Garden Warbler <i>Sylvia borin</i> migration in sub‐Saharan West Africa: a comment on Ottosson <i>et al</i>. (2005)

Smith, V. W.

doi:10.1111/j.1474-919x.2006.00646.x

Cited by 17 publications

(20 citation statements)

References 9 publications

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“…The maximum gain recorded at Djoudj was 3.1 g (2.6% LBM/day, while recorded rates at Amurum were up to 4.3% LBM/day). Garden Warblers were absent from Djoudj in December-February, as was essentially the case for all sites considered by Smith (2007) and Ottosson et al (2005), and did not reappear until the return migration, principally in April (Fig 2): this is further evidence that Garden Warblers do not spend the winter in the northern Sahel region.…”

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confidence: 59%

“…They concluded that Garden Warblers stop over in both the Sahel and Guinea-savannah regions of West Africa during autumn but only in the latter in spring, and that neither of these regions regularly hosts wintering birds. A further comment by Smith (2007) indicates that the data of Ottosson et al (2005) largely agree with those he had collected himself some 40 years earlier (Smith 1963(Smith , 1965(Smith , 1966 The earliest capture at Djoudj was on 13 October, over a month later than recorded by Smith (2007) or Ottosson et al (2005), whilst the latest, on 20 November, was over three weeks earlier (Table 1; see Fig 1 for study site locations). The later autumn arrival at Djoudj is most likely an artefact of capture effort, as little or no effort took place in September, whilst the earlier departure is probably a reflection of the more northerly location of Djoudj relative to the other sites (see Fig 1).…”

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confidence: 60%

“…In particular, the regions or sites used in preparation for crossing the Sahara Desert during spring migration, which generally requires large fuel loads (Wood 1989), may be vital to the success of migration and even carry over into reproductive success (Newton 2004). Amongst migratory passerines the ecology of the Garden Warbler Sylvia borin has been well studied (eg Bairlein 1991, Schaub & Jenni 2000 and a growing body of information details the migration of this species in West Africa (Ottosson et al 2005, Smith 2007). To add to one of the most complete pictures for a migratory passerine in sub-Saharan Africa, we present a brief summary of current knowledge and compare it to data collected in Senegal by the Wetland Trust.…”

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confidence: 99%

“…Indeed, the mean estimated flight range Table 1. Comparison of body mass recordings and passage times between data collected at Djoudj and all sites considered by Smith (2007) and Ottosson et al (2005) in sub-Saharan West Africa during autumn and spring migration. All body mass measurements are given in grams and where measurements are absent it signifies that the data were not presented, whilst NC = no captures.…”

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confidence: 99%

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Garden WarblerSylvia borinmigration in sub‐Saharan West Africa

Bayly

Rumsey

2010

Ringing & Migration

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Garden WarblerSylvia borinmigration in sub‐Saharan West Africa

Bayly

Rumsey

2010

Ringing & Migration

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“…The phenology of migration and body mass patterns of Garden Warblers at Malamfatori (Sahel zone of Northern Nigeria) and Amurum (Guinea savanna zone of Nigeria) has been reported by Ottosson et al (2005). Also, data from previous studies have shown that the species does not spend the winter in the Sahel and Guinea Savanna (Ottosson et al 2005, Smith 2007, Bayly & Rumsey 2010. Thus, drawing from these published works, it is clear that during the autumn passage, and after a few months in the Guinea savanna region of Nigeria, Garden Warblers embark on a new leg of migration, presumably to their final wintering quarters.…”

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confidence: 87%

The stopover behaviour of the Garden Warbler Sylvia borin in Obudu, southeast Nigeria

Iwajomo¹,

Ottosson²,

Barshep

et al. 2011

Ornis Svec

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The Garden Warbler breeds in the Palaearctic and migrates to sub-Saharan Africa for the non-breeding season. We studied its passage, body mass and moult at the Obudu Plateau in southeast Nigeria in October–December 2005 and December 2007–January 2008. In Nigeria, Garden Warblers in the Guinea savanna have been shown to increase body mass in October–November, preparing for migration to wintering sites further south. They begin to arrive at Obudu from mid-October and the numbers gradually increase with time; median date of passage was 3 December. This influx is clearly different from that which has been recorded for other sites in West Africa. The patterns in wing length and size-corrected body mass of individuals suggest a difference in the migration time of individuals of different sizes in the two years. Average fuel loads were lower at Obudu than has been reported in Central Nigeria. This, and the capture of moulting individuals, suggests that Garden Warblers may not embark on a longer journey southwards in mid winter, and possibly may even winter at Obudu.

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Automating Discovery and Classification of Transients and Variable Stars in the Synoptic Survey Era

Bloom¹,

Richards²,

Nugent³

et al. 2012

Publications of the Astronomical Society of the Pacific

173

153

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The rate of image acquisition in modern synoptic imaging surveys has already begun to outpace the feasibility of keeping astronomers in the real-time discovery and classification loop. Here we present the inner workings of a framework, based on machine-learning algorithms, that captures expert training and ground-truth knowledge about the variable and transient sky to automate 1) the process of discovery on image differences and, 2) the generation of preliminary science-type classifications of discovered sources. Since follow-up resources for extracting novel science from fast-changing transients are precious, self-calibrating classification probabilities must be couched in terms of efficiencies for discovery and purity of the samples generated. We estimate the purity and efficiency in identifying real sources with a two-epoch image-difference discovery algorithm for the Palomar Transient Factory (PTF) survey. Once given a source discovery, using machine-learned classification trained on PTF data, we distinguish between transients and variable stars with a 3.8% overall error rate (with 1.7% errors for imaging within the Sloan Digital Sky Survey footprint). At >96% classification efficiency, the samples achieve 90% purity. Initial classifications are shown to rely primarily on context-based features, determined from the data itself and external archival databases. In the ∼one year since autonomous operations, this discovery and classification framework has led to several significant science results, from outbursting young stars to subluminous Type IIP supernovae to candidate tidal disruption events. We discuss future directions of this approach, including the possible roles of crowdsourcing and the scalability of machine learning to future surveys such a the Large Synoptical Survey Telescope (LSST).

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Garden Warbler Sylvia borin migration in sub‐Saharan West Africa: a comment on Ottosson et al. (2005)

Cited by 17 publications

References 9 publications

Garden WarblerSylvia borinmigration in sub‐Saharan West Africa

Garden WarblerSylvia borinmigration in sub‐Saharan West Africa

The stopover behaviour of the Garden Warbler Sylvia borin in Obudu, southeast Nigeria

Automating Discovery and Classification of Transients and Variable Stars in the Synoptic Survey Era

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