Editing Common buzzard (section)

===Breeding success rates===
Numerous factors may weigh into the breeding success of common buzzards. Chiefly among these are prey populations, habitat, disturbance and persecution levels and innerspecies competition.<ref name= Brown/> In Germany, intra- and interspecific competition, plumage morph, laying date, precipitation levels and anthropogenic disturbances in the breeding territory, in declining order, were deemed to be the most significant bearers of breeding success.<ref name="Kruger"/> In an accompanying study, it was found that a mere 17% of adult birds of both sexes present in a German study area produced 50% of offspring, so breeding success may be lower than perceived and many adult buzzards for unknown causes may not attempt to breed at all.<ref name= Kruger2>Krüger, O., & Lindström, J. (2001). ''Lifetime reproductive success in common buzzard, Buteo buteo: from individual variation to population demography''. Oikos, 93(2), 260–273.</ref> High breeding success was detected in [[Argyll]], Scotland, due likely to hearty prey populations (rabbits) but also probably a lower local rate of persecution than elsewhere in the British isles. Here, the mean number of fledglings were 1.75 against 0.82–1.41 in other parts of Britain.<ref name= Austin/> It was found in the English [[The Midlands|Midlands]] that breeding success both by measure of clutch size and mean number of fledglings, was relatively high thanks again to high prey populations. Breeding success was lower farther from significant stands of trees in the Midlands and most nesting failures that could be determined occurred in the incubation stage, possibly in correlation with predation of eggs by [[corvid]]s.<ref name= Sim/> More significant than even prey, late winter-early spring was found to be likely the primary driver of breeding success in buzzards from southern [[Norway]]. Here, even in peak [[vole]] years, nesting success could be considerably hampered by heavy snow at this crucial stage. In Norway, large clutches of 3+ were expected only in years with minimal snow cover, high vole populations and lighter rains in May–June.<ref name= Selas3/> In the Italian [[Alps]], the mean number of fledglings per pair was 1.07.<ref name= Sergio/> 33.4% of nesting attempts were failures per a study in southwestern [[Germany]], with an average of 1.06 of all nesting attempts and 1.61 for all successful attempt. In Germany, weather conditions and rodent populations seemed to be the primary drivers of nesting success.<ref name= Rockenbauch/> In [[Region of Murcia|Murcia]] part of [[Spain]] contrasted with [[Biscay]] to the north, higher levels of interspecific competition from [[booted eagle]]s and [[northern goshawk]]s did not appear to negatively affect breeding success due to more ample prey populations (rabbits again) in Murcia than in Biscay.<ref name= Zuberogoitia/>

In the [[Westphalia]] area of Germany, it was found that intermediate colour morphs were more productive than those that were darker or lighter.<ref name= Kruger2/> For reasons that are not entirely clear, apparently fewer parasites were found to afflict broods of intermediate plumaged buzzard less so than dark and light [[phenotype]]s, in particular higher [[melanin]] levels somehow were found to be more inviting to parasitic organism that effect the health of the buzzard's offspring.<ref>Chakarov, N., Boerner, M., & Krüger, O. (2008). ''Fitness in common buzzards at the cross‐point of opposite melanin–parasite interactions''. Functional Ecology, 22(6), 1062–1069.</ref> The composition of habitat and its relation to human disturbance were important variables for the dark and light phenotypes but were less important to intermediate individuals. Thus selection pressures resulting from different factors did not vary much between sexes but varied between the three phenotypes in the population.<ref name= Kruger3>Krüger, O. (2002). ''Dissecting common buzzard lifespan and lifetime reproductive success: the relative importance of food, competition, weather, habitat and individual attributes''. Oecologia, 133(4), 474–482.</ref> Breeding success in areas with wild [[European rabbit]]s was considerably effected by [[Myxomatosis|rabbit myxomatosis]] and [[rabbit haemorrhagic disease]], both of which have heavily depleted wild rabbit population. Breeding success in formerly rabbit-rich areas were recorded to decrease from as much as 2.6 to as little as 0.9 young per pair.<ref name="Moore, N. W. 1957"/><ref>Moore, N. W. (1956). ''Rabbits, buzzards and hares. Two studies on the indirect effects of myxomatosis''. Les conséquences biologiques dues à la présence de la myxomatose.</ref><ref>Lees, A. C., & Bell, D. J. (2008). ''A conservation paradox for the 21st century: the European wild rabbit Oryctolagus cuniculus, an invasive alien and an endangered native species''. Mammal Review, 38(4), 304–320.</ref> Age of first breeding in several radio-tagged buzzards showed only a single male breeding as early as his 2nd summer (at about a year of age). Significantly more buzzards were found to start breeding at the 3 summer but breeding attempts can be individually erratic given the availability of habitat, food and mates.<ref>Davis, P. E., & Davis, J. E. (1992). ''Dispersal and age of first breeding of buzzards in central Wales''. British Birds, 85(11), 578–587.</ref> The mean life expectancy was estimated at 6.3 years in the late 1950s, but this was at a time of high persecution when humans were causing 50–80% of buzzard deaths.<ref name= Mebs/> In a more modern context with regionally reduced persecution rates, the lifespan expected can be higher (possibly in excess of 10 years at times) but is still widely variable due to a wide variety of factors.<ref name= Kruger3/>