Refuse dumps in the biology and conservatio of birds in Spain
Authors: José Antonio DONÁZAR
Published: Volume 39(2), December 1992. Pages 29-40.
Original Title: Muladares y basureros en la biología y conservación de las aves en España
Refuse dumps and places where domestic animal carcasses are usually laid, represent predictable trophic resources which benefit birds that under natural circumstances exploit unpredictable food sources. This can induce changes in some features of the species life strategies, from the diet itself to the time and energy devoted to foraging. When the availability of other kinds of food is low, the survival rates, specially in preadult stages, can artificially increase. These hypotheses are supported by numerous circumstantial evidences, found in studies over a wide range of birds. Nevertheless, many different situations can arise depending on the variable local conditions of each population. Before promoting conservation measures involving the setting up of new predictable food sources (like “vulture-restaurants”), it must be first clearly stablished which species are intended to encourage, if the status of their populations really demand this kind of investment, and if a positive impact can be expected in view of the species biology and the framework of local conditions. On the other hand, the possible negative effects derived from the likely population increase of other species without conservation interest, must be taken into account. Finally, on the opposite side there seems to be a pressing need for evaluating the effects that the progressive elimination of refuse dumps in Spain could have on the populations of some threatened species (like Lammergeier, Black Vulture and Red Kite).