﻿BIRD 
  BANDING 
  LINCOLN 
  337 
  

  

  its 
  efficiency. 
  The 
  records 
  of 
  banded 
  birds 
  are 
  transmitted 
  regularly 
  

   to 
  the 
  bureau, 
  where 
  they 
  are 
  indexed 
  and 
  filed 
  so 
  as 
  to 
  be 
  readily 
  

   available 
  for 
  reference 
  and 
  study. 
  

  

  The 
  foundation 
  that 
  has 
  been 
  laid 
  through 
  these 
  activities 
  at 
  the 
  

   present 
  time 
  (July 
  1, 
  1927) 
  consists 
  of 
  about 
  300,000 
  banded 
  birds, 
  

   from 
  which 
  a 
  total 
  of 
  about 
  15,000 
  returns 
  have 
  been 
  received, 
  not 
  

   counting 
  the 
  thousands 
  of 
  repeat 
  records 
  which 
  in 
  themselves 
  show 
  

   many 
  interesting 
  facts. 
  Explanation 
  of 
  the 
  term 
  " 
  return 
  " 
  is 
  neces- 
  

   sary, 
  because 
  of 
  its 
  broad 
  application 
  in 
  the 
  records 
  of 
  banded 
  birds. 
  

   By 
  return 
  is 
  meant 
  the 
  record 
  of 
  any 
  banded 
  bird 
  recovered 
  in 
  a 
  

   ;succeeding 
  season, 
  or 
  the 
  record 
  of 
  any 
  bird 
  terminated 
  by 
  its 
  death. 
  

   This 
  means 
  that 
  the 
  returns 
  available 
  consist 
  of 
  the 
  records 
  of 
  birds 
  

   banded 
  at 
  one 
  point 
  and 
  recovered 
  at 
  another, 
  retrapped 
  at 
  the 
  point 
  

   of 
  banding 
  during 
  a 
  different 
  season 
  (it 
  being 
  assumed 
  that 
  in 
  the 
  

   meantime 
  migration 
  has 
  taken 
  place), 
  or 
  of 
  those 
  that 
  for 
  one 
  cause 
  

   or 
  another 
  die 
  at 
  the 
  point 
  of 
  banding 
  without 
  having 
  left 
  the 
  

   vicinity. 
  Ducks 
  and 
  other 
  birds 
  killed 
  by 
  hunters 
  supply 
  most 
  of 
  the 
  

   data 
  of 
  the 
  fir.st 
  type, 
  the 
  activities 
  of 
  station 
  operators 
  in 
  retrapping 
  

   the 
  smaller 
  nongame 
  species 
  furnish 
  the 
  records 
  of 
  the 
  second 
  class, 
  

   while 
  in 
  the 
  third 
  are 
  included 
  those 
  cases 
  of 
  adult 
  birds 
  accidentally 
  

   or 
  otherwise 
  dying 
  at 
  the 
  trapping 
  stations 
  within 
  a 
  short 
  time 
  of 
  

   banding 
  and 
  of 
  fledgling 
  birds 
  that 
  die 
  before 
  reaching 
  maturity. 
  

  

  It 
  is 
  obvious 
  that 
  data 
  of 
  the 
  first 
  two 
  kinds 
  have 
  the 
  most 
  inter- 
  

   esting 
  features, 
  but 
  those 
  of 
  the 
  third 
  class, 
  which 
  are 
  termed 
  " 
  short- 
  

   time 
  returns," 
  also 
  are 
  being 
  carefully 
  assembled 
  with 
  the 
  belief 
  that 
  

   through 
  their 
  study 
  it 
  will 
  be 
  possible 
  to 
  furnish 
  valuable 
  information 
  

   on 
  the 
  mortality 
  rates 
  of 
  certain 
  species 
  under 
  known 
  conditions. 
  

   During 
  the 
  early 
  phases 
  of 
  the 
  work 
  the 
  activities 
  of 
  many 
  persons 
  

   were 
  concerned 
  solely 
  with 
  the 
  banding 
  of 
  fledglings, 
  which 
  no 
  doubt 
  

   led 
  to 
  more 
  or 
  less 
  organized 
  nest 
  hunting. 
  For 
  a 
  tim.e 
  such 
  work 
  

   was 
  tolerated 
  as 
  it 
  was 
  hoped 
  that 
  the 
  interest 
  of 
  the 
  participants 
  

   would 
  reach 
  a 
  point 
  where 
  they 
  would 
  operate 
  the 
  more 
  productive 
  

   trapping 
  stations. 
  Being 
  well 
  aware, 
  however, 
  of 
  the 
  attendant 
  men- 
  

   ace 
  to 
  bird 
  life 
  on 
  account 
  of 
  unskillful 
  handling 
  of 
  the 
  birds 
  and 
  to 
  

   human 
  scent 
  trails 
  unwittingly 
  laid 
  from 
  nest 
  to 
  nest 
  for 
  prowling 
  

   house 
  cats 
  and 
  other 
  predators, 
  the 
  Biological 
  Survey 
  finally 
  stopped 
  

   all 
  work 
  of 
  this 
  character, 
  except 
  for 
  the 
  nests 
  located 
  upon 
  the 
  

   grounds 
  of 
  a 
  trapping 
  station 
  where 
  it 
  is 
  assumed 
  that 
  natural 
  

   enemies 
  of 
  birds 
  are 
  kept 
  under 
  control. 
  The 
  banding 
  of 
  the 
  young 
  

   of 
  colonial 
  birds 
  is 
  authorized, 
  however, 
  when 
  undertaken 
  by 
  oper- 
  

   ators 
  who 
  are 
  thoroughly 
  familiar 
  with 
  such 
  special 
  work. 
  

  

  Some 
  birds 
  acquire 
  " 
  the 
  trap 
  habit," 
  that 
  is, 
  they 
  will 
  repeatedly 
  

   return 
  to 
  a 
  trap 
  (pi. 
  2, 
  fig. 
  2), 
  occasionally 
  being 
  taken 
  several 
  

  

  