﻿JAN. 
  4, 
  1922 
  proceedings: 
  philosophical 
  society 
  21 
  

  

  ORNITHOLOGY. 
  — 
  Food 
  habits 
  of 
  seven 
  species 
  of 
  American 
  shoal-water 
  

   ducks. 
  Douglass 
  C. 
  Mabbott. 
  Bull. 
  U. 
  S. 
  Dept, 
  Agric. 
  862. 
  Pp. 
  

   67, 
  pis. 
  7. 
  1920. 
  

  

  The 
  food 
  of 
  Chaulelasmtis 
  streperus 
  to 
  a 
  large 
  extent 
  consists 
  of 
  leaves 
  

   and 
  stems 
  of 
  water 
  plants, 
  and, 
  with 
  the 
  exception 
  of 
  that 
  of 
  Mareca 
  americana, 
  

   includes 
  a 
  larger 
  percentage 
  of 
  vegetable 
  matter 
  than 
  any 
  other 
  species. 
  

   The 
  food 
  of 
  Mareca 
  americana 
  is 
  almost 
  the 
  same 
  as 
  that 
  of 
  the 
  previous 
  

   species. 
  As 
  many 
  as 
  64000 
  seeds 
  of 
  the 
  spike 
  rush 
  {Eleocharis) 
  have 
  been 
  

   noted 
  in 
  a 
  single 
  stomach. 
  The 
  diet 
  of 
  Mareca 
  penelope 
  and 
  Nettion 
  carolinense 
  

   is 
  made 
  up 
  principally 
  of 
  water 
  plants 
  and 
  their 
  seeds. 
  

  

  The 
  blue-winged 
  teal 
  (Querquedtda 
  discors) 
  feeds 
  to 
  a 
  large 
  extent 
  on 
  the 
  

   seeds 
  and 
  other 
  parts 
  of 
  water 
  plants, 
  although 
  nearly 
  one-third 
  of 
  its 
  food 
  

   is 
  animal 
  matter, 
  mostly 
  mollusks, 
  insects, 
  and 
  crustaceans. 
  The 
  food 
  of 
  

   Querquedula 
  cyanoptera 
  is 
  very 
  similar. 
  

  

  Vegetable 
  matter 
  comprises 
  about 
  seven-eighths 
  of 
  the 
  diet 
  of 
  Dafila 
  acuta 
  

   tzitzihoa, 
  and 
  this 
  is 
  chiefly 
  seeds 
  and 
  other 
  parts 
  of 
  plants, 
  principally 
  those 
  

   growing 
  in 
  or 
  near 
  water. 
  Individual 
  birds 
  have 
  been 
  known 
  to 
  consume 
  

   for 
  a 
  single 
  meal 
  28000 
  seeds 
  of 
  Salicornia 
  amhigua. 
  The 
  remaining 
  portion 
  

   of 
  the 
  food 
  of 
  this 
  duck 
  consists 
  of 
  animal 
  matter, 
  such 
  as 
  mollusks, 
  crusta- 
  

   ceans, 
  and 
  insects. 
  

  

  The 
  well-known 
  Aix 
  sponsa 
  feeds 
  mostly 
  on 
  the 
  seeds 
  and 
  other 
  parts 
  of 
  

   water 
  plants, 
  on 
  acorns, 
  grapes, 
  berries, 
  and 
  the 
  seeds 
  of 
  trees 
  and 
  shrubs. 
  

   From 
  a 
  single 
  stomach 
  10000 
  seeds 
  of 
  lizard's 
  tail 
  {Saururus 
  cernuus) 
  have 
  

   been 
  taken. 
  About 
  one-tenth 
  of 
  its 
  diet 
  is 
  animal 
  matter, 
  chiefly 
  insects 
  

   and 
  spiders. 
  

  

  In 
  all, 
  2888 
  stomachs 
  of 
  the 
  seven 
  species 
  have 
  been 
  examined, 
  and 
  the 
  

   various 
  items 
  of 
  food 
  identified 
  in 
  each 
  species 
  are 
  shown 
  in 
  an 
  extended 
  

   table 
  which 
  closes 
  this 
  bulletin. 
  Harry 
  C. 
  Oberholser. 
  

  

  ORNITHOLOGY. 
  — 
  Records 
  of 
  several 
  rare 
  birds 
  from 
  near 
  Washington, 
  

   D. 
  C. 
  B. 
  H. 
  Swales. 
  Proc. 
  Biol. 
  Soc. 
  Wash. 
  33: 
  181-182. 
  1920. 
  

   The 
  following 
  interesting 
  birds 
  are 
  here 
  recorded 
  from 
  the 
  region 
  about 
  

   Washington, 
  D. 
  C., 
  all 
  except 
  one 
  from 
  specimens 
  obtained: 
  Colymbus 
  hol- 
  

   boellii, 
  Oceanites 
  oceanicus, 
  Phalaropus 
  fulicarius, 
  Numenius 
  americanus, 
  

   Pluvialis 
  dominica 
  dominica, 
  Coragyps 
  urubu 
  urubu, 
  and 
  Aquila 
  chrysaetos. 
  

  

  H. 
  C. 
  Oberholser. 
  

  

  PROCEEDINGS 
  OF 
  THE 
  ACADEMY 
  AND 
  AFFILIATED 
  

  

  SOCIETIES 
  

  

  PHILOSOPHICAL 
  SOCIETY 
  

   856th 
  meeting 
  

  

  The 
  856th 
  meeting 
  of 
  the 
  Philosophical 
  Society 
  of 
  Washington 
  was 
  held 
  

   in 
  the 
  Cosmos 
  Club 
  auditorium, 
  Nov. 
  19, 
  1921. 
  It 
  was 
  called 
  to 
  order 
  at 
  

   8:20 
  p.m. 
  by 
  President 
  Faris 
  with 
  49 
  persons 
  present. 
  

  

  The 
  first 
  paper 
  of 
  the 
  evening, 
  on 
  Dip-needle 
  errors 
  arising 
  from 
  minute 
  

   pivot 
  defects, 
  'was 
  presented 
  by 
  Mr. 
  H. 
  W. 
  Fisk, 
  and 
  was 
  illustrated. 
  It 
  was 
  

   discussed 
  by 
  Messrs. 
  L. 
  A. 
  Bauer 
  and 
  L- 
  J. 
  Briggs. 
  

  

  After 
  all 
  compensating 
  reversals 
  of 
  instrument 
  and 
  needle 
  have 
  been 
  made 
  

   in 
  determining 
  the 
  magnetic 
  inclination 
  or 
  dip, 
  with 
  a 
  dip 
  circle, 
  there 
  will 
  

  

  