| 1. |
- Andueza, Miren, et al.
(författare)
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Connectivity in Reed Warblers Acrocephalus scirpaceus between breeding grounds in Europe and autumn stopover sites in Iberia
- 2013
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Ingår i: Ardea. - : Netherlands Ornithologists' Union. - 0373-2266. ; 101:2, s. 133-140
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Tidskriftsartikel (refereegranskat)abstract
- We determined the degree of connectivity in the Eurasian Reed Warbler Acrocephalus scirpaceus between breeding regions in central and northern Europe and stopover sites in Iberia, during the autumn migration. We used both recovery data and wing length analyses to achieve this. Biometric data were obtained during 2009 at 11 sampling localities in Iberia, which we amalgamated into four major migratory areas within the region (Central, Western, Eastern and Southwestern Iberia, hereafter CI, WI, EI, SW). From the EURING database, we selected birds captured at their breeding sites in Europe and recaptured in Iberia during the autumn migration. Reed Warblers passing through WI had shorter wings than those in CI, EI and SW, suggesting that birds in WI migrated shorter distances, a fact also supported by recovery data. Although Reed Warblers showed some population overlap when passing through Iberia, we found that birds passing through EI and CI came from areas further to the east (continental Europe) than those passing through WI (mainly British Isles), thus supporting parallel migration. Reed Warblers tended to converge in southwestern Iberia, suggesting an effect of nearby geographical barriers.
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| 2. |
- Andueza, Miren, et al.
(författare)
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Geographic variation in body mass of first-year Reed Warblers Acrocephalus scirpaceus in Iberia
- 2014
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Ingår i: Ornis Fennica. - 0030-5685. ; 91:2, s. 88-99
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Tidskriftsartikel (refereegranskat)abstract
- On their route to tropical Africa, European trans-Saharan migrants must cross two major geographical barriers, the Mediterranean Sea and the Sahara Desert, which necessitates the accumulation of large fuel loads. While northern Africa is the chief region where most migrants gain fuel for the Sahara crossing, Iberia is a target area to gain fuel before the sea crossing existing between Europe and Africa. Despite the large body of studies approach- ing the question of fuel accumulation before geographic barriers, it is still poorly known which factors apart from distance to a certain barrier shape the geographical pattern of fuel reserves. To investigate this question in detail we used data of first-year Reed Warblers from 12 localities within Iberia during the autumn migration period of 2009. We run linear models to analyze the effects of location in Iberia, date, and body size on body mass variation at each migratory flyway (eastern, central and western Iberia). Flight ranges from each site were also calculated. Our results showed that Reed Warblers in Iberia had the necessary fuel needed to arrive in northern Africa but not to tropical Africa. However, body mass patterns varied depending on the geographical region (eastern, central or west- ern Iberia). Date did not affect body mass in central and western Iberia, but in eastern Ibe- ria heavier birds tended to pass later. Thus, the factors shaping body mass of Reed War- blers in Iberia before the sea crossing to Africa seemed to be more complex than just the distance to this geographical barrier, with underlying stopover quality-associated factors possibly playing a relevant role.
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| 3. |
- De La Hera, Ivan, et al.
(författare)
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Inferring the migratory status of woodland birds usisng ringing data: the case of a constant-effort site located in the Iberian highlands.
- 2014
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Ingår i: Ardeola. - : Ardeola. - 0570-7358 .- 2341-0825. ; 61:1, s. 77-95
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the spatiotemporal distribution of birds is crucial for effective management and conservation of their populations. However, we still have only limited knowledge not only of the wintering destinations of many Iberian breeding migrants but also of aspects as general as the migratory behaviour of the populations of many common avian species that breed in the Iberian highlands. We used bird-ringing data to shed light on the migratory status (migratory, partially-migratory or sedentary) of the breeding populations of 13 common species occurring year-round in a woodland located on an Iberian plateau (Garaio,Araba, Spain; 574 m.a.s.l.), where ringing activities have been carried out over the last 20 years. To assess the extent to which birds breeding on this site remain in the area during winter and/or are replaced by conspecifics coming from other areas, we analysed: (1) changes in relative abundance of birds between summer and winter, (2) the frequency of sedentary individuals (birds captured both in summer and winter period in the study area) in relation to the number of individuals captured only in summer (summer visitors) or in winter (wintering birds), and (3) variation in wing length among summer, wintering and sedentary birds. Our results revealed great variation among species in the intensity of migratory behaviour, and a general arrival of foreign conspecifics during the winter for most of the species studied. Likewise, our study represents an illustrative example of how long-term ringing can be used to shed light on the migratory status of bird populations.
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| 4. |
- Kvist, Laura, et al.
(författare)
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Endangered subspecies of the Reed Bunting (Emberiza schoeniclus witherbyi and E. s. lusitanica) in Iberian Peninsula have different genetic structures.
- 2011
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Ingår i: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7192 .- 2193-7206. ; 152:3, s. 681-693
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Tidskriftsartikel (refereegranskat)abstract
- In the Iberian Peninsula, populations of two subspecies of the Reed Bunting Emberiza schoeniclus have become increasingly fragmented during the last decades when suitable habitats have been lost and/or the popula- tions have gone extinct. Presently, both subspecies are endangered. We estimated the amount of genetic variation and population structure in order to define conservation units and management practices for these populations. We found that the subspecies lusitanica has clearly reduced genetic variation in nuclear and mitochondrial markers, has a drastically small effective population size and no genetic differentiation between populations. In contrast, the sub- species witherbyi is significantly structured, but the popu- lations still hold large amounts of variation even though the effective population sizes are smaller than in the non- endangered subspecies schoeniclus. We suggest several management units for the Iberian populations. One unit includes subspecies lusitanica as a whole; the other three units are based on genetically differentiated populations of witherbyi. The most important genetic conservation mea- sure in the case of lusitanica is to preserve the remaining habitats in order to at least maintain the present levels of gene flow. In the case of the three management units within witherbyi, the most urgent conservation measure is to improve the habitat quality to increase the population sizes.
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