Gonzalo M. Arroyo

Replacement clutches by Kentish plovers

We examined factors affecting renesting rates in a population of Kentish Plovers (Charadrius alexandrinus) in southern Spain over six breeding seasons. We show that renesting was mainly constrained by time, and not by female body condition. Renesting partially compensated for initial clutch losses. The interval from loss of the first clutch to initiation of the replacement clutch was not affected by the number of days of incubation preceding nest loss. Renesting plovers moved considerable distances from first nests. Distances moved between nesting attempts by pairs that had lost chicks were similar to those of pairs that lost eggs. Nest cover did not differ between first and second nests when the first nest was successful, but it was greater in second nests when the first nest was unsuccessful. Yet, nest cover had no influence on the fate of such replacement clutches, probably due to a high diversity of predators at our study site. Females that laid replacement clutches did not delay breeding or breed less frequently in years after they had laid replacement clutches. Even when the success of replacement clutches is moderate, this breeding strategy may be important in accounting for individual lifetime productivity, especially when nest predation is high, as in the studied population.

Reuse of nesting scrapes by Kentish Plovers

We studied reuse of nesting scrapes within breeding seasons by Kentish Plovers (Charadrius alexandrinus) in an inland lake of southern Spain over six years. Overall, 5.6% of original nests were reused at least once. We tested whether nest reuse is adaptive, but found no differences in breeding success between those pairs that reused nests and those that did not. We also tested whether nest reuse should be more frequent when scrapes are difficult to excavate than when it is easier to excavate them, and found that nests on hard substrates were more frequently reused than nests on soft substrates, and that nest reuse was more frequent in the second half of the season, when the nesting substrate is harder, than in the first half of the season. This suggests that nest reuse may save Kentish Plovers some energy.

Autumn Migration of Lesser Spotted Eagle Aquila pomarina in the Strait of Gibraltar: Accidental or Regular?

Onrubia A., Muñoz A.-R., Arroyo G.M., Ramírez J., de la Cruz A., Barrios L., Meyburg B.-U., Meyburg C. & Langgemach T. 2011. Autumn migration of Lesser Spotted Eagle Aquila pomarina in the Strait of Gibraltar: accidental or regular? Ardea 99: 113–116. The Lesser Spotted Eagle (LSE) migrates to its winter quarters via the eastern Mediterranean corridor. During 1998 to 2009, 47 LSEs have been registered in the Strait of Gibraltar during a monitoring program of bird migration. All observations were made between 6 August to 12 October (mean 16 September, median 12 September). Of thirteen age-identified LSEs, ten birds were nonjuveniles. Six out of 86 LSEs fitted with a satellite transmitter at the western limit of its distribution followed the western route. Three of those birds reached Africa via the Strait of Gibraltar. The presence of LSE in our study area, albeit in small numbers, indicates the existence of a minor migration route across the Iberian Peninsula.

Assessment of offshore wind farm effects on birds and needs to plan their future development in Spain

Summary.— Wind farms have a negative impact on several animal populations, with birds and bats assumed to be among the most heavily affected taxa. In addition to the extensive development of wind power on land, currently several European countries have offshore wind farms (OWFs) in operation, as well as proposals to build many more. Considering that seabirds spend more than 90% of their life at sea, it is clear that they may interact with these man-made structures. To date, information on how to measure the impact of OWFs on seabirds is very scarce. In many cases it comes from non-peer reviewed reports made for specific assessment studies, very often carried out without appropriate standard methodologies, that raise questions regarding the level of confidence that they merit. In this paper, we describe the current political framework concerning the possible development of OWFs in Spain. Based on this, we comment on both the relevant variables necessary to assess the impacts of OWFs on birds and the methodologies available to collect those variables in the field, discussing the strengths and weaknesses of each method. We show the importance of collision risk models, vulnerability indexes, cumulative impact assessment and population viability analysis as management tools. Mitigation measures that have the potential to minimise impacts are also summarised. We conclude with a discussion of the different steps to follow to attain a ‘clean’ development of offshore wind energy in Spain.