﻿BIRDS 
  OF 
  NEW 
  YORK 
  IIQ 
  

  

  that 
  the 
  tail 
  feathers 
  are 
  about 
  three 
  inches 
  shorter 
  than 
  the 
  dimensions 
  

   given 
  bv 
  Swainson 
  and 
  Richardson. 
  There 
  seems 
  no 
  doubt 
  also 
  that 
  the 
  

   specimens 
  from 
  Gowanus 
  bay 
  [Birds 
  of 
  L. 
  I. 
  p. 
  365] 
  may 
  be 
  the 
  young 
  of 
  

   the 
  Parasitic 
  jaeger. 
  The 
  specimen 
  to 
  which 
  he 
  refers 
  as 
  L 
  e 
  s 
  t 
  r 
  i 
  s 
  

   r 
  i 
  c 
  h 
  a 
  r 
  d 
  s 
  o 
  n 
  i 
  [p. 
  367] 
  is 
  a 
  Parasitic 
  jaeger 
  in 
  the 
  dark 
  phase; 
  thus 
  it 
  

   appears 
  that 
  none 
  cf 
  Giraud's 
  specimens 
  can 
  be 
  referred 
  with 
  certainty 
  to 
  

   the 
  species 
  longicaudus, 
  although 
  he 
  himself 
  refers 
  two 
  to 
  that 
  species. 
  

   DeKa3^'s 
  Lestris 
  richardsoni 
  is 
  undoubted!}^ 
  a 
  Parasitic 
  jaeger. 
  

   His 
  L. 
  buffoni 
  is 
  probably 
  the 
  same 
  species, 
  although 
  it 
  may 
  be 
  the 
  

   intemiediate 
  phase 
  of 
  longicaudus. 
  

  

  Family 
  LARIDA.H> 
  

  

  Gulls 
  and 
  Terns 
  

  

  Gulls 
  and 
  terns 
  are 
  distinguished 
  by 
  the 
  structure 
  of 
  their 
  bills, 
  which 
  

   are 
  more 
  or 
  less 
  epignathous 
  and 
  somewhat 
  compressed, 
  with 
  a 
  protuberant 
  

   gonys, 
  but 
  lacking 
  the 
  horny 
  saddle 
  of 
  the 
  jaegers. 
  The 
  nostrils 
  are 
  linear 
  

   or 
  oblong, 
  placed 
  toward 
  the 
  middle 
  or 
  in 
  the 
  basal 
  half 
  of 
  the 
  bill, 
  and 
  are 
  

   open 
  transversely. 
  Among 
  the 
  gulb, 
  especially 
  the 
  larger 
  sx)ecies, 
  the 
  

   bill 
  is 
  stout, 
  and 
  hooked 
  near 
  the 
  end, 
  and 
  the 
  short 
  symphysis 
  of 
  the 
  

   branches 
  of 
  the 
  lower 
  mandible 
  makes 
  a 
  prominent 
  gonys, 
  or 
  angle 
  of 
  the 
  

   jaw. 
  There 
  is 
  a 
  continuous 
  graduation 
  in 
  the 
  size 
  and 
  shape 
  of 
  the 
  bill 
  

   from 
  the 
  heavy 
  hooked 
  beak 
  of 
  the 
  Great 
  black 
  -backed 
  gull, 
  to 
  the 
  slender, 
  

   nearly 
  straight 
  bill 
  of 
  Bonaparte 
  and 
  Sabine 
  gulls; 
  and 
  among 
  the 
  terns 
  

   from 
  the 
  ponderous 
  beak 
  of 
  the 
  Caspian 
  tern 
  and 
  the 
  gull-like 
  beak 
  of 
  

   Gelochelidon 
  to 
  the 
  slim 
  and 
  delicate 
  bill 
  of 
  the 
  Black 
  tern. 
  The 
  tail 
  is 
  

   nearly 
  square 
  in 
  most 
  gulls; 
  in 
  terns 
  and 
  some 
  gulls 
  it 
  is 
  forked. 
  The 
  

   legs 
  are 
  short, 
  especially 
  in 
  terns, 
  the 
  tibiae 
  being 
  bare 
  for 
  a 
  short 
  dis- 
  

   tance. 
  The 
  Jegs 
  are 
  placed 
  near 
  the 
  center 
  of 
  the 
  body, 
  so 
  that 
  they 
  

   stand 
  and 
  walk 
  with 
  ease, 
  carrying 
  the 
  body 
  in 
  a 
  nearly 
  horizontal 
  posi- 
  

   tion. 
  The 
  plumage 
  is 
  long 
  and 
  dense 
  on 
  the 
  breast 
  so 
  that 
  they 
  rest 
  

   lightly 
  on 
  the 
  water, 
  "swimming 
  high" 
  in 
  comparison 
  to 
  divers 
  or 
  even 
  

   ducks. 
  Gulls 
  and 
  terns 
  are 
  very 
  uniform 
  in 
  coloration, 
  being 
  mostly 
  white 
  

   with 
  a 
  darker 
  mantle 
  over 
  the 
  back 
  and 
  wing 
  coverts, 
  which 
  ranges 
  

   from 
  slaty 
  black 
  in 
  marinus 
  to 
  pale 
  pearl-gra}^ 
  in 
  hyperboreus, 
  

   but 
  is 
  pure 
  white 
  in 
  the 
  Ivory 
  gull. 
  They 
  have 
  dusky 
  or 
  black 
  

   markings, 
  of 
  greater 
  or 
  less 
  extent, 
  on 
  the 
  primaries, 
  excepting 
  in 
  

   hyperboreus, 
  leucopterus 
  etc., 
  where 
  they 
  are 
  nearly 
  pure 
  

   white. 
  A 
  great 
  point 
  is 
  made 
  of 
  these 
  markings 
  in 
  the 
  determination 
  of 
  

   species 
  [see 
  pi. 
  5, 
  6]. 
  The 
  molt 
  occurs 
  twice 
  a 
  year 
  so 
  that 
  there 
  is 
  a 
  slight 
  

   difference 
  between 
  the 
  summer 
  and 
  winter 
  plumages. 
  Immature 
  birds 
  

  

  