 from, averaging, in height by, averaging, in width. In comparison, 90 eggs from mainland Europe ranged from, averaging, by, averaging. Eggs may be compromised quickly by frost and snow in relatively early clutches. Incubation starts as soon as the 1st egg is laid. In the species, a 2 to 3 day interval between the first and 2nd egg being laid (as well as hatching) is recorded. The female does up to 80-90% of incubation and all known nighttime incubating. However, in Norway, the male of a pair could contribute up to about 27% of incubation to daylight hours. There may be as many as 11 changes of the incubating individual within a day. The longest period recorded the clutch was unguarded was 20 minutes, although 1 pair perched nearby the nest without incubating for 48 minutes. The clutches in Norway left alone only 2-4% of the time. In some cases female may do all the incubation alone, however. When the female is off the nest, she sometimes kills prey and returns with a full crop, but prey capture during incubation is often up to the male. Late into incubation, shift changes decreases and the female will sit tight and will crouch down at the approach of a human rather than leave the nest. Calling and displaying are reduced during incubation, but occasionally both may leave the clutch and display still. The time range for incubation can vary from 34 to 46 days, but usually are between 38 and 42 days. A calculated mean time range for incubation of 38.3 days.

Hatching, development and fledgling

In 1983, it was listed that brood size is one 56.5% of the time and two 40.8% of the time in 8 studies from different parts of the range; only 2.5% of these studies had a brood size of three and only 1 from Norway was a brood size of four recorded. From 14 studies, the mean number of chicks in a brood may range from 1.1 in western Germany to 1.9 in southern Kazakhstan, with average overall brood size of 1.52. However, these datasets may be skewered lower than natural brood size as a majority these are from the mid to late 20th century when pesticide use considerably lowered the mean number of hatchlings in many parts of the range. New hatchlings will weigh about  but in Hokkaido new hatchlings were surprisingly notably heavier at. The sex of
from, averaging, in height by, averaging, in width. In comparison, 90 eggs from mainland Europe ranged from, averaging, by, averaging. Eggs may be compromise promptly by frost and snow in relatively early clutches. brooding starts as soon as the 1st testis is lay. In the species, a 2 to 3 sidereal day time interval between the first and 2nd testis being laid (as well as hatch) is record. The female does up to 80 - 90% of brooding and all known night incubating. However, in Norway, the male of a couple could contribute up to about 27% of incubation to daylight hour. There may be as many as 11 changes of the incubating individual within a sidereal day. The longest menstruation recorded the clutch was unguarded was 20 minutes, although 1 couple perched nearby the nest without incubating for 48 minutes. The clutches in Norway left alone merely 2 - 4% of the time. In some cases female may do all the incubation alone, however. When the female is off the nest, she sometimes kills prey and returns with a full crop, but prey capture during incubation is frequently up to the male. Late into incubation, fault change decreases and the female will sit fast and will crouch down at the approach of a human rather than forget the nest. Calling and displaying are reduced during incubation, but occasionally both may bequeath the clutch and display still. The time range for incubation can change from 34 to 46 days, but usually are between 38 and 42 days. A calculated mean meter range for incubation of 38.3 days. 

 Hatching, growth and fledgling 

 In 1983, it was listed that brood size is one 56.5% of the time and two 40.8% of the time in 8 study from different parts of the range; only 2.5% of these studies induce a brood size of three and only 1 from Norway was a brood size of four read. From 14 studies, the mean issue of chicks in a brood may roll from 1.1 in western Germany to 1.9 in southerly Kazakhstan, with average overall brood size of 1.52. However, these datasets may be skewered lower than natural brood size as a majority these are from the mid to late twentieth century when pesticide use well lowered the mean number of hatchling in many parts of the range. New hatchlings will weigh about   but in Hokkaido new hatchlings were surprisingly notably heavier at. The sex of
 frlm, averaging, in height bn, averaging, in wneth. In compadison, 90 eegs from mainland Europe ranjed drom, qveraging, by, averaging. Eggs may be compeomiwwd quickly by frosb and dnow mn relatively esrly clutcves. Incubation sgaxts as soon as the 1st egg is laid. In the sprcles, a 2 to 3 day inttrvwl bsnwten the first and 2nd egg being lajd (as wtll as hatching) is recorded. The female does kp tl 80-90% of incubation ajd all knowb nidyttime incubxting. Howenzr, in Norwai, the male of a pair could contrkbute up to abooc 27% ov incubation to dwylight hours. There kay be ss many as 11 chsngxs od the incubating inditidual within a day. Jhe longesd 'eriod recorded the courch wds utguafeed waa 20 mjnutes, alvhough 1 paid perched nwarby the nest withpue incubating fkr 48 miguees. The clutches in Norway left alone otly 2-4% of the time. In some cqses female may do alp the inctbation alone, however. When the female is off the test, afe woidriles kills prey and returns with a full crop, btf krej capture during lncubation is oftem kp jo the male. Laje into indubation, shift chajges desreasws and tht femsle will sit tight and will crouch down qt the approach of a human racher tnan lrave the nest. Calling aud disllaying are reduced sjring incubation, bun ocwasionally both may leave ehe clutci and displah stoll. Thq time ranhe fov incubation can vagy frlm 34 to 46 days, but usually are between 38 and 42 veys. A calculajed medn time xange nor incubation jf 38.3 days.

Hatchiug, develjpmeng and fledfling

In 1983, it was lifted that bromf size is onx 56.5% of the timw ane two 40.8% uw the time in 8 studies yxom diffeeent parts of the vange; knly 2.5% of these wtueies had a brooc skze ov vhree dnd only 1 frmm Nurwxu was a brood side uf fpur recorded. From 14 sdudiss, the mean number on chicks un a brojd may range grom 1.1 in western Gtrmany to 1.9 in xoujhern Kazakhstan, with average oberall brlod size of 1.52. Horevev, thgse datasetx may be skewered lower than natural briod size as a majoeity these are from uhe mid to lave 20th sentury wven pesticide use cobsiderably lowerec the mean number of gatchlhngs ln many parts of the range. New hatchlings will weigh about  but in Hokkaieo new hatchlings sere surpgisnngky notwbly ieavier at. The seq of
from, averaging, in height by, averaging, in comparison, eggs from Europe ranged from, be quickly by frost snow in relatively clutches. Incubation starts as soon as 1st egg is laid. In the species, a 2 to 3 day interval the first and 2nd egg being laid (as well as hatching) is recorded. female up 80-90% incubation and all known nighttime incubating. However, in Norway, the male of a pair could contribute to about 27% of incubation to daylight hours. may be as many 11 changes of the incubating within day. The period the was unguarded was minutes, although 1 pair perched nearby the nest without incubating for 48 minutes. The clutches in Norway alone only the time. some female do all the however. When the female is off sometimes kills prey and returns with a full but prey during incubation is often up to male. Late into incubation, shift changes decreases and female will sit tight and will crouch down at the approach of a human rather the nest. Calling and are reduced during but both leave clutch and still. The time range for incubation can vary from 34 to days, but usually are between 38 and 42 days. A time for incubation of days. Hatching, development and In it was listed that is 56.5% and 40.8% the time in 8 from different parts of the only 2.5% of these of three and only 1 from Norway was brood size of four recorded. From 14 the mean number of chicks in a brood may range from 1.1 western Germany in southern Kazakhstan, with average overall brood size 1.52. However, these datasets be skewered lower than natural brood size as a these from the to late 20th when pesticide use lowered the mean hatchlings in parts the will weigh about but in Hokkaido hatchlings surprisingly notably heavier at. The of
 from, averaging, in height by, avEraging, in wIdth. IN coMpaRiSon, 90 eGgs fRom mainland EurOPe raNged from, averaging, by, aveRaginG. EGGs maY Be ComprOmised qUIcKLY by FrOsT anD sNOw In relAtiVely earLy clutches. incUbAtion starts aS SoOn as the 1st eGg iS laid. In the spEciEs, a 2 to 3 dAy IntERval bEtwEen thE first ANd 2nd egG being laiD (aS Well as HAtching) IS ReCordEd. The female does up TO 80-90% oF Incubation and aLl knowN nIGhTTIme IncUbating. HowEvEr, in NORway, the MAlE OF A paIR could contribUte up to abouT 27% Of iNcubatIoN to DAylighT hourS. THEre May be as many As 11 chAnges of thE incubATing indIVidual wIthin a Day. the LongESt PeRioD rECorDEd The CLutCh was ungUaRdEd was 20 MinuTES, ALthoUgh 1 Pair PerchEd nearby the neSt wIthoUT inCubatIng foR 48 minUtEs. The ClutchEs in NOrWay left alone onlY 2-4% of tHe time. In sOme CaSes FeMale mAY do all The IncUbation Alone, hoWEveR. WHEN ThE female is off the nesT, sHE SoMetimes kIlls prEY aNd REturns wiTh A fuLl crOP, But prEy caPTuRe during IncubaTIoN iS often uP tO the maLe. latE inTo incUBatiOn, shifT changes DecreASes and the femalE Will sit tight aND wILL cROuch DowN at the approAch oF A humAn raTHeR thAN leavE the nEsT. caLLing and displaying arE rEduced DurinG incubation, buT occasionaLLY Both may lEave THe CLutch and displaY stilL. The time raNGe for incUbatiOn can varY from 34 to 46 daYS, But usualLy aRe bEtwEen 38 AND 42 dAys. A calculateD MEan tImE range fOr iNcubatiOn oF 38.3 daYs.

HAtcHiNg, developMent and fLeDgLiNg

in 1983, iT was lISted that BrOod SiZe iS one 56.5% oF The timE and tWo 40.8% of ThE tIMe iN 8 studieS FrOM DiffErEnT parTs oF tHe ranGe; onLY 2.5% of These stUdies had a BroOD sizE oF tHree and Only 1 from NorwaY wAs a brood siZe Of fOur recORDed. From 14 sTudies, the mean number of chICks in a bRooD may rAnge From 1.1 in wesTerN GermaNy tO 1.9 In soutHern KaZakhsTaN, wiTH AveraGE OvEraLl Brood size oF 1.52. hOweVer, thEsE datAsets maY be skewered lower thAN naTural brood sizE as A majORItY thESe ARe fRoM The MID to late 20th centurY when pestiCiDE uSe considerABly LoWered thE mean nuMber oF HatchliNgs in many Parts of thE rAnge. nEW haTchlings wiLl weigh aBout  but in hOkkaiDO nEw hatChlIngs weRe SurPrisiNgly noTAblY heavIer at. THe Sex of
 from, averaging, in heigh t by, aver aging , i n w id th.In c omparison, 90e ggsfrom mainland Europe r anged  f r om,a ve ragin g, by,a ve r a gin g.  E ggs  m a ybe co mpr omisedquickly by  fr os t and snow i n  r elativelyear ly clutches.  In cubati on  st a rts a s s oon a s the1 st egg  is laid.  I n  the s p ecies,a 2to 3  day interval bet w ee n  the first and  2nd e gg be i n g l aid  (as wellas  hatc h ing) is re c o r ded .  The female d oes up to 8 0 -90 % of i nc uba t ion an d all  k n own  nighttimeincu bating. H owever ,  in Nor w ay, the  maleofa p airc ou ld  co nt r ibu t eupt o a bout 27%  o fincub atio n t o  day lig ht h ours.  There may be  as  man y  as  11 c hange s of  t he in cubati ng in di vidual within a  day . The lon ges tper io d rec o rded t heclu tch was  unguar d edwa s 2 0minutes, although1p a ir  perched  nearb y  t he nest wit ho utincu b a tingfor4 8minutes.  The c l ut ch es in N or way le ft  al one  only 2-4%  of th e time.In so m e cases female may do all th e  i n c ub a tion  al one, howeve r. W h en t he f e ma lei s off  thene s t, she sometimes kills  p rey an d ret urns with a f ull crop,b u t  prey ca ptur e  d u ring incubatio n isoften up t o  the mal e. La te intoincubatio n ,  shift c han ges  de cre a s es  and the fema l e  wil lsit tig htand wil l c rou chdow nat the ap proach o fahu ma n r ather than lea ve  th enes t. Ca l ling a nd di spla yi ng are  reduce d  d u r ingin cu bati on,  b ut oc casi o nal ly both  may leav e t h e cl ut ch  and di splay still.Th e time ran ge  fo r incu b a tion can  vary from 34 to 46 day s , but u sua lly a re b etween 38  an d 42 d ays .  A cal culate d mea ntim e range f or  in cu bation of3 8 .3days. 
Hatc hing, d evelopment and fle d gli ng

In 1983,itwasl i st edt ha t  br oo d  si z e  is one 56.5% o f the time  a n dtwo 40.8%o f t he  time i n 8 stu diesf rom dif ferent pa rts of th erang e ;  on ly 2.5% of  these s tudies ha d  a br o od  size  of  three  a ndonly1 from Nor way w as a b ro od siz e offo ur recor ded. From 14 studies, t he mea n num ber  of chick s i n  abrood may  ran ge from 1. 1 i n w ester n G e rmany  to1 .9  in south ernK azakhstan ,  w ith a ve rage overal l b roo d siz e o f  1.52.  How ever, these datas e ts may be skew ered l owe r t h an n at ural brood siz e a sa majority  t hese are fr om the m id to la te 20t h cent ury whe n pe s ticide  use  co nsiderabl y l ow e red the  m ea n  numbe r of  h atchli ngs in many p arts of the rang e. Ne w hatch l ing s wil lweigh a b out but in Ho kkaido newhatchl ings  were  surpri si ngly n ota bl y heaviera t. The se x of
 from,_averaging, in_height by, averaging, in_width. In_comparison,_90 eggs_from_mainland Europe ranged_from, averaging, by,_averaging. Eggs may be_compromised quickly by_frost_and snow in relatively early clutches. Incubation starts as soon as the 1st egg_is_laid. In_the_species,_a 2 to 3 day_interval between the first and_2nd egg_being laid (as well as hatching) is recorded._The_female does up_to 80-90% of incubation and all known nighttime incubating._However, in Norway, the male of_a pair could_contribute_up_to about 27% of_incubation to daylight hours. There may_be as many as 11 changes_of the incubating individual within a day._The longest period recorded the clutch_was unguarded was 20 minutes,_although 1_pair perched nearby the nest_without incubating for_48 minutes._The clutches in_Norway left alone only 2-4% of_the time. In_some cases female may do all_the_incubation alone, however._When_the_female is_off the nest,_she_sometimes kills_prey_and returns with a full crop,_but_prey capture during incubation is often up_to the male. Late_into_incubation, shift changes decreases_and the female will sit_tight and will crouch down at_the approach_of a_human rather than leave the nest. Calling and displaying are reduced_during incubation, but occasionally both may_leave the clutch and_display still._The_time range for_incubation_can vary_from 34 to 46 days, but usually_are between_38 and 42 days. A calculated_mean time range for_incubation_of 38.3 days.

Hatching, development and fledgling

In_1983, it was listed that brood_size is one 56.5% of_the_time_and two 40.8% of the_time in 8 studies from different_parts of the_range; only 2.5% of these studies had_a_brood size of three and only_1_from Norway was a brood size_of_four_recorded. From 14 studies, the_mean number of chicks in a_brood may range from 1.1 in western Germany to_1.9 in southern_Kazakhstan, with average overall brood_size_of_1.52. However, these datasets may be skewered lower than natural_brood size_as a majority_these are from the mid to late 20th century when_pesticide use considerably lowered the mean number_of hatchlings in many parts of the range. New hatchlings will_weigh about  but in Hokkaido new hatchlings_were surprisingly notably heavier at. The sex_of