Farming influences on the food and hunting of Kestrels

Shrubb, M.

doi:10.1080/00063658009476666

Cited by 48 publications

(19 citation statements)

References 4 publications

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“…Field margins and cereals showed a similar hunting yield, and we can expect that hunting yields in those habitats unused by Lesser Kestrels will be very low, as was confirmed in other radio‐tracking studies on Lesser Kestrels (Donázar et al 1993). This could be due to lower prey availability or to differences in the structure of vegetation among habitats determining prey accessibility (Shrubb 1980;Bechard 1982;Toland 1987). This seems unlikely, however, because differences in height and cover of vegetation among habitats are almost negligible in the study area (Tella et al 1996 b , personal observation).…”

Section: Discussionmentioning

confidence: 99%

Conflicts between Lesser Kestrel Conservation and European Agricultural Policies as Identif ied by Habitat Use Analyses

Tella¹,

Forero

Hiraldo

et al. 1998

Conservation Biology

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European pseudo-steppes have suffered from extensive changes in agricultural practices during the past decades with the disappearance of field margins and fallow systems and the increase of biocide treatments. The negative effect on wildlife has led to the adoption by the European Union of policies more compatible with environmental conservation, but decisions about optimal land use are difficult to make because of lack of information. We studied habitat use by the Lesser Kestrel ( Falco naumanni ), a globally vulnerable species, in a Spanish pseudo-steppe (Los Monegros) where traditional agro-grazing systems are still being practiced, and we compared the results with those of another Spanish pseudo-steppe where modern and intensive agriculture has been implemented. We focused on the use by Lesser Kestrels of habitats subject to changes provoked by recent agricultural policies. Habitat availability was determined in a 3-km radius around 11 colonies, where 23 Lesser Kestrels were radio-tracked during the chick-rearing stage. Habitat selection was determined through compositional analysis. The rank of selected habitats was similar for all kestrels, considering both habitats surveyed and habitats where kestrels hunted. Kestrels selected field margins and cereal fields and rejected abandoned crops and scrubland. This selectivity seemed to be due to prey availability. In the intensively cultivated areas the kestrels selected similar habitats but used only small foraging patches and obtained smaller prey than in the traditional agro-grazing systems, probably because of the irregular distribution of prey resources as a result of the intensive biocide treatments. Consequently, in intensively cultivated habitats Lesser Kestrels had larger home ranges (63.65 km 2 ) than in those with traditional systems (12.36 km 2 ). These differences are reflected in the productivity and population trends of both populations. Thus, the best strategy for conserving the Lesser Kestrel seems to be the maintainance of traditional cereal cultures with low biocide treatments and numerous field margins. Both agricultural intensification and marginal land abandonment (with subsequent scrubland invasion) have detrimental consequences for this and probably for other pseudo-steppe species. Positive management steps can be encouraged by recent agro-environmental regulations such as the 2078/92 European Union Reglament, which favors the creation of programs in which agricultural practices accord with wildlife conservation. Conflictos Entre la Conservación del Cernícalo Priniilla y la Politica Agraria Comunitaria Determinados por Estudios Sobre Uso del HábitatResumen: Durante las últimas décadas, las prácticas agrícolas en las pseudo-estepas europeas han sufrido fuertes cambios; los márgenes entre campos y los sistemas de barbechado han tendido a desaparecer mientras se incrementaba el uso de biocidas. Estas tendencias se aceleraron con la puesta en marcha de la Política Agraria Comúniteria (PAC) de la Unión Europea (UE). Sus efectos negativos sobre l...

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Section: Discussionmentioning

confidence: 99%

Conflicts between Lesser Kestrel Conservation and European Agricultural Policies as Identif ied by Habitat Use Analyses

Tella¹,

Forero

Hiraldo

et al. 1998

Conservation Biology

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“…2000). Studies of aerial hunters such as kestrels Falco tinnunculus and F. sparverius (Shrubb 1980, Toland 1987) have also shown that foraging activity and hunting success are higher over less densely vegetated habitats, although other species adapt behaviourally to hunting in vegetation of different structure. For example, although Loggerhead Shrikes Lanius ludovicianus prefer to hunt using perch‐and‐wait tactics over short vegetation, Yosef and Grubb (1993) found that the birds’ hunting frequency and success over high vegetation could be maintained (perhaps at greater energetic cost) by switching to hunting by hovering and aerial chases.…”

Section: How Does Vegetation Structure Affect Birds?mentioning

confidence: 99%

The management of crop structure: a general approach to reversing the impacts of agricultural intensification on birds?

Wilson¹,

Whittingham²,

Bradbury³

2005

Ibis

177

144

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Agricultural intensification is accepted widely as a cause of bird population declines on farmland in Europe and North America. Although intensification is multivariate, one common theme is the impact on variation in crop structure, both within and between fields. Intensification creates simpler, more homogeneous and denser swards in both tillage crops and grassland. This influences predation risk, exposure to weather extremes and the diversity, abundance and accessibility of food. Birds trade off these pressures in different ways, so that the more uniform and dense the vegetation, the fewer the number of birds and range of species that are able to nest and forage successfully. Reversing recent trends towards dense, simplified and homogeneous swards will improve nesting and foraging habitat conditions for a wide range of species across farming systems, and may represent a cost‐effective mechanism for the further improvement of agri‐environment scheme options designed to assist the recovery of farmland bird populations.

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“…For example hedgerow removal, with the maintenance of field boundaries as strips of rough grassland, may have favoured both voles and the ability of Kestrels to catch them. Shrubb (1980) has shown that Kestrels hunt mainly on the permanent features of the farming landscape, such as field boundaries and clover leys; cereal fields, comprising 60% of the study area, were ignored during the breeding period, but were widely hunted during the winter. O'Connor (1982) has shown that, with the large increase in the Kestrel population, the diversity of nesting habitat has increased and a delay in breeding has occurred, resulting in a reduction of clutch size.…”

Section: Resultsmentioning

confidence: 99%