THE USE OF FALLOWS BY NESTING LITTLE BUSTARD TETRAX TETRAX FEMALES: IMPLICATIONS FOR CONSERVATION IN MOSAIC CEREAL FARMLAND

We describe the use of different agricultural habitat types by little bustard females nesting and rearing young chicks, based on observations gathered over a five-year period (2001-2005) in central Spain. The frequency of occurrence of nest or family locations within male lekking territories is also evaluated, as well as their association to habitat types preferred by females for nesting or chick rearing. A total of 28 nesting or brood locations (19 nests plus 9 families) were recorded over the study period. Habitat use did not differ significantly between nesting females and families. Both for the total sample (nests plus families) and the only-nests sample, the frequency of recorded locations differed between agricultural habitat types, with long-term fallows (older than two years) being the most frequently used. Young fallows (1-2 years old) were significantly more frequently used than cultivated habitats and ploughed-fields together, but less than long-term fallows in both samples. Nest plus family locations were more frequently found within estimated male territories than outside. Both in the total and the only-nests samples, locations within territories were found only in long-term and young fallows, the former being the most frequently used habitat type. These results from a mosaic cereal landscape provide further support to the role of long-term fallows as a critical habitat for breeding female little bustards found in other, more extensive, study areas, and reinforce the role of young fallows as an alternative breeding habitat when the former are absent or unsuitable. The strong dependence of breeding little bustards on fallows highlights the need to maintain their vegetation structure suitable as nesting and chick rearing habitats in order to prevent the species' current population decline in Spain.