RT Journal Article
T1 The Decline of Common Birds Exemplified by the Western Jackdaw Warns on Strong Environmental Degradation
A1 Blanco, Guillermo
A1 Domínguez Nevado, Luis
A1 Fernández, Luis
A1 Martínez, Félix
A1 González del Barrio, José L.
A1 Frías, Óscar
A1 Cuevas, Jesús A.
A1 Carrete, Martina
AB Bird populations associated with agricultural ecosystems have declined markedly in Europeduring the last quarter of the 20th century due to land-use intensification. This has meant that somevery common species, in some cases even species considered as pests, are now threatened or subject tomanagement programs to ensure their conservation. Considered pests of crops and predators of smallgame species, corvids are among the most persecuted common farmland birds. The considerationthat these birds are pests lacks any scientific evaluation and is justified by the subjective impressionthat they are abundant. Here, using estimates of absolute and relative abundances of both the totaland the breeding population, we show how jackdaws Corvus monedula have shown a marked negativepopulation trend in central Spain during the last 40 years. Decline involves the loss of multiplecolonies, the apparent absence of the species as a breeder in riverside forests, and an overall numericaldecrease of about 75% (from 35,000 to 9000 individuals) according to counts in communal roosts.The population decline seems to be more pronounced in areas where land use has been intensified,probably in response to the reduction in the availability of once-abundant food (i.e., invertebratesand weed seeds) but also due to more direct effects such as intoxication and medium to long-termaccumulation of agricultural pollutants which may have also affected reproduction and survival.Intensive hunting over decades has undoubtedly contributed to this decline and should thereforebe made forbidden urgently. Generally, it seems that high-intensity agricultural management moredrastically affects smaller and less adaptable common species, which are expected to decline beforeand at a higher extent and magnitude than jackdaws. Given that global population estimates basedon direct counts of individuals are readily achievable through simultaneous counts in communalroosts, the jackdaw can serve as a model for assessing temporal trends potentially linked to large-scaleanthropogenic modifications of open and agricultural environments
PB MDPI
SN 2673-7159 (electrónico)
YR 2022
FD 2022
LK http://hdl.handle.net/10272/20717
UL http://hdl.handle.net/10272/20717
LA eng
NO Blanco, G., Domínguez, L., Fernández, L., Martínez, F., González del Barrio, J. L., Frías, Ó., Cuevas, J. A., & Carrete, M. (2022). The Decline of Common Birds Exemplified by the Western Jackdaw Warns on Strong Environmental Degradation. In Conservation (Vol. 2, Issue 1, pp. 80–96). MDPI AG. https://doi.org/10.3390/conservation2010007
NO We thank C. Palacín, J.A. López Septiem, J. Lavado, J.L. Hidalgo, A. Nuñez,F. Roviralta, J. Prieto, P. Alcazar, M. Garcés, J. Osorio, S. Rebollo, J.A. Martín, J.A. Fargallo, D. Gil,A. Aparicio, Ó. Llama, A. Rodríguez, S. del Pozuelo, J.C. Quintana, R. Moreno-Opo, A. Ortega, A.Victoria, B.J. Condori, I. Farias, J.M. Rodríguez, E. García, J.A. Matesanz, C. Serrano, R. Bocca, M.Vicente, C. Ferrero, P.J. Sanz, E. Ramírez, F. Álamo and M.A. Letón for their help in the counts incommunal roosts in 2021
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026