Diet Variation of a Generalist Predator, the American Kestrel Falco sparverius, in a Gradient of Agricultural Intensification in Central Argentina

AbstractLand-use changes due to agricultural intensification and climatic factors can affect avian reproduction. We use a top predator of agroecosystems, the American kestrel (Falco sparverius) breeding in nest boxes in Central Argentina as a study subject to identify if these two drivers interact to affect birds breeding. We analyzed their breeding performance across a gradient of agricultural intensification from native forest, traditional farmland to intensive farmland. The surface devoted to soybean was used as a proxy of agriculture intensification; however, it did not affect the breeding performance of American kestrels. Even though the presence of pastures was important to determine the probability of breeding successfully. Climatic variables had strong effects on the species breeding timing, on the number of nestlings raised by breeding pairs and on the probability of those pairs to breed successfully (raising at least one fledgling). Our results highlight the relevance of pastures and grasslands for American kestrel reproduction. These environments are the most affected by land-use change to intensive agriculture, being transformed into fully agricultural lands mostly devoted to soybean production. Therefore, future expansion of intensive agriculture may negatively affect the average reproductive parameters of American Kestrels, at least at a regional scale. Further research will be needed to disentangle the mechanisms by which weather variables affect kestrel breeding parameters.

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Food Caching Behaviour in the American Kestrel (Falco sparverius)

Zeitschrift für Tierpsychologie ◽

10.1111/j.1439-0310.1974.tb01792.x ◽

2010 ◽

Vol 34 (2) ◽

pp. 105-114 ◽

Cited By ~ 5

Author(s):

Helmut C. Mueller

Keyword(s):

Falco Sparverius ◽

American Kestrel ◽

Food Caching

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The influence of Trichinella pseudospiralis infection on the behaviour of captive, nonbreeding American kestrels (Falco sparverius)

Canadian Journal of Zoology ◽

10.1139/z88-243 ◽

1988 ◽

Vol 66 (7) ◽

pp. 1685-1692 ◽

Cited By ~ 7

Author(s):

Michèle D. Saumier ◽

Manfred E. Rau ◽

David M. Bird

Keyword(s):

Falco Sparverius ◽

Competitive Fitness ◽

American Kestrel ◽

Behavioural Changes ◽

Trichinella Pseudospiralis ◽

Behavioural Effects ◽

American Kestrels ◽

Muscle Larvae ◽

Adult Phase ◽

Muscle Groups

Trichinella pseudospiralis infections induced mild behavioural changes in the American kestrel host (Falco sparverius) within the first 5 days postinoculation, a period that corresponds to the adult phase of the infection. However, more severe effects on mobility were precipitated as the larvae migrated and became established in the musculature. The debilitation persisted for at least 5 weeks postinoculation and involved a reduction in exercising, flying, elevated perching, and preening, and was accompanied by an increase in the frequency of walking and floor perching. Such behavioural effects, attributable to the presence of muscle larvae, may reduce the competitive fitness of infected individuals. The muscle larvae were randomly distributed among various muscle groups.

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