar Stokke ◽  
Oddmund Kleven ◽  
Arne Moksnes ◽  
Geir Rudolfsen ◽  
...  
Keyword(s):  
Annual Variation ◽  
Bird Species ◽  
Long Distance ◽  
Spring Phenology ◽  
Resident Bird ◽  
Better Than

scholarly journals Temporal Variation in Bird Counts Within a Hawaiian Rainforest

The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 469-481
Author(s):  
John C. Simon ◽  
Thane K. Pratt ◽  
Kim E. Berlin ◽  
James R. Kowalsky ◽  
Steven G. Fancy ◽  
...  
Keyword(s):  
Breeding Season ◽  
Annual Variation ◽  
Bird Species ◽  
Elevational Gradient ◽  
Temporal Variations ◽  
Native Forest ◽  
Nectar Production ◽  
Density Estimates ◽  
Generalist Species ◽  
Resident Bird

Abstract We studied monthly and annual variation in density estimates of nine forest bird species along an elevational gradient in an east Maui rainforest. We conducted monthly variable circular-plot counts for 36 consecutive months along transects running downhill from timberline. Density estimates were compared by month, year, and station for all resident bird species with sizeable populations, including four native nectarivores, two native insectivores, a non-native insectivore, and two non-native generalists. We compared densities among three elevational strata and between breeding and nonbreeding seasons. All species showed significant differences in density estimates among months and years. Three native nectarivores had higher density estimates within their breeding season (December–May) and showed decreases during periods of low nectar production following the breeding season. All insectivore and generalist species except one had higher density estimates within their March–August breeding season. Density estimates also varied with elevation for all species, and for four species a seasonal shift in population was indicated. Our data show that the best time to conduct counts for native forest birds on Maui is January–February, when birds are breeding or preparing to breed, counts are typically high, variability in density estimates is low, and the likelihood for fair weather is best. Temporal variations in density estimates documented in our study site emphasize the need for consistent, well-researched survey regimens and for caution when drawing conclusions from, or basing management decisions on, survey data. Variación Temporal en Conteos de Aves en una Selva Lluviosa de Hawai Resumen. Estudiamos la variación mensual y anual en estimaciones de la densidad de nueve especies de aves a lo largo de un gradiente altitudinal en una selva lluviosa del este de Maui. Realizamos conteos mensuales en parcelas circulares por un período de 36 meses consecutivos a lo largo de transectas ubicadas desde la línea del bosque hacia abajo. Las estimaciones de densidad fueron comparadas entre meses, años y estaciones considerando todas las especies de aves residentes con poblaciones considerables, incluyendo cuatro nectarívoros nativos, dos insectívoros nativos, un insectívoro no nativo y dos generalistas no nativos. Comparamos densidades entre tres estratos altitudinales y entre las estaciones reproductivas y no reproductivas. Todas las especies mostraron diferencias significativas en las estimaciones de densidad entre meses y años. Tres nectarívoros nativos presentaron estimaciones de densidad mayores durante sus épocas reproductivas (diciembre–mayo) y mostraron disminuciones durante períodos de baja producción de néctar luego de la estación de cría. Excepto una, todas las especies insectívoras y generalistas presentaron mayores estimaciones de densidad durante sus épocas reproductivas (marzo–agosto). Las estimaciones de densidad de todas las especies también variaron con la altitud, y se encontraron cambios estacionales en las poblaciones de cuatro especies. Nuestros datos muestran que el mejor momento para realizar conteos de aves nativas de selva en Maui es enero–febrero, cuando las aves están criando o preparándose para criar, los conteos son típicamente altos, la variabilidad en las estimaciones de densidad es baja y la probabilidad de buen tiempo es más alta. La variación temporal en las estimaciones de densidad documentadas en nuestro sitio de estudio enfatizan la necesidad de regímenes de muestreo consistentes y bien establecidos, y sugiere cautela a la hora de sacar conclusiones para conservación o tomar decisiones de manejo a partir de datos de muestreos.

scholarly journals Patterns of bird species richness explained by annual variation in remotely sensed Dynamic Habitat Indices

2021 ◽  
Vol 127 ◽  
pp. 107774
Author(s):  
Martina L. Hobi ◽  
Laura S. Farwell ◽  
Maxim Dubinin ◽  
Dmitrij Kolesov ◽  
Anna M. Pidgeon ◽  
...  
Keyword(s):  
Species Richness ◽  
Annual Variation ◽  
Bird Species ◽  
Remotely Sensed ◽  
Bird Species Richness ◽  
Dynamic Habitat

scholarly journals Brain regions associated with visual cues are important for bird migration

2015 ◽  
Vol 11 (11) ◽  
pp. 20150678 ◽  
Author(s):  
Orsolya Vincze ◽  
Csongor I. Vágási ◽  
Péter L. Pap ◽  
Gergely Osváth ◽  
Anders Pape Møller
Keyword(s):  
Visual Cues ◽  
Optic Lobe ◽  
Brain Size ◽  
Relative Size ◽  
Bird Species ◽  
Interspecific Variation ◽  
Brain Regions ◽  
Long Distance ◽  
Migration Distance ◽  
Whole Brain

Long-distance migratory birds have relatively smaller brains than short-distance migrants or residents. Here, we test whether reduction in brain size with migration distance can be generalized across the different brain regions suggested to play key roles in orientation during migration. Based on 152 bird species, belonging to 61 avian families from six continents, we show that the sizes of both the telencephalon and the whole brain decrease, and the relative size of the optic lobe increases, while cerebellum size does not change with increasing migration distance. Body mass, whole brain size, optic lobe size and wing aspect ratio together account for a remarkable 46% of interspecific variation in average migration distance across bird species. These results indicate that visual acuity might be a primary neural adaptation to the ecological challenge of migration.

scholarly journals Flight range, fuel load and the impact of climate change on the journeys of migrant birds

2018 ◽  
Vol 285 (1873) ◽  
pp. 20172329 ◽  
Author(s):  
Christine Howard ◽  
Philip A. Stephens ◽  
Joseph A. Tobias ◽  
Catherine Sheard ◽  
Stuart H. M. Butchart ◽  
...  
Keyword(s):  
Climate Change ◽  
Bird Species ◽  
Climate Impact ◽  
Fuel Load ◽  
Migratory Species ◽  
Long Distance ◽  
Avian Flight ◽  
Flight Range ◽  
Combine Information ◽  
The Impact

Climate change is predicted to increase migration distances for many migratory species, but the physiological and temporal implications of longer migratory journeys have not been explored. Here, we combine information about species' flight range potential and migratory refuelling requirements to simulate the number of stopovers required and the duration of current migratory journeys for 77 bird species breeding in Europe. Using tracking data, we show that our estimates accord with recorded journey times and stopovers for most species. We then combine projections of altered migratory distances under climate change with models of avian flight to predict future migratory journeys. We find that 37% of migratory journeys undertaken by long-distance migrants will necessitate an additional stopover in future. These greater distances and the increased number of stops will substantially increase overall journey durations of many long-distance migratory species, a factor not currently considered in climate impact studies.

scholarly journals Birdsong and Sound Transmission: The Benefits of Reverberations

The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 564-573 ◽  
Author(s):  
Hans Slabbekoorn ◽  
Jacintha Ellers ◽  
Thomas B. Smith
Keyword(s):  
Bird Species ◽  
Sound Transmission ◽  
Acoustic Properties ◽  
Signal Design ◽  
Signal Attenuation ◽  
Long Distance ◽  
Animal Vocalizations ◽  
Distance Communication ◽  
The Relationship ◽  
Insight Into

Abstract Animal vocalizations used for long-distance communication are shaped by acoustic properties of the environment. Studies of the relationship between signal design and sound transmission typically focus on habitat-induced limitations due to signal attenuation and degradation. However, signal design may not entirely be explained by habitat limitations, but rather by beneficial consequences of reverberations. Narrow-frequency bandwidth notes (NFB notes) are pure notes that change little in frequency, and are typical for many bird species living in dense tropical forests. In contrast to frequency-modulated notes, we show that reverberations lead to a longer and louder signal after transmission for NFB notes. Furthermore, playback experiments to territorial males of an African passerine indicated that longer notes led to a stronger behavioral response. These results suggest that reverberations may benefit signal efficiency depending on the signal design, and add new insight into the selection pressures imposed on acoustic signals by the environment. Canto de Aves y Transmisión de Sonido: Beneficios de las Reverberaciones Resumen. Las vocalizaciones utilizadas por animales para la comunicación a larga distancia están condicionadas por las propiedades acústicas del entorno. Los estudios sobre la relación entre el diseño de las señales y la transmisión del sonido suelen centrarse en los límites impuestos por el hábitat debido a la atenuación y degradación de la señal. Sin embargo, es posible que el diseño de la señal no esté regido exclusivamente por las limitaciones del habitat, sino por las consecuencias beneficiosas de las reverberaciones. Las notas de frecuencia de banda estrecha (notas NFB) son notas puras que cambian poco de frecuencia y son típicas de varias especies que habitan bosques tropicales densos. Al contrario que en las notas de frecuencia modulada, mostramos que las reverberaciones alargan y aumentan la señal de las notas NFB. Asimismo, experimentos de playback con machos territoriales de un paseriforme africano indican que las notas más largas provocan una mayor respuesta. Estos resultados sugieren que las reverberaciones pueden mejorar la eficiencia de la señal, dependiendo del diseño de la misma, y añaden un nuevo componente a nuestro conocimiento sobre las presiones selectivas impuestas por el entorno sobre las señales acústicas.

scholarly journals Animal movement drives variation in seed dispersal distance in a plant–animal network

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182007 ◽  
Author(s):  
E. Rehm ◽  
E. Fricke ◽  
J. Bender ◽  
J. Savidge ◽  
H. Rogers
Keyword(s):  
Seed Dispersal ◽  
Animal Movement ◽  
Bird Species ◽  
Dispersal Distance ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Gut Passage ◽  
Dispersal Distances ◽  
Seed Dispersal Distance ◽  
Passage Times

Frugivores play differing roles in shaping dispersal patterns yet seed dispersal distance is rarely quantified across entire communities. We model seed dispersal distance using gut passage times and bird movement for the majority (39 interactions) of known bird–tree interactions on the island of Saipan to highlight differences in seed dispersal distances provided by the five avian frugivores. One bird species was found to be a seed predator rather than a disperser. The remaining four avian species dispersed seeds but differences in seed dispersal distance were largely driven by interspecific variation in bird movement rather than intraspecific variation in gut passage times. The median dispersal distance was at least 56 m for all species-specific combinations, indicating all species play a role in reducing high seed mortality under the parent tree. However, one species—the Micronesian Starling—performed 94% of dispersal events greater than 500 m, suggesting this species could be a key driver of long-distance dispersal services (e.g. linking populations, colonizing new areas). Assessing variation in dispersal patterns across this network highlights key sources of variation in seed dispersal distances and suggests which empirical approaches are sufficient for modelling how seed dispersal mutualisms affect populations and communities.

scholarly journals Nest Survival Patterns in Willow Ptarmigan: Influence of Time, Nesting Stage, and Female Characteristics

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 377-388 ◽  
Author(s):  
Scott Wilson ◽  
Kathy Martin ◽  
Susan J. Hannon
Keyword(s):  
British Columbia ◽  
Annual Variation ◽  
Nest Survival ◽  
Bird Species ◽  
Ecological Factors ◽  
Individual Characteristics ◽  
Willow Ptarmigan ◽  
Female Age ◽  
Daily Nest Survival ◽  
Survival Patterns

Abstract Nest predation is the most important factor limiting reproductive success of Willow Ptarmigan (Lagopus lagopus), as it is for many bird species. Using program MARK, we examined patterns of daily nest survival in two widely separated populations of Willow Ptarmigan in Manitoba and British Columbia, Canada, by examining variation among years, over the course of the breeding season or in relation to the age of the nest, or age and condition of the female. At La Pérouse Bay, Manitoba, daily nest survival increased linearly throughout the season, with moderate annual variation. Nests also had higher daily survival during laying and late in incubation, and lower survival early in incubation. At Chilkat Pass, British Columbia, daily nest survival varied strongly by year and nests had higher survival early and late in the season, but survival was not affected by the age of the nest. At both sites, but especially at Chilkat Pass, periods of lower nest survival tended to coincide with peak breeding periods, suggesting predators may adjust their search effort based on the likelihood of locating nests. Neither female age nor condition were included in the best models. Thus, in both ptarmigan populations, nest survival patterns appeared to be influenced more by ecological factors than by individual characteristics of breeding females. The extent of annual variation and seasonal patterns may have differed between sites due to the different predator and alternative prey communities.

scholarly journals Forest passerines as a novel dispersal vector of viable bryophyte propagules

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182253 ◽  
Author(s):  
Matthew W. Chmielewski ◽  
Sarah M. Eppley
Keyword(s):  
Temperate Forest ◽  
Bird Species ◽  
Forest Birds ◽  
Forest Community ◽  
Spore Dispersal ◽  
Long Distance ◽  
Dispersal Vectors ◽  
Migratory Routes ◽  
Dispersal Vector ◽  
Spore Load

Animal dispersal influences the community structure and diversity of a wide variety of plant taxa, yet the potential effects of animal dispersal in bryophytes (hornworts, liverworts, and mosses) is poorly understood. In many communities, birds use bryophyte-abundant niche space for foraging and gathering nest material, suggesting that birds may play a role in bryophyte dispersal. As highly motile animals with long migratory routes, birds potentially provide a means for both local and long-distance bryophyte dispersal in a manner that differs greatly from passive, aerial spore dispersal. To examine this phenomenon, we collected and germinated bryophyte propagules from the legs, feet and tails of 224 birds from 34 species within a temperate forest community. In total we found 1512 spores, and were able to germinate 242 bryophyte propagules. In addition, we provide evidence that topical (externally-carried) spore load varies by bird species and behaviour. Tail feather spore abundance is highest in bark and foliage gleaning species and is positively correlated with tarsal length. Together, these data suggest that a variety of forest birds exhibit the potential to act as dispersal vectors for bryophyte propagules, including an abundance of spores, and that understanding the effects of animal behaviour on bryophyte dispersal will be key to further understanding this interaction.

scholarly journals Aspergillosis, Avian Species and the One Health Perspective: The Possible Importance of Birds in Azole Resistance

2020 ◽  
Vol 8 (12) ◽  
pp. 2037
Author(s):  
Aryse Martins Melo ◽  
David A. Stevens ◽  
Lisa A. Tell ◽  
Cristina Veríssimo ◽  
Raquel Sabino ◽  
...  
Keyword(s):  
One Health ◽  
Plant Pathogens ◽  
Bird Species ◽  
Sensu Stricto ◽  
Urban Environments ◽  
Avian Species ◽  
Azole Resistance ◽  
Natural Environments ◽  
Long Distance ◽  
The One

The One Health context considers health based on three pillars: humans, animals, and environment. This approach is a strong ally in the surveillance of infectious diseases and in the development of prevention strategies. Aspergillus spp. are fungi that fit substantially in this context, in view of their ubiquity, as well as their importance as plant pathogens, and potentially fatal pathogens for, particularly, humans and avian species. In addition, the emergence of azole resistance, mainly in Aspergillus fumigatus sensu stricto, and the proven role of fungicides widely used on crops, reinforces the need for a multidisciplinary approach to this problem. Avian species are involved in short and long distance travel between different types of landscapes, such as agricultural fields, natural environments and urban environments. Thus, birds can play an important role in the dispersion of Aspergillus, and of special concern, azole-resistant strains. In addition, some bird species are particularly susceptible to aspergillosis. Therefore, avian aspergillosis could be considered as an environmental health indicator. In this review, aspergillosis in humans and birds will be discussed, with focus on the presence of Aspergillus in the environment. We will relate these issues with the emergence of azole resistance on Aspergillus. These topics will be therefore considered and reviewed from the “One Health” perspective.

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