THE  ASSUMPTION  AND  CHANGES  OF  PLUMAGE  IN  BIRDS. 
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colour  of  her  plumage,  the  young  birds  of  both  sexes,  in  their  first  feathers,  resemble 
the  female  ;  the  young  males  afterwards  putting  forth  the  colours  that  indicate  their  sex. 
When  the  adult  male  and  female  are  of  the  same  colour,  the  young  then  have  a  plumage 
peculiar  to  themselves.  To  these  laws  which  appear  to  govern  the  assumption  of  plu- 
mage in  young  birds,  and  of  the  first  of  which  (to  select  in  illustration  examples  the  most 
familiar  among  land  and  water  birds,)  the  various  Pheasants  and  Ducks  may  be  named  ; 
and  of  the  second,  the  Partridges  and  Gulls ;  a  third  law  may  be  added :  whenever 
adult  birds  assume  a  plumage  during  the  breeding  season  decidedly  diflferent  in  colour 
from  that  which  they  bear  in  the  winter,  the  young  birds  have  a  plumage  intermediate  in 
the  general  tone  of  its  colour  compared  with  the  two  periodical  states  of  the  parent  birds, 
and  bearing  also  indications  of  the  colours  to  be  afterwards  attained  at  either  period. 
There  are  three  modes  by  which  changes  in  the  appearance  of  the  plumage  of  birds 
are  produced : — 
By  the  feather  itself  becoming  altered  in  colour. 
By  the  bird's  obtaining  a  certain  number  of  new  feathers  without  shedding  any  of  the 
old  ones ;  and 
By  an  entire  or  partial  moulting,  at  which  old  feathers  are  thrown  off,  and  new  ones 
produced  in  their  places. 
The  first  two  of  these  changes  are  observed  in  adult  birds  at  the  end  of  spring,  indi- 
cating the  approach  of  the  breeding  season ;  the  third  change  is  partial  in  spring,  and 
entire  in  autumn.  That  the  colours  of  the  plumage  are  more  brilliant  during  the 
breeding  season  is  well  known  ;  and  ichthyologists  have  observed  that  the  scales  of 
fishes  become  brighter  as  the  season  for  spawning  approaches. 
A  fourth  mode  may  be  noticed,  though  its  effects  are  limited.  It  is  observable  in 
spring,  as  the  breeding  season  approaches,  by  the  wearing  off"  of  the  lengthened  lighter- 
coloured  tips  of  the  barbs  of  the  feathers  on  the  body,  by  which  the  brighter  tints  of  the 
plumage  underneath  are  exposed,  as  has  been  noticed  by  Sir  William  Jardine  and 
Mr.  Blyth.    The  effect  is  most  conspicuous  in  the  Buntings,  Finches,  and  Warblers. 
Young  birds  of  the  year  in  various  species,  after  the  autumn  moult,  continue  through 
the  winter  to  assume,  by  degrees,  the  more  intense  colours  characteristic  of  adults, 
without  changing  the  feather.  This  colour  commences  generally  at  that  part  of  the 
web  nearest  the  body  of  the  bird,  and  gradually  extends  outwards  till  it  pervades  the 
whole  feather. 
In  many  birds  the  spring  change  is  common  to  both  sexes,  as  in  the  species  of  the 
genera  Limosa,  Tringa,  Totanus,  Phalaropus,  &c.  In  others  the  males  only  are  af- 
fected. The  rapidity  of  this  assumption  of  vivid  and  particular  colours  previously  to 
the  breeding  season  bears  a  relation  to  the  sexual  vigour  of  the  birds  ;  and  one  of  the 
great  objects  of  existence  being  accomplished  in  the  reproduction  of  the  species,  the 
plumage  almost  immediately  indicates  the  commencement  of  a  return  to  the  colours 
peculiar  to  winter. 
