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Capsule: The Dupont’s Lark Chersophilus duponti in Iberia has relatively high breeding success in both core and fragmented habitats, so population declines are more likely to be the result of low juvenile or adult survival. Aims: To measure important aspects of the reproductive biology of one of the most endangered and least known larks: the Dupont’s Lark C. duponti. Methods: We monitored 36 nests in 2 Spanish shrub-steppes, one holding one of the largest European populations (250 pairs) and one composed by fragmented habitat patches holding a smaller population (50 pairs). Results: The breeding season went from late-March to early July. Overall mean (±sd) clutch size was 3.47 ± 0.56, and the number of fledglings per successful nest was 3.0 ± 1.15. Mean nestling period was short (8.2 days). Nests showed similar daily survival rate during the incubation period (0.9750 ± 0.0110) as during the nestling period (0.9545 ± 0.0168), with a mean breeding success of 50%. Predation was the main cause of complete nest failure (83.3% of failed nests in both localities). Conclusion: Breeding parameters did show no significant variation between populations. Breeding success in both sites was generally higher than recorded in previous studies of this and most other lark species, which suggests that breeding success does not compromise long-term viability of these populations. The decline of the studied populations should be explained by other causes, such as a general decrease in habitat quality, habitat loss or habitat fragmentation.

A comprehensive review of the natural history of the Dupont’s Lark Chersophilus duponti in Spain.

In Europe, Dupont’s Lark Chersophilus duponti is a threatened open-habitat bird. Prescribed burning has sometimes been proposed for its conservation, but without evidence of its effectiveness. To evaluate the short-term effects of a summer wildfire on this species, we performed several transect counts in the burnt and unburnt parts of a shrubsteppe in central Spain. The same transects were counted within a three-year interval prior to the fire and were repeated during the first two springs after the fire. We also measured the vegetation during the first two springs after the fire. In the burnt area, we observed a decrease of about 85–100% in Dupont’s Lark abundance, and about 7–15% in the control area. The disappearance of the scrub cover after fire and its slow regeneration, as well as the large increase in grass cover during the second year, may explain the decrease in this habitat-specialist bird species. Fire should be avoided in areas occupied by the Dupont’s Lark, as its negative effects in the short-term may cause local extinctions. However, prescribed burning may be used in neighboring areas to create new open habitats that may be subsequently colonized by this species.

In Europe, Dupont’s Lark Chersophilus duponti is a threatened open-habitat bird. Prescribed burning has sometimes been proposed for its conservation, but without evidence of its effectiveness. To evaluate the short-term effects of a summer wildfire on this species, we performed several transect counts in the burnt and unburnt parts of a shrubsteppe in central Spain. The same transects were counted within a three-year interval prior to the fire and were repeated during the first two springs after the fire. We also measured the vegetation during the first two springs after the fire. In the burnt area, we observed a decrease of about 85–100% in Dupont’s Lark abundance, and about 7–15% in the control area. The disappearance of the scrub cover after fire and its slow regeneration, as well as the large increase in grass cover during the second year, may explain the decrease in this habitat-specialist bird species. Fire should be avoided in areas occupied by the Dupont’s Lark, as its negative effects in the short-term may cause local extinctions. However, prescribed burning may be used in neighboring areas to create new open habitats that may be subsequently colonized by this species.

Se estudia la razón de sexos de los adultos de alondra ricotí (Chersophilus duponti) en dos localidades del valle del Ebro, y de los pollos en una localidad del Sistema Ibérico (Layna, Soria). Los pollos (n = 16) se sexaron molecularmente, resultando una razón de sexos de 0,50. Los adultos se capturaron mediante cepos dispuestos al azar y sin reclamo y fueron sexados biométricamente, resultando una razón de sexos de 0,72 durante el periodo reproductor y 0,61 fuera de éste. La capturabilidad teórica de cada sexo durante el periodo de reproducción, analizada mediante un modelo que considera las características de los territorios de machos y hembras, fue un 32 % menor en las hembras. Al corregir la razón de sexos obtenida durante la época reproductora mediante el resultado de este modelo, la razón de sexos fue de 0,61, valor idéntico al obtenido durante el periodo no reproductor y no diferente estadísticamente de la relación teórica 1:1. No obstante, esta razón de sexos ligeramente sesgada hacia machos hace disminuir el número de parejas efectivas de la población europea de la especie, incrementando su grado de amenaza.

Dupont's lark Chersophilus duponti was categorized globally as Near Threatened on the IUCN Red List in 2005, largely because of reported declines in Spain and an estimated population of 2,000–3,000 breeding pairs in Morocco. However, the range and size of the species' North African populations were still unknown, despite being critical for assessment of the species' global conservation status. Here we report on the breeding distribution of Dupont's lark in Morocco, probably the largest population in its North African range, as well as on its preferred habitat, population density and size. Fieldwork and analysis of satellite images were combined to locate suitable habitat for the species, assess its presence (eliciting territorial calls by broadcasting the males’ songs and calls), and estimate densities using 83 km of linear censuses. Total number of birds located was 461 (305 from song playback and 156 from transects) across an extent of occurrence of c. 11,000 km2, comprising 2,067 km2 of suitable habitat and an effective area of occupancy of 1,645 km2. Mean density was 0.60 ± SD 0.52 birds per 10 ha and was highest in dense stands of Stipa tennacissima. Our estimate of Dupont's lark breeding population in Morocco is c. 15,400 singing males (lower and upper limits 11,220–20,167, respectively). Evidence of habitat loss and degradation was found in one of the main areas of the species' distribution in Morocco, although this does not seem to be a general pattern in the lark's Moroccan range. Further studies are required of the dynamics of suitable habitat for the species to prevent long-term consequences for the conservation of Dupont's lark and other bird species of the steppe.

Identifying genetically and phenotypically distinct populations of threatened species is critical if we are to delineate appropriate plans for their conservation. We conducted an integrated analysis of population genetic structure, historical demographic events, current gene flow (all based on mtDNA sequences) and morphological variation of three geographically separated groups of populations of Dupont’s lark Chersophilus duponti, located in the Iberian Peninsula (three populations), Morocco (two populations), and Tunisia (one population). Unusually, this lark species is the only one among the genus Chersophilus. Our results revealed the early historical divergence of an eastern Dupont’s lark lineage (in Tunisia) and a western lineage (in Morocco and Spain), consistent with subspecies taxonomy and distribution. The western lineage subsequently split into two lineages, following the isolation of Iberian and African populations. Such pattern of historical differentiation caused great population genetic structure, with differences among geographic areas explaining more than 80% of total genetic variation. Mismatch distributions and coalescent estimates of divergence time showed that lineage divergence was associated with sudden population expansion events, which apparently took place during the last glaciation, when steppe habitats were widespread across the Mediterranean region. Extant populations from different geographic areas hardly shared any haplotype (only one out of 16 ND2 haplotypes was shared by Tunisian and Moroccan Dupont’s larks), and consequently gene flow between geographic areas was found to be virtually absent. Apart from showing great genetic differentiation, Dupont’s larks from different geographic areas were morphologically distinct, showing substantial variation in body size and feeding-related traits (length of feet and bill). We conclude that Dupont’s lark populations isolated in the Iberian Peninsula, Morocco, and Tunisia are distinct evolutiona

In this paper, we analyse the non-breeding distribution of Dupont's Lark, one of Europe's most threatened and least known passerines, using breeding and wintering censuses, published and unpublished records of individuals outside their breeding areas, and data on radio-tagged individuals and field observations. Results suggest that most breeding Dupont's Larks remain around the breeding sites during the non-breeding season, including those populations from areas with harsh winter weather conditions. The probability of winter presence of Dupont's Larks in breeding areas was significantly correlated with population size, but the altitude of the locality studied did not influence winter presence. Records outside breeding areas indicate that part of the population moves some distance after breeding, occupying lower sites and principally those with agrarian substrates. We also found several records far from well-known breeding areas during the breeding period. Our results suggest that Dupont's Lark seems to be a partial migrant, wintering in breeding areas in large numbers (probably the adult fraction of the population) but with some part of the populations moving to other areas. The movements are short-distance in most cases, although medium- and long-distance dispersive movements were also detected. We discuss the implications of these results for the design of specific conservation measures for the species.

[ES] Se analiza la reducción del área de distribución y del tamaño poblacional de la amenazada. Alondra ricotí (Chersophilus duponti) en Andalucía mediante datos históricos y actuales. Se consi- deraron las citas del período reproductor (1) publicadas, (2) comunicadas a los autores por otras personas, y (3) datos propios inéditos. Además, se re-analizaron los censos de 1988-89 efectados por los autores y durante 2004-05 se muestrearon todas las localidades en que se había citado la especie desde 2000. Los resultados sugieren que la especie ha experimentado una notable reducción en su área de distribución desde el s. XIX, siendo su distribución actual más semejante a la de los años 1970-90 que a la de siglos precedentes. Desde los años 70-90 hasta la actualidad, la especie ha desaparecido en algunas zonas, aunque también se ha mantenido en pequeños núcleos de tamaño inferior a 3 machos territoriales. En este mismo periodo, se estima que la población total andaluza ha experimentado una reducción del 65-72%, siendo en la actualidad de unos 24-31 machos territoriales, localizados en 3 núcleos principales. Las causas y la intensidad de la retracción desde los años 70-90 son complejas y varían entre localidades. Debido a su reducido tamaño y a su alejamiento (87 km de media entre los núcleos principales) la probabilidad de extinción de las poblaciones ha debido ser y es muy alta, por lo que sorprende la persistencia de los núcleos. Se sugiere que debe existir una cierta concectividad con otras poblaciones ibéricas, lo cual ha permitido la supervivencia temporal de estas poblaciones. La espe- cie desbería ser catalogada como "En Peligro Crítico" en Andalucía de acuerdo con los criterios de la UICN., [EN] We analized the trends in the distribution and population size of the endangered Dupont's lark (Chersophilus duponti) in Andalucia, from the old times to nowadays. We considered all records during the breeding périod of (1) published records, (2) observations communicated by other persons, and (3) own unpublished data. Moroever, the 1988-89 census of the authors were re-analysed and we sampled during 2004-05 all the localities were the species was recorded from 2000. The results suggest that the species range has reduced drastically from c. XIX, being more similar between years 1970-90 to nowadays than previous centuries. However, the species has desappered or its population size has been reduced in some localities from 1970-90 to nowadays, although some populations with less than 3 singing males have persisted. We estimated than from 1970-90 to 2004-2005, the total population of Andalucia has been reduced between 65-72%, being today between 24-31 singing males, and in all casses less than 50 singing males. The causes and intensity of the decline from the 70-90' are complex and differ between areas. Due to the small population size and distance between them (average minimun distance between the main areas, 87 km) the extinction probability must has been, and it is, very high, and it is surpri- sing that the populations have survived. It is suggested that only a certain conectivity with other Iberian populations would allow the survival of these populations. According with the IUCN cri- teria, Dupont's lark most be classified as "Critically Endangered" in Andalucía.