The "British birds" marking scheme. Progress for 1931
01 March 1932
Main paper
Nestlings. Total. 22,513 29,554 In 1920 5,276 ,, 1921 8,997 , 1922 9,289 12,866 , 1923 · . , 1924 . . 18,189 , 1925 · · 18,233 , 1926 · 23,432 21,625 , 1927 · , 1928 · 24,479 , 1929 · · 25,243 28,610 , i93...
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