Breeding habitat use and conservation status of the ...

Ardeola 59(2), 2012, 291-300

BREEDING HABITAT USE AND CONSERVATION STATUS OF THE TURTLE DOVE STREPTOPELIA TURTUR IN NORTHERN SPAIN USO DEL HÁBITAT DE REPRODUCCIÓN Y ESTADO DE CONSERVACIÓN DE LA TÓRTOLA EUROPEA STREPTOPELIA TURTUR EN EL NORTE DE ESPAÑA Mario SÁENZ DE BURUAGA1, Alejandro ONRUBIA1, José María FERNÁNDEZ-GARCÍA2 *, Miguel Ángel CAMPOS1, Felipe CANALES1 and José María UNAMUNO1

SUMMARY.—We investigated the abundance and breeding habitat use of the turtle dove Streptopelia turtur in the Basque Country (northern Spain). Censuses employed 500 m transects, distributed across 100 km2 grid cells where the species was previously known to occur. Turtle doves were only detected in two out of four biogeographic sectors sampled. The species was found in forested habitats, riparian forests and evergreen oak patches in particular, but its abundance decreased as tree cover increased. The abundance in farmland was lower, probably as a consequence of the scarcity of adequate nest sites. The range contraction described for this population stresses its unfavourable conservation status and the need to implement action, especially in relation to its breeding habitats. Key words: Basque Country, breeding abundance, Columbidae, farmland, population decline, riparian forest. RESUMEN.—Se investigó la abundancia y el uso del hábitat durante la época de reproducción por la tórtola europea Streptopelia turtur en el País Vasco (norte de España). Los censos se desarrollaron mediante transectos de 500 m distribuidos en cuadrículas de 100 km2 con presencia anteriormente conocida de la especie. De los cuatro sectores biogeográficos estudiados, sólo en dos se detectaron ejemplares. La especie utilizó hábitats forestales, en particular bosques de ribera y parches de encinar, pero con abundancias decrecientes al aumentar la cobertura arbórea. La abundancia en cultivos resultó bastante inferior, seguramente como consecuencia de la falta de sustratos adecuados para instalar el nido en estos ambientes. La reducción del área de distribución de esta población remarca su desfavorable estado de conservación y la conveniencia de adoptar medidas, en particular respecto al hábitat de reproducción. Palabras clave: abundancia reproductiva, bosque de ribera, Columbidae, declive poblacional, País Vasco, paisajes cultivados.

1 2

Consultora de Recursos Naturales S.L., Castillo de Quejana, 11, 01007 Vitoria, Spain. IHOBE, Granja Modelo s/n, 01192 Arkaute, Álava, Spain.

*

Corresponding author: [email protected]

292

SÁENZ DE BURUAGA, M. et al.

INTRODUCTION The turtle dove Streptopelia turtur is a summer visitor to Europe, with breeding strongholds reported from the Mediterranean basin (France, Italy, Spain, Turkey) and Russia (Burfield and Van Bommel, 2004). Western European populations winter in the SahelianSudanian savannah belt of western Africa (Senegal, Mauritania and Mali; Morel, 1987), and migratory flyways include southern France, the Iberian Peninsula and Morocco (Aebischer, 2002). Conservation of this population is therefore of international concern. Western European populations of the turtle dove have undergone a steep decline through the 1980s and 1990s. Bird monitoring programmes at country level, migration counts, breeding range evolution and bag statistics show this decline, both in the large populations in Spain and France and the smaller ones in Portugal, Britain, The Netherlands, Belgium and Germany (Boutin and Lutz, 2007). As a consequence, the turtle dove is considered to have an unfavourable conservation status in Western Europe (Burfield and Van Bommel, 2004). Although the impacts of climate change, droughts and food supply in wintering areas (Eraud et al., 2009), hunting (Boutin, 2001; Hidalgo and Rocha, 2001) and competition with the collared dove Streptopelia decaocto remain poorly known or require further assessments (but see Jarry, 1999; Zwarts et al., 2009), this long-term decline has been primarily attributed to breeding habitat loss and changes in agricultural land-use (Boutin and Lutz, 2007). Farmland habitat diversity has decreased in Europe (Pain and Pienkowski, 1997; Chamberlain and Fuller, 2000), with resulting woodland and hedgerow removal and absolute loss of nesting cover (Fuller et al., 2004). The increased use of herbicides, eradication of hedgerows and woodland patches within farmland, field enlargement and the reduced extent of cereal cultivation Ardeola 59(2), 2012, 291-300

have been proposed as human-related factors putting pressure on populations. Habitat degradation may have also taken place, with a reduction in availability of specific requirements, such as tall, overgrown bushes for nesting or wild plants in non-arable grasslands for feeding (Rocha and Hidalgo, 2002). This role of diminished breeding habitat quality in the decline of the turtle dove populations has been stressed by several investigations (review in Boutin and Lutz, 2007; Reif et al., 2008). A likely conclusion, using the available information, is that major changes in breeding habitats have led to dietary shift, extended home ranges and longer distances travelled between nesting and feeding sites, driving a reduction in the populations’ breeding output, which underlies population decline (Browne et al., 2005). In such a context, precise knowledge of the species’ habitat requirements across its home ranges is urgently needed to understand the role of certain habitat features in favouring higher turtle dove densities, and to develop targeted and effective conservation measures (Browne and Aebischer, 2005; Boutin and Lutz, 2007). In addition, this could enable management options at landscape or patch scales to be identified, targeting turtle dove population enhancement and conservation. However, few quantitative studies have addressed these questions in Europe (Browne and Aebischer, 2005). Here we present and analyse field data to assess varying densities of the turtle dove across a contrasting study area with a gradient of Atlantic-Mediterranean habitats and to describe and model breeding habitat use at landscape and patch scales, using presence and abundance of the species as dependent variables.

MATERIAL AND METHODS Our study area was the Basque Country, a region of 7,230 km 2 in northern Spain, straddling the Atlantic and Mediterranean

293

TURTLE DOVE BREEDING HABITAT CONSERVATION

biogeographical domains in Western Europe. This implies the existence of a defined ecological gradient in a relatively small region. Fieldwork was performed in the 29 Universal Transverse Mercator (UTM) 100 km2 grid cells where turtle dove presence was detected in the Spanish breeding bird atlas, with data recorded during 1998-2001 (Balmori,

2003; fig. 1). These cells were distributed across four different large sectors, showing particular climatic, vegetational and land use characteristics: coastal (8 cells), central plain (7), transition valleys (7) and the Ebro river plain (7). Based on a digital layer of the EUNIS habitat map at 1:10,000 scale, habitat polygons

Coastal

Central plain Transition valleys Ebro plain

FIG. 1.—Study area, sampled sectors and UTM 100 km2 grid cells. [Área de estudio, sectores biogeográficos y cuadrículas UTM de 100 km2 muestreadas.] Ardeola 59(2), 2012, 291-300

294


in the 29 cells were reclassified into broader structural types: woodland (pine Pinus spp., oak Quercus spp., evergreen oak Quercus ilex, beech Fagus sylvativa), scrub (heath, thorn bush, juniper Juniperus spp.), farmland (cereal, orchard and vineyard), riparian forests, wetland, urban, gardens and others. Locations at altitudes above 1,000 m were excluded, since the turtle dove avoids mountain habitats (Browne and Aebischer, 2005). Fieldwork took place between 15 June and 6 July 2006, taking into account that turtle dove singing activity and detection rates remain fairly constant until mid-July (Calladine et al., 1999). Censuses were only performed in the early mornings, excluding days of unsuitable weather conditions (wind, rain). Turtle dove presence and abundance were recorded by a qualified observer along transects 500 m long. Transects were recorded as global positioning system (GPS) tracks and transferred to a geographic information system (GIS) layer. The number of transects in each cell was distributed in proportion to the pooled surface of woodland, scrub, farmland and riparian patches within each cell, calculated using GIS software ArcView 3.2. Therefore, field effort involved 342 transects in total, from four to eighteen transects per cell (mean = 11.8, sd = 3.8, N = 29). Transects were previously selected according to the availability of walking paths across targeted habitat patches, but homogeneous distribution throughout the cell was also intended. Average altitude and vegetation structural type for each transect was extracted using a digital elevation model and the reclassified EUNIS habitat map. Average cover for woodland, scrub and pastureland were visually estimated in the field. Every observation of a turtle dove along transects, either heard or seen, was assigned to one of four distance strips, parallel to the progression line: 0-25, 25-50, 50-75 and 75100 m. Several microhabitat features were Ardeola 59(2), 2012, 291-300

recorded in a circular plot (50 m radius) around each turtle dove observation point: topographic exposure, altitude, vegetation structural type, tree cover, scrub cover, pasture cover, tree height and dominant tree species. Turtle dove density per transect (D) was calculated using the Emlen formula D = n / 2 × L × W × CD, with n as the number of observations per transect, L the transect length (500 m), W the maximum strip width (100 m), and CD the coefficient of detectability, estimated in particular for woodland, scrub, farmland and riparian transects, through the distribution function of turtle observations in census strips (Emlen, 1977; Tellería, 1986). The Emlen formula applies when counting strips are used, instead of precise distances to contacts (Bibby et al., 1998). Fieldwork was intended to maximise the number of transects sampled, so rapid data collection was preferred. In the case of riparian transects, only data from one side of each transect was considered, given the linear spatial structure of this type of habitat. Density per cell was expressed as mean ± sd and range (maximum-minimum). The relative abundance of turtle doves was simply expressed as the total number of birds observed per transect. After considering the distribution of turtle dove abundance across the whole study area, habitat analysis was only performed using data from the Ebro plain. One-way ANOVA and post hoc Bonferroni method (Dytham, 2003) were performed using relative abundance data, to assess differences in the use of broad habitat structural types at transect or landscape scales. Levene’s statistic was previously used to test for homogeneity of variances. The Pearson product-moment correlation coefficient and linear and quadratic regression analysis were used to describe relationships between turtle dove abundance per transect and tree, scrub and pasture cover; data was previously log-transformed. A logistic regression model (forward


295

stepwise) was used to determine which independent variables (altitude, habitat structural type, tree cover, scrub cover, pasture cover and presence of water) best explained turtle dove presence across transects (Dytham, 2003). Finally, the number of observations was plotted against microhabitat variables and categories, to describe habitat use at the patch scale. Statistical analyses were performed with Statgraphics Plus 4.0.

RESULTS Densities A total of 127 turtle doves were recorded during field transects, 104 inside census strips. Seventy-one transects were surveyed in the coastal area, and 96 in the central plain, without recording any turtle doves. In the transitional valleys, 77 transects were surveyed, recording nine turtle doves (six inside census strips). Finally, 98 transects were surveyed on the Ebro plain, and 118 turtle doves were found (98 of them within census strips). Mean estimated densities (birds per ha) were 0.10 ± 0.04 (range 0.07-0.14) for riparian patches in transitional valleys, 0.19 ± 0.09 (0.10-0.28) for woodland on the Ebro plain, 0.05 ± 0.02 (0.02-0.07) for farmland on the Ebro plain, and 0.26 ± 0.05 (0.21-0.30) for riparian patches on the Ebro plain. Regarding broad vegetation structural types, the density of turtle doves in farmland was significantly lower than in woodland and riparian habitats (F 2, 13 = 6.95, P < 0.01; Bonferroni 95 % confidence intervals; fig. 2).

Habitat use The mean percentage tree cover for sampled transects on the Ebro plain was 15.84 ± 23.05 (range 0-100), scrub cover

FIG. 2.—Density (birds/ha, average value and sd) of turtle doves Streptopelia turtur on the Ebro plain sector of the study area, within broad habitat structural types. [Densidad (aves/ha, promedio y sd) de tórtola europea Streptopelia turtur en el sector valle del Ebro del área de estudio, según ambientes.]

was 26.51 ± 24.17 (0-100), pasture cover was 58.93 ± 29.28 (0-100) and altitude was 539.44 ± 11.57 (385-748) metres above sea level. Turtle dove abundance per transect increased with tree cover but tended to decrease slightly when this was over 40% (y = 1.51 + 0.05 × –0.0004x2, r2 = 0.04, F = 0.54, N = 31). Abundance was high with low scrub cover but decreased sharply at over 25% cover (y = 4.37 – 0.13x + 0.001 × 2, r 2 = 0.26, F = 6.21, p < 0.01, N = 38). In pasture, abundance tended to decrease with increasing cover (y = 3.16 – 0.02x, r2 = 0.08, F = 3.03, N = 39; fig. 3). The logistic regression model showed significant relationships between turtle dove presence in transects, scrub cover, pasture cover and presence of water (table 1). The model correctly classified 83% of cases. A large proportion (42%) of turtle dove contacts (N = 118) were in plots with a southern exposure, while only 17% accounted for a western, eastern or northern and 41% did Ardeola 59(2), 2012, 291-300

296


TABLE 1 Logistic regression model for the probability of presence of turtle dove Streptopelia turtur in the Ebro plain sector of the study area. B, regression coefficient; SE, standard error. [Modelo de regresión logística para la probabilidad de aparición de tórtola europea Streptopelia turtur en el sector valle del Ebro del área de estudio. B, coeficiente de regresión; SE, error estándar.]

SE

Wald

P

Exp (B)

Pasture cover

–0.07 0.02

14.79

0.001

0.93

Scrub cover

–0.08 0.02

12.55

0.001

0.92

2.05 0.61

11.21

0.01

7.75

Variable

Presence of water

FIG. 3.—Simple regressions between the dependent variable “turtle dove abundance per transect” (number of birds recorded) and percentage tree cover (a), scrub cover (b) and pasture cover (c) on the Ebro plain sector of the study area. [Gráficas de regresión simple entre la variable dependiente “abundancia de tórtola europea por transecto” (número de aves contabilizadas) y el porcentaje de cobertura de arbolado (a), matorral (b) y herbazales (c) en el sector valle del Ebro del área de estudio.] Ardeola 59(2), 2012, 291-300

B

not show a definite exposure. About 40% of turtle dove contacts were in plots including 10-30% tree and scrub cover. Plot distribution in relation to pasture cover was quite homogeneous, although the maximum number of contacts (24%) was observed with 30-40% cover. Tree height ranged between 5 and 15 m in 72% of plots and 85% of contacts were on poplars Populus nigra, P. alba, evergreen oak, ash Fraxinus angustifolia and pine Pinus halepensis. The distribution of contacts was strongly biased towards plots with forest vegetation, whether riparian (60%), evergreen oak (20%) or pine patches (10%). Finally, 53% of turtle dove contacts were at 350449 m altitude with much lower proportions at 450-549 m (11%), 550-649 m (14%) and 650-749 m (22%), although the distribution of transects across these four altitudinal categories was homogenous.


DISCUSSION Little quantitative information is available on breeding habitat use by turtle dove populations at landscape and patch scales throughout Europe (Browne and Aebischer, 2005), although several studies have addressed the breeding ecology and have described the microhabitat (tree) favoured for supporting and protecting nests (Murton, 1968; Peiró, 1990; Aubineau and Boutin, 1998; Rocha and Hidalgo, 2002; Browne and Aebischer, 2004; Browne et al., 2005; Hanane and Baamal, 2011). In Britain, agricultural plots were under-used within home ranges, as opposed to wooded plots, probably reflecting the species’ territorial behaviour close to nest sites. As a result, turtle doves avoided extensive open areas and dense, large woodland tracts, their densities in farmland being related to the length of interspersed hedgerows and woodland edges (Browne et al., 2004). In western Spain, Rocha and Hidalgo (2002) described much higher densities in wooded pastureland (dehesas) and, in southern Spain, Gutiérrez (2001) found a strong preference for poplar Populus sp. plantations and a weak one for evergreen oak woodlands. Browne et al. (2005) presented evidence on regional variations in habitat use that supplements detailed research on this topic. In our study, forested areas clearly provided the principal breeding habitats for the turtle dove population, whereas farmland played a much more secondary role. In particular, linear riparian forests, whether natural or planted, harboured the highest frequency of contacts and numbers of birds, followed by patches of open evergreen oak forest, interspersed with crops. This pattern is related to the selection of these habitats for performing territorial displays (Browne and Aebischer, 2003), and to the availability of trees at least 5-6 m high to support nests (Hinsley et al., 1995; Peiró, 2001; Browne et al., 2005). However, an increasing dominance of tree cover also reduces

297

turtle dove use, the species avoiding mature, large and dense forest tracts (Bakaloudis et al., 2009) because of its dependence on grassland and arable land as feeding sites. Densities of the species across its breeding range are highly variable, from 0.5 to more than 40 pairs per km2 (Boutin, 2001; Browne and Aebischer, 2005). But comparisons between published censuses are not straightforward because there is an apparent latitudinal trend in abundance (higher densities to the south of the range, Hanane and Baamal, 2011) and the marked variations in hourly singing activity influence detectability (Calladine et al., 1999). In our case, fieldwork was undertaken at comparable times of day, so that the geographical and habitat differential densities shown are conclusive. Riparian forest patches are definitely important habitats for this and other turtle dove populations (Gutiérrez, 2001) but it is unknown whether breeding outputs differs between artificial poplar plantations and natural forests (Balmori, 2004; Anderson et al., 2004). This probably deserves further investigation, since numerous natural habitat patches are disappearing in Spain whereas plantations are becoming increasingly frequent in the landscape, and this regional trend is expected to accelerate in the near future (Ministerio de Medio Ambiente, 2002; Álvarez and Garavilla, 2007). The long-term decline of the western European turtle dove populations has been described in terms of decreasing abundance and contracting range, both at regional and wider scales (Gibbons et al., 1993; Juillard and Jiguet, 2005; Roux et al., 2007; Boutin and Lutz, 2007; Eaton et al., 2009; SEO/BirdLife, 2012). The picture in Europe as a whole is of a “moderate decline” over recent decades (Burfield and Van Bommel, 2004; PECBMS, 2012). In the study area, the breeding population of the turtle dove was known to have been broadly distributed during the 1980s (Álvarez et al., 1985). However, fifteen years later, the Ardeola 59(2), 2012, 291-300

298


breeding range was reduced (Balmori, 2003) to the four sectors investigated here: coastal, central plain, transitional valleys and Ebro valley plain. Its persistence in these separate areas could be a reflection of the species favouring low altitudes and warm, temperate climates (Browne and Aebischer, 2005), since the rest of the study area, from where the species has disappeared, comprises mountain ranges and higher than average altitudes. This numerical decrease has also taken place in other regions in northern Spain, such as Navarra and Cataluña, as shown by quantitative changes in turtle dove range (Estrada et al., 2004; Fernández and Gainzarain, 2006). Range change is correlated with population change and repeated atlas data is a valuable tool for monitoring (Donald and Fuller, 1998; Gibbons et al., 2007). Therefore, a longterm population decline of the turtle dove in northern Spain can also be assumed. We failed to detect its presence in two of the four sectors within the study area and we suggest that range contraction has continued recently, although we cannot be certain on account of the lack of standardization of the atlas data. Although the turtle dove in Spain is a game species and is not legally considered as protected or endangered, detailed monitoring and targeted conservation actions should be implemented, in view of this continuous and extended decline (Balmori, 2004; Boutin and Lutz, 2007). The key breeding habitats supporting the highest densities on the northern Spanish plains are open woodland patches within the farmland matrix and, especially, riparian woodlands. The spatial configurations of these habitats maximise the length of edges between woodland and farmland, which correlates positively with turtle dove densities (Browne et al., 2004). Management options should include the preservation and extension of such patchy habitats, to increase both the availability of nesting sites and the breeding output of the population (Browne and Aebischer, 2005). Ardeola 59(2), 2012, 291-300

ACKNOWLEDGEMENTS.—This study was funded by the Environment, Landscape Planning and Agriculture Department of the Basque Government. Juan Carlos Reboreda, José Antonio Gainzarain and Ernest Garcia made valuable comments. We also thank Anthony Clevenger for checking the English.

BIBLIOGRAPHY AEBISCHER, N. J. 2002. European turtle dove. In, C. Werham, M. Toms, J. Marchant, J. Clark, G. Siriwardena and Baillie, S. (Eds.): The Migration Atlas. Movements of the Birds of Britain and Ireland, pp. 420-422. Poyser. London. ÁLVAREZ, J., BEA, A., FAUS, J. M., CASTIÉN, E. and MENDIOLA, Í. 1985. Atlas de los Vertebrados Continentales de Álava, Vizcaya y Guipúzcoa (excepto Chiroptera). Gobierno Vasco. Bilbao. ÁLVAREZ, C. and GARAVILLA, V. 2007. Bosques cultivados y bosques de ribera en La Rioja. Foresta, 35: 72-79. ANDERSON, G. Q., HASKINS, L. R. and NELSON, S. H. 2004. The effects of bioenergy crops on farmland birds in the United Kingdom: a review of current knowledge and future predictions. Biomass and Agriculture. Sustainability, Markets and Policies, pp. 199-218. Organisation for Economic Co-operation and Development. Paris. AUBINEAU, J. and BOUTIN, J. M. 1998. L’impact des modalités de gestion du maillage bocager sur les colombidés nicheurs dans l’ouest de la France. Game and Wildlife Science, 15: 55-63. BAKALOUDIS, D. E., VLACHOS, C. G., CHATZINIKOS, E., BONTZORLOS, V. and PAPAKOSTA, M. 2009. Breeding habitat preferences of the turtle dove (Streptopelia turtur) in the Dadia-Sougli National Park and its implications for management. European Journal of Wildlife Research, 55: 597-602. BALMORI, A. 2003. Streptopelia turtur. In, R. Martí, and J. C. del Moral (Eds.): Atlas de las Aves Nidificantes de España, pp. 306-307. Ministerio de Medio Ambiente. Madrid. BALMORI, A. 2004. Streptopelia turtur. In, A. Madroño, C. González, and J. C. Atienza (Eds.): Libro Rojo de las Aves de España, pp. 281-285. Ministerio de Medio Ambiente. Madrid.


BIBBY, C., JONES, M. and MARSDEN, S. 1998. Expedition Field Techniques. Bird Surveys. Royal Geographic Society. London. BOUTIN, J. M. 2001. Elements for a turtle dove (Streptopelia turtur) management plan. Game and Wildlife Science, 18: 87-112. BOUTIN, J. M. and LUTZ, M. 2007. Management Plan for Turtle Dove (Streptopelia turtur) 2007-2009. European Commission. Luxembourg. BROWNE, S. J. and AEBISCHER, N. J. 2004. Temporal changes in the breeding ecology of European turtle doves Streptpelia turtur in Britain, and implications for conservation. Ibis, 146: 125-137. BROWNE, S. J. and AEBISCHER, N. J. 2005. Studies of West Palearctic birds: turtle dove. British Birds, 98: 58-72. BROWNE, S. J., AEBISCHER, N. J. and CRICK, H. Q. 2005. Breeding ecology of turtle doves Streptopelia turtur in Britain during the period 19412000: an analysis of BTO nest record cards. Bird Study, 52: 1-9. BROWNE, S. J., AEBISCHER, N. J., YFANTIS, G. and MARCHANT, J. H. 2004. Habitat availability and use by turtle doves Streptopelia turtur between 1965 and 1995: an analysis of Common Birds Census data. Bird Study, 51: 1-11. BURFIELD, I. and VAN BOMMEL, F. 2004. Birds in Europe. Population Estimates, Trends and Conservation Status. BirdLife International. Cambridge. CALLADINE, J., BUNER, F. and AEBISCHER, N. J. 1999. Temporal variations in the singing activity and the detection of turtle doves Streptopelia turtur: implications for surveys. Bird Study, 46: 74-80. CHAMBERLAIN, D. R. and FULLER, R. J. 2000. Local extinctions and changes in species richness of lowland farmland birds in England and Wales in relation to recent changes in agricultural landuse. Agriculture, Ecosystems and Environment, 78: 1-17. DONALD, P. F. and FULLER, R. J. 1998. Ornithological atlas data: a review of uses and limitations. Bird Study, 45: 129-145. DYTHAM, C. 2003. Choosing and Using Statistics. A Biologist’s Guide. Blackwell Publishing. Oxford.

299

E ATON , M. A., B ROWN , A. F., N OBLE , D. G., MUSGROVE, A. J., HEARN, R. D., AEBISCHER, N. J., GIBBONS, D. W., EVANS, A. and GREGORY, R. D. 2009. Birds of conservation concern 3: the population status of birds in the United Kingdom, Channel Islands and Isle of Man. British Birds, 102: 296-341. EMLEN, J. T. 1977. Estimating breeding season bird densities from transect counts. The Auk, 94: 455-468. ERAUD, C., BOUTIN, J. M., RIVIERE, M., BRUN, J., BARBRAUD, C. and LORMÉE, H. 2009. Survival of turtle doves Streptopelia turtur in relation to western Africa environmental conditions. Ibis, 151: 186-190. E STRADA , J., P EDROCCHI , V., B ROTONS , L. and HERRANDO, S. 2004. The Catalan Breeding Bird Atlas 1999-2002. Lynx. Barcelona. FERNÁNDEZ, J. M. and GAINZARAIN, J. A. 2006. Tendencias poblacionales recientes de la avifauna del País Vasco y de Navarra, según las variaciones de su distribución. In, J. M. Fernández (Ed.): Actas del Encuentro de Ornitología en Álava, pp. 25-40. Diputación Foral de Álava. Vitoria. FULLER, R. J., HINSLEY, S. A. and SWETNAM, S. A. 2004. The relevance of non-farmland habitat, uncropped areas and habitat diversity to the conservation of farmland birds. Ibis, 146: 22-31. GIBBONS, D. W., DONALD, P. F., BAUER, H. G., FORNASARI, L. and DAWSON, I. K. 2007. Mapping avian distributions: the evolution of bird atlases. Bird Study, 54: 324-334. GIBBONS, D. W., REID, J. B. and CHAPMAN, R. A. 1993. The New Atlas of Breeding Birds in Briatin and Ireland: 1998-1991. Poyser. London. GUTIÉRREZ, J. E. 2001. Les populations de tourterelles des bois en Andalousie. Faune Sauvage. Cahiers Techniques, 253: 36-43. HANANE, S. and BAAMAL, L. 2011. Are Moroccan fruit orchards suitable breeding habitats for turtle doves Streptopelia turtur? Bird Study, 58: 57-67. HIDALGO, S. J. and ROCHA, G. 2001. Valoración de la presión cinegética sobre la tórtola común en Extremadura. In, A. Bea, and J. M. Fernández (Eds.): Biología y gestión de colúmbidos silvestres. II Coloquio Internacional. Naturzale. Cuadernos de Ciencias Naturales, 16: 157-171. Ardeola 59(2), 2012, 291-300

300


HINSLEY, S. A., BELLAMY, P. E., NEWTON, I. and S PARKS , T. H. 1995. Habitat and landscape factors influencing the presence of individual breeding bird species in woodland fragments. Journal of Avian Biology, 26: 94-104. JARRY, G. 1999. La tourterelle des bois (Streptopelia turtur), une spece dont le declin est principalement lie a la scheresse en Afrique tropicale. In Actes du Colloque International Oiseaux Migrateurs Chasses en Mauvais Etat de Conservation et Points Chauds Europeens, pp. 11-18. Orgambidexka Col Libre. Bayonne. JUILLARD, G. and JIGUET, F. 2005. Statut de conservation en 2003 des oiseaux communs nicheurs en France selon 15 ans de programme STOC. Alauda, 73: 345-356. MINISTERIO DE MEDIO AMBIENTE. 2002. Plan Forestal Español. Madrid. MOREL, M. Y. 1987. La tourterelle des bois Streptopelia turtur dans l’ouest africain: mouvements migratoires et regime alimentaire. Malimbus, 9: 23-42. MURTON, R. K. 1968. Breeding, migration and survival of turtle doves. British Birds, 61: 193-212. PAIN, D. J. and PIENKOWSKI, M. W. 1997. Farming and Birds in Europe: the Common Agricultural Policy and its Implications for Bird Conservation. Academic Press. London. PECBMS. 2012. Population Trends of Common European Breeding Birds 2012. Czech Society for Ornithology. Prague. PEIRÓ, V. 1990. Aspectos de la reproducción de la tórtola común (Streptopelia turtur) en Madrid. Mediterránea (Serie Biología), 12: 89-96.

Ardeola 59(2), 2012, 291-300

PEIRÓ, V. 2001. Écologie de la reproduction de la tourterelle des bois en Espagne. Faune Sauvage. Cahiers Techniques, 253: 63-65. R EIF, J., STORCH, D., VORÍSEK, P., STASTNÝ, K. and BEJCEK, V. 2008. Bird-habitat associations predict population trends in central European forest and farmland birds. Biodiversity and Conservation, 17: 3307-3319. ROCHA, G. and HIDALGO, S. J. 2002. La Tórtola Común Streptopelia turtur. Análisis de los factores que afectan a su status. Universidad de Extremadura. Cáceres. ROUX, D., LORMEE, H., ERAUD, C., BOUTIN, J. M., LANDRY, P. and DEJ, F. 2007. Suivi des Populations Nicheuses des Oiseaux de Passage en France. Office National de la Chasse et de la Faune Sauvage. Nantes. SEO/BIRDLIFE. 2012. Programas de Seguimiento de SEO/BirdLife en 2011. SEO/BirdLife. Madrid. TELLERÍA, J. L. 1986. Manual para el Censo de los Vertebrados Terrestres. Raíces. Madrid. Z WARTS , L., B IJLSMA , R., VAN D ER K AMP, J. and WYMENGA. E. 2009. Living on the Edge. Wetlands and Birds in a Changing Sahel. KNNV Publishing. Zeist. Received: 15 November 2011 Accepted: 26 September 2012 Editor: Juan C. Reboreda