﻿KELATION 
  OF 
  BIRDS 
  TO 
  DISPERSION. 
  13 
  

  

  ing 
  injury, 
  it 
  would 
  undoubtedly 
  offer 
  a 
  valid 
  explanation 
  of 
  the 
  

   cause 
  for 
  some 
  of 
  the 
  outlying 
  colonies 
  which 
  have 
  been 
  found. 
  In 
  

   the 
  report 
  of 
  Forbush 
  and 
  Fernald, 
  already 
  cited, 
  detailed 
  accounts 
  

   arc 
  given 
  of 
  the 
  part 
  played 
  by 
  practically 
  all 
  the 
  insectivorous 
  

   birds 
  which 
  are 
  at 
  all 
  common 
  in 
  eastern 
  Massachusetts. 
  At 
  the 
  

   time 
  the 
  observations 
  were 
  made 
  a 
  large 
  number 
  of 
  trained 
  field 
  

   observers 
  were 
  constantly 
  employed, 
  and 
  few, 
  if 
  any, 
  of 
  these 
  re- 
  

   ported 
  that 
  birds 
  were 
  found 
  feeding 
  upon 
  eggs 
  of 
  the 
  gipsy 
  moth. 
  

   In 
  fact, 
  the 
  report 
  states 
  that 
  the 
  only 
  bird 
  that 
  has 
  been 
  found 
  

   feeding 
  upon 
  these 
  eggs 
  in 
  the 
  field 
  is 
  the 
  English 
  sparrow, 
  and, 
  as 
  it 
  

   is 
  normally 
  a 
  grain-feeding 
  species 
  and 
  one 
  that 
  frequents 
  cities 
  or 
  

   centers 
  of 
  population, 
  it 
  is 
  doubtful 
  whether 
  the 
  moth 
  would 
  be 
  dis- 
  

   persed 
  to 
  any 
  great 
  extent 
  if 
  it 
  were 
  possible 
  for 
  the 
  eggs 
  to 
  pass 
  

   through 
  the 
  bird 
  without 
  injury. 
  

  

  Fortunately, 
  during 
  the 
  winter 
  of 
  1909-10 
  two 
  sets 
  of 
  experi- 
  

   ments 
  were 
  conducted 
  for 
  the 
  purpose 
  of 
  determining 
  whether 
  gipsy- 
  

   moth 
  eggs 
  would 
  pass 
  through 
  the 
  alimentary 
  canal 
  of 
  birds 
  without 
  

   injury. 
  These 
  tests 
  were 
  made 
  independently, 
  and 
  in 
  both 
  cases 
  

   it 
  was 
  necessary 
  to 
  disguise 
  the 
  eggs 
  in 
  other 
  food 
  or 
  force 
  the 
  birds 
  

   to 
  feed 
  upon 
  them. 
  One 
  set 
  of 
  experiments 
  was 
  begun 
  in 
  February, 
  

   1910, 
  by 
  Mr. 
  C. 
  W. 
  Collins, 
  1 
  of 
  the 
  parasite 
  laboratory 
  of 
  the 
  Bureau 
  

   of 
  Entomology. 
  He 
  used 
  a 
  number 
  of 
  English 
  sparrows 
  and 
  a 
  single 
  

   pigeon. 
  

  

  The 
  sparrows 
  were 
  fed 
  by 
  placing 
  gipsy-moth 
  eggs 
  in 
  their 
  mouths 
  

   and 
  requiring 
  them 
  to 
  take 
  a 
  swallow 
  of 
  water 
  to 
  wash 
  them 
  down. 
  

   Of 
  35G 
  eggs 
  fed 
  in 
  this 
  wav 
  112 
  were 
  found 
  intact 
  in 
  the 
  excrement 
  

   and 
  the 
  balance 
  were 
  broken 
  during 
  the 
  process 
  of 
  digestion 
  or 
  re- 
  

   mained 
  in 
  the 
  gizzard. 
  Only 
  seven 
  eggs 
  hatched, 
  which 
  shows 
  that 
  

   under 
  this 
  artificial 
  treatment 
  the 
  chances 
  for 
  survival 
  of 
  the 
  eggs 
  are 
  

   very 
  small. 
  None 
  of 
  the 
  eggs 
  fed 
  to 
  the 
  pigeon 
  hatched 
  after 
  being 
  

   voided. 
  

  

  These 
  experiments 
  indicate 
  the 
  extreme 
  improbability 
  of 
  either 
  

   of 
  these 
  birds 
  selecting 
  gipsy-moth 
  eggs 
  for 
  food, 
  and 
  the 
  chances 
  

   of 
  the 
  insect 
  being 
  disseminated 
  in 
  this 
  way 
  appear 
  very 
  slight, 
  both 
  

   on 
  account 
  of 
  the 
  injury 
  to 
  the 
  eggs 
  in 
  passing 
  through 
  the 
  bird 
  and 
  

   because 
  the 
  distances 
  of 
  migration 
  of 
  the 
  species 
  are 
  relatively 
  small. 
  

  

  The 
  other 
  set 
  of 
  experiments 
  was 
  conducted 
  by 
  Mr. 
  Wm. 
  Rieil',- 
  

   of 
  the 
  Bussey 
  Institution, 
  Harvard 
  University, 
  during 
  March 
  of 
  the 
  

   same 
  year. 
  As 
  no 
  native 
  birds 
  were 
  available 
  for 
  the 
  tests 
  the 
  follow- 
  

   ing 
  species 
  were 
  used: 
  German 
  canary 
  bird, 
  English 
  yellow-hammer, 
  

   English 
  chaffinch, 
  Japanese 
  robin, 
  screech 
  owl, 
  and 
  carrier 
  pigeon. 
  

   The 
  cans 
  were 
  disguised 
  in 
  food, 
  such 
  as 
  bread 
  crumbs. 
  In 
  the 
  case 
  

  

  1 
  Some 
  Results 
  from 
  Feeding 
  Eggs 
  of 
  Porthetria 
  Mepor 
  t<> 
  Birds. 
  Journal 
  of 
  Economic 
  

   Entomology, 
  vol. 
  ::, 
  qo. 
  L, 
  Aug., 
  1910, 
  i>. 
  348. 
  

  

  ■ 
  Some 
  Experiments 
  on 
  the 
  Resistance 
  of 
  Gypsj 
  Moth 
  i:^-s 
  to 
  the 
  Digestive 
  Fluids 
  ol 
  

   Birds, 
  Psyche, 
  vol. 
  it. 
  No. 
  t, 
  Aug. 
  1010, 
  i>. 
  191. 
  

  

  