Feeding behaviour and diet composition of Marsh Harriers <i>Circus aeruginosus</i> in agricultural landscapes

Cardador, Laura; Planas, Enric; Varea, Anna; Mañosa, Santi

doi:10.1080/00063657.2011.648165

Cited by 20 publications

(12 citation statements)

References 23 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2 and 3, Table A1.1). Therefore, we cannot preclude the possibility that the low diversity in the diet of Little Bustard in irrigated farmland is reflecting the reduced availability of alternative resources as a consequence of agricultural intensification as has been reported in other species (Britschgi et al 2006, Moorcroft et al 2006, Cardador et al 2012.…”

Section: Discussionmentioning

confidence: 99%

Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices

Bravo¹,

Cuscó²,

Morales³

et al. 2017

ACE

Self Cite

View full text Add to dashboard Cite

ABSTRACT. Foraging strategies and diet selection play an essential role in individual survival and reproductive success. The study of feeding ecology becomes crucial when it concerns endangered species such as the Little Bustard (Tetrax tetrax), whose populations are suffering strong declines as a consequence of agricultural intensification. Despite the fact that several populations are overwintering in areas affected by agricultural transformation, nothing is known about how feeding behavior responds to these changes. We studied for the first time the winter diet composition of the Little Bustard in Spain and compared it between areas with two different farming systems: dry and irrigated farmland. Diet was studied through the micro-histological analysis of 357 droppings collected in 16 locations across the wintering range of the Little Bustard in Spain. Up to 62 plant species were identified. Most consumed species were cultivated legumes (46.7%) and dicotyledon weeds (45.6%), while monocotyledons were scarcely consumed (7.7%). Diet composition differed significantly between dry and irrigated farmland areas. In irrigated areas, diet was mainly composed of legumes, in particular alfalfa (Medicago sativa). In contrast, in dry farmland areas diet was more diverse, composed mainly of weeds (Compositae, Papaveraceae, and Cruciferae) and also cultivated legumes, particularly vetch (Vicia sativa). These results suggest that legume crops could be an effective measure to improve habitat quality in areas with scarce food resources. However, in the case of irrigated areas, the strong reliance on alfalfa could make the Little Bustard more vulnerable to changes in land use. This study is the first step to understand the winter trophic requirements of the endangered Little Bustard, but further research is necessary to understand the food requirements of this species during the entire annual cycle.Régime alimentaire d'un oiseau de steppe en diminution, l'Outarde canepetière (Tetrax tetrax), en lien avec les pratiques agricoles RÉSUMÉ. Les stratégies d'alimentation et le choix du régime alimentaire jouent un rôle essentiel dans la survie et le succès reproducteur d'un individu. L'étude de l'écologie alimentaire revêt une importance cruciale lorsqu'il s'agit d'une espèce en voie de disparition telle que l'Outarde canepetière (Tetrax tetrax), dont les populations subissent des diminutions très marquées en raison de l'intensification des pratiques agricoles. Malgré le fait que plusieurs populations hivernent dans des endroits où se produisent des changements agricoles, on ne sait pas comment les oiseaux adaptent leur comportement alimentaire face à ces changements. Nous avons étudié pour la première fois la composition du régime alimentaire hivernal de l'Outarde canepetière en Espagne, et l'avons comparée dans deux systèmes agricoles : des terres cultivées sèches ou irriguées. Le régime alimentaire a été examiné au moyen de l'analyse micro-histologique de 357 fèces récoltées sur 16 sites répartis dans l'aire d'hivernage de l'outar...

show abstract

Section: Discussionmentioning

confidence: 99%

Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices

Bravo¹,

Cuscó²,

Morales³

et al. 2017

ACE

Self Cite

View full text Add to dashboard Cite

show abstract

“…These results suggest that selection for early arrival of males and at lower latitudes is buffered by other factors in our study species. In this regard, it is worth noting that Marsh Harrier is a generalist predator (Cardador et al 2012), with a differential but broad diet in both sexes, and therefore unlikely to optimize its spring arrival and laying dates to the phenology of any one single prey species. Moreover, they increasingly breed in agricultural landscapes (incl.…”

Section: Migration Timingmentioning

confidence: 99%

Western Marsh Harriers Circus aeruginosus from nearby breeding areas migrate along comparable loops, but on contrasting schedules in the West African–Eurasian flyway

et al. 2020

View full text Add to dashboard Cite

Much of our knowledge about migratory behaviour comes from single-population tracking studies. Some such studies had a considerable impact on migration research at large. However, it is often unclear how representative such studies are for other populations, even of the same species. We compared migration corridors and schedules of GPS-tracked adult Western Marsh Harriers (Circus aeruginosus) from two nearby breeding areas within the West African–Eurasian flyway: the Low Countries (LC, N = 6) and southern Sweden (SW, N = 4). Assuming the migration patterns revealed by decade-old satellite-tracking of SW harriers are representative for the species, we expected LC harriers to make a narrow loop migration involving a western spring detour out of Africa, but according to an earlier schedule tuned to the earlier onset of spring in the Low Countries. In autumn, LC harriers migrated significantly further west than SW harriers all the way to their common non-breeding range. In spring, both groups detoured westward across the Sahara, as expected, and diverged towards their breeding areas after reaching mainland Europe. LC harriers migrated slightly earlier than SW harriers in autumn. However, LC harriers unexpectedly left their non-breeding sites up to a month before SW harriers, after which they made long stop-overs in northwest Africa. Late-departing SW harriers forewent these stop-overs, and thus caught up with LC harriers in northwest Africa, so that both groups reached their breeding areas simultaneously. While we anticipated strong overlap between LC and SW migration corridors in spring, we failed to anticipate the earlier and more variable spring departures of LC harriers. Early spring departures did not result in earlier arrivals by LC harriers. Instead, we suspect they departed early to escape faster deteriorating foraging conditions at their non-breeding sites. Such environmental modulation of migratory behaviour may complicate generalization of migration patterns in other birds.

show abstract

“…Thus, anthropogenic land-use appeared to improve prey accessibility for Dark-chanting Goshawks, through tree clearance and a reduction of grass height resulting from livestock grazing, but reduced the quality of individual prey items. Although prey size has been found to vary with land-use in other raptors (Rodríguez et al 2006, Cardador et al 2012), to our knowledge this is the first study that demonstrates a deterioration of prey quality with land transformation in an African raptor. These results seem indicative of constraints on body mass of small vertebrates in transformed habitat, assuming that Dark-chanting Goshawks will attempt to maximise their foraging returns by focusing on the most profitable prey available to them (Stephens and Krebs 1986).…”

Section: Discussionmentioning

confidence: 71%

Response to habitat modification by foraging Dark-chanting Goshawks Melierax metabates in a West African savanna

Buij

Dorst

Salomons

et al. 2014

Bird Conservation International

View full text Add to dashboard Cite

SummaryAnthropogenic habitat alteration has probably contributed significantly to the decrease of raptor populations in West African savannas. To evaluate the impact of habitat degradation on foraging by sedentary Afrotropical raptors, we investigated the differences in microhabitat selection, foraging effort and energy returns between Dark-chanting Goshawks Melierax metabates inhabiting natural and transformed savannas in Cameroon. We expected that the agro-ecosystems in the transformed savannas have become unprofitable for Dark-chanting Goshawks due to scarcity of food resources. In both savanna types we radio-tracked six mated, adult males during the non-breeding season and determined foraging effort, by time spent at each perch and distance covered between perches, and energy intake through estimation of the energy value of prey items. Goshawks in natural habitats had smaller home-ranges and exploited their range more intensively than Goshawks in transformed habitats. In both natural and transformed habitats, Goshawks selected foraging patches with comparatively tall trees, underlining their importance to foraging Goshawks. The extent of shrub and herbaceous layer cover, agriculture cover, and tree density were other important predictors of foraging patch use, but their importance differed between habitats. The extent of shrub, herbaceous layer and agriculture cover were positively associated with foraging patch use in transformed habitats, suggesting that cultivated fields and ground vegetation support important prey resources for Goshawks in agro-ecosystems. The composition of broad prey categories to the diet, foraging effort and returns were comparable between habitats. However, we found indications that the proportion of heavy-bodied lizard species among reptile prey items was higher in natural than transformed habitats, whereas on average smaller lizards were more commonly caught in the latter. Mean herbaceous layer height and tree density within home ranges, both higher in natural habitat, were negatively related to prey capture rates. Tree clearance and livestock grazing thus favored greater prey capture rates in transformed habitat, offsetting a lower meal energy value compared to natural habitat. We conclude that foraging Dark-chanting Goshawks may cope with moderate land transformation, but practices focused on conservation of tall trees and ground vegetation cover would be beneficial by maintaining important prey resources and their exploitability under growing land pressure.

show abstract

Feeding behaviour and diet composition of Marsh Harriers Circus aeruginosus in agricultural landscapes

Cited by 20 publications

References 23 publications

Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices

Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices

Western Marsh Harriers Circus aeruginosus from nearby breeding areas migrate along comparable loops, but on contrasting schedules in the West African–Eurasian flyway

Response to habitat modification by foraging Dark-chanting Goshawks Melierax metabates in a West African savanna

Contact Info

Product

Resources

About