﻿378 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  192 
  9 
  

  

  female 
  deposits 
  all 
  her 
  eggs 
  in 
  nests 
  of 
  a 
  single 
  species. 
  That 
  is, 
  one 
  

   cuckoo 
  may 
  parasitize 
  only 
  meadow 
  pipits, 
  another 
  may 
  lay 
  its 
  eggs 
  

   only 
  in 
  nests 
  of 
  hedge 
  sparrows, 
  while 
  still 
  another 
  may 
  victimize 
  

   reed 
  warblers 
  exclusively. 
  Each 
  individual 
  has 
  its 
  own 
  particular 
  

   species 
  of 
  victim 
  to 
  which 
  it 
  generally 
  limits 
  its 
  attention. 
  The 
  

   species 
  Cuculus 
  canorus 
  canorus 
  lays 
  its 
  eggs 
  in 
  the 
  nests 
  of 
  a 
  great 
  

   number 
  of 
  different 
  kinds 
  of 
  birds, 
  but 
  each 
  individual 
  tends 
  to 
  use 
  

   the 
  nest 
  of 
  but 
  one 
  kind. 
  The 
  parasitic 
  habit 
  in 
  Cucnlus 
  canorus 
  

   canorus 
  may 
  therefore 
  be 
  said 
  to 
  be 
  characterized 
  by 
  individual 
  host 
  

   specificity. 
  In 
  the 
  Indo-Malayan 
  region 
  there 
  are 
  a 
  great 
  many 
  

   genera 
  and 
  species 
  of 
  parasitic 
  cuckoos, 
  some 
  of 
  which 
  have 
  carried 
  

   this 
  specificity 
  to 
  an 
  extreme 
  with 
  the 
  result 
  that 
  the 
  great 
  majority 
  

   if 
  not 
  all, 
  of 
  the 
  eggs 
  are 
  laid 
  in 
  nests 
  of 
  a 
  single 
  species 
  or 
  group 
  of 
  

   allied 
  species. 
  Thus 
  the 
  Indian 
  koel, 
  Eudynamis 
  honorata, 
  lays 
  its 
  

   eggs 
  wholly 
  in 
  nests 
  of 
  crows 
  and 
  jays. 
  In 
  British 
  India 
  it 
  victimizes 
  

   the 
  Indian 
  crow, 
  Corvus 
  splendens, 
  and 
  the 
  jungle 
  crow, 
  Corvus 
  

   macrorhynchus; 
  in 
  Burma 
  it 
  foists 
  its 
  eggs 
  upon 
  the 
  Burmese 
  crow, 
  

   Corvus 
  insolens, 
  and 
  the 
  Burmese 
  jay, 
  Pica 
  sericea; 
  in 
  southern 
  China 
  

   the 
  victim 
  is 
  the 
  starling, 
  Graculipica 
  nigricollis. 
  In 
  large 
  districts 
  

   in 
  its 
  range 
  practically 
  all 
  the 
  individual 
  koels 
  victimize 
  the 
  same 
  

   species 
  of 
  bird. 
  In 
  other 
  words, 
  within 
  each 
  of 
  these 
  districts 
  the 
  

   individual 
  host 
  specificity 
  of 
  each 
  individual 
  koel 
  is 
  the 
  same 
  as 
  that 
  of 
  

   eYBTy 
  other 
  one, 
  and 
  taking 
  into 
  consideration 
  the 
  entire 
  range 
  of 
  the 
  

   species 
  the 
  number 
  of 
  host 
  species 
  is 
  so 
  small 
  and 
  the 
  species 
  so 
  closely 
  

   related 
  that 
  the 
  individual 
  host 
  specificities 
  of 
  all 
  the 
  koels 
  are 
  very 
  

   similar. 
  The 
  parasitic 
  habit 
  in 
  Eudynamis 
  honorata 
  may 
  therefore 
  be 
  

   said 
  to 
  be 
  characterized 
  by 
  specific 
  host 
  specificity. 
  

  

  The 
  development 
  of 
  specific 
  from 
  individual 
  host 
  specificity 
  may 
  

   readily 
  be 
  accounted 
  for 
  by 
  natural 
  selection 
  operating 
  under 
  con- 
  

   ditions 
  which 
  would 
  tend 
  to 
  emphasize 
  the 
  value 
  of 
  small 
  differences. 
  

   Thus, 
  in 
  the 
  case 
  of 
  Eudynamis 
  honorata 
  the 
  bird 
  (and 
  its 
  egg) 
  is 
  too 
  

   large 
  to 
  be 
  successful 
  with 
  small 
  fosterers 
  . 
  The 
  crows 
  are 
  everywhere 
  

   common 
  and 
  their 
  nests 
  open 
  and 
  plainly 
  visible 
  and 
  the 
  birds 
  (and 
  

   their 
  eggs) 
  fairly 
  close 
  in 
  size 
  to 
  the 
  koels. 
  An 
  abundant, 
  accessible 
  

   group 
  of 
  species 
  being 
  everywhere 
  available, 
  the 
  individual 
  koels 
  

   having 
  crows 
  as 
  their 
  individuall}'^ 
  specific 
  hosts 
  would 
  rapidly 
  increase 
  

   and 
  gradually 
  eliminate 
  their 
  less 
  successful 
  fellows 
  that 
  depended 
  on 
  

   more 
  precarious 
  and 
  more 
  uncertain 
  specific 
  hosts. 
  In 
  time 
  the 
  entire 
  

   membership 
  of 
  the 
  species 
  Eudynamis 
  honorata 
  would 
  be 
  composed 
  of 
  

   individuals 
  parasitic 
  on 
  crows. 
  

  

  During 
  the 
  course 
  of 
  my 
  field 
  work 
  in 
  Africa 
  I 
  found 
  that 
  the 
  various 
  

   parasitic 
  cuckoos 
  were 
  ecologically 
  isolated 
  from 
  each 
  other 
  to 
  a 
  

   very 
  considerable 
  extent, 
  i. 
  e., 
  one 
  species 
  lived 
  in 
  dense 
  forest, 
  an- 
  

   other 
  in 
  open 
  country, 
  and 
  among 
  species 
  of 
  different 
  genera 
  living 
  in 
  

   the 
  same 
  type 
  of 
  country, 
  one 
  species 
  restricted 
  its 
  parasitism 
  to 
  open, 
  

  

  