Reproduction and eggs thumb|The much plainer egg of the common buzzard contrasted with that of the European honey buzzard. The breeding season commences at differing times based on latitude. Common buzzard breeding seasons may fall as early as January to April but typically the breeding season is March to July in much of Palearctic. In the northern stretches of the range the breeding season may last into May–August. Mating usually occurs on or near the nest and lasts about 15 seconds, typically occurring several times a day. Eggs are usually laid in 2 to 3-day intervals. The clutch size can range from to 2 to 6, a relatively large clutch for an accipitrid. More northerly and westerly buzzard usually bear larger clutches, which average nearer 3, than those further east and south. In Spain, the average clutch size is about 2 to 2.3. From 4 locations in different parts of Europe, 43% had clutch size of 2, 41% had size of 3, clutches of 1 and 4 each constituted about 8%.Holdsworth, M. (1971). Breeding biology of Buzzards at Sedbergh during 1937–67. British Birds, 64, 412–420. Laying dates are remarkably constant throughout Great Britain. There are, however, highly significant differences in clutch size between British study areas. These do not follow any latitudinal gradient and it is likely that local factors such as habitat and prey availability are more important determinants of clutch size. The eggs are white in ground colour, rather round in shape with sporadic red to brown markings sometimes lightly showing. In the nominate race, egg size is in height by in diameter with an average of in 600 eggs. In the race of vulpinus, egg height is by with an average of in 303 eggs. Eggs are generally laid in late March to early April in extreme south, sometime in April in most of Europe, into May and possibly even early June in the extreme north. If eggs are lost to a predator (including humans) or fail in some other way, common buzzards do not usually lay replacement clutches but they have been recorded, even with 3 attempts of clutches by a single female. The female does most but not all of the incubating, doing so for a total of 33–35 days. The female remains at the nest brooding the young in the early stages with the male bringing all prey. At about 8–12 days, both the male and female will bring prey but the female continues to do all feeding until the young can tear up their own prey.
Reproduction and eggs thumb|The much plainer egg of the common buzzard contrasted with that of the European honey buzzard. The breeding season commences at differing times based on latitude. Common buzzard breeding seasons may fall as early as January to April but typically the breeding season is March to July in much of Palearctic In the northern stretches of the range the breeding season may last into May–August. Mating usually occurs on or near the nest and lasts about 15 seconds, typically occurring several times a day. Eggs are usually laid in 2 to 3-day intervals. The clutch size can range from to 2 to 6, a relatively large clutch for an accipitrid. More northerly and westerly buzzard usually bear larger clutches, which average nearer 3, than those further east and south. In Spain, the average clutch size is about 2 to 2.3. From 4 locations in different parts of Europe, 43% had clutch size of 2, 41% had size of 3, clutches of 1 and 4 each constituted about 8%.Holdsw.orth, M. (1971). Breeding biology of Buzzards at Sedbergh during 1937–67. British Birds, 64, 412–420. Laying dates are remarkably constant throughout Great Britain. There are, however, highly significant differences in clutch size between British study areas. These do not follow any latitudinal gradient and it is likely that local factors such as habitat and prey availability are more important determinants of clutch size. The eggs are white in ground colour, rather round in shape with sporadic red to brown markings sometimes lightly showing. In the nominate race, egg size is in height by in diameter with an average of in 600 eggs. In the race of vulpinus, egg height is by with an average of in 303 eggs. Eggs are generally laid in late March to early April in extreme south, sometime in April in most of Europe, into May and possibly even early June in the extreme north. If eggs are lost to a predator (including humans) or fail in some other way, common buzzards do not usually lay replacement clutches but they have been recorded, even with 3 attempts of clutches by a single female. The female does most but not all of the incubating, doing so for a total of 33–35 days. The female remains at the nest brooding the young in the early stages with the male bringing all prey. At about 8–12 days, both the male and female will bring prey but the female continues to do all feeding until the young can tear up their own prey.