El halcón de Eleonora en Españapoblación en 2004-2007 y método de censo

Laburpena

The breeding population of Eleonora’s falcon in Spain is currently distributed in three different regions: the Canary Islands, the Balearic Islands and the region of Valencia. Within these, the populations of the species is encountered only in certain sectors of the coast, thus the area occupied is relatively small. In the Canaries, four isles or islets in one of the two provinces of the archipelago host the population of Eleonora’s falcon: Montaña Clara, Alegranza, Roque del Este and Roque del Oeste. The population includes 272-302 pairs, 28.4% of the national population. The only location for the species in the region of Valencia, is the Columbretes Isles, between the coast of the province of Castellón and the Balearics. Breeding pairs are recorded in the main isle of the archipelago (Grossa Isle), and three associated islets: Ferrera, Foradada and Carallot. These colonies tally a 56-pair population, 5.9% of Spain’s total for the species. The population of the Balearics is split between two of the large islands, Mallorca and Ibiza, and in four isles or islets: Cabrera, Dragonera, Tagomago and Els Vendrans. The archipelago hosts the largest population within Spain, with some 629 pairs (1,257 individuals recorded) in the last census available (2004). This entails 65.7% of Spain’s total for the species. According to the distribution described, the population of Eleonora’s falcon in Spain is estimated to be between 957 and 1,170 pairs for the period 2004-2007, some 8% of the total European population. A significant increase in the Canaries’ population has occurred ever since the first records for the species were registered there. Such an increase seems to have occurred in all islands of the archipelago where the species is present, and has been estimated at 395% within the last 20 years, 51% since 2000. The trend for the population in the region of Valencia is also positive. The first records in the Columbretes archipelago are rather old; the results of yearly monitoring ongoing ever since it became a Nature Reserve in 1988 show that the population of the species has doubled in the period 1988-2007. In the Balearics, a positive trend is also concluded for all islands and isles where the species occurs.The population has increased from 254 pairs (1976 census) to 629 (2004 census). The net increase for population in the Balearic Islands can be set at 112% for the last 25 years and 20% since the year 2000. Thus, there is a positive trend in all three regions ever since records are kept, and also in the last years, when censuses have been improved. The overall increase for Spain within the last three decades could reach 67%. Eleonora’s falcon breeds in marine cliffs where accurate monitoring of breeding parameters is very difficult to accomplish. Under certain conditions, even estimating the number of pairs in a given colony is a difficult task. The few existing references and the data gathered in the census presented in this monograph allow concluding that the values for the main breeding parameters could be as follows: productivity 1.74; breeding success 1.78, and fledging rate 2.03. According to the latest information available and following the interpretation of IUCN’s Criterion C1, the population of Eleonora’s falcon in Spain can be classified as «Nearly Threatened».