scholarly journals Rainfall-induced changes in food availability modify the spring departure programme of a migratory bird

2011 ◽  
Vol 278 (1723) ◽  
pp. 3437-3443 ◽  
Author(s):  
Colin E. Studds ◽  
Peter P. Marra

Climatic warming has intensified selection for earlier reproduction in many organisms, but potential constraints imposed by climate change outside the breeding period have received little attention. Migratory birds provide an ideal model for exploring such constraints because they face warming temperatures on temperate breeding grounds and declining rainfall on many tropical non-breeding areas. Here, we use longitudinal data on spring departure dates of American redstarts ( Setophaga ruticilla ) to show that annual variation in tropical rainfall and food resources are associated with marked change in the timing of spring departure of the same individuals among years. This finding challenges the idea that photoperiod alone regulates the onset of migration, providing evidence that intensifying drought in the tropical winter could hinder adaptive responses to climatic warming in the temperate zone.

2014 ◽  
Author(s):  
Kristen C Ruegg ◽  
Eric Anderson ◽  
Kristina Paxton ◽  
Vanessa Apkenas ◽  
Sirena Lao ◽  
...  

Neotropical migratory birds are declining across the Western Hemisphere, but conservation efforts have been hampered by the inability to assess where migrants are most limited–the breeding grounds, migratory stopover sites, or wintering areas. A major challenge has been the lack of an efficient, reliable, and broadly applicable method for connecting populations across the annual cycle. Here we show how high-resolution genetic markers can be used to identify populations of a migratory bird, the Wilson's warbler (Cardellina pusilla), at fine enough spatial scales to facilitate assessing regional drivers of demographic trends. By screening 1626 samples using 96 single nucleotide polymorphisms (SNPs) selected from a large pool of candidates (~450,000), we identify novel region-specific migratory routes and timetables of migration along the Pacific Flyway. Our results illustrate that high-resolution genetic markers are more reliable, accurate, and amenable to high throughput screening than previously described tracking techniques, making them broadly applicable to large-scale monitoring and conservation of migratory organisms.


Author(s):  
Marco Parolini ◽  
Michela Sturini ◽  
Federica Maraschi ◽  
Antonella Profumo ◽  
Alessandra Costanzo ◽  
...  

AbstractTrace elements are widespread contaminants that can potentially threaten ecosystems and human health. Considering their distribution and toxicity, monitoring their presence in animals represents a priority in environmental risk assessment. Migratory birds have been suggested to be useful biomonitors for trace elements because they can provide information on contaminants even from remote areas that they may exploit during their life cycle. The aim of this study was to analyse the contamination fingerprint of trace elements of African non-breeding staging grounds and European breeding areas in a long-distance migratory passerine bird, the barn swallow (Hirundo rustica). We collected feathers grown in the African non-breeding grounds and those grown in the breeding areas of Northern Italy and measured the levels of 12 trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn) by DRC-ICP-MS. Multivariate analysis showed that elemental profiles of feathers grown in African non-breeding areas and in the Italian breeding ones clearly differed, with feathers grown in Africa showing higher concentrations of Al, Cu, Fe, Mn and Ni, but lower concentrations of As, Se and Zn, compared to those grown in Italy. In addition, levels of trace elements were age-dependent, with higher levels in older individuals than in younger ones. Our results add to the growing evidence that feathers of long-distance migratory birds are useful tools to monitor trace elements contamination profiles across continents.


2012 ◽  
Vol 20 (1) ◽  
pp. 50-58 ◽  
Author(s):  
József Gyurácz ◽  
Sándor Kalmár ◽  
Réka Baráth

AbstractThe local abundance and spatial distribution of the short- to medium-distance migratory and daytime stopover passerines (Robin Erithacus rubecula, Blackcap Sylvia atricapilla, Chiffchaff Phylloscopus collybita, Blue tit Parus caeruleus, Great tit P. major) were studied in a West Hungarian stopover ground during post-breeding season. The dispergation index of all migratory bird species revealed clumped distribution both in „smallest annual capture year” (abb. SACY) and the „largest annual capture year” (abb. LACY). According to the PCA the spatial occurrences of Blackcap, Blue tit and Great tit captured in LACY showed significantly higher concentration than of those migrating in SACY. The studied species appeared in all four habitats (bushy, forest, grassland, marsh) of the study stopover area, but their clumped spatial distribution showed habitat preference. The abundance-dependent shift of habitat selection was found only in Great tit, the most of them captured in SACY concentrated in grassland with bushy, while the ones captured in LACY grouped in forest habitat type. Blackcaps were grouped the grassland with bushes habitat type where many Dwarf elder (Sambucus ebulus) bushes were available during autumn migration.


2021 ◽  
Vol 9 ◽  
Author(s):  
J. David Blount ◽  
Joshua J. Horns ◽  
Kyle D. Kittelberger ◽  
Montague H. C. Neate-Clegg ◽  
Çağan Hakkı Şekercioğlu

An estimated 17% of migratory bird species are threatened or near threatened with extinction. This represents an enormous potential loss of biodiversity and cost to human societies due to the economic benefits that birds provide through ecosystem services and ecotourism. Conservation of migratory bird species presents many unique challenges, as these birds rely on multiple geographically distinct habitats, including breeding grounds, non-breeding grounds, and stopover sites during migration. In particular, stopover habitats are seldom studied relative to breeding and non-breeding habitats, despite their importance as refueling stations for migratory birds. In this study, we summarize the current research on the use of temporary primary crops by birds during migration and we assess the species characteristics and agricultural practices most often associated with the use of cropland as stopover habitat. First, we conducted a systematic review of the literature to document the effects various farming practices and crop types have on the abundance and diversity of migratory birds using agricultural areas for stopovers. Second, we analyzed the ecological correlates of bird species in the Northern Hemisphere that predict which species may use these areas while migrating. We ran a GLMM to test whether primary diet, diet breadth, primary habitat, habitat breadth, or realm predicted stopover use of agricultural areas. Our review suggests that particular crop types (principally rice, corn, and sunflower), as well as farming practices that result in higher non-cultivated plant diversity, encourage the use of agricultural areas by migrating birds. We found that cropland is used as stopover habitat by bird species that can utilize a large breadth of habitats, as well as species with preferences for habitat similar in structure to agricultural areas.


2020 ◽  
Author(s):  
Javier Gutierrez Illan ◽  
Guiming Wang ◽  
Fred L Cunningham ◽  
D Tommy King

Abstract Background: Resource utilization strategies of avian migrants are a major concern for conservation and management. Consequently, the ability to predict potential shifts in migratory species spatial use and migratory behaviour is a pressing challenge for predictive ecology under global changes. There are two main strategies of resource use adopted by migratory birds: niche tracking for similar environmental conditions and niche switching between different environmental conditions between seasons. Our objective was to examine whether the niche tracking/niche switching hypothesis would better explain seasonal variations in the ecological niche overlap of the American White Pelicans (AWPE, Pelecanus erythrorhynchos). We also tested whether recent changes in the non-breeding ground land-use have altered habitat selection and space use by AWPE. Methods: We used Dirichlet-multinomial models to detect differences in habitat selection between regions and over times with the GPS locations of 36 tracked AWPEs. We estimated climatic and land-cover niche overlap between the breeding and non-breeding grounds to test for niche switches between seasons using ordination methods. Results: Our habitat selection models did not detect shifts in habitat selection by AWPE after 2005. American white pelican strongly selected open water and wetland at the non-breeding and breeding grounds. American white pelicans showed little climatic niche overlap but substantial landscape niche overlap between breeding and non-breeding grounds.Conclusions: Declines in aquacultural acreage did not change AWPE habitat selection in the Northern Gulf of Mexico. Our results did not support the hypothesis that AWPE would be a climatic niche tracker. However, AWPE tracked its foraging habitats, exhibiting strong selection for open water and wetland at both the breeding and non-breeding grounds. Climatic niche switching suggests that AWPE may adapt to future climate changes.


Birds ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 261-274
Author(s):  
Heather L. Bateman ◽  
Sidney B. Riddle ◽  
Erin S. Cubley

Passive acoustic recorders have been used successfully as automated survey tools to detect terrestrial wildlife. However, few studies have monitored Neotropical migratory bird use of riparian forest habitat using this technology. Within dryland ecosystems, the forests along rivers support high bird diversity. Many bird species of conservation concern require these floodplain forest habitats for foraging, migration stop-overs, and breeding. Few studies have explored the use of acoustic records in riverine systems designated for conservation for their natural resource value via the Wild and Scenic Rivers Act in the USA. Using acoustic recorders, we document vocal activity of four riparian-obligate species (Bell’s Vireo, Vireo bellii; Summer Tanager, Piranga rubra; Yellow Warbler, Setophaga petechial; and Yellow-billed Cuckoo, Coccyzus americanus) to determine species occurrence along a Wild and Scenic River. We established three study reaches along the perennial Lower Verde River, in the Sonoran Desert of central Arizona, USA. Nine acoustic recorders were used over the period of 80–120 days during the summer of 2018. We measured vegetation composition and structure in 100 m2 plots paired with acoustic recorders. Visualizing vocal activity showed that three species were calling and singing at each reach; whereas, one species, the cuckoo, had fewer recordings and occurred later in the summer. We demonstrate the utility of acoustic monitoring even when applied to rare birds in complex riparian habitats. This information is important for land management and conservation efforts concerning these species of interest and identifying important habitat features in Southwestern US riparian woodlands.


2015 ◽  
Vol 26 (1) ◽  
pp. 39-51 ◽  
Author(s):  
PERRI EASON ◽  
BASEM RABIA ◽  
OMAR ATTUM

SummaryDuring autumn migration, people set trammel nets along most of the Mediterranean coast of Egypt, with migrating Common Quail Coturnix coturnix as their primary target. These nets capture large numbers of quail, but also illegally capture other birds, which are then killed. We present the results of surveys from 2008 to 2012 along these lines of nets on the coast of North Sinai, Egypt. In desert scrub, which covers most of the Sinai coast, the mean number of quail killed reached a high of 357.1 per km per day in 2012, with a grand mean over the study period of 191.9 per km per day. Trammel nets also captured 54 other bird species in 28 families. Species captured at the highest rates in desert scrub included Corncrake Crex crex, Isabelline Wheatear Oenanthe isabellina and Greater Short-toed Lark Calandrella brachydactyla. Based on mean rates of capture from 2008 to 2012 in desert scrub and sand bar habitats, we estimate 2.0 million quail and 0.5 million birds of other species are killed annually in North Sinai during the 45 days of peak migration. In 2012, however, after the use of MP3 players to attract quail became widespread, we estimate that 3.3 million quail and 0.5 million other birds were captured. Hunters near the coast have recently begun covering shrubs and trees with mist nets to catch passerines. From 2010 to 2012, mist nets along our survey routes caught birds of 17 species in three families, with seven of these species caught only in this type of net. Hunting is likely to be a contributing factor to population declines for some species that migrate across Egypt and further studies of migratory bird hunting along the southern Mediterranean shore are badly needed.


The Auk ◽  
2019 ◽  
Author(s):  
Émile Brisson-Curadeau ◽  
Kyle H Elliott ◽  
Pascal Côté

Abstract The phenology of migrating birds is shifting with climate change. For instance, short-distance migrants wintering in temperate regions tend to delay their migration in fall during spells of warmer temperature. However, some species do not show strong shifts, and the factors determining which species will react to temperature changes by delaying their migration are poorly known. In addition, it is not known whether a slower migration or a postponed departure creates the observed delays in fall migration because most studies occur far south of the boreal breeding areas making it difficult to separate those 2 mechanisms. We used 22 yr of data at a northern observatory in eastern North America, at the southern edge of the boreal forest, to examine how 21 short-distance migrants responded to changing temperatures. We investigated if those species responding to temperature share life-history features (i.e. diet, size, total migration distance, breeding habitat, timing of migration). The period of migration in each species was, by far, the most important factor predicting the response of a species to temperature. Eight of the 13 species migrating in October changed their migration onset with temperature (usually by delaying migration by 1–2 days/°C), while the migration timing of none of the 8 species migrating in September was dependent on temperature. Furthermore, the absence of a greater migration delay by birds breeding farther from the study site (i.e. Arctic-breeding birds) suggests the mechanism is a postponed departure rather than a slower migration. We conclude that temperature variations in late fall influence the conditions on the breeding grounds, so that birds still present at that time benefit more from postponing their departure in warm weather.


The Auk ◽  
2019 ◽  
Vol 136 (3) ◽  
Author(s):  
David V Gesicki ◽  
Erica L Cech ◽  
Verner P Bingman

Abstract Migratory birds encounter the Great Lakes while moving through eastern North America toward breeding grounds to the North, which offers a good opportunity to study variation in migratory behavior as birds face a potentially influencing topographical feature. Using passive infrared technology, we documented the direction of relatively low-flying, nocturnal, mostly passerine migration in spring along the southern coast of Lake Erie’s western basin. We examined the extent to which spring migrants flew across Lake Erie as a continuation of the inland, northeasterly broad front migratory direction, as determined by weather radar and infrared observations, or displayed a tendency to deviate to more closely follow the direction of the coastline. We found that an estimated 62% of all low-flying migrants deviated their flight directions toward the coast of Lake Erie at 2 coastal sites, Cedar Point and Ottawa, which were characterized by northwest–southeast oriented coastlines. Migrants at a third coastal location, Maumee Bay, which has a more east–west oriented coastline, did not display similarly deviated flight directions. We found that even when winds were energetically favorable for a lake crossing, many migrants still routinely displayed deviated flight directions that approached paralleling the coastline. Further, the mean flight direction at one site, Ottawa, shifted more in the direction of the coastline as the night progressed, suggesting that time of night could influence the shift to a more coastal flight direction. The data indicate that the western basin of Lake Erie acts as a salient topographical feature influencing the flight directions of nocturnal migrants. The data further suggest that birds are making active decisions while in flight, based on current environmental and physiological conditions, about whether to continue to cross Lake Erie or take a coastal detour.


The Condor ◽  
2004 ◽  
Vol 106 (4) ◽  
pp. 905-909 ◽  
Author(s):  
Keith A. Hobson ◽  
Yves Aubry ◽  
Leonard I. Wassenaar

Abstract The measurement of the abundance of naturally occurring deuterium (δD) in feathers grown in North America can provide geographical information on location where the feather was grown. Previously, we used this technique to link populations of Bicknell's Thrush (Catharus bicknelli) breeding in northeastern North America (to 46°N) with wintering grounds in the Dominican Republic. That study indicated the presence of a subpopulation of wintering birds with more depleted feather δD values than those measured on their known breeding grounds. This suggested either a more northerly or a higher altitude breeding source population than previously measured. We located two populations of Bicknell's Thrush in Quebec, Canada, at Mine Madeleine (49°N) and at Mont Gosford (45°N). The Mine Madeleine birds had feather δD values overlapping those of the unidentified subpopulation found wintering in the Dominican Republic. At Mont Gosford, hatch-year birds were more depleted in their feather δD values than after-second-year birds suggesting their more northerly origins and capture during the early fall migration period. Our study demonstrates how the stable-isotope approach can be used to document connectivity between breeding and wintering populations of migratory birds. Conectividad Migratoria en Catharus bicknelli: Localización de Poblaciones Perdidas con Isótopos de Hidrógeno Resumen. La medición de la abundancia de deuterio en estado natural (δD) en las plumas formadas en América del Norte puede brindar información geográ fica sobre la localización en donde se formó la pluma. Anteriormente usamos esta técnica para relacionar las poblaciones de Catharus bicknelli que se reproducen en el noreste de América del Norte (hasta 46°N) con las áreas de invernada en República Dominicana. Ese estudio indicó la presencia de una subpoblación de aves invernantes con valores de δD en las plumas por debajo de los valores medidos de los sitios conocidos de cría. Esto sugirió la presencia de una población reproductiva proveedora de individuos localizada más al norte o a mayor elevación que las registradas anteriormente. Localizamos dos poblaciones de C. bicknelli en Québec, Canadá, una en Mine Madeleine (49°N) y otra en Mont Gosford (45°N). Las aves de Mine Madeleine tuvieron valores de δD en las plumas que se superpusieron con aquellos de la subpoblación no identificada encontrada invernando en República Dominicana. En Mont Gosford, las aves del primer año de edad presentaron valores más bajos de δD en las plumas que aquellos encontrados en aves del segundo año de edad o mayores, sugiriendo un origen más boreal y que fueron capturadas durante el inicio del período de migración otoñal. Nuestro estudio demuestra como el mé todo de isótopos estables puede ser usado para documentar conectividad entre poblaciones reproductivas e invernales de aves migratorias.


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