Breeding Performance of the Grasshopper Buzzard (<i>Butastur rufipennis</i>) in a Natural and a Human-Modified West African Savanna

Buij, Ralph; Kortekaas, Kim E.; Krimpen, Roderick R. D. Van; Wijk, Rien Van; Zanden, Saskia Van Der; Iongh, Hans H. de; Heitkönig, Ignas M. A.; Snoo, G.R. de; Komdeur, Jan

doi:10.1525/cond.2012.120049

Cited by 11 publications

(7 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Average DSR of ferruginous hawks during our study was high (>0.99 for anthropogenic substrates and >0.98 for natural substrates) and comparable to estimates for other birds of prey: ≥0.96 for Aplomado falcon ( Falco femoralis septentrionalis ; Brown and Collopy ), ≥0.99 for barn owl ( Tyto alba ; Martin et al ), and 0.99 for grasshopper buzzard ( Butastur rufipennis ; Buij et al ). Average probability of success for ferruginous hawk nests on anthropogenic substrates (0.83, 95% CI = 0.67–0.98) was higher than estimates for all substrate types from other studies that accounted for length of observation periods (0.59, Van Horn ; 0.40–0.57, Lehman et al ), whereas nesting success on natural substrates was slightly lower (0.48, 95% CI = 0.26–0.70).…”

Section: Discussionsupporting

confidence: 76%

Human‐made structures, vegetation, and weather influence ferruginous hawk breeding performance

et al. 2015

View full text Add to dashboard Cite

Studies of anthropogenic impacts on wildlife may produce inconclusive or biased results if they fail to account for natural sources of variation in breeding performance and do not use probabilistic sampling at a scale functional for management. We used stratified random sampling and generalized linear mixed models to test hypotheses on relationships of daily nest survival rate (DSR) and fledgling production with anthropogenic and environmental factors that influence reproduction in the ferruginous hawk (Buteo regalis). We conducted the study across ferruginous hawk range in Wyoming, USA, 2010-2012. We performed extensive field surveys of prey, vegetation, and nest substrates, and used spatially explicit data to quantify weather, and the most widespread forms of anthropogenic infrastructure (i.e., roads, oil and gas well pads) in ferruginous hawk territories. We found strong evidence that DSR and productivity were greater for nests on anthropogenic structures (i.e., artificial nest platforms, gas condensation tanks, abandoned windmill platforms, power poles) compared to natural substrates (i.e., trees, cliffs, rock outcrops). Additionally, ferruginous hawks produced more fledglings at territories with greater shrub cover and fewer severe storms during the June brood-rearing period. Amount of oil and gas development and prey was not associated with either measure of breeding performance. Our results suggest that artificial nest platforms are an effective tool to improve breeding success of ferruginous hawks and nesting on anthropogenic structures does not constitute an ecological trap for this species. Although ferruginous hawks nested in some areas with very little vegetative cover, territories with greater amounts of shrub cover produced more fledglings. The negative impact of severe spring storms on fledgling production illustrates the importance of including future weather scenarios in management planning for this species because storms are predicted to increase in frequency and intensity as a result of climate change. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

show abstract

Section: Discussionsupporting

confidence: 76%

Human‐made structures, vegetation, and weather influence ferruginous hawk breeding performance

et al. 2015

View full text Add to dashboard Cite

show abstract

“…For many West and Central African raptors the impact of the trade may be limited compared to other anthropogenic and climate-related factors that influence their food resources, nest availability, and population dynamics (e.g. Buij et al, 2013a,b). The commercial trade, however, can be implicated in the decline of vultures and other large raptors in the region.…”

Section: Discussionmentioning

confidence: 99%

Trade of threatened vultures and other raptors for fetish and bushmeat in West and Central Africa

Buij

Nikolaus

Whytock

et al. 2015

Oryx

View full text Add to dashboard Cite

Diurnal raptors have declined significantly in western Africa since the 1960s. To evaluate the impact of traditional medicine and bushmeat trade on raptors, we examined carcasses offered at markets at 67 sites (1–80 stands per site) in 12 countries in western Africa during 1990–2013. Black kiteMilvus migransand hooded vulture Necrosyrtes monachus together accounted for 41% of 2,646 carcasses comprising 52 species. Twenty-seven percent of carcasses were of species categorized as Near Threatened, Vulnerable or Endangered on the IUCN Red List. Common species were traded more frequently than rarer species, as were species with frequent scavenging behaviour (vs non-scavenging), generalist or savannah habitat use (vs forest), and an Afrotropical (vs Palearctic) breeding range. Large Afrotropical vultures were recorded in the highest absolute and relative numbers in Nigeria, whereas in Central Africa, palm-nut vultures Gypohierax angolensis were the most abundant vulture species. Estimates based on data extrapolation indicated that within West Africa 73% of carcasses were traded in Nigeria, 21% in Benin and 5% elsewhere. Offtake per annum in West Africa was estimated to be 975–1,462 hooded vultures, 356–534 palm-nut vultures, 188–282 Rüppell's griffons Gyps rueppellii, 154–231 African white-backed vultures Gyps africanus, 143–214 lappet-faced vultures Torgos tracheliotos, and 40–60 crowned eagles Stephanoaetus coronatus. This represents a sizeable proportion of regional populations, suggesting that trade is likely to be contributing significantly to declines. Stronger commitment is needed, especially by governments in Nigeria and Benin, to halt the trade in threatened raptors and prevent their extirpation

show abstract

“…This conclusion is further supported by analyses of nest success and productivity, which did not vary with land use in the study area (Buij et al . ). Migratory Grasshopper Buzzards thus appear to be less vulnerable to habitat exploitation compared with sedentary raptors, which typically depend on productive, year‐round territories with a stable supply of predominantly vertebrate prey (Thiollay & Clobert ).…”

Section: Discussionmentioning

confidence: 97%

“…However, productivity and nest success were found to be unaffected by land use in Cameroon (Buij et al . ), suggesting that when assessed by these metrics Grasshopper Buzzards appear to cope fairly well with habitat changes. Here, we examined the influence of land use and rainfall on nestling growth and condition at fledging.…”

mentioning

confidence: 92%

Effects of land‐use change and rainfall in Sudano‐Sahelian West Africa on the diet and nestling growth rates of an avian predator

Buij

Folkertsma

Kortekaas

et al. 2012

Ibis

Self Cite

View full text Add to dashboard Cite

Raptor populations in Sudano-Sahelian West Africa are being severely affected by widespread habitat alteration which depletes prey populations, potentially aggravated by changing rainfall patterns. We studied Grasshopper Buzzards Butastur rufipennis at nests in natural and transformed habitats in the Sudano-Sahelian region of northern Cameroon to assess the effects of habitat transformation and rainfall on nestling diet and growth. Grasshoppers and small mammals were more frequently taken in natural habitat, whereas lizards were most frequently taken in transformed habitats. These dietary differences reflected differences in prey availability around nests in natural and transformed habitats. Land use was a significant predictor of asymptotic weight: nestlings in natural habitat attained a higher mass than those in transformed habitats, when potentially confounding variables such as hatch order, gender, hatch date, rainfall or the presence of siblings were taken into consideration. These results suggest that body condition at fledging was habitat-dependent, with potential consequences for subsequent survival. However, we recorded no differences in caloric content of food delivered to nests in natural and transformed habitat, which was possibly related to prey caught during twilight hours. There was a positive relationship between precipitation levels during the nestling phase and nestling growth rate. We predict unfavourable future conditions for nestling growth of raptors in Sudano-Sahelian savannas as a consequence of continued widespread habitat transformation and diminished rainfall.

show abstract

Breeding Performance of the Grasshopper Buzzard (Butastur rufipennis) in a Natural and a Human-Modified West African Savanna

Cited by 11 publications

References 47 publications

Human‐made structures, vegetation, and weather influence ferruginous hawk breeding performance

Human‐made structures, vegetation, and weather influence ferruginous hawk breeding performance

Trade of threatened vultures and other raptors for fetish and bushmeat in West and Central Africa

Effects of land‐use change and rainfall in Sudano‐Sahelian West Africa on the diet and nestling growth rates of an avian predator

Contact Info

Product

Resources

About